RU2751470C1 - Composite crankshaft - Google Patents

Abstract

FIELD: mechanical engineering.SUBSTANCE: invention relates to the field of mechanical engineering, and more specifically to the crank mechanisms of internal combustion engines of automotive engines. The composite crankshaft includes separately manufactured support links. Each support link is pre-fabricated separately and is a single element. The supporting links consist of the main journals and two cheeks located in two parallel planes perpendicular to the axis of the main journal. On the ends of each cheek, grooves are made for installing a separately manufactured connecting rod link in them. The outermost support links - front and rear - also represent one-piece, single elements. The front support link includes a support journal, on the left of which, perpendicular to its axis, there is a cheek with a groove on its end, and on the right, an end for installing the gears of the drive of engine mechanisms. The rear support link includes a main journal, on the right of which the cheek is located perpendicular to its axis, and on the left is a flange for installing a flywheel. A groove is also made at the end of the cheek piece for installing the connecting rod journal. The assembly of the shaft is carried out directly during the general assembly of the engine. One of the advantages of the composite crankshaft of the proposed design is that it can be assembled on engines with a different number of cylinders by changing the number of support links. The connecting rod journals in the grooves on the ends of the cheeks are installed and fixed with a cover and two bolts through a set of adjustable liners. This design allows, if necessary, to adjust the piston stroke (increase or decrease).EFFECT: increasing maintainability in the event of failure of individual connecting rod or main journals, reducing the number of operations (in increasing productivity) when removing the connecting rod-piston group from the block and installing it back into the block, versatility (adaptability) of the proposed design of the crankshaft for engines with different numbers of cylinders, as well as expansion of the field of application, as well as the possibility of changing the compression ratio in the combustion chamber of automotive engines.2 cl, 10 dwg

Description

The invention relates to the field of mechanical engineering, and more specifically to the crank mechanisms of internal combustion engines of automotive engines.

Known compound crankshaft of an internal combustion engine [1], which contains cheeks with through cylindrical holes connecting rod and main journals. The main journals with their ends are rigidly (with an interference fit) installed in the through cylindrical holes of the cheeks and have segmental recesses at their ends. The connecting rod neck is made separately from the cheeks and pressed into the cheek holes. For a given crankshaft, the moment that tends to turn the cheek relative to the main journal is perceived by the friction moment at the site of the journal landing in the hole. An analysis of the design of the crankshaft of this design shows its low reliability, since when assembling the mates, the connecting rod journal - the cheek hole, the cheek hole - the main journal used an interference fit, which is unreliable. An interference fit itself is not stable, since its reliability depends on the assembly method, the roughness of the mating surfaces, and the temperature of the mating parts. Since the crankshaft operates under conditions of large dynamic alternating loads and vibrations, with such a design of the crankshaft, it will have low reliability and resource. This is the main disadvantage of the crankshaft of this design.

The closest in technical essence to the proposed invention is the crankshaft [2], which contains interconnected main and connecting rod journals with the corresponding half-blades. In order to simplify the technology, the crankshaft elements are connected to each other by welding. Although the object of the invention is to simplify the manufacturing process of the crankshaft, upon careful analysis of the crankshaft of this design, there will be no actual simplification of the manufacturing process for the following reasons. The crankshaft of this design consists of a large number of elements, and each element must be manufactured separately, using a separate technology. That is, the manufacture of a crankshaft must be considered as a whole, and not only as a technological process of assembly by welding, therefore the manufacturing process is not simplified, but on the contrary, becomes more complicated. The crankshaft is a product of high accuracy in terms of the relative angular position of the connecting rod and main journals and other geometric parameters. The disadvantage of the welding process is that due to overheating of the welding seams and the material of the part, the product as a whole is deformed, which leads to large errors in the geometric parameters of the crankshaft, which consists of a large number of elements and is assembled by welding. In addition, it is known that welded joints do not work well under vibration conditions, and the crankshaft undergoes alternating loads and vibrations during operation. Therefore, for crankshafts made using this technology, reliability and durability will be very low, this is a big drawback.

Thus, the known designs of composite crankshafts have significant drawbacks both from the point of view of simplifying their manufacturing technology and from the point of view of applicability in internal combustion engines. They are structurally complex and consist of a large number of separately manufactured elements. The use of such technological processes as welding and pressing during assembly significantly reduces their reliability and service life.

The purpose of the invention is to improve maintainability in the event of failure of individual connecting rod or main journals, in reducing the number of operations (in increasing productivity) when removing the connecting rod-piston group from the block and installing it back into the block, the versatility (adaptability) of the proposed design of the crankshaft for various engines the number of cylinders, that is, the expansion of the field of application, as well as the possibility of changing the compression ratio in the combustion chamber of automotive engines.

