EP1358397A1

EP1358397A1 - Rocker arm for a valve train in an internal combustion engine with device for independent setting/adjustment of the valve play

Info

Publication number: EP1358397A1
Application number: EP02715421A
Authority: EP
Inventors: Günter Kampichler
Original assignee: Motorenfabrik Hatz GmbH and Co KG
Current assignee: Motorenfabrik Hatz GmbH and Co KG
Priority date: 2001-02-08
Filing date: 2002-01-12
Publication date: 2003-11-05
Anticipated expiration: 2022-01-12
Also published as: WO2002063142A1; CN1457386A; DE50212436D1; US6612278B2; CN1255620C; DE10105807C1; US20030029404A1; EP1358397B1

Abstract

The invention relates to a pivoting or rotating mounted rocker arm, for a valve train in an internal combustion engine, fitted with a mechanical valve play adjuster element, for the independent setting/adjustment of a first pre-set valve play between rocker arm and valve stem end. The valve play adjuster element comprises a hollow cylinder mounted in the rocker arm in a rotating manner, with planar surfaces (slide patches) formed around the hollow cylinder circumference and a turning spring which turns the slide patches in a pre-determined direction. The independent rotation of the slide patches is prevented by contact of the relevant rear surface edge of the planar surface on the valve stem end, so long as a second given valve play is not reached.

Description

Rocker arm for a valve train of an internal combustion engine with a device for automatic adjustment / readjustment of the valve clearance

The present invention relates to a rocker arm for a valve drive of an internal combustion engine for the open actuation of a valve stem against the spring force of a valve spring closing the valve, which is equipped with a mechanical valve lash adjusting element.

A typical internal combustion engine uses an array of valves to control the intake and discharge of gases into and out of an engine cylinder. A valve is usually opened and closed electromagnetically or purely mechanically, in that the valve stem is actuated via a lever arrangement which in turn is controlled by a camshaft driven by the crankshaft of the engine. The generally downward movement of the lever arrangement and the associated actuation of the valve stem end are associated with a lifting of the valve head from its valve seat. This movement is countered by the restoring force of a suitably arranged valve spring, which ensures that the valve head is pulled back into its sealing engagement with the valve seat at a suitable time in the engine cycle.

To prevent tolerances in the valve train and temperature changes during operation of the internal combustion engine from a hard encounter of the valve train to CQ. <N CQ 0

H Ω Φ 0 ^" S Ω P

P tr Ch li μ- t P. * o tr CQ

Φ Ω Φ Ω μ- <μ- tr Q tr Φ Φ = CΛ rt Φ tΛ P tr tr -s μ- P φ rt

Φ Φ SD = 3 P μ- li Ch tr 3 <h- ¹

P * μ- li rt Φ Ch CQ

H- P Φ Φ P Φ Ω

Φ CQ P ii rt CQ tr

CQ rt μ-SD

^ -> j- ¹ <Ml Q μ- P- S rt Φ rt

H- P Φ μ- ii P

0 CQ P μ- rt Ml

Ch Q, φ μ- 0- "φ d Φ tr tr

CQ μ- φ CQ CQ left

H- P rt rt 0 Φ φ φ i 1 P N P ii μ- - '0

? f φ Ω 0 o Ω tr ii <Q P

3 ii Q 0 = Φ φ P,

• Ö 0 = tτö P ≤ Λ & Φ rt P ⁾ = SD

H- φ φ μ- P ⁴ 0

N CQ <i CΛ

H-N 0 CQ φ

Φ 0 <li Ω Φ H ü - φ N tr μ- i rr ii 0 SD CQ φ

-5 tr CQ Mi rt 3

H- D li Φ rt Φ

3 CQ φ tr P P *

P Φ φ SD

N P P µ-CQ

0 0 P μ- r-h P CQ CQ tr 0 CQ ö <rt μ-

SD P CQ μ- Φ Ω

0 Φ 3 φ P Φ tr li 0 CQ rt CQ Φ

0 3 rt Φ μ- H p 0 = 0 CQ tr φ. P ü CQ Φ

CQ CQ P ^< ni Ω μ- μ- J

Φ tr <3 Φ P rr Φ 3 P

SD Φ H rt rt 1 P 1

tiv expensive to manufacture, so that their use in simple internal combustion engines is unsuitable.

In addition, mechanical valve lash adjusters are known.

DE 43 39 433 AI describes a valve lever with a deflection device which comprises an adjustment wedge having two wedge surfaces, which is arranged between a support wedge arranged in the valve lever in the adjustment direction of the adjustment wedge and a feed wedge in the valve lever transversely to the adjustment direction of the adjustment wedge in the direction of the gas exchange valve movably guided valve thrust piece is arranged. With this device, it is possible to significantly reduce the surface pressure between the valve pressure piece and its guidance in the valve lever.

A mechanical valve lash adjuster is also described in EP 0 331 901 A2, in which a rocker arm interacts with an eccentric disk to eliminate the valve lash. The eccentricity of the eccentric disc is selected so that during the actuating stroke of the valve the gear ratio of the rocker arm is reduced, but after the valve returns to its closed position and the transmission forces cease to exist, the spring swivels the eccentric disc until the valve clearance is eliminated.

