DE3408557A1 - ROCKER LEVER AND METHOD FOR PRODUCING IT - Google Patents

Description

Henkel, Pfenning, Feiler, Hänzel & Meinig - 3 - Patent Attorneys

. ". 'uye'ci -seils'

_> ■ phi! G Hcnkt M j'ν "- '' Hz / ld Dipi Ida J Pie ^r i '.'^; B ₁ ··, '· L)! rer! idi L Feui / tv "i / k '■ · ■ - f 'ip -Ir. j V »Hüri.'d f Λ, ι'κ '' ' D'p Phyt K H K'tv; • g be -'- Dr Ing A Bute ^ ccnoi n. Bet '- Mohlstrasse 37 D-800C Muncher 80 Tel 089/96 20 8; .- 87 lelex 0529802 nnki d Telegrams ellipsoid FP84O8-2 -

March 8, 1984

MITSUBISHI JIDOSHA KOGYO KABüSHIKI KAISHA, Tokyo, Japan

Rocker arm and process for its manufacture

Rocker arm and process for its manufacture

The invention relates to a rocker arm for valve control in internal combustion engines and a method for the production of such a rocker arm.

As a result of the wear and tear of the intake and exhaust valves of an internal combustion engine, it turns out to be necessary that Periodically repair and / or replace sliding surfaces or adjust the play. Due to wear and tear The upper end of the valve stem is displaced more between the valve seat and the valve surface (disk) and more under the influence of the valve spring to the rocker arm until it keeps the valve open and thus impairs the tightness of the cylinder. Due to wear and tear between the upper end of the valve stem and the engagement surface of the rocker arm the play between the two parts increases, which generates noise and reduces machine performance has the consequence. For this reason, a zero rush adjuster is often used. of the oil-hydraulic type used to keep the play between rocker arm and valve (stem) constantly on one keep optimal size.

A previous rocker arm has the structure shown in FIG. A rocker arm 1 is placed on a rocker arm shaft 300 gg, see above. that he corresponds to the rotation of a

Camshaft 500 swings and thereby the axial shaft end of an intake or exhaust valve 400 via a Play compensation device 3 is applied and pressed down perpendicularly. The lash adjuster 3 is included inserted into a cylinder bore formed in the rocker arm ·. To prevent premature deformation of the cylinder bore due to insufficient strength is a cylindrical chuck or a sleeve 2 made of iron or copper. Valve controls of this type are currently used widely because Rocker arms made of light metal alloys in an effort to reduce the inertia forces to achieve higher machine speeds to be preferred.

The chuck or the can is required in particular for the following reasons:

1. In the event of a failure of the pressure oil supply or after When the machine is switched off, the body 130 of the lash adjuster 3 is displaced only in one

* ^v small area of 0-2 mm corresponding to the automatic lash adjustment range for the valves, which prevents even lubrication of this body.

2. If the point of contact between the approach 25

at the end of the body 130 and the shaft end of the Valve 400 moves due to the pivoting movement of the rocker arm 1 when the valve is actuated the body 130 is intermittently applied with lateral pressures so that it moves according to the game tilts in its cylinder bore, which results in hard metal / metal contact. In the case the use of light metal alloys in such an arrangement can cause damage

(Chafing and plague eating) occur. 35

The machining steps of the rocker arm cylinder bore for the installation of the lash adjuster with chuck or bush

1. the pressing in of this sleeve and 5

2. The finishing of the inner surface of the liner to the nominal diameter.

The conditions for grinding, etc. must be chosen so that they are both that of iron or copper manufactured liner as well as the light metal alloy bottom of the rocker arm cylinder bore are adapted. In addition to the increased weight of the can, this requires several complicated operations. An improvement this previous constructions and processes is therefore urgently required.

The object of the invention is thus to create an improved rocker arm and a cost-effective method for the production of rocker arms which protect against damage without using a sliding bush and are wear-resistant.

In a method for producing a rocker arm, this object is achieved according to the invention in that a plate made of sintered iron alloy is cast onto a lever part made of an aluminum alloy a thin (protective) layer is formed on the outer surface of the plate (and the adjacent surface), a porous anodic oxide layer is formed on the lever part, followed by electrolysis in one Ammonium thiomolybdate solution, with molybdenum sulfide being introduced into the pores (of the anodic oxide layer) and then the thin (protective) layer is removed.

The invention also relates to a rocker arm that is characterized in that it has a lever part made of aluminum alloy with a porous anodic oxide layer, in the pores of which molybdenum sulfide has been introduced, and one that is cast onto the lever part Plate which can be brought into sliding contact with a control cam includes.

