Piston machine mechanism without connecting rods

Abstract

A piston machine mechanism without connecting rods converts reciprocating motion into rotary motion and vice versa. Disposed inside a housing 1 are pairs of opposed cylinder-piston groups 10, 11. The pistons in each pair are coupled to one another by rods 9. The axes of the cylinder-piston groups 10, 11 are perpendicular to one another. Arranged inside the housing 1 is a working shaft 3 with a power takeoff in the middle part thereof. The shaft 3 has an opening 6 which is offset from its axis of rotation and which has rotatably seated therein a crankshaft 4 having at each of its ends elements 12,13 that provide for the external seating of the crankshaft 4 on the working shaft 3 with the aid of bearings 18. Said elements 12, 13 have oppositely arranged journals 15 which are connected via bearings 19 to the rods 9.

Description

[0001] Connecting rodless mechanism of a piston engine

[0002] The invention relates to mechanical engineering, namely to mechanisms for converting reciprocating motion into rotary motion and vice versa, and can be used in internal combustion engines, compressors, pumps, etc.

[0003] A connecting rod-less mechanism with paired eccentrics is known (see Balandin's book, p. 14, fig. Iv). It comprises a crankshaft mounted on bearings in a housing. A paired eccentric with two opposing eccentric sections is mounted on the crankshaft crankshaft using bearings. One of the eccentrics of the paired eccentric is connected by a rod bearing to the piston rods of a pair of opposing cylinder-piston groups lying on the same axis. The other eccentric is similarly connected to the piston rods of a pair of cylinder-piston groups lying on a crossing axis. The use of paired eccentrics not only allows for a significant reduction in the longitudinal dimensions of the mechanism, but also, with a one-piece crankshaft design, ensures constant alignment of the eccentric bearings with the crankshaft journals without the need for an additional connecting shaft.In this mechanism, given that the twin eccentric is mounted on a single crankshaft, its bearings can only be separable plain bearings. This dramatically increases the sliding speed of the rubbing surfaces and friction forces, making this mechanism only effective in low-power engines with short piston strokes and abundant lubrication. Rolling bearings can only be used in this mechanism by cutting the inner crankshaft. Joining the shaft sections together significantly reduces its strength, which is unacceptable.

[0004] A connecting rod-less internal combustion engine mechanism is known, described in patent RU 2 222 704 and chosen by us as a prototype. The mechanism comprises opposing cylinder-piston assemblies, rigidly connected in pairs by piston rods. The pairs of cylinder-piston assemblies and piston rods are arranged crosswise. The drive shaft is mounted on bearings in the housing, with a power take-off in its middle section. The drive shaft has a bore offset from its axis of rotation. The crankshaft is mounted in the bore of the drive shaft on bearings ensuring an internal fit. The crankshaft has two opposing journals located at the ends of the shaft. The journals extend beyond the drive shaft. The crankshaft journals are connected to the piston rods of the cylinder-piston assemblies through bearings. This mechanism has the same problem as the one described above, namely, the bearings on which the solid crankshaft is mounted inside the working shaft can only be separable plain bearings with all the disadvantages inherent in them.

[0005] Thus, the technical result of the invention is the ability to mount the crankshaft on rolling bearings. An additional technical result is the reduction in the dimensions of the connecting rod-less mechanism.

[0006] These technical results are achieved by the fact that the connecting rod-less mechanism, like the prototype, contains opposing cylinder-piston groups connected by piston rods. The axes of the opposing groups are positioned at an angle to each other. The drive shaft is supported by bearings in the housing, with a power take-off in its middle section. The drive shaft has a bore offset from the drive shaft's axis of rotation, in which the crankshaft is mounted for rotation. The crankshaft has two oppositely positioned journals at each end. The journals are connected to the piston rods via bearings. Unlike the prototype, the crankshaft is equipped with elements rigidly connected to the shaft at both ends, and these elements allow the crankshaft to be mounted externally on bearings on the drive shaft. Two oppositely positioned crankshaft journals are formed on these elements.

[0007] The rigid connection of the external fit elements with the crankshaft is ensured by the fit of each element simultaneously on the end of the shaft and on the eccentric projection made on the end of the shaft.

[0008] The invention is illustrated with graphic materials.

[0009] Fig. 1 shows a diagram of the prototype mechanism, in which, for clarity of perception, the second cylinder-piston group is rotated by 90 degrees relative to its actual position. Fig. 2 shows a similar view of the proposed mechanism, to the same scale. (In Figs. 1 and 2, elements common with the prototype are designated by the same numbers). Fig. 3 shows the actual arrangement of the cylinder-piston groups in the proposed mechanism (the axes of cylinder-piston groups 10 and 11 are perpendicular to each other). Fig. 4 shows a general view of the crankshaft with external fit elements at its ends, and Fig. 5 shows a general view and relative positions of the external fit elements. Fig. 6 illustrates the external fit of the crankshaft on the working shaft on rolling bearings. Fig. 7 shows a disassembled connecting rodless mechanism (the housing is not shown in the figure).