In contrast, it is desirable to have a simple and inexpensive to produce, purely mechanical, automatically acting device for adjusting / adjusting the valve clearance. This object is achieved by a rocker arm according to claim 1 of the present invention. Advantageous embodiments of the invention are specified by the dependent claims.

According to the invention, the valve lash adjusting element mentioned at the outset is characterized in that it comprises a hollow cylinder rotatably mounted in the rocker arm with flat surfaces (“sliding block”) formed around the hollow cylinder circumference and a torsion spring rotating the sliding block in a predetermined direction of rotation. Adjacent flat surfaces are separated from one another by their surface edges.

The torsion spring for rotating the sliding block in a predetermined direction of rotation has a much lower spring force than the valve spring closing the valve, so that the closing of the valve is not impaired by a force component in the opposite direction of the spring force of the torsion spring.

According to the invention, the sliding block is designed such that the flat surfaces formed around the circumference of the hollow cylinder are each arranged parallel to the hollow cylinder axis. This implies that there is a perpendicular to the hollow cylinder axis for each flat surface. The direction of this solder corresponds to a radial direction of the circular cross sections of the hollow cylinder. According to the invention, the solder defines the shortest distance of the flat surface from the hollow cylinder axis by means of a flat surface on the hollow cylinder axis. Q Ml rt CQ Ξ; <CQ CQ P <Ch CQ CQ ü CQ PM tsi><Φ Φ α μ- Ω fÖ ≤ JM ü

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Φ φ CQ rt rt CQ 3 tr tr μ- μ- rt CQ P CQ φ PP ⁴ ? R rt Φ

P ii Ω tr Φ μ. 3 rq <CQ CQ CQ CQ PP SD Pi Φ φ Pi Φ μ- X rt rt Φ CD tr μ- li H et μ- ¹ Φ CD 0 rt H rt rt H i P φ CQ P φ i P SD 0 Φ P 0 "

Ch Mi SD P Ch CQ Φ Φ SD = P P P φ P Φ rt SD: 0 φ Pi li Φ P φ P P 0 Φ

SD 0 = Hi rt ü • d CQ CQ Ω rt ?? CQ D: Ω P ii P ^ P rt CQ ö SD P P

CQ tr rt φ Φ μ- P ⁴ μ- li CQ rt P ⁴ CQ SD Pi N CQ Ω SD <J Φ li 0 Pi Φ i Φ li tr Φ <<φ Φ Φ 0 Ω 0 μ- φ CQ Ω Φ ^> <Φ SD = M Ω 0 P CQ Φ Ml P

<rt P Φ Φ φ Φ CQ Ω μ- P tr P CQ P CQ tr li CQ Ω Φ tr ii μ- P ⁴ Pi

Φ CPP CQ PP <! Ω P ⁴ P CQ μ> CQ Φ φ CQ μ- Φ tr μ- P ⁾ Φ P 0 SD

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0 SD = CQ μ- Q CQ α rt Φ CQ rt li li 0 0 Φ ii Φ μ- Φ φ φ li μ- Pi cd tr Q CQ Ω Ω "d φ Φ> tr Φ φ I- ¹ μ- Mi tr SD PP μ- P μ- φ Φ φ SD Φ

Ω P CQ P ⁴ Ω l_l. tr μ- li P tr Φ «cd P ⁴ CQ CQ S 0 = Ω P Pi ι_ι. CQ N 0 P

P ⁴ φ φ φ SD φ CQ P μ- φ 0 Φ rt Φ M tr ΪO φ φ Φ IS! 0 Ω

SD SD CQ P φ Ch M N Φ et φ • Ü 0 rt P μ- μ- CQ μ- φ μ- P Pi 0 Ω CQ tr -5

Ml CQ Ω X μ- Φ rt • ^ SD P • d P SD = CQ ⁱ "^> CQ CQ Φ Ω li CQ tr Ch Φ ii μ ^J Φ rt ro tr SD rt H Φ 0 PP ⁴ CQ rt Φ Φ Φ φ tr et μ- Φ P Φ SD N μ-

Φ J- "P CQ CQ H μ- P 1 Φ μ- li μ- P P CQ rt N P K μ- 0 0 Q

P φ 0 rt rt Φ PP P. tr so. CQ Φ rt • 0 0 0 Ω r <! φ 0 rt Mi Φ φ μ- CQ Φ Φ tr μ- Ch α SD = Φ Φ 0 CQ ⁱ Φ P ⁴ - ^> P li tr Φ 0 tr tr Q μ- P

Φ P CQ μ- Φ CQ Pi φ Pi Φ Ω CQ P 0 li μ- μ- CQ SD li li Φ rt P φ Φ PP rt Φ i φ ii P ⁴ CQ CQ Ω ii tr P φ <! ü Φ P ISl Φ μ- SD N

