RU2348822C2 - Crankshaft-rocker-coupler mechanism - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention is related to machine building, in particular, to mechanisms for transformation of reciprocal motion to rotary motion and may be used, for instance, in internal combustion engines, pumps and compressors. According to invention, mechanism comprises actuator, in particular case, piston hingedly fixed to stem, which is connected in guide and is hingedly fixed to rocker. Every arm of rocker is hingedly connected to couplers, which in its turn are hingedly connected to two synchronously rotating crank shafts. Besides, every end of rocker is connected to appropriate shaft by means of single coupler, and couplers may each move in their plane.

EFFECT: simplification of design, reduction of mass and dimensional parameters and increase of durability and reliability and also in provision of possibility to adjust characteristics of mechanism torque, speed and value of actuator stroke, without change of crankshafts radiuses.

4 cl, 17 dwg

Description

This device relates to mechanical engineering and can be used in internal combustion engines, pumps, compressors and mechanisms for transferring the reciprocating movement of any part to the rotational movement of the crankshafts (cranks) and vice versa, the rotational movement of the crankshafts to the reciprocating movement of or parts with the ability to set parameters for the characteristics of this reciprocating motion and torque characteristics on its shafts without changing the radius of the cranks.

Known crank mechanism used in a piston machine (AS SU No. 1267013, publ. 10/30/1986), which consists of two connecting rods connected to the piston with a single finger, and two crankshafts, each of which is connected with one of the connecting rods, and the shafts are connected to each other using a bevel gear, and the crankshafts and connecting rods are located symmetrically about the axis of the piston.

As a prototype, a two-shaft universal crank-rocker-crank mechanism (patent RU No. 2275519, publ. 2006.04.27) can be adopted, having the ability to adjust the speed and magnitude of the stroke of the working body and torque characteristics on the shafts regardless of the radius of the cranks and consisting of two synchronously rotating crankshafts arranged in parallel and connected to each other by gears with a gear ratio equal to one of the rocker arm, the ends of which are pivotally connected to the connecting rods of the same name two x crankshafts, and a rod fixed with the possibility of movement in the guide, the rod at one end connected to the middle hinge of the rocker arm and the other end connected to the part or piston, while each end of the rocker arm is pivotally connected to the connecting rod neck of one of the crankshafts a pair of connecting rods in such a way that a pair of connecting rods connected to one of the crankshafts is located by a crosshair to a pair of connecting rods connected to another crankshaft.

The disadvantages of the known mechanism are the complexity and cumbersome design and increased wear of the rod and the guide due to the complexity of installation and fastening in this design of the guide rod with a minimum distance to the middle hinge of the rocker arm to provide a minimum shoulder when exposed to maximum force directed perpendicular to the axis of the rod resulting from the impact of the connecting rods on the beam, which significantly reduces the durability and reliability of the known mechanism.

The technical result of the claimed device is to simplify the design, reduce weight and size parameters and increase the durability and reliability of the crank-rocker-connecting rod mechanism, with the ability to adjust the characteristics of the torque of the mechanism, speed and magnitude of the stroke of the working body without changing the radius of the cranks.

The specified technical result is achieved due to the fact that the proposed crank-rocker-connecting rod mechanism consists of a working body, in the particular case of a piston, pivotally connected to the rod, which is located in the guide and pivotally connected to the beam. Each rocker arm is pivotally connected to connecting rods, which in turn are pivotally connected to two synchronously rotating crankshafts, which are connected to each other by gears with a gear ratio equal to one. In this case, the beam has a shape that allows you to connect its end with the corresponding shaft by means of one connecting rod, and the connecting rods have the ability to move each in its own plane. The working body and the beam can also be connected by two rods, and the rods are shaped so as to allow the rods to move freely. Crankshafts can be located both parallel and coaxial. With the coaxial arrangement of the crankshafts, they are single-bearing and are interconnected by means of at least one bevel gear, which ensures their counter rotation.

