Connecting rod for reciprocating internal combustion engine

The present invention relates to mechanical engineering, more particularly to the construction of connecting rods and is intended for reciprocating engines and reciprocating compressors.

Connecting rod for the reciprocating internal combustion engine is known («ABτoMθ6HJiBHBie #BHraτeJiH»/ Hop, oβmeϋ peflaκn,HeI M. C. XoBaxa. - MocKBa: «MaπiHHθcτpoeHHe», 1967. - c. 389-400) and intended for reciprocating internal combustion engines. The above mentioned connecting rod includes a small-end part, a stem, a big-end fork part, a big- end cap, and connecting elements. Bolts or pins are used as connecting elements. Bosses with thread are made on the big-end cap. Big-end cap is fastened to the big-end fork part of a rod by means of the bosses, bolts and pins, mentioned above. Large weight and dimensions of the mentioned rod are considered disadvantages of the given construction with regard to the bosses made on the big-end fork part and on big-end cap meant for threaded connection, and big dimensions of a rod lead to increasing the crank case dimensions. Low reliability of threaded connection under changing load should be also considered disadvantage of the construction.

Connecting rod for reciprocating internal combustion engine found in Pat. application No. RU 200111426 is known, including a stem, a small-end part, a big-end fork part, a big-end cap and connecting elements. According to the invention the connecting elements are bolts. The bosses with thread are made on the big-end cap. The big-end cap is fastened to the big-end of a rod by means of the above mentioned bosses and at least by two bolts.

Large weight and dimensions of the mentioned connecting rod are considered disadvantages of the given construction, in connection with necessity of making the big-end fork part and big-end cap bosses meant for the threaded connection and big dimensions of a rod lead to the crank case

dimensions increasing. Low reliability of the threaded connection under changing load should be also considered as disadvantage of the construction.

The most closely related to the invention per technical nature, purpose, results achieved, and chosen to be a prototype is connecting rod described in Patent No. RU 2159875 comprising a stem, a small-end part, a big-end fork part, a big-end cap and connecting elements. The connecting elements of the invention are L-shaped bolts and nuts. The socket for L-shaped bolt is provided with hole for bolt rod and a cavity for a head of a bolt, made in bosses of a rod. Cavity is made in shape of base, side walls and rare wall formed by cylindrical surface. Thus, projections are formed, preventing L- shaped bolt from turning.

Rather large weight of the rod is considered disadvantage because of the big-end and big-end cap constructions containing bosses with the socket for L-shaped bolt and a cavity for a nut. Large dimensions of the rod should be also considered disadvantage of the invention because of the big-end fork part and big-end cap bosses containing the socket for L-shaped bolt and a cavity for a nut that leads to widening of the engine crank case.

Besides, such a connecting rod construction has low reliability with regard to the L-shaped bolt and nut which represents the threaded connection which results in low reliability under changing load.

The complicated rod construction related with fixing of the big-end cap on the big-end fork part of a rod by means of L-shaped bolt and a nut, representing the threaded connection, is worth to be mentioned. Rather high manufacturing cost of the connecting rod on account of high labour-consumption of the rod components manufacturing is concerned as disadvantage that is related to the technological operations in manufacturing of the bosses and making holes for threaded connection in them.

The objects put into the basis of the invention are to reduce weight and dimensions, to increase the reliability, simplify the connecting rod

construction and decrease manufacturing cost.

For the accomplishment of the above mentioned objects the connecting rod for reciprocating internal combustion engine containing a small-end part, a stem, a big-end fork part, joined with a big-end cap by means of connecting elements is proposed. According to the invention, the connecting elements are made as integrated threadlike element twisting the big-end fork part of the rod and the big-end cap in which grooves for connecting element winds arranging are made.

Besides the minimal cross-section area of a connecting element is 1 μm , and maximum cross-section area is 1 mm .

In a particular embodiment of the invention a metal tape or a wire is used as the connecting element.

This invention may be variously otherwise embodied with the connecting elements made of a non-metallic high-strength threadlike material. The high-molecular connection is used as a non-metallic high-strength threadlike material.