CQ ii P Φ D Φ li PJ 3 φ! Ω μ- rt N 0 SD Φ Φ "<! Μ- φ P 0

O ü P μ- n α Φ φ α Φ tr P Φ φ 0 ü * τ] li P μ- ⁱ P P. H

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N Φ P tr Ω P ⁴ CQ Φ φ Ω & rt CQ Φ φ CQ ^ φ μ- Q φ SD: Ω ii tr SD

0 li ^ Φ tr 3 r μ- CQ tr Φ P μ- α Φ NP 3 rt P Ω P ⁴ SD Φ ii ISl

Φ φ P> Φ Φ Φ P rt ω ii CQ 0 rt P li I ^Q SD-- 0 Pi 3 H- ^• P ⁴ φ Ω μ- C SD

WP, PP Φ φ μ- P μ- CQ φ Φ Ω P φ rt CQ SD φ P tr P μ- l- ¹ φ φ> τ | μ- ¹ Φ P α Ω Pi tr tr tr φ Φ Ω PP CQ φ φ μ- μ- r] li SD SD Φ 0 ü P, μ- tr CQ l_l. Ml Φ Φ P ⁴ w PP ⁴ rt XN φ Φ P

P Ϊ P): CQ CQ μ- P CQ> φ Ml Pi Ω Φ φ P P 3 0 = Φ SD 0 <ö H P

Φ SD = ü Ω Φ P CQ rt tr Q Ml tr Φ tr ^• ≤ Pi Φ li ö P ^• d 0 H φ Φ ii Ω SD P ⁴ CQ φ Φ CQ φ Φ ü SD Φ φ SD PN li i rt 0 PJ ü Φ - ü tr Ml Φ Ch φ CQ N CD et tu l μ- Mi μ- ii Pi P α Φ Φ D Φ P li tr tr J α rt Φ 0 PJ 0 φ Φ rt SD rt φ CQ tr CQ rt PJ Φ Ml * | Ω li P SD li tr CQ li <! P tr PP Φ CQ tr CQ Φ P rt li CQ 0 Φ H CQ Φ M tr

Φ ^• Ch P CQ φ 0 PN φ rt CQ Φ CQ P Φ μ- P ii rt P. SD = CQ tr SD Φ ISJ rt Q td NQ μ- ≤> i Ω CQ Q Φ μ- Φ Ω Φ

0 P li P. 0 rt φ Φ b ⁴ P. ^ [SJ φ ^• d CQ P μ- Pi <SD> tr Φ Ω 3 ii P ⁴

P rt SD CQ JD: tr rt Φ φ -> = ^> li li φ H μ- 0 Pi tr rt μ- Φ tr Φ. 3 Φ * Ö Q Φ ü CQ Φ et Φ SD = 1 ü μ- μ- Φ r-> Φ - Φ P μ- CQ 0 P μ φ P rt tr P SD li P ⁴ μ- P t P CQ α Ω SD μ- rt PJ rt P φ P μ- Φ Φ I li

P <φ <! o = CQ Φ μ- Φ Pi Ω ii tr P P Φ φ Pi SD: CQ φ Pi • fl SD

Φ tr φ li Φ P tr Φ tr Φ φ Φ P tr Φ Φ P Φ

CQ P μ- Φ ü Φ tr P Φ ü P α P PJ 1

CQ P Φ 1

Td ö C ^Q tr CQ Ω td CQ P. φ Q Φ ö SD rt P li ISl α 0: «cd CQ CQ μ- Pi H rt Ω μ- m μ- rt ii rt Φ ii Ω σ ii 0 μ- μ - Φ 0 0 SD tr μ- Φ φ i P Φ P Φ H

SD = Mi μ- P Φ φ Mi Φ li CQ tr Φ Φ Hl Φ P P H CQ SD: Φ • d μ- tr 0 P μ- Φ

Ω Mi φ et μ- μ- rt SD P tr CQ ü CQ CQ Ω ii * 0 = P Pi Pi P μ-

P ⁴ Φ> - • Φ rt P CQ Hl Φ 0 li rt Ω Td <CQ tr tr td Ü Pi φ CQ Φ CQ rt

Φ ii 0 CQ i 0 Ω $ rt P 0 ^• »P ⁴ P. Φ 0 φ i Φ φ μ- ii rt ii C ^Q

PD CD CD P rt 0 P tr Φ φ CQ P SD S = Φ ü φ tr rt CQ P. Φ μ- rt w P μ- P CQ Φ P CQ HP CQ H i ^• ≤ Mi Ω CQ CQ CD P Φ SD = CD φ CQ H CQ P CD

SD ISl P μ- CQ 0 P SD = O rt P ⁴ M μ- μ- rt P u rt Ω μ-

P ^ ISl P CQ Pi tTb Pi Ω SD Pi i Φ Φ <0 = P φ <CQ H- Φ 0 tr α P et NN 0 CQ CQ Φ CQ Pi φ tr P Φ 0 D φ EΛ CQ CQ φ CQ P ⁴ Pi P ii C ^Q

Φ S ≤: ii φ CD rt PJ 3 Φ P li ii μ- P Φ Φ rt P $, 0 μ- 0 H- ¹ CQ 0 φ μ- Φ Ω Pi 3 φ CQ Ω ü P rt ü CQ et μ- PP ü 0 CΛ tr ⁱ CQ μ- P ⁴ Cd 0 SD = «<μ- CQ T tr μ- μ- 0 rt μ- ti CQ rt Ω P Pi CQ ü CQ