The claimed crank-rocker-connecting rod mechanism (hereinafter KKSHM) is illustrated by the drawings:

Figure 1 shows the kinematic diagram of KKSHM;

Figure 2 shows a bottom view of the kinematic scheme KKShM;

Figure 3 shows the kinematic diagram of the design of the internal combustion engine (hereinafter ICE);

Figure 4 shows the kinematic diagram of the inventive KKShM in ICE when moving the piston in the expansion cycle;

Figure 5 shows the kinematic diagram of the internal combustion engine with the inventive KKShM when moving the piston in the compression cycle;

In Fig. 6, the KKShM kinematic diagram and the forces acting in it during its operation are shown, where P is the gas pressure; φ is the angle of rotation of the shafts, N1, N2 are the transverse forces of equal magnitude;

Figure 7 shows the kinematic diagram of the CABG in the internal combustion engine in the position when the transverse forces are not equal in magnitude;

On Fig depicts the characteristics of the torque on the shafts of the KKShM in the internal combustion engine at various angles α - installation of one crank relative to another (at a pressure of the working gas Rg and the radii of the cranks R, taken equal to unity), where Mkr - torque; A - characteristic at α = 15 °, B - characteristic at α = 30 °, C - characteristic at α = 45 °, D - characteristic at α = 60 °;

Figure 9 shows a graph of the actual value of the torque of the mechanism Mkr from the angle of rotation of the shafts φ when the working gas pressure is applied to the piston for one cycle, where: Mkr is the effective torque; A - effective torque when installing cranks relative to each other at α = 15 °, B - effective torque when installing cranks relative to each other at α = 30 °, C - effective torque when installing cranks relative to each other at α = 45 ° , D is the effective torque when installing the cranks relative to each other at α = 60 °;

Figure 10 shows a graph of the dependence of the movement of the working body on the angle φ of rotation of the shafts, where N is the stroke of the working body, A is the characteristic of the single-shaft system, B is the characteristic of the movement of the working body in the inventive KKShM;

Figure 11 shows the intrinsic characteristics of the transmission torque Mkr mechanisms depending on the angle φ of rotation of the shafts, with gas pressure on the piston, taken equal to unity, and the same radius of the cranks, taken equal to unity, where: A is a characteristic of a single-shaft system, B is a characteristic the claimed KKShM;

On Fig shows a kinematic diagram of KKSHM with two rods, bottom view;

On Fig shows a kinematic diagram of the CABG with the coaxial arrangement of single-bearing crankshafts;

On Fig depicts the kinematic diagram of KKSHM with the coaxial arrangement of single-bearing crankshafts, side view;

On Fig depicts the kinematic diagram of KKSHM with the coaxial arrangement of single-bearing crankshafts, bottom view.

In Fig.16 shows a diagram of the crankshaft in the internal combustion engine with two coaxial single-bearing crankshafts in the compression cycle.

On Fig shows a diagram of the crankshaft in the internal combustion engine with two coaxial single-bearing crankshafts in the expansion cycle.

Declared KKShM has several options:

Option 1 performance KKShM used in the design of ICE.

The proposed mechanism consists of two parallel located crankshafts (cranks) 1 and 2 with gears 3 and 4 mounted on them. Crankshafts 1 and 2 have the ability to synchronously rotate in any direction and are connected via hinges 5 and 6 with rods 7 and 8. Cranks 7 and 8 are in different planes and pivotally connected to the opposite ends of the beam 9. The beam 9 is located between the connecting rods 7 and 8 and is connected to the rod 10 with its middle hinge. The beam 9 has a shape that allows each end to be connected to the corresponding shaft m through one connecting rod, while the connecting rods 7 and 8 have the ability to move each in its own plane. The rod 10 is connected with the working body and is installed in the guide 11 with the possibility of reciprocating movement. As a guide 11, a sleeve, a pair of rollers, or another design that provides reliable support and easy movement of the rod 10 can be used. The rod 10 has a shape that allows the rods 7 and 8 to move freely, can be, as one of the options, made in the form of a fork. As a working body, in this embodiment, a piston 12 is used, which is movably mounted in the cylinder 13. The use of a beam of this shape in the KKShM allows you to place and fix the guide 11, providing a minimum distance to the middle hinge of the beam when the piston 12 is in TDC. With this position of the piston 12, the pressure of the working gas is maximum and maximum value of the transverse forces that have a bending effect on the rod 10.

If the proposed mechanism is used in an internal combustion engine, then it works as follows.

During combustion of the fuel-air mixture, the expanding gases act with a force P on the piston 12, which causes it to move inside the cylinder 13 (see figure 3). The piston 12 pushes the rod 10, which, through the rocker arm 9 and the connecting rods 7 and 8, drives the crankshafts (cranks) 1 and 2 into rotation. When the piston 12 reaches the bottom dead center (hereinafter referred to as BDC), the combustion products are released, after which a new portion of the fuel-air mixture is supplied (see Fig. 4). Next, the rod 10 is affected by the inertia force from the rotating crankshafts 1 and 2, which moves the piston 12 to the TDC position, thereby compressing the fuel-air mixture (see Fig. 5). Next, the cycle repeats.