The following are preferred exemplary embodiments of the invention in comparison with the prior art the drawing explained in more detail. Show it:

Fig. 1 is a side view of a previous, with lash adjuster equipped rocker arm, 15

Fig. 2 is a partially sectioned representation to illustrate the movement of a Rocker arm according to the invention and

Fig. 3 is a side view of a rocker arm according to the invention.

Fig. 1 has already been explained at the beginning.

According to FIGS. 2 and 3, a rocker arm 1 according to the invention comprises a lever part 1001 and a cast on this, Chip 1003 made of sintered alloy, which is in sliding contact with rising and falling surfaces 501, 502 of a camshaft 500 stands. Since no bushing is provided for the lash adjuster 3 is, the cylinder bore 1000 has a slightly smaller diameter than the previous rocker arm « As indicated in FIG. 3 by the hatched section A, the plate 1002 and its surroundings are been masked or covered during the remainder

Part of the lever part 1001 has been subjected to an alumite treatment to produce a solid lubricant is. The masking or covering is carried out by immersing the section A in a coating solution Plastic or paraffin and then remove ■ this section to cool and solidify (of the coating) in the ambient air. In this way, a plastic or the like. Cover formed simply will.

In Fig. 3 three sections are shown which particularly require an alumite treatment, namely

1. the wall 1000a of the cylinder bore 1000, on which the body 130 of the lash adjuster with There is sliding contact,

2. the top of the cylinder bore 1000b, with which the spacer 110 (still to explain) is in sliding contact, and

3. the inner peripheral surface 100 2a of the axial bore 1002, which is penetrated by the rocker arm axis 300 (to be described) with sliding contact.

In this treatment, alumite layers of a predetermined depth, i.e. 10-40 µm, are applied to the surfaces 1000a, 1000b, 1002a, etc. are formed.

The method for manufacturing the rocker arm described is explained below. The lever part 1001 is injection molded from an aluminum alloy (ADC12 (JIS)). First a Sintered iron alloy platelets 1003 inserted into the metal mold, this platelet 1003 with its surface is cast on the lever part 1001.

Then the plate 1003 is connected to the

■ 3-

Immerse the portion of the lever part 1001 thus formed in a molten solution at 150-160C for about 2 seconds a thermoplastic synthetic resin with paraffin and polyethylene (melting point: 130 C) and immersed then cooled. This creates a thin thermoplastic synthetic resin coating on the plate 1003 Thickness of 2 - 3 ram.

According to a method similar to that according to JP-AS 56-4155, jQ the lever part 1001 is then in an aqueous solution

of mixed acid bath containing sulfuric acid and oxalic acid immediately electrolyzed (anodized) to its Surface to form a porous anodic oxide layer, whereupon the resulting layer is treated with water ^ g will wash. The lever part 1001 is then used for activation its surface is immersed in an aqueous nitric acid solution and then washed with water. The lever part 1001 is then used as an anode and using a carbon rod as a cathode 2Q direct current in an aqueous heated to 15-20 ° C Ammonium thiomolybdate solution electrolyzed (anodized) and then washed with water.

Subsequently, the lever part 1001 is immersed in 2g water at 40 C in order to soften the thin synthetic resin layer and their removal (by a worker) from the chip 1003 and from the adjoining portion of the Lever part 1001 to facilitate. In the above treatment, molybdenum sulfide is formed, which is the tiny pores the anodic oxide layer on the lever part 1001 fills. To complete the rocker arm 1 is then a lash adjuster unit 1004 assembled in advance is inserted into the cylinder bore 1000.

Since the fine pores of the alumite coating on the surface

Before the lever part 1001 (with the exception of the platelet 1003) is filled with molybdenum sulfide, this surface has a coefficient of friction corresponding to 1/2 - 1/3 of that of a surface that has only been subjected to the alumite treatment. In addition, the surface hardness achieved by improving the frictional resistance a Hv of about 400. The play compensation unit 1004 can therefore in receiving them bore 10OO move friction without damage such as chafing IQ and seizing elicit; in particular, their actuation when starting and / or switching off the internal combustion engine becomes more uniform or with less friction. The sliding surface 1002a of the lever part 1001, which is in contact with the rocker arm shaft 300, has also been subjected to the alumite treatment with the formation of molybdenum sulfide. The rotary movement of the rocker arm 1 on the rocker arm shaft 300 therefore takes place with little friction (smooth), so that the mechanical (friction) losses are lower and the stability is improved.

Since the chip 1003 and the subsequent portion in the alumite treatment in the electrolyte solution and the formation of molybdenum sulfide are coated with the thermoplastic synthetic resin, dissolving of the Platelets 1003 in the electrolyte solution can be avoided during the treatment. Because this synthetic resin coating through simply dipping the wafer 1003 and its adjacent portion in a liquid thermoplastic Resin has been made, the

QQ thin strip plating layer with the aid of a simple tool, after it has been immersed in about 40 ⁰ C hot water up to the softening.