Φ Ω rt Φ Φ ii μ- Φ φ P φ Φ Φ Pi P φ) l- ¹ SO, Φ P ⁴ CQ Φ rt μ- 0 ü tr Φ P rt Ω • d 0 PP -> Pi p. Φ CQ CQ P CQ P. ü CQ φ Ω P

Φ ^Q fT- = tr μ- • d P rt rt tr Φ μ- li • d - P Ω Pi Φ Φ Pi N tr P ⁱ

Φ P SD rt CD tr CQ CQ μ- Φ CQ ii φ P μ- rt tr μ- CQ P μ- 0 «rt φ tr <! P μ- rt Φ • d ii rt? Ϊ μ ^J ö φ CQ Φ SD φ Φ li μ- 0 0 ü

Φ α 0 rt CQ P tr Pi li Q <! li CQ SD li 0 Φ Hi CQ <J Td> d P P P

P Φ Φ 0 P. Φ Φ Φ Ω CQ Φ SD Φ CQ Φ CQ <3 rt φ φ ö cd • d CQ CQ

Φ 3 D ⁴ P SD μ- μ- ¹ CQ Ω P ⁴ rt li Hl μ- ¹ Φ tr Φ Φ P SD = l Φ tr • ISl

P Φ CQ CQ CQ Φ CQ tr SD Φ CQ rt tr w P- SD P <P ≥! rt Ω Φ rt φ 0 i CD Φ φ <Φ Hl et CQ CQ et μ- CQ rt Φ φ μ- tr tr SD: tr φ

TP ⁾ rt tr Pi D! φ P rt SD = Ch rt Φ Φ φ CQ μ- P Φ μ- Φ Ml rt Φ CQ φ

Ch μ- μ- Φ P Φ o P i Φ 0 P Φ rt CQ rt P Q CQ P Φ μ- μ-

SD = μ- 3 P CQ Φ b-> i rt PPP ⁱ li SD = Φ tr tr CQ μ- 0 Ω * "Pi CQ CQ <P

Ω SD 3 Pi ii tr μ- <Pi CQ h- ¹ rt P 0 μ- φ • d SD P tr SD φ 0 Φ tr r Φ <J CQ μ- μ ^j φ Φ μ- ü μ- PP μ- μ - Q 0 Q SD PHPPP 3

Φ Φ Φ ii φ N rt φ CQ i N Ω ü CQ Si CQ rt φ Ω Hi Hi rt CQ φ rt

PD rt P 0 rt CQ CQ P 0 tr Φ φ SD Φ P> P ⁴ CQ Pi rt Φ tr μ- μ- <rt li SD = rt 0 li μ- ii tr CD ISl li 0 SD Φ φ Φ Φ Pi CQ 0

0 <μ- r. P 0 = Ω P Hl ö 0 Φ CQ P Hl tr M CQ ISl £. Q rt Q H

P tr φ CQ Φ μ- Pi Λ tr td 0 Φ ii <ii li φ rt 0 0 μ- CQ C ^Q

CQ P 0 CQ tr CQ Φ et φ ü i Φ CD φ μ- Φ tr φ i 3 H Q 0 • d

Pi rt rt Ω Φ φ Pi ii rt φ tr P td μ- CQ P Φ tr 0 <μ- P SD

Φ PJ μ- SD P ⁴ P Φ rt <SD-- Φ li 0 rt φ SD = Ω rt P Φ li <et Φ Ω Pi P li PHP SD Φ ö i Φ 0 rt μ- P μ- rt Ω P ⁴ Φ P Ω Φ Φ P tr P α CQ CQ Mi P li μ- P Φ CQ SD = tr Φ <! 0 Φ tr PP rt Pi Φ

N Φ rt Φ Φ α <CQ CQ μ- C ^Q rt φ P Φ <PP rt μ- Pi Φ P μ- Φ Td tr P Φ 0 φ P α Ω μ- PP ii 0 i ^ H-> μ- Ü

Φ φ CQ 0 rt P SD P rt CQ φ P ⁴ CQ? Φ CQ T μ- P CQ φ ⁱ μ- ii H SD SD = P CQ rt 0 CQ N φ CQ SD 0 SD ii Ω μ- ¹ Pi Tp CQ M Ω Φ φ

P - CQ CQ Ω CQ • d μ- Mi Φ rt Ml PP tr Hi μ- SD = "d Ω SD tr φ PC ^Q

Pi P ⁴ φ tr ü H ⁱ PN Ω rt CQ rt <φ Ω φ tr CQ SD tr rt φ μ- fi- <P ⁴ Φ Pi Φ Q μ- Φ rt Φ Φ φ φ SD = tr P SD φ Mi Φ CD Ω ii P SD Φ 0 = φ Ω • d Φ CQ. Φ PM μ- Ω φ Φ Mi rt P • d