The characteristic of the torque on crankshafts 1, 2 and the speed of movement of the piston 12 in the forward and reverse directions with a constant radius of the cranks can be different and depend on the installation angle α of one crank relative to another. Also, the characteristics of the torque on crankshafts 1, 2 and the speed of movement of the piston 12 can be set by the geometric dimensions of the connecting rods 7 and 8, the rocker arm 9, the interaxal distance of the shafts 1 and 2, as well as by changing their proportions. Changes in the characteristics of the torque on crankshafts 1, 2 and the speed characteristics of the reciprocating motion of the piston 12 in both forward and reverse directions without changing the radii of the crankshafts 1 and 2 and their given angular velocity can be made by changing the length of the connecting rods 7 and 8. The greater the length of the connecting rods 7 and 8 with unchanged other geometric parameters of the mechanism, the smaller the ratio of the angle of rotation of crankshafts 1 and 2 when the piston moves from BDC to TDC to the rotation angle when moving from TDC to BDC and, accordingly, also b children vary the speed ratio of the piston 12 when moving from BDC to TDC for piston velocity 12 from TDC to BDC. The same regularities obey the ratio of the maximum torques on the shafts in these ranges. The greater the length of the connecting rods, the smaller the ratio of these values and, conversely, the smaller the length of the connecting rods, the greater the ratio of speeds and maximum torques and the minimum length of the connecting rods is limited by the structural ratios of the remaining geometric parameters of the mechanism, ensuring its operability, unimpeded rotation of the shafts 1 and 2 and excluding jamming mechanism.

The torque of the mechanism is determined by the formula: Mkr = M1 + M2, where:

M1 - crankshaft torque 1;

M2 - crankshaft torque 2.

The torque of the shaft 1 is determined by the formula: M1 = T1 × R1, where:

T1 - tangential force of the crankshaft 1;

R1 - radius of the crankshaft (crank) 1.

The torque of the shaft 2 is determined by the formula: M2 = T2 × R2, where:

T2 - tangential force of the crankshaft 2;

R2 - crankshaft radius 2.

The tangential force of the shaft 1 is determined by the formula: T1 = P × Sinγ1 / Cosβ1, where:

P is the pressure of the gases on the piston.

The tangential force of the shaft 2 is determined by the formula: T2 = P × Sinγ2 / Cosβ2, where:

P is the pressure of the gases on the piston.

To find the torque characteristic of this mechanism depending on its geometric dimensions and the angle of the shafts relative to each other, we take P = 1, R1 = R2 = 1, when setting the shafts relative to each other at angles of 15, 30, 45 and 60 °, and we get curves A, B, C and D (see Fig. 8). Substituting the actual value of the working gas pressure for one expansion cycle at a given angle of rotation of the shafts, we obtain the effective torque for the characteristics A, B, C and D. The work during rotational motion is found by the formula:

Where: MKR - torque on the ICE shafts, acting over an angle from 0 to φ2 - the angle by which the shafts rotate when the working gas expands and the piston travels from TDC to BDC.

Work in one cycle of expansion of the working charge is equal to the sum of the torques acting during the rotation of the shafts, during which the expansion of the working gases occurred. From this it follows: the area under the curves will be equal to the perfect work of the actual cycle, then you can find the efficiency of the internal combustion engine, which shows the ratio of the work received to the supplied heat. In the graphs of Fig. 9 we see that the area under the curves A, B, C, D becomes larger when the maximum torque is shifted to the maximum working gas pressure, that is, the work done is increased, and since in all cases the amount of heat supplied is the same, then there is an increase in the efficiency of the internal combustion engine.

Efficiency of ICE = W result / W sub, where:

W received - received work;

Wsupply - summed up heat.

Changing the installation angle α of one crank relative to another allows you to set the maximum MKR - the torque of the mechanical characteristics of the mechanism at the beginning of the expansion of the working gases, which allows more efficient use of the energy of the expanding charge, increase the torque on its shafts, power, efficiency and economy of the internal combustion engine without increasing fuel consumption . In the process of operation of the claimed mechanism on the rod 10, in addition to the longitudinal force P, the transverse forces N1 and N2 act, which are directed counter and perpendicular to the longitudinal axis of the rod 10 (see Fig.6).

In case of asymmetric construction of the mechanism (installation of crankshafts with a shift by any angle relative to each other), an inequality of the transverse forces and a bending force of the rod occurs, which requires increased strength of the rod and, accordingly, an increase in its cross section and its mass, increases the wear of the "rod guide "and significantly reduces the durability and reliability of the mechanism. In order to reduce the bending moment acting on the bar, it is necessary to reduce the shoulder application of the resulting transverse forces. To do this, the guide 11 is installed at a minimum distance to the middle hinge of the rocker arm in the position when the piston is in TDC (see Fig. 7). Due to this arrangement of the guide, the resulting transverse force acts on the rod-guide assembly with a minimum shoulder, which can significantly reduce the load on the assembly and the overall dimensions of this assembly.