The composite material developed on the basis of non-metallic fibers and a polymeric matrix can be also used as a non-metallic high-strength material. In one of the preferred embodiments of the invention the small-end part, the stem, and the big-end fork part of a rod are made of two stamped sheet metal pieces fixed together.

The use of the invention enables to reduce the weight of the connecting rod assembly due to using the integral thread-like elements as connecting elements and the grooves made on the big-end cap for the connecting elements winds arranging. This enables to avoid the bosses in the construction of the big-end cap and the big-end fork part of a rod, increasing the construction weight.

In the invention claimed the rod assembly weight is reduced by using a metal tape or a wire as connecting elements and the grooves for the

connecting elements winds arranging are made on the big-end cap and big- end fork part of a rod. This enables to avoid the bosses on the big-end cap and big-end fork part of a rod, increasing the construction weight.

Besides, the present invention enables to increase the connecting rod reliability by using the integral thread-like elements as connecting elements which results in higher reliability under changing load than threaded connections.

According to the invention simplification of the rod construction is provided by connecting the big-end fork part of a rod to the big-end cap by means of the connecting elements made of the integral thread-like elements which have simple construction.

It is worth to be mentioned that use of the present invention enables to decrease the manufacturing cost by labour-consumption lowering during the rod components manufacturing. This is possible due to the absence of technological operations related with the bosses manufacturing and making holes for threaded connection in them.

FIG. 1 - is the perspective view of the connecting rod for reciprocating internal combustion engine;

FIG. 2 - is the side view of the connecting rod for reciprocating internal combustion engine;

FIG. 3 - is the view of the big-end and big-end cap in assembly. The connecting rod for reciprocating internal combustion engine, comprises a small-end part 1, a stem 2, a big-end fork part 3, a big-end cap 5 fixed together by means of connecting elements 4. The connecting elements 4 are made as integrated thread-like element which ties up the big-end fork part 3 and big-end cap 5 in which grooves 6 for the connecting element winds arranging 4 are made, and the rod is made of two pressed sheet metal pieces 7.

The minimal cross-section area of the connecting element is 1 μm ² , and the maximum cross-section area of the connecting element is 1 mm ² . The

connecting elements 4 are made of a metal tape or a wire, for example steel, aluminum or titanic wire. The connecting elements 4 may be made of the non-metallic high-strength thread-like material. The high molecular connection, for example fiberglass, carbon or boron fiber could be used as the non-metallic high-strength thread-like material. A composite material developed on the basis of non-metallic fibers and a polymeric matrix, for example fiberglass, boron plastic, coal plastic could be used as the non- metallic high-strength material.

The small-end part 1, the stem 2, and the big-end fork part 3 are made of two stamped metal sheet pieces fixed together.

Using the connecting elements 4 as the integrated thread-like element, with the cross-section area smaller than 1 μm is economically unsuitable with regard to the high cost of the connecting element production.

On application of the connecting element 4, made as integrated thread- like element with cross-section area greater than 1 mm the rod for reciprocating internal combustion engine weight and dimensions increase but construction reliability characteristics stay permanent.

The most effective use of the connecting elements 4 as an integrated thread-like element is achieved in the above indicated cross-section area range.

The invention is used as follows:

The big-end cap 5 is mounted on the big-end fork part of a rod 3. Then the big-end cap 5 is fixed on the big-end of a rod 3 by reeling up of the connecting elements 4 in the grooves 6. The connecting element winds 4 reel up in the groove 6 closely to each other in correct, not tangled lines, without kinks in such a manner that each wind of the connecting element 4 covers and ties up the big-end fork part of a rod 3 and the big-end cap 5.

The invention claimed enables to reduce the connecting rod weight and to reduce the big-end cap dimensions, and to simplify the connecting rod construction. That enables to reduce the internal engine crank case sizes and

weight and also simplify the manufacturing techniques, to reduce the amount of technological operations for the connection rod manufacturing and accordingly to reduce the manufacturing cost.