Due to the improved friction resistance and hardness, the lever part 1001 also proves to be without use

a chuck to be satisfactorily wear-resistant. Reduced because of the omission of such a sleeve the total weight (mass) of the valve train, which increases the speed limit at which a Valve bouncing occurs, increased accordingly. As a result, valve bounce is reduced in normal operation and the weight of the internal combustion engine itself is reduced.

In the embodiment described, the plate is 1003 formed from a sintered iron alloy, and before being aluminized (alumite) with a thermoplastic synthetic resin coated. If the chip 1003 is molded from ceramic, it is one Coating obviously unnecessary.

In the following, with reference to Fig. 2, the structure and mode of operation of the lash adjuster (zero rush adjuster) and the rocker arm having these described. According to FIG. 2, the rocker arm 1 is axially on a rocker arm axis 300 placed, and he actuates an inlet valve 400 to open and close a not shown Inlet or suction port. The rocker arm 1 is here to carry out tilting vibrations of the rocker arm axis 300 between the camshaft 500 and the valve 400.

The lever part 1002 contains the lash adjuster, in which a lash adjuster unit 1004 on the Valve opposite side 1a is inserted into the cylinder bore 1000. Unit 1004 in turn includes a spacer (stop) 110, a body 130, a piston 180, etc. The lever part 1001 has a convex cam abutment surface on the side 100b of the camshaft 500 700 and swings in the direction of arrow B when it moves through the rotation of the camshaft 500

Cam rise surface 501 is pushed up.

The top (bottom) 1000b of the cylinder bore is spherical or dome-shaped, and you The center of curvature is aligned with the center line 2 of the cylinder bore 1000. This top side 1000b stands in sliding contact with the spacer 110, the one with respect to its shape to the top of the cylinder bore 1000b has adapted curvature or dome surface 100, the center of curvature Q with the center line 1 of the cylinder bore is aligned. The spacer 110 provided with a central bore 111 has one of the spherical cap surface 100 opposite mating surface 1.20. The spacer 110 thus leads a sliding rotary movement on the cylinder bore top 1000b around the center of curvature Q by. The body 130 (as a cylinder sleeve) is slidably guided along the wall 1000a of the cylinder bore 10000, and the projection 131 formed on the lower end of the body 130 acts on the upper end face 140 of the a bore of 800 protruding valve stem. The end facing the cylinder bore upper part 1000b of the body 130 is spaced from the wall surface of the cylinder bore, so that a gap 150 between the two is set, which communicates with an oil channel 160. Oil under a predetermined pressure is removed from a central oil passage 170 of the hollow rocker arm shaft 300 via the oil channel 160 of the lash adjuster 3 supplied. The top 1000b of the cylinder bore is in its central area with the oil channel 160 in connection; through the oil fed in in this way the frictional resistance between upper side 1000b and dome surface 100 of spacer 110 is reduced. In the body 130 a cylindrical piston 180 is guided displaceably borrowed, the upper end of which rests on the counter surface

before applying 120 (of the pressure part) of the spacer capable and which has a base 183 opposite to the extension 131 of the body 130. The piston head 183 and the approach 131 have opposite one another Areas that define an oil pressure chamber 190, .which has an oil inlet 184 with a cavity 181 of the piston is connectable. The oil inlet 184 is through a arranged in the oil pressure chamber 190 Non-return valve closable. The latter includes a ball 201 of a diameter exceeding the diameter of the oil passage 184, a spring 202 for elastic Pressing the ball 201 against the oil passage 184 and a spring 202 to act on the piston bottom 183 with the ball supporting holder 203. In the oil pressure chamber 190 is still a control or Adjustment spring 210 is used, which presses the projection 131 against the upper end 140 of the valve stem and thereby the extension 131 of the body 130 and the piston head 183 presses apart. This adjustment spring 210 presses the holder 203 at its upper end against the piston head 183.

The operation of the lash adjuster 3 is described below. From the central oil passage 170 of the rocker arm axle is pressurized oil via the oil channel 160 to the cylinder head gap 150 supplied, wherein the pressure oil enters the cavity 181 via the bore 111 of the spacer to then to act on the ball 201 via the oil inlet 184.

The ball 201 is only displaced to the oil pressure chamber under an oil pressure force exceeding the force of the spring 202 190 so that pressurized oil can enter the oil pressure chamber 190 from the cavity 181. If the in the pressure prevailing in the oil pressure chamber 190 is that in the cavity 181 approaches the prevailing pressure, the Ku-

gel 201 the oil inlet 184 under the force of the spring 202, whereby it prevents an oil leakage from the oil pressure chamber 190 even if the oil pressure is in the latter elevated. When iiti operation of the internal combustion engine oil of a predetermined pressure via the oil channel 160 is delivered to the oil pressure chamber 190, the Piston 180 with its upper end to the spacer 110, while the body with its extension 131 the applied to the upper end face 140 of the valve stem.

