DE2929890A1 - IC engine valve tappet - is of light metal or alloy and has wear-resistant coating on rubbing surfaces - Google Patents

Abstract

The IC engine valve tappet takes the form of a cup with cylindrical sides and it is made at least partially of light metal or alloy. Its rubbing surfaces are given a wear-resistant coating, pref. a galvanically deposited layer of Eloxal. (RTM) A wear-resistant plate is bonded to the base. In the case of tappets with a circumferential flange holding a clearance-adjustment shim, this flange, in the form of a ring bonded to the tappet body, and the shim only need be of wear-resistant material.

Description

AUDI NSU AUTO UNION

Ingolstadt, July 18, 1979 IP 1612 Za / L

Tappet for the valve train of an internal combustion engine

The invention relates to a tappet for the valve drive of an internal combustion engine according to the preamble of the main claim .

Known tappets for the valve train of: internal combustion engines are made of cast iron or steel due to the high wear requirements. This results in a relatively high weight the tappet, which is particularly important in the case of internal combustion engines with tendons is disadvantageous because of the high valve accelerations and can lead to malfunctions in the valve train.

The object of the invention is to provide the generic plunger under Maintaining the most cost-effective production possible and sufficient wear resistance to reduce weight.

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This object is achieved according to the invention with the characterizing Features of the main claim solved. As has surprisingly been found / can, such a device according to the invention The tappets withstand the wear requirements within the valve train, with a weight reduction of up to 50% achievable is. The plunger can be made of aluminum or magnesium or an Al-Mg alloy in an extrusion process and with a wear-resistant layer, e.g. B. chrome or molybdenum be covered.

For the shaft of the plunger, however, the application of a diffusing, wear-resistant layer is in accordance with the patent claim more advantageous, as this does not require any post-processing and also meets the wear requirements. The anodizing can be applied by electroplating in a known manner.

Appropriately, the on the cam of the camshaft of the valve train approaching bottom area or bottom of the plunger by a wear-resistant one firmly connected to the rest of the plunger Plate, e.g. B. made of steel or cast iron, formed or covered. As a result, the durability of the plunger is at its most stressed Place ensured, but also still

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a considerable weight saving can be achieved. The plate can be interlocked with the rest of the plunger during the Extrusion or by electron or laser beam welding.

The invention is advantageous on so-called. Pot pestle applicable, which have a circumferential web protruding from the floor and enclosing an adjustment plate. The entire plunger can come out here Made of light metal and anodized on its shaft, while the adjusting plate to be inserted when assembling the valve train is made of steel or cast iron as usual and serves as a friction partner to the cam.

When this pot tappet is pushed away from the camshaft against the force of a valve spring when the valve clearance is set must - so that the adjusting plate can be lifted out and replaced by one with a different thickness - should the Ümfangssteg be designed according to claim 4 expediently. This avoids the circumferential web from being pushed away by means of a picking tool acting on the circumferential web while the pot tappet is being pushed away is deformed and assembly difficulties as well as damage to the shaft (flaking of the anodized layer) and the causes adjacent shaft guide. The wear-resistant layer could e.g. B. be applied by build-up welding.

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However, the peripheral web can be more expedient according to the features of claim 5 be formed. The ring, e.g. B. a steel ring, can be shrunk onto the bottom of the Topfstoßis or be glued on.

Alternatively, however, the pot tappet can also according to the Features of claim 6 be made.

The invention is explained in more detail below on the basis of several exemplary embodiments.
The drawing shows in

Fig. 1 shows a cross section through a plunger according to the invention with an applied to its bottom, wear-resistant plate,

2 shows a cross section through a pot tappet according to the invention with an adjusting plate and

Fig. 3 shows a cross section through a pot tappet according to the invention, the shaft of which by a . wear-resistant sleeve is formed.

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FIG. 1 shows a plunger 2 made of the aluminum alloy Al Zn Mg Cu 0.5 in the extrusion process with a hollow cylindrical shaft 4 and a bottom 6. The shaft 4 is on its outer surface or sliding surface "with a wear-resistant anodized layer. The anodized layer is applied in a known manner by electroplating.

On the bottom 6 of the plunger 2, a wear-resistant plate 8 made of hardened cast steel is applied, which by electron beam welding is firmly connected to the bottom 6. While the plate 8 is in operation within the valve train (not shown) runs against the cam of a camshaft, the shaft 4 serves as a guide for the tappet 2 within the internal combustion engine .

The pot tappet 10 shown in Figure 2 consists of a hollow cylindrical shaft 12 and a bottom 14 together and is made of the aluminum alloy Al Cu Si Mn in the extrusion process manufactured. The sliding surface of the shaft 12 is provided with a galvanically applied, wear-resistant anodized layer .

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The bottom 14 has an annular step 16 on the a ring 18 made of steel projecting over the base 14 in the manner of a circumferential web is attached. The ring 18 can be used during the Extrusion of the Topfstoßis 10 in one operation with pressed will. An adjusting plate 20 made of steel is inserted into the ring 18. The adjusting plate 20 serves on the one hand as Friction partner for the camshaft of the valve train and on the other hand for setting the valve clearance. The ring 18 prevents damage of the plunger 10 by an auxiliary tool acting on the end face of the circumferential web or ring 18 during the valve clearance adjustment or during the replacement of the adjusting plates.

Finally, FIG. 3 shows a pot tappet 22, which consists of a Wear-resistant sleeve 24 made of steel and a base 26 made of the aluminum alloy Al Cu Mg 1 is composed. Within the sleeve 24 is formed in the area of the bottom 26, a groove profile with which the bottom 26 by pressing under high Pressure is positively and frictionally connected. Since the sleeve 24 projects beyond the bottom 26, a circumferential web 30 is also formed, which includes the adjusting plate 32.

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Claims (6)

AUDI NSU AUTO UNION φ "/! 929890 Ingolstadt, July 18, 1979 IP 1612 Za / L Tappet for the valve train of an internal combustion engine Expectations [1.J tappet for the valve train of an internal combustion engine, with a hollow cylindrical shaft and a bottom, thereby characterized in that the plunger (2, 10, 22) is at least partially made of light metal or a light metal alloy is made and covered on its sliding surfaces with a wear-resistant material. 2. plunger according to claim 1, characterized in that net that at least the shaft (4, 12) with an anodized layer is provided. 3. plunger according to claims 1 and 2, characterized in that the bottom (6) with a fixed connected, wear-resistant plate (8) is covered. 0300 * 67/0269 4. plunger according to claim 1 or 2, with a protruding from the bottom ümfangssteg which encloses an adjustment plate, characterized in that the circumferential web is formed from wear-resistant material. · 5. plunger according to claim 4, characterized in that the ümfangssteg by a wear-resistant Ring (18) is formed, which is fixed to the bottom (14) connected is. 6. plunger according to claim 4, characterized in that that the shaft is formed from a wear-resistant sleeve (24) which is fixed to a base (26) made of light metal is connected, and that the circumferential web (30) is formed on the sleeve (24). -3- 030067/0269