FIG. 1 (front view) shows a general view of the assembled crankshaft of the proposed design, where the following designations are adopted: a, b, c, d, e - respectively supporting links; f, g, h, i - connecting rod links, respectively; 1, 2, 3, 4, 5 - root necks, respectively; 6, 7, 8, 9 - respectively connecting rod journals; 10 - cheek of the support link a; 11 - left cheek of the support link b; 12 - the right cheek of the support link b; 13 - the left cheek of the support link in; 14 - the right cheek of the support link; 15 - left cheek of the support link g; 16 - right cheek of the support link g; 17 - cheek support link d; 18 - end for installation of drive gears of engine mechanisms; 19 - flange for flywheel installation; 20 - pins for locating the flywheel relative to the flange;

FIG. 2 (front view) a fragment of the support link a, the designations are the same as in FIG. one.

FIG. 3 (front view) a fragment of the support link b, the designations are the same as in Fig. one.

FIG. 4 (front view) a fragment of the support link c, the designations are the same as in FIG. one.

FIG. 5 (front view) a fragment of the support link d, the designations are the same as in FIG. one.

FIG. 6 (front view) a fragment of the support link d, the designations are the same as in FIG. one.

FIG. 7 (front view) shows the crank pin 6 between the cheeks 10 and 11 of FIG. one.

FIG. 8 (side view) shows the crank pin 6 between the cheeks 10 and 11 of FIG. one.

FIG. 9 (front view) shows the support links a and b connected by a connecting rod 6. The designations are the same as in Fig. 1.

FIG. 10 (side view) shows the conjugation of the crankpin 6 with the cheek 10 of the support link a, where the following designations are adopted: 21 - adjusting liners; 22 - cheek cover 10; 23 - bolts for fastening the cover to the cheek 10. The rest of the designations are the same as in FIG. one.

The essence of the invention lies in the fact that the composite crankshaft includes separately manufactured support links a, b, c, d and e (respectively, Fig. 1, 2, 3, 4, 5 and 6). Each support link is pre-fabricated separately and is a one-piece piece. Support links b, c and d consist of a root neck and two cheeks located in two parallel planes perpendicular to the axis of the root neck. The plane of symmetry of the cheeks passes through the axis of the radical neck. On the ends of each cheek, grooves are made for installing in them a separately manufactured connecting rod link of FIG. 10. Extreme support links front - d and rear - and also represent one-piece made separate elements. The front support link - d includes a support neck 5, on the left of which, perpendicular to its axis, there is a cheek 17 with a groove on its end, and on the right, an end 18 for installing the gears of the drive of the engine mechanisms. The rear support link - a includes the main neck 1, on the right of which the cheek 10 is located perpendicular to its axis, and on the left is the flange 19 for installing the flywheel. At the end of the cheek 10, a groove is also made for installing the connecting rod journal. Two pins 20 on flange 19 serve to locate the flywheel relative to the crankshaft flange. The design feature of the composite crankshaft of the proposed design is that it is assembled directly during the general assembly of the engine.

Figure 1 shows a composite crankshaft using the example of a four-cylinder four-stroke engine. One of the advantages of the composite crankshaft of the proposed design is that it can be assembled on engines with a different number of cylinders by changing the number of support links. The front and rear support links will in any case exist for any number of cylinders. Figures 9 and 10 explain the design of installing the connecting rod journal 6 into the grooves on the ends of the cheeks 10 and 11. The connecting rod journal 6 in the grooves on the ends of the cheeks 10 and 11 is installed and fixed not directly by the cover 22 and two bolts 23, but through a set of adjustable washers 21. Such the design allows, if necessary, to adjust the piston stroke (increase or decrease). Changing the piston stroke may be required when installing the crankshaft assembly on multi-fuel engines. When installing washers 21 (Fig. 10) from the bottom side, as shown in Fig. 10, the piston stroke is reduced, thereby reducing the compression ratio in the combustion chamber. When installing liners 21 from the upper side, the piston stroke increases, thereby increasing the compression ratio in the combustion chamber. During operation, the parts of the cylinder-piston group wear out, which leads to a decrease in compression in the combustion chamber and a decrease in the efficiency of the engine. The use of shims in the proposed design of the crankshaft makes it possible to increase the piston stroke, thereby increasing the compression ratio and compensating for the decrease in compression and increasing the efficiency of the engine.

The assembly and installation of the proposed prefabricated crankshaft into the engine block (for example, a four-cylinder and four-stroke internal combustion engine) is carried out in the following technological sequence.

Dowel pins 20 (Fig. 1) are pressed into the crankshaft flange 19. A gear or a block of gears is heated in oil to a temperature of 110 ... 130 ° C and pressed onto the front end 18 of the support link d until it stops.

