DE1476062A1 - Pistons for internal combustion engines - Google Patents

Description

DR. HUGO WILCKEN · DIPLHNG. THOMAS WILCKEN

D - 24 LÜBECK. WIDE STREET 52-54

10 Nov 1969 Cz. / I

Ref .: P 14 76 062.4-13

Inmelder: Hepworth & Grandage Limited, Badford 4, St. John's Work, Yorkshire, England

Pistons for internal combustion engines

The invention relates to a piston for internal combustion engines, consisting from a piston head and a piston skirt with two perpendicular to its diametrically opposite Qleltflächen existing piston pin hubs, each of which has at least two plate-like hubs that nestle against the inside of the piston skirt ι inserts extending between the Qleitflachen are assigned, which are different from the piston material Have coefficients of thermal expansion,

In the known pistons of this type, the control elements are used or the inserts that the radial expansion of the piston skirt along the length of the piston skirt in the case of a piston in operation, preferably a light metal piston, is reduced compared to a piston without control elements. However, here the radial thermal expansion of the piston skirt is along the entire length of the piston skirt is not constant; she ninunt

ο in the direction of the open end of the piston skirt or the piston

apron off. This has the consequence that the piston skirt at the

i ^ manufacture crowned must be made in order to achieve the differing

ω chen to compensate for thermal expansion during operation. Die-crowned © · »Machining the piston skirt, however, leads to an expensive

9 Lübeck (0451) 7 58 88, private: Dr. H. Wildten, Curan (04505) 210 · DipL-Ing. Th. Wildten, Lübeck! 0451) 2 51 59 Bank ι Commerzbank AG, FiI. Lübeck, account no. 39 0187 Posischeck: Hamburg 1381 1?

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th manufacture of the piston.

The object of the invention is to create a piston with control elements or inserts for internal combustion engines, wherein the piston skirt extends along its extension viewed in the longitudinal direction of the piston, in particular along the sliding surfaces under the influence of V / arm expands radially evenly in magnitude.

The solution to the problem is that in the piston mentioned at the beginning, each piston pin hub of the shaft is closed Inserts, a different amount of thermal expansion among each other and arranged in a known manner at different heights on the piston skirt with respect to the piston longitudinal axis are. An advantageous embodiment of the invention consists in that the furthest away from the piston head, with the piston skirt connected with inserts made of a metal a higher coefficient of expansion than the metal inserts closest to the piston head, with all inserts have a lower coefficient of expansion compared to the piston material.

With this solution it is achieved that the piston skirt is at The amount of heating along its entire length extends evenly in the radial direction. This is how it is It is no longer necessary to make the piston sliding surfaces spherical, but they can be made exactly straight. A The advantage of this is the cheaper production of the piston. Another advantage is that there is no less installation clearance. Such material is advantageously chosen for the inserts or this material is shaped in such a way that the inserts in addition

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Samraenarbeit with the material of the piston skirt an elongation

of the shaft in the radial direction, which is approximately the radial Expansion of the cylinder belonging to the piston corresponds to when the internal combustion engine is started or is in operation. As a result, the clearance between piston and cylinder is both in the cal constant or almost constant, as well as when the machine is warm constant, which is why the piston skirt has a tight installation clearance can be produced. The tight installation clearance leads to the further advantage that the rattling noises of the working piston in cylinders are reduced, which makes the machine run more smoothly is improved and the service life of the piston and cylinder is significantly extended in terms of wear.

For a better understanding of the invention, reference is now made to / Snlie-

from the following drawings. Show it:

1 shows a longitudinal section through a light metal piston according to an embodiment of the invention,

Fig. 2 is a cross-section along the line A-A of Fig. 1

Fig. 3 is a longitudinal sectional view of a piston according to a second embodiment of the invention _r e,

FIG. 4 shows a cross section along the line B-B in FIG. 3.