SD rt CQ P li μ- CQ P ⁴ μ- CQ s ^" μ- Pi Φ CQ CΛ tr tr P Pi r p. Φ Φ H Φ

Ω Φ rt Φ P φ φ rt <φ α rt φ CD Φ ii tr μ- Φ φ Φ Φ CQ Φ μ- tr ii Pi μ- PP ^• »φ P μ- CQ li 0 = Φ CQ P CQ CQ P i Td Ω rt

CD Φ Φ Pi i Pi P P φ rt! CΛ Pi Φ φ Pi SD tr CQ

Φ P H Φ Φ φ μ- i rt Φ Φ Φ Φ Φ μ- SD CQ Φ N 0 SD: Φ

P ii PP μ- Pi μ- HP r P 0 Φ • 0 Hi Ω P tr μ- P Φ CQ Mi P tr φ CQ rt Φ

and corresponds to the shortest distance of this flat surface from the cylinder axis. However, wear on the rear surface edge, which can be expected in practice, shortens the readjustment interval.

Since the vertical distance of the axis of rotation of the hollow cylinder from the end of the valve stem is essentially constant in a certain position of the rocker arm in the closed position of the valve, it is possible for each flat surface to reach the rotational position for actuating the valve stem by the automatic rotation of the sliding block. A first predetermined valve clearance is introduced or removed via the increasing shortest distance between the flat surfaces and the cylinder axis. be adjusted.

In the basic setting of the sliding block, it is set so that the flat surface with the smallest shortest distance from the hollow cylinder axis reaches a rotary position for actuating the valve stem. The first predetermined valve clearance is set.

The rocker arm is preferably designed in such a way that the torsion spring is a two-mounted helical spring which is arranged around the hollow cylinder axis and has a fixed bearing on the sliding block and the other fixed bearing on the rocker arm. This simplifies the design, saves space and costs.

An advantageous embodiment of the invention provides that the rocker arm is equipped with at least four flat surfaces, whereby at least one four times on / adjustment of the first predetermined valve clearance can be detected.

It is further preferred that the first predetermined valve clearance is the same for each flat surface in its rotational position for actuating the valve stem. This results in repeated readjustment of the valve clearance to the same predetermined value. In particular, for example, a constant minimum valve clearance can be set for each readjustment stage.

Likewise, it is preferred that the second predetermined valve clearance is the same for each flat surface in its rotational position for actuating the valve stem. This ensures that a certain valve clearance, which is the same for each flat surface in the rotational position for actuating the valve stem, is not exceeded. In conjunction with a constant first predetermined valve clearance, the valve clearance can thus be kept within the limits defined by the first and the second predetermined valve clearance.

The first predetermined valve clearance is preferably in the range from 0.01 mm to 1 mm; this is preferably 0.1 mm.

The second predetermined valve clearance preferably has a difference from the first predetermined valve clearance which is in the range of 0.05 mm-1 mm; this is preferably 0.2 mm.

An advantageous embodiment of the invention provides that the flat surfaces of the sliding block on both sides 3 3 μ- Φ rt ii rt

pi

Φ 0

3 3 left φ 0 ^: ü CQ

Hl et μ- φ

P P

Pi -

0

P μ-

CQ P

CQ P.

CQ Φ

Φ 3

3

SD = Pi

EΛ Φ

Φ H

P tr

^ μ- μ- CQ

• d tr

^• d Φ tr ii

Φ tr <!

Φ Φ ü s;

SD Φ

0 P

CQ Pi

CQ Φ

Φ rt rt Φ

SD

0

CQ μ-

Ω • d tr • d et tr

Φ

= ^> tr μ- Φ

H

In the following the invention is illustrated by way of example with reference to the accompanying drawings.

1 shows a perspective view of a rocker arm according to the invention in engagement with a valve stem;

2a shows a top view of part of the rocker arm according to the invention;

2b shows a top view of an enlarged section of the rocker arm according to the invention from FIG. 2a;

Fig. 3 shows a cross-sectional view of a first example of the sliding block with seven flat surfaces; and

Fig. 4 shows a cross-sectional view of a second example of the sliding block with nine flat surfaces.

1, a rocker arm 1 according to the invention is in engagement with the valve stem end of a valve stem 4 via a sliding block 2. The valve stem 4 is slidably arranged in a valve stem guide 6. The valve stem 4 is pressed by a valve spring 8 into a position in which the valve plate 11 comes into sealing engagement with the valve ring 12. The valve spring 8 is supported on the one hand against the cylinder head 13 and on the other hand against a projection 10 attached to the valve stem. The rocker arm 1 is attached to the engine block via a stem 3. The sliding block 2 is rotatably mounted at one end of the rocker arm 1 in a corresponding recess between washers 7. A fixed bearing of a torsion spring 5 Pi>«<≤ rt CQ SD CQ μ ¹ <N td?: Td CQ CQ tr d ^ CQ CQ μ- 3 Φ CQ φ H Pi ü μ- 0 μ- φ μ- 0 0 0 Φ φ Φ P Φ Φ Ω 0 0 Φ μ- rt Ω P μ- tr rt tr P φ ii