As long as the cam contact surface 700 of the rocker arm 1 runs down from the rising surface 501 of the cam and rests on its waste surface 502, piston 180 and body 130 are caused by the oil pressure and the force of the adjustment spring 210 toward the cylinder bore centerline 1 extended so that the gap or the play between the counter surface 120 of the spacer and the upper face 140 of the valve stem is canceled.

If, on the other hand, the cam contact surface 700 is acted upon by the rising surface 501 of the cam, shorten it the piston 180 and the body 130, which by the adjustment spring 210 to the greatest distance between Counter surface 120 and upper valve stem face have been extended, due to the pressure prevailing in the oil pressure chamber 190, this distance is not, when they are compressed towards the center line 1 of the cylinder.

When the rocker arm 1 swings clockwise, the projection 131 of the body 130 is through the valve stem end face 140 is acted upon by pressure as a counterforce in the direction of the center of curvature P of the projection 131. At the same time, the approach is subject to a frictional force, because its spherical or dome shape

surface the point of contact with the upper face 140 of the valve stem in the clockwise direction Swinging movement of the rocker arm 1 moves. As the sum of these forces as well as those caused by them Side pressure and the rotational movement around the center of curvature P apply an eccentric load on the body 130. The body 130 therefore inclines toward the gap Cb on the wall 1000a. The gap Ca between body 130 and piston 180 is selected smaller than the gap Cb, and the piston 180 inclines (therefore) with the body 130. It slides the dome surface of the spacer 110 on the cylinder bore upper side 1000b around its center of curvature Q, so that it becomes effective and thus the pressure acting on the side of the body 130 almost uniformly on the cylinder bore top 1000b is transmitted. The pressurized body 130 slides together with the piston 180 over the Counter surface 120 (of the pressure element), rests against the inner wall of the cylinder bore and transfers its Side pressure evenly. If the spacer tilts slightly around its center of curvature Q, the upper end of the piston 180 can slide more easily over or on the mating surface 120. Since the Center of curvature Q of the spacer dome surface 100 only slightly from the center of curvature P of the attachment 131 differs and is very close to it, body 130 and piston 180 can then, if that Spacer 110 executes a rotary movement, easily rotate together, with the sliding movement of spacer 110 on the top of the cylinder bore 1000b takes place evenly and without jerks.

The above statements also apply to the movement of the rocker arm 1 in a counterclockwise direction. There-

1 at the body 130 tilts in the opposite direction, while the spacer 110 is assured a similar effect shifted in the opposite direction.

Claims (6)

-r- PATENT CLAIMS 1. A method for producing a rocker arm, characterized in that a plate made of sintered iron alloy is cast onto a lever part made of an aluminum alloy, on the outer surface of the Plate (and the adjacent surface) a thin (protective) layer is formed on the lever part a porous anodic oxide layer is formed, followed by electrolysis in an ammonium thiomolybdate solution, whereby molybdenum sulfide is introduced into the pores (of the anodic oxide layer), and then the thin (protective) layer is removed. 2. The method according to claim 1, characterized in that the plate in a thermoplastic synthetic resin melt is immersed and then cooled so that on the outer surface of the plate (and the adjacent section) a thin (protective) layer is created. 3. The method according to claim 2, characterized in that the thermoplastic synthetic resin made of paraffin and There is polyethylene and that the thin (protective) - layer is stripped off after heating the same. 4. The method according to claim 1, characterized in that the plate forming a cam sliding surface made of sintered iron alloy on the toggle lever part Cast aluminum alloy and in the latter _ ΟΙ a cylinder bore is formed at the same time, that on the outer surface of the plate (and the adjacent section) a thin (protective) layer is formed that a porous anodic oxide layer is generated on the lever part that then by Electrolysis in an ammonium thiomolybdate solution molybdenum sulfide is introduced into the pores that then the thin (protective) layer is removed and that a lash adjuster unit in the cylinder bore for eliminating the gap or play on the upper face of an intake / exhaust valve an internal combustion engine is used. 5. rocker arm, characterized in that it has a Lever part off. Aluminum alloy with a porous anodic oxide layer with molybdenum sulfide in the pores has been introduced, and a cast on the lever part plate that is in sliding contact can be brought with a control cam includes. 6. rocker arm according to claim 5, characterized in that that in a cylinder bore formed in the lever part a lash adjuster to cancel the Space or play is used on the upper end face of an inlet-outlet valve.