Opposed crank-connecting rod mechanism

Abstract

The invention relates to the field of mechanical engineering, and more particularly to a mechanism for transmitting motion. An opposed crank-connecting rod mechanism comprises a cylinder with a piston and a rod. The piston is rigidly attached to the forked rod. The arms of the forked rod are connected to coaxial shafts that are capable of compound translational and rotational motion. Said coaxial shafts each have two axially spaced apart, diametrically oppositely oriented crank arms. The centre crank arms are connected by a crankpin. A connecting rod having a pivot pin inside a housing is oppositely arranged on the other side from the working cylinder in relation to the axis of a main shaft. The axis of the connecting rod at top dead centre and at bottom dead centre lies on a continuation of the straight line of the axis of the cylinder. Crank arms on the main shaft are connected by pivot pins to the crank arms on the coaxial shafts, and the length of the connecting rod is more than twice the crank radius of the main shaft. The result is the mutual conversion of rotational and rotational-translational motion.

Description

[0001] Opposite crank mechanism

[0002] Field of technology

[0003] The invention relates to the field of mechanical engineering and can be used for the design of double-acting piston machines.

[0004] Prior art

[0005] A crank-connecting rod mechanism is known according to patent RU No. 2613748, comprising a driven link, which can be made in the form of a slider or a rocker arm, a connecting rod pivotally connected to it, and a crank, forming a hinged pair with a second connecting rod, constituting a hinged three-link with a connecting rod and a rocker arm-connecting rod, having a hinged support, characterized in that the support in it has the ability to move along a guide, the trajectory of which is within a zone determined by circles, the centers of which coincide with the axis of rotation of the crank, wherein the radius of one is equal to the length of the rocker arm-connecting rod minus the difference in the lengths of the second connecting rod and the crank, and the radius of the second is equal to the length of the rocker arm-connecting rod plus the difference in the lengths of the second connecting rod and the crank.In this mechanism, the trajectory of the rocker arm-connecting rod guide support is made in the shape of a circle, the radius of which is equal to the length of the rocker arm-connecting rod, while its center is located in the zone determined by circles, the radius of one of which is equal to the sum of the lengths of the second connecting rod and the crank, and the radius of the second is their difference.

[0006] This solution provides for the expansion of the technical capabilities of the known crank mechanism, which consists in increasing the range of variation of the value of the joint movement of the connecting rod-driven link and, as a consequence, the range of variation of its movement speed, as well as the possibility of changing the speed of movement of the joint of the connecting rod-driven link over time. A crank mechanism with an offset crank journal is known according to patent RU No. 2597703, comprising a working cylinder, a piston with a piston pin, a connecting rod and a crankshaft crank pivotally connected to each other, characterized in that the axis of the crank head is rigidly connected to the crank, is offset from the piston axis and the crank symmetry axis by an angle equal to 10°. The technical result of this invention is to increase the resource of the crank mechanism, the torque on the engine shaft and to simplify the design of the mechanism.

[0007] The disadvantages of all known crank mechanisms, which are eliminated by the declared technical solution, are:

[0008] - cannot be used in piston machines with double-acting cylinders;

[0009] - the occurrence of a lateral force exerted by the piston on the cylinder liner, leading to elliptical wear of trunk engines;

[0010] - insufficient load capacity, leading in particular to the impossibility of increasing the boost pressure in diesel engines;

[0011] - insufficient mechanical efficiency, limited by the crank radius.

[0012] - impossibility of eliminating the reactive overturning moment;

[0013] - the need to balance engines to counteract shock and vibration loads;

[0014] - the impossibility of realizing the moments of a pair of forces.

[0015] Disclosure of invention

[0016] The objective of the invention is to create an opposite crank mechanism in which the above-mentioned disadvantages are eliminated. The essence of the invention is expressed in the following set of essential features, sufficient to obtain the technical result provided by the invention.

[0017] According to the invention, an opposed crank-connecting rod mechanism comprising a cylinder with a piston and a rod is distinguished in that the piston is rigidly fixed with a forked rod, the horns of the forked rod are connected to coaxial axes capable of performing a complex translational-rotational motion, the coaxial axes have two diametrically oppositely directed cranks spaced apart in axial directions, wherein the middle cranks