Φ CQ J P φ ii Mi P ISl P μ- CQ μ- tr P P α T Φ tr rt Φ φ Φ CQ Φ

CQ CQ • d rt i N - 0 rt rt φ rt SD CQ Q φ> d SD Pi PPP Pi tr φ D tr μ- φ X P- P μ- μ- Hi CQ ü tr Hi Φ P. Φ Φ Φ 0 li P φ ix Pi Φ t SD = H CQ μ- CQ μ- rt CQ Pi Ϊ Φ 0 rt li Φ p> li μ- P

CQ tr li M SD CQ φ Ω CD 3 μ- • d φ rt φ H tr P φ 3 tr d Td Q td CQ Φ μ- ISl 0 CQ rt <J tr Ω Ch Ω ^• d P Φ CQ SD Φ CQ P ö m μ- ¹ Ω ^• d φ • d P 0 CD 0 CQ P ⁴ SD tr φ sPi Hi P. <rt SD ii tr Pi

^• ≤ 0 CQ ii <li rt PJ CD tr P φ Ω et CD Pi φ Φ Φ PJ = SD Ω 0 Φ Φ φ CQ ISO 0 = S3 φ Hl H • 0 Φ CQ tr P Ω P tr P tr CQ Q μ - μ- Ω μ- P Pi Pi rr 3 ISl Φ Pi P Φ Ch μ> CQ CQ rt tr Φ P. Φ

0 rt Φ 3? R φ et μ- μ- Φ μ- Φ CQ φ CQ μ- Φ 0 rt μ- Φ Φ Ω

P μ- P Pi μ- φ φ P et μ- CQ Q rt K Pi <P Φ Ch μ- m μ- ¹ Q 0 rt ISJ μ- φ Pi CQ φ tr CQ SD φ Pi Q PJ Pi Φ P φ

P CQ ^ P ii φ 33 Φ h φ P φ et α CD P Ω 0 CQ C ^Q H μ-

SD Φ N tr φ • Φ ii μ- Hi Φ ii rt Pi 0 tr Hl rr «rt

0 ISl CQ μ- CD CQ 0 Φ CQ 3 CD 3 • d μ- μ- Φ <! μ- φ P SD tr Ω Φ CQ

Hi 0 Φ P φ φ P CQ td μ- μ-> τj PP tr φ 3 CQ Hi &-> rt Q ii P Pi μ- CD Φ Φ rt φ Ω P rt tr Pi CQ Hl P CQ rt μ- Φ l - ¹ Φ li 0 = Φ P Ω μ- li μ- P φ M φ rt <: ISl φ Φ P. μ- 0 μ-

0 Ω ii φ tr P T Φ φ P. tr μ- o Ch μ- 0 φ 0 P Φ rt P P

P? Φ PT P φ Ω Pi μ- P Φ Φ Ω Φ P P ii Pi td 3 CQ CQ CQ

Pi 3 0 0 3 ⁽ SD =? Μ- rt SD 3 P "P ii CQ Pi rt φ 0 rt

0 TP i CQ Ω φ φ CQ Ω CQ Φ φ T μ- cd. tr? Φ Pi to

Pi P Hl μ- CQ CQ tr CQ rr tr Ω μ- σi μ- Pi Φ I- ¹ 0 = μ- Φ

Φ P. P ⁴ Ω Φ Φ Φ P Φ Φ H Φ CQ φ φ CQ rt ISl N ii PC ^Q tr li Q tr P Φ φ ii μ- 0 Φ tr et r ü Ω D: 3 * <N CQ Φ i N Φ et * - μ- C CQ PP μ- N Φ Φ tr rt μ- φ Ω Mi φ φ N Φ CQ Φ cd rt rt 0 P CQ ≤ <φ SD μ- CQ μ- Q 3 μ-

Φ li μ- 0 P Pi P 3 <Φ t Φ CQ i Φ μ- μ- 0 P Hi CQ Ω P rt μ- φ P

Pi CQ CQ Pi Φ φ 3 P rt Ω ü li rt rt 0 P ⁴ Pi φ rt μ- Pi

Φ <φ φ Φ P ⁴ rt <P φ μ- Φ o = Td tr "• CQ P Φ φ P rt φ li Φ ii PP • Φ Φ rt CQ P 0 μ- Hi rt> d CQ P ii Pi C ^Q rt

Ϊ P CQ PP μ- 0 PP Hi (D: Pi Φ α li μ- P> F φ rt li rt μ- s td Pi et P t? SQi P Ω μ- P 0 Φ Φ Pi l_l. Ω 0 3 Φ CQ

SD μ- P φ μ- φ N μ- CQ CQ H- t 0 tr φ i Ω Q Φ φ tr rt μ- μ-

Hi PHP li Φ TJ P tr P Φ CQ Ω tr rt CD i CQ CQ P Ω rt CQ P. CQ μ- Q μ- 3 cQ Φ SD CQ μ- Φ P ⁴ Φ Φ φ P. φ C ^Q P ⁴

Ω s Φ H <rt Ω Φ 0 li rt 0 N P P μ- <H ~ Φ ii

P. tr μ- P μ- Φ • d tr EΛ μ- SD = CQ Pi 0 tr α Pi P Φ li μ- t SD

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Φ rt μ- ü 0 Φ Φ Φ tr CQ ö Φ EΛ Ω Hl P N SD

P 1 1 tr 1 tr H P. I tr Φ P

Φ φ Φ Φ Φ φ Φ I Si li 1 1 CQ

8 without losing engagement with the flat surface of the sliding block 2.