5 shows a longitudinal section through a piston according to a third embodiment of the invention,

Fig. 6 shows a cross section along the line C-C in Fig. 5,

7 shows a longitudinal section through a piston according to a fourth embodiment of the invention,

Fig. 8 shows a cross section along the line D-D in Fig. 7,

Figure 9 is perspective views of two modified and ten types of inserts.

Referring to Figures 1 and 2, there is shown a piston cast from, for example, an aluminum or magnesium alloy a crown 1, a pipe part 2 carrying the piston ring,

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a pair of diametrically opposite pin projections 3, which are carried by the piston crown 1 via webs 4 and from a piston skirt 5, which is provided with diametrically opposed pressure surfaces 6 which are at an angle of 90 to the axis of the pin projections 3 are arranged.

A pair of inserts 7 and 8 are molded into each pin boss 3, in each case above and below the axis of the pin projections, with their contiguous edges spatially are arranged separated from each other and the opposite outer ends of each insert against a rib or Abut shoulder 9, which forms one piece with the interior of the apron 5 in the area of a pressure surface 6. The inserts 7 and S are made by stamping or otherwise to assume the shape shown, with the lower insert consists of a metal that has a lower thermal value Has expansion coefficients than that of the piston alloy and that of the upper insert. .7 has a lower thermal Coefficient of expansion as the metal of the lower insert

When the piston is working, the heat generated causes the piston to expand radially to a greater extent than the cylinder, in which he runs back and forth. However, this radial expansion is not constant along the longitudinal axis of the piston, but rather increases towards the open end of the skirt according to changes in the thickness or other dimensions of the piston skirt from, and / or also according to changes in working temperatures along the length of the piston. By the lower insert 8 from a material with a higher coefficient of expansion than

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that of the metal of the upper insert 7 is made to compensate for the controlling effect of the lower insert achieved on the radial extent of the pressure surfaces of the apron.

In the embodiment shown in FIGS. 3 and 4, the inserts 7 and 8 are similar to those of FIGS. 1 and 2 and are molded into a piston and are generally described in British Patents 946,733 and 616,820. In this embodiment, the crown 1 and the supporting part 2 are partially separated from the skirt 5 by a pair of transverse and M part of the circumferential slots 10 lying on either side of the axis of the pin projections 3. Each end of each slot 10 ends above and adjacent to a pin projection 3 and is provided with an inclined slot 11, which extends downwards towards the skirt 5 in the direction of the associated pin projection 3.

Through the slots 10 and 11, the heat transfer from the crown 1 to the skirt 5 during normal operation of the piston greatly diminished, and the resulting expansion the piston skirt 5 is correspondingly reduced. This construction enables the application of a reduced cold Clearance between the piston and the associated cylinder.

FIGS. 5 and 6 show an embodiment in which the two Inserts, instead of being spatially separated from one another with respect to the longitudinal axis of the piston, are mutually exclusive abut along their adjoining edges, and the ribs 9 are cast around the outer ends of the inserts and embrace them, as can be clearly seen in FIG. Also in this one Embodiment are the crown 1 and the supporting ring groove part

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2 partially from the apron 5 alone by a pair transversely extending slots 10 separately.

In Figs. 7 and 8, a differently shaped lower insert 8 is shown, with extensions 8a on its opposite Ends is provided. The piston itself, on the other hand, is basically the same as that in Figs.

Alternatively, the inserts shown in FIGS. 1 to 8 can be used 7 and 8 can be designed as shown in FIGS. 9 and 10

By choosing materials for the missions, which have different coefficients of thermal expansion, it has become possible to hate the changes in expansion to compensate for the length of the piston and thereby a more precise control of the skirt expansion and especially the radial one To achieve expansion of the pressure areas. In particular, it is now possible to use a piston with a minimum of working cycle to build, which at working and resting temperatures as well as over is maintained over the entire temperature range of the machine. It is also possible to make the apron simpler, which e.g. can be sanded generally parallel along its length.

