RU2228469C2 - Lining of engine crankshaft journal - Google Patents

Abstract

FIELD: transport mechanical engineering; construction of crankshafts of internal combustion engines. SUBSTANCE: proposed lining of engine crankshaft journal includes two engageable inserts which are identical in shape and sizes and are provided with beads over end faces; said inserts tightly adjoin surfaces of shaft journals and have lubricating holes in their center portion. Beads have projections on either side at level of joint which tightly adjoin surfaces of shaft cheeks and have holes for securing them to these cheeks provided with tapped holes. Each two adjacent projections are covered with one metal plate having two holes coaxial relative to holes in projections of inserts with bending ends. Fillets of inserts and chamfers of their inner end edges correspond to sizes of fillets of shaft journals. EFFECT: increased service life of engine; facilitated procedure of engine repair. 1 dwg

Description

The invention relates to transport machinery, in particular to the automotive industry, and can be applied in other industries, for example in tractor manufacturing.

The crankshaft necks wear out unevenly: the main necks become oval, and the connecting rod necks become oval and conical at the same time. The greatest wear on the connecting rod journals is observed from the side facing the axis of rotation of the shaft. These defects are eliminated by grinding the necks on special machines. Four main repair dimensions are used with an interval for connecting rod necks of 0.75 mm, for main necks - 0.5 mm and designate them with the letters P1, P2, P3, P4. Between the main repair dimensions, intermediate (additional) repair sizes are also provided with an interval of 0.25 mm, which are denoted by the letters D1, D2, D3, etc. After grinding, the necks are polished on special machines [1].

The disadvantages of this method of restoring the circumference of the necks are:

1. Grinding reduces the thickness of the neck, which is the most wear-resistant cement layer, and their diameter, thereby reducing their strength and, consequently, the overall service life of the shaft — the main engine part.

2. Grinding and polishing necks require the use of special overall machines, which is possible only in specialized repair plants or workshops. But this is not possible in many agricultural enterprises, associations, cooperatives, etc.

3. It takes a lot of time, electricity and labor to grind and polish the shafts.

The purpose of the invention is to simplify the repair of the crankshaft and extend its service life.

The goal is achieved by using special linings on all shaft shafts made of high-strength wear-resistant steel, the outer surfaces of which serve as the surfaces of the necks, and the inner surfaces are covered with a thin layer of babbitt or a similar less hard alloy to more tightly fit them to the necks and prevent the formation of hardening on the surfaces of the necks.

The drawing shows a diagram of the proposed lining.

The lining of the neck of the crankshaft of the internal combustion engine contains two identical in shape and size interchangeable liners 1 and 2 with collars 3 at the ends, tightly adjacent to the surfaces of the neck of the shaft and having lubrication holes 4 in the middle. The shoulders 3 on both sides of the liners at the level of the connectors have protrusions 5 that fit snugly against the surfaces of the ribs of the shaft cheeks, with holes 6 for screws 8 for attaching them to said cheeks having threaded holes. In this case, for each two adjacent protrusions impose one metal plate 7 with two holes coaxial with the above holes in the protrusions of the liners and with bent ends. And the fillet of the liners and the chamfers of their inner end edges correspond to the size of the fillets of the neck of the shaft.

Before laying the shaft in the main bearings of the engine block, plates are installed on all its necks. At the same time, the inserts are put in the kit, in pairs and only in a normal size. They should fit snugly against the surfaces of the necks, and their protrusions should fit snugly against the surfaces of the ribs of the cheeks. For each two adjacent protrusions, one metal plate 7 with two holes is applied, the liners are fixed to the cheeks with screws 8, under which there are threaded holes on the cheeks, and the ends of the plates are bent up to prevent them from being unscrewed.

The shaft is laid in the block bearings and the piston-rod group is assembled in accordance with the technical conditions for each engine brand.

The working process of the shaft with the linings of the necks is carried out in the same way as the working process of the shaft without the linings. However, at the same time, the entire shock load and friction force are absorbed by the plates, transferring to the necks only the weakened pressure force from shock loads and thereby preserving them from wear and tear.

Each time the engine is repaired, the worn liners and bearings should be replaced with new ones of a normal size, without the use of other sizes.

Comparison of the shaft with the plates of the necks with the shaft without the plates allows you to draw the following conclusions:

1. Currently, the manufacture and repair of the shaft is carried out according to provisions that are inherently opposite: some of them are aimed at hardening the shaft, while others are aimed at weakening it.

2. The use of linings is the simplest and most economical way to resolve existing contradictions. It allows you to save the initial parameters of the necks and cheeks of the shaft, as well as the initial radii of the cranks and the parallelism of the axis of the connecting rod journals to the axes of the main journals throughout the life of the shaft, which is very important for the normal operation of the engine, especially diesel. The preservation of the shapes and sizes of the necks also contributes to the preservation of their strength, and, consequently, to the lengthening of the shaft life. Here the truth lies in the field of sound logic and encourages the adoption of technically logical decisions.

3. The use of covers allows the engine to be repaired even in unpretentious conditions in simple repair shops of agricultural enterprises, which is very important for small settlements located far from large villages and good roads, especially in the vast expanses of the northern regions of the country.

4. The use of plates allows to produce their liners and bearing shells of only one normal size. This greatly simplifies and speeds up both the production of engines and their repairs. Therefore, it is possible and appropriate to apply the linings on all models of newly designed internal combustion engines.

Sources of information

1. Repair of tractors, cars and agricultural machinery. Ed. 2nd, rev. and add. - M .: Kolos, 1973, p. 140-150.

Claims (1)

The lining of the neck of the crankshaft of the internal combustion engine, containing two identical in shape and size interchangeable liners with collars at the ends, tightly adjacent to the surfaces of the shaft necks and having lubricating holes in the middle, collars on both sides of the liners at the level of the connectors have protrusions that are tightly adjacent to the surfaces the shaft cheeks, with screw holes for attaching them to the indicated cheeks having threaded holes, with each two adjacent protrusions impose one metal plate with two holes coaxial with the aforementioned openings in the protrusions of the liners and with curving ends, and the fillet of the liners and the chamfers of their inner end edges correspond to the size of the fillet of the neck of the shaft.