In the end position of the rocker arm 1, its end equipped with the sliding block 2 is again at a distance from the valve stem end, in which the valve clearance between the flat surface in engagement with the valve stem end and the valve stem end is made possible.

The flat surface remains in engagement with the valve stem end as long as the rear surface edge hurrying in the direction of rotation of the sliding block 2 lies against the valve stem end. The sliding block 2 is only biased by the torsion spring 5 in this state.

If the valve clearance increases in the course of the operating life of the engine, the valve clearance can become so large that it reaches the value of the second predetermined valve clearance at which the rear surface edge no longer abuts the valve stem end. The sliding block is then rotated due to the preloading spring force of the torsion spring until the next flat surface comes into contact with the valve stem by contacting its rear surface edge. The originally increased valve clearance is reduced again by the comparatively larger shortest distance between the flat surfaces and adjusted to the first predetermined valve clearance.

As soon as, for example, the valve clearance reaches the value 0.3 mm in the first stage, the sliding block rotates to the next surface stage and the output valve clearance of 0.1 mm is immediately obtained again. It is therefore ensured that a minimum there is valve clearance and the valves do not remain open.

2a and 2b each show a top view of the rocker arm 1 equipped with the sliding block 2. The torsion spring 5 can be seen as a centrally arranged helical spring which has a fixed bearing on the sliding block 2 and the other fixed bearing in a clutch of the rocker arm 1. The sliding block 2 has the shape of a hollow cylinder with flat surfaces formed around its circumference. The torsion spring 5 is arranged in the hollow center of the hollow cylinder. To fit into its rotatable mounting, the sliding block is also equipped with two washers 7 arranged on both sides of the flat surfaces.

In Fig. 3, the sliding block 2 is shown in cross section. The direction of the rotation of the sliding block caused by the torsion spring 5 is indicated by the arrow. The hollow cylinder of the sliding block has the radius _x in its circular cross section. The flat surfaces likewise shown in section are formed around the circumference of the hollow cylinder. The intersection lines of the flat surfaces form a closed polygon around the circumference of the hollow cylinder, which moves further and further away from the circumferential surface in the opposite direction of rotation. Only the straight line with the shortest vertical radial distance from the axis of rotation touches the circumferential surface of the hollow cylinder. This line of intersection or the corresponding flat surface of the sliding block is set in the initial basic setting of the sliding block for actuating the valve stem end. The vertical radial distance the line of intersection from the hollow cylinder axis corresponds to the perpendicular of the flat surface to the hollow cylinder axis.

The first predetermined valve clearance results from the difference between the vertical distance of the axis of rotation of the hollow cylinder from the end of the valve stem and the shortest distance between the flat surface and the cylinder axis. In the basic setting of the sliding block the first predetermined valve play lies within ie the difference between R _x and R _J + _J.

The second predetermined valve clearance corresponds to the difference between the radial distance of the rear surface edge of the flat surface from the cylinder axis and the shortest distance of the flat surface from the cylinder axis. In the basic setting of the sliding block, the second predetermined valve clearance is therefore _x .

As long as the valve clearance does not reach the full difference between R _α and ^ X- _L , ie x _x , the automatic rotation of the sliding block is prevented by the rear surface edge resting against the end of the valve stem.

As soon as the valve clearance reaches the value of x ₂ , the sliding block jumps to the next rest position, in which the next flat surface in the opposite direction to the direction of rotation comes into engagement with the valve stem end. The shortest distance between the flat surface and the axis of rotation is now R ₂ = R ₁ + x ₁ -y ₁ . In this position of the sliding block, the first predetermined valve clearance lies within the difference between ^R ₂ ^{= R} _ι + ^χ _ι -y _ι ^and -d R ₂ ^{+ x} ₂ - ^the second predetermined valve ^clearance is x ₂ . As long as the valve clearance does not reach the full difference between R ₂ = R ₁ + x ₁ -y ₁ and R ₂ + x ₂ , ie x ₂ , the automatic rotation of the sliding block is prevented by the rear surface edge resting on the valve stem end.

As soon as the valve clearance reaches the value of x ₂ , the sliding block jumps over to the next latching position, in which the flat surface in the opposite direction to the direction of rotation comes into engagement with the valve stem end. The shortest distance between the flat surface and the axis of rotation is now R ₃ = R ₂ + x ₂ ~ y ₂ .

In this position of the sliding block, the first predetermined valve clearance lies within the difference between R ₃ = R ₂ + x ₂ -y ₂ and R ₃ + x ₃ . The second predetermined valve clearance is x ₃ . As long as the valve clearance does not reach the full difference between R ₃ = R ₂ + x ₂ -y ₂ and R ₃ + x ₃ , ie x ₃ , the automatic rotation of the sliding block is prevented by the rear surface edge resting on the valve stem end.