This mechanism has the ability to change various parameters, such as increasing the torque without increasing the radius of the cranks, increasing and shifting to the beginning of the rotation angle the maximum value of the intrinsic asymmetric mechanical characteristic of the transmission of torque of the mechanism in the opposite direction of the piston movement, which shows how the torque on the shafts of the mechanism changes when acting on a rod or piston of constant force - P and crank radius - R, taken per unit, depending on the angle φ rotation of the shafts, changing the piston stroke without changing the radius of the cranks (see figure 10), reducing the set values of the acceleration of the piston when changing the direction of movement in the BDC and TDC, respectively, reducing the inertial loads on the parts of the mechanism.

The above parameters can be changed depending on the task, varying the shift of the angle α between the cranks and the geometric dimensions of the rocker arm, connecting rods, the interaxal distance of the shafts and the change in their proportions, which are limited by the specified weight and size parameters of the mechanism and the strength of the materials used.

Option 2 execution KKShM used in the design of ICE

On Fig shows a kinematic scheme KKSHM, similar to the mechanism according to option 1, with the difference that the piston 12 is connected to the beam 9 by two rods 10. This fact also allows the use of one connecting rod per shaft, which also contributes to the achievement of the claimed technical result .

Option 3 design KKShM used in the design of ICE

13-15 show a KKShM kinematic diagram similar to the mechanism of embodiment 1, with the difference that the single-bearing crankshafts 1 and 2 are aligned and connected by at least one bevel gear that provides counter-rotation of the shafts. In Fig.16-17 depicted KKSHM ICE with two coaxial single-bearing crankshafts. The coaxial arrangement of the shafts allows to reduce the length of the connecting rods and, accordingly, to reduce the weight and size characteristics of the internal combustion engine with the same technical characteristics. The magnitude of the piston stroke in the KKShM with parallel shafts depends on the radius of the crankshafts and their center distance, and the coaxial arrangement of the shafts allows the piston stroke to be made dependent only on the magnitude of the radius of the crankshafts and the angle of installation between the shafts. Moreover, to increase the torque by increasing the radius of the cranks of the coaxial shafts, we slightly increase the piston stroke and its linear speed.

Option 4 of the KKShM version used in the design of the pump

The design of the pump is similar to the design of the ICE described in option 1. During the operation of this pump, the crankshafts 1 and 2 are rotated, for example, by an electric motor or other device. Rotating crankshafts 1 and 2 by means of connecting rods, rocker arm and rod communicate reciprocating motion to piston 12 inside cylinder 13. Piston 12 affects the pumped liquid or gas and sets it in motion.

Option 5 execution KKShM, use in the design of the mechanism with reciprocating movement of the working body

The design of this mechanism is similar to the design described in option 1, with the difference that a tool is used as a working body to perform a specific operation. As a working body, the following can be used: die cutter, needle, saw, cutter, printing matrix, manipulator and other tools. In the process of this mechanism, the crankshafts 1 and 2 are driven into rotation, for example, by an electric motor or other device. Rotating shafts 1 and 2 by means of connecting rods, rocker and rod inform the tool reciprocating motion.

Thus, the described structures make it possible to apply one connecting rod to each shaft and install a guide with a minimum distance to the middle hinge of the rocker arm when the working body is in the TDC, simplify the design, reduce overall dimensions and increase the durability and reliability of the crank-beam-crank mechanism having the ability to adjust the stroke characteristics of the working body and the characteristics of the torque on its shafts by changing the geometric proportions of the mechanism without changing the radius o cranks.

Claims (4)

1. Crank-yoke-connecting rod mechanism, consisting of a working body pivotally connected to the rod, which is located in the guide and pivotally connected to the beam, each arm of which is pivotally connected to the connecting rods, in turn, pivotally connected to two synchronously rotating crankshafts, gears connected to each other with a gear ratio equal to one, characterized in that the beam has a shape that allows its end to be connected to the corresponding shaft by means of one connecting rod, while the connecting rods have ozhnost move each in its own plane. 2. The mechanism according to claim 1, characterized in that the working body and the beam are connected by two rods. 3. The mechanism according to claim 1, characterized in that the shafts are coaxial and interconnected by at least one bevel gear, providing counter-rotation of the shafts. 4. The mechanism according to claim 1, characterized in that the rod has a shape that allows the rods to move freely.

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