It goes without saying that various modifications can be made to the subject matter of the invention. For example the different expansion dimensions of the upper and lower inserts, instead of or in addition to the measure that ' Manufacture inserts from materials with different coefficients of expansion by shaping the inserts appropriately can be achieved and / or by making the stakes different. thick and / or by placing the lower inserts _ 7 _

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be perforated or by any other way the extent or the amount of control effect on the lower Stakes is reduced.

In addition, the upper and / or lower insert of each pair can not only be in engagement with its associated pin projection his or be embedded in it, but it can also be arranged separately from it in the longitudinal direction. E.g. everyone can lower insert are completely below the pin projection, closer to the open end of the apron, and when you have it., if desired, an additional insert or inserts can be provided underneath each of the aforementioned inserts.

The inserts can be embedded in the piston skirt at their ends or adjacent to their ends, instead of resting against the ribs or the like, which are integral with the skirt. Although the inserts have been shown here as parts extending generally transversely with respect to the piston longitudinal axis, one or more inserts can be arranged at a small angle to the piston axis or to one another. %

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Claims (6)

D - 24 LÜBECK. WIDE STREET S2-S4 Nov 10 1969 C z / L Ae .: P H 7b 062.4-13 Applicant: Hepworth & Grandage Limited, Badford 4, St.Johns Work, Yorkshire, England Claims 1. Pistons for internal combustion engines, consisting of a piston ^ head and a piston skirt with two perpendicular to its diametrically opposed sliding surfaces Follow bolt hubs with at least two each on the inside Assigned to the piston skirt nestling, plate-like, extending between the sliding surfaces inserts which have a coefficient of thermal expansion different from that of the piston material, characterized in that that the inserts (7, 8) assigned to each piston pin hub (3) of the shaft (5) have a different degree of thermal expansion have and with respect to the piston longitudinal axis in a known manner at different heights on Piston skirt are arranged. 2. Piston according to claim 1, characterized in that the farthest from the piston head (1) lying with the Piston skirt (5) connected inserts (8,8a) from one Q consist of metal with a higher coefficient of expansion co than the metal inserts closest to the piston head t *> (7), whereby all inserts have a ° "have a lower coefficient of expansion. ^ S LOiMdc (0451) 75888, private: Dr. H. Wilden, Curau (04505) 210 ■ Dipl.-Ing. Th. Wlldcen, LGbedt (0451) 251 59 Bank. Commerzbank A.G. , FiI. Lübeck, account no. 37 0187 Post check: Hamburg 1381 19 ¹ ; egg. : ■ »-nteflagen (* γ ⁺ 7 § 1 Paragraph 2 No. 1 Sn» r - - i-xj-.jae. V.4.o "jsv>. H76062 3. Piston according to claims 1 and 2, characterized in that the diametrically opposed inserts (7 or 8) of the piston skirt (5) are arranged in a known V / eise in the same piston cross-sectional plane and the same Have coefficients of thermal expansion. 4. Piston according to claims 1 to 3, characterized in that each piston pin hub (3) is assigned a pair of inserts is, which engages in the bolt hub or is arranged adjacent to this, wherein the one insert part (7) above ^ and the other insert part '(8) below the piston pin hub axis is provided. * 5. A piston according to claims 1 to 4, characterized in that _r that the insert located below the Boljsennabenachee * (8) at their ends with E: hte ^ $ eWft | eft (8a) verse advantage sense, _c tj * s> in the near de * unteVerv * Ko ^ eiliiiihÄftend ^ s range,. « _# y \ V 6. Piston after, the An · ^ rUdJi, eH »1 jbifc, 5.» d * 4ureh g% ke.nnzeicb ^ ie ^ i ** that the ends of the Efhsäts «<7> 3) 1l | i bo) t $ pnt & t · WIb * i * area of the (ileitflachen (6) with Schiilterifc W ^ r Rifqptfea (3) - ·. _{Λ of} the shaft (5) are engaged or in the reeds ^ dingebetv · ^ * are tet. ^: '' *. * ■ '■>. ' 009813/0314 ORIGINAL BATHROOM.