As soon as the valve clearance reaches the value of x ₃ , the sliding block jumps to the next latching position, in which the next flat surface in the opposite direction to the direction of rotation comes into engagement with the valve stem end. An analogous consideration applies to all other flat surfaces. The number of levels can be selected as required. For example, wear of 1 mm can be easily compensated. FIG. 3 shows 7 steps or edges as examples. Fig. 4 shows a second example of the sliding block according to the invention with nine flat surfaces. An exact design of the sliding block is given for clarification.

The first and second predetermined valve clearances are the same for each flat surface. The first predetermined valve clearance is 0.1 mm. Every time the next flat surface assumes the rotary position for actuating the valve stem, the first predetermined valve clearance of 0.1 mm is readjusted. In the basic setting, a valve clearance of 0.1 mm is set. The second predetermined valve clearance is 0.3 mm. The difference between the second predetermined valve clearance and the first predetermined valve clearance is 0.2 mm. After wear of 0.2 mm, each flat surface snaps into the rotary position for actuating the valve stem and reduces the actual valve clearance from 0.3 mm to 0.1 mm again. In addition, the angles between the adjacent solders are given by the flat surfaces on the hollow cylinder axis.

In this example, the hollow cylinder has a length of 14.4 mm, an outer diameter of 7 mm and an inner diameter of 3.7 mm. The flat surfaces have a width along the hollow cylinder axis of 6 mm. The length of the hollow cylinder on both sides of the area occupied by flat surfaces is 4.2 mm in each case.

With the rocker arm according to the invention, equipped with the device for adjusting / adjusting the valve clearance according to the present examples, an average service life of 5000 hours can be achieved until the last flat surface engages in the rotary position for actuating the valve stem. The rear one <

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Claims

Expectations

1. rocker arm for a valve train of an internal combustion engine for the opening actuation of a valve stem (4) against the spring force of a valve spring closing the valve (8), equipped with a mechanical valve lash adjuster, characterized in that the valve lash adjuster rotatably mounted in the rocker arm (1) Sliding block (2) as a hollow cylinder with flat surfaces formed around the hollow cylinder circumference and a torsion spring (5) rotating the sliding block (2) in a predetermined direction of rotation, wherein a) the flat surfaces are each arranged parallel to the hollow cylinder axis and the solder on the respective flat surface through the hollow cylinder axis corresponds to the shortest distance of the flat surface from the hollow cylinder axis, b) the flat surfaces each have a leading surface edge leading in the predetermined direction of rotation and a trailing rear surface edge which are parallel to the hollow cylinder axis, c) which eb surfaces in the opposite direction to the predetermined direction of rotation, increasing short distances from the cylinder axis and an increasing radial distance of the associated rear surface edges from the cylinder axis, d) the flat surfaces due to the automatic rotation of the sliding block (2) in each case The next rotary position for actuating the valve stem is a first predetermined valve clearance resulting from the difference between the vertical distance of the axis of rotation of the hollow cylinder from the end of the valve stem and the shortest distance of the flat surface from the cylinder axis, the automatic rotation of the sliding block (2) due to the system of the rear surface edge of the flat surface to the valve stem end is prevented as long as a second predetermined valve clearance larger than the first predetermined valve clearance and the difference between the radial distance of the rear surface edge of the flat surface from the cylinder axis and the shortest distance of the flat surface from corresponds to the cylinder axis, is not reached.

2. Rocker arm according to claim 1, characterized in that the torsion spring (5) is arranged around the hollow cylinder axis, two-bearing coil spring, which has a fixed bearing on the sliding block (2) and the other fixed bearing on the rocker arm.

3. rocker arm according to claims 1 and 2, characterized in that the sliding block (2) has at least four flat surfaces.

4. rocker arm according to one of claims 1 to 3, characterized in that the first predetermined valve clearance is the same for each flat surface in its rotational position for actuating the valve stem (4).

5. Rocker arm according to one of claims 1 to 4, characterized in that the second predetermined valve clearance for each flat surface in its rotational position for actuation. the valve stem (4) is the same.

6. rocker arm according to one of claims 1 to 5, characterized in that the first predetermined valve clearance is in the range of 0.01 mm - 1 mm, but is preferably 0.1 mm.

7. rocker arm according to one of claims 1 to 6, characterized in that the second predetermined valve clearance has a difference to the first predetermined valve clearance, which is in the range of 0.01 mm - 1 mm, but is preferably 0.2 mm.

8. rocker arm according to one of claims 1 to 7, characterized in that the flat surfaces of the sliding block (2) are limited on both sides by washers mounted on the hollow cylinder.

9. rocker arm according to one of claims 1 to 8, characterized in that the second predetermined valve clearance of the flat surface with the greatest shortest distance is chosen so large that for an average Operating time of the internal combustion engine the rear surface edge is guaranteed.

10. Rocker arm according to one of claims 1 to 9, characterized in that the sliding block (2) is made of chilled cast iron, sintered material, cold-pressed or extruded steel.