[0010] The mechanism of the proposed invention in Fig. 2, like the mechanism of the prototype in Fig. 1, contains a housing 1 in which a working shaft 3 is placed on bearings 2. In the prototype, a crankshaft 4 is seated on plain bearings 5 ​​in an opening 6 inside the working shaft 3 (see Fig. 1). The opening 6 is offset from the axis 001 of the working shaft 3 by a distance e. The crankshaft 4 has two opposite journals 7 at opposite ends of the shaft, articulated through bearings 8 with the rods 9 of the cylinder-piston groups 10 and 11. Moreover, the axes of the cylinder-piston groups in this particular example are perpendicular to each other, as can be seen from Fig. 3. A variant with a larger number of cylinder-piston groups is also possible, but then the angle between them will be determined as 360 degrees divided by the number of pistons. In Fig. 1 and 2, the letters CC1 designate the axes of the crankshaft 4, and the letters DD1 designate the axes of the journals of the crankshaft 4.

[0011] In the proposed mechanism in Fig. 2, the crankshaft 4 also passes through an opening 6 in the working shaft 3, offset by the same distance e as in the prototype. However, its fit in this opening is ensured by elements 12 and 13, rigidly fixed at its ends (see Fig. 4). In this particular device, a rigid fit is ensured by the fact that each of the elements 12 and 13 is simultaneously seated on the crankshaft 4 and on eccentric opposite projections 14 made on the ends of the crankshaft 4. Such a fit on two eccentrics offset relative to each other ensures a rigid connection of elements 12 and 13 with the crankshaft 4. In principle, a rigid fit of elements 12 and 13 can also be achieved by another known method, for example, using splines.

[0012] In turn, each of the elements 12 and 13 (see Fig. 5, 6) is made in the form of two cylindrical parts 15 and 16 of different diameters, eccentrically offset relative to each other. The inner surface 17 of part 16 of each of the elements 12 and 13 serves for external fitting on the working shaft 3 by means of rolling bearings 18. The cylindrical parts 15, offset relative to the axis CC1 of the crankshaft 4 in different directions, essentially perform the function of the journals of the crankshaft 4. These journals, as in the prototype, are articulated by means of bearings 19 with the rods 9 of the cylinder-piston groups 10 and 11. Power take-off from the working shaft 3 in this design is ensured by means of a gear 20, seated in the middle part of the shaft. 3. The take-off can also be carried out by means of a belt drive. This design of the mechanism allows the use of a crankshaft 4 seat inside the working shaft 3 on rolling bearings, which is impossible to do in the prototype.Replacing bearings reduces friction losses and allows for an increase in the number of revolutions while maintaining the same service life of the device.

[0013] Let us consider the operation of a connecting rod-less mechanism of a piston machine in engine mode, where the input element is the cylinder-piston groups, into which the working medium is alternately supplied under pressure (hydraulic and pneumatic motors) or the ignition of the air-fuel mixture occurs (internal combustion engine).

[0014] Let's turn to Figures 2 and 3. In the position shown in Figure 2, the pistons of the cylinder-piston group 10 are at the extreme points of the cylinders, i.e., in the "dead zone." When the working medium is supplied to the volume 21 of the cylinder-piston block 11, its pistons with rods 9 move towards the volume 22 in Figure 2. In Figure 3, the arrow shows the actual direction of movement of the rods. Rods 9, due to the eccentric position of the journal 13, through bearings 19 displace the journal, setting the crankshaft 4 in orbital motion. In turn, the orbital motion of shaft 4, due to its eccentric fit relative to the working shaft 3, sets the latter in rotation, i.e., rotates it by a quarter of a turn in one piston stroke cycle. At the same time, the pistons of the cylinder-piston block 10, due to the movement of the crankshaft journal 12 in the bearings 19, leave the “dead zone”, and the supply of the working medium in the cylinder-piston group 10 is carried out into the volume 23 formed between the piston and the cylinder.The processes then repeat as in the previous case. The repetition of these cycles causes continuous rotation of the working shaft 3.

[0015] It should be noted that if the mechanism's input and output are reversed, i.e., if the working shaft 3 is rotated, the pistons of cylinder-piston groups 10 and 11 will sequentially reciprocate within the cylinders, compressing the working fluid. When equipped with the appropriate valves, this mechanism will operate in pump mode.

[0016] With the same piston stroke as the prototype, which is determined by the eccentricity value e, the proposed mechanism has a smaller diametrical dimension because, when the crankshaft is seated on bearings 5 ​​within bore 6, as in the prototype (see Fig. 1), the size of this bore must be increased by the difference between the outer and inner diameters of the bearing, with a corresponding increase in the diameter of the working shaft. In the proposed device, when the crankshaft is seated in bore 6 using bearings 18 externally on working shaft 3, the diameter of bore 6 is comparable to the diameter of crankshaft 4. This allows for a reduction in the diameter of working shaft 3 and the device as a whole. At the same time, the axial dimension increases somewhat due to the elements of the external fit. However, the overall dimensions and weight of the mechanism will be smaller, since they are proportional to the square of the radius and linearly depend on the length.

Claims

Invention formula 1. A connecting rod-less mechanism of a piston machine, comprising opposite cylinder-piston groups, interconnected by rods, the axes of which are located at an angle to each other, a housing in which a working shaft with a power take-off in its middle part is placed on bearings and has an opening offset from the axis of rotation of the working shaft, in which a crankshaft is mounted with the possibility of rotation, having at different ends two oppositely located journals articulated through bearings with the rods, characterized in that the crankshaft is equipped at both ends with elements rigidly connected to the shaft, and these elements ensure an external fit of the crankshaft on the working shaft with the help of bearings, and its two oppositely located journals are made on these elements.

2. A connecting rod-less mechanism according to paragraph 1, characterized in that the rigid connection of the external fit elements with the crankshaft is ensured by the fit of each element on the end of the shaft and on an eccentric projection made on the end of the shaft.

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