The correctness of completing the crankshaft with liners is checked: they must be selected in accordance with the markings applied to the crankshaft site, or in accordance with the repair size of the crankshaft journals. The nuts are unscrewed and the caps of the main bearings are removed, the beds of the block of the surface of the caps are lubricated and the liners are installed in accordance with the serial number of the main bearing and the conditional marking of the upper and lower shells. The liners installed in the block bed have a lubrication hole that must match the oil channel in the block, and there are no holes in the depressions installed in the cover. Swinging the liners in the sockets or hanging them on the fixing sleeves is not allowed.

Then the covers are put in place and tightened with nuts to the nominal tightening torque. The internal size of the liners is measured with an indicator bore gauge: it must be equal to the nominal size of the installed liners. The normal clearance between the journal of the shaft and the bushings is determined as the difference between the measured bore of the bushings, tightened in the block, and the journal of the shaft.

Then the covers are removed, the fit of the liners to the block bed and the cover is checked.

The design feature of the crankshaft of the proposed design is that the crankshaft is assembled directly in the engine block, and not as a separate unit (separate crankshaft) in known designs.

Stage 1. Lubricate the liners and journals of the crankshaft bearing links with engine oil. Install the crankshaft support links and main bearing caps in their places and tighten the nuts with normal force. Check the ease of rotation of each support link separately.

2. stage. Support links b, c and d are exposed with grooves in the cheeks 12, 13, 14, 15, in a vertical plane with the grooves up. Remove from the cheeks 12, 13, 14, 15 cover 22 (Fig. 10), freeing the grooves for installing the connecting rod journals 7 and 8 of the crankshaft. The holes for the oil supply of the connecting rod links are combined with the openings for the oil supply in the cheeks 12 and 13, 14 and 15 of the support links b, c and d. The connecting rod journals 7 and 8 are installed in the corresponding grooves and the bolts 23 are tightened with normal force. The installation locations of the adjusting liners 21 are determined by the type of motor fuel used.

Stage 3. The assembled fragment of the crankshaft is turned 180 ° with the grooves in the cheeks 11 and 16 upward and set in the vertical plane. Also set in a vertical plane with grooves in the cheeks 10 and 17 the support links a and d. Remove the support links d and a from the cheeks 10 and 11, 16 and 17 of the support links d and a cover 22, freeing the grooves for installing the connecting rod pins 6 and 9. Combine the holes for the oil supply connecting rod journals 6 and 7 with holes for oil supply in the cheeks 10 and 11 and 16 and 17 of the support links a and b and d and e. Install the connecting rod journals 6 and 9 in the corresponding grooves and tighten the bolts 23 with normal force.

In this case, depending on the need to increase or decrease the piston stroke, liners 21 are installed either on the upper or lower side of the connecting rod link. The inserts have holes.

Check the tightening torque of the threaded connections of the covers of the supporting and connecting rod links of the crankshaft. Check the ease of rotation of the crankshaft.

The shaft should rotate easily by hand by the pin 20 on the crankshaft flange 19.

This completes the assembly and installation of the proposed crankshaft using the example of a four-cylinder four-stroke engine; further assembly of the engine is carried out according to generally accepted technology.

The technical effect of the use of a composite crankshaft of the proposed design lies in the increased manufacturability of the components and replacement during the repair of not the entire crankshaft, but only its failed component, while reducing the amount of ballast work, saving the material of the crankshaft by replacing only the failed component and the ability to adapt the internal combustion engine to different grades of motor fuel by changing the compression ratio in the combustion chamber.

Sources of information

1. Composite crankshaft of an internal combustion engine. RF patent No. 2115036, F16C 3/10, publ. 10.07.1998.

2. Composite crankshaft. Auth. wit. USSR No. 365493, IPC F16 c3 / 10, publ. 01/08/1973, Bul. No. 6.

Claims (3)

1. Composite crankshaft containing interconnected main and connecting rod journals with corresponding half-legs and the elements of which are connected to each other by welding, characterized in that the support links are made together with the main journal and two cheeks located oppositely in parallel planes, the support link , adjacent to the flywheel flange, is made integral with the flange and cheek, and the first support link is made integral with the cheek, the main journal and with the end for installing the gears of the drive of the engine mechanisms, on the ends of the cheeks, which are as far as possible from the crankshaft axis, grooves are made for subsequent installation in them of separately manufactured connecting rod journals and adjusting inserts. 2. A composite crankshaft according to claim 1, characterized in that its assembly is carried out directly during the general assembly of the engine. 3. A composite crankshaft according to claim 1, characterized in that it allows to adjust the piston stroke by selecting the number of adjusting liners, as well as changing their location from the side of the cheek cover or from the side of the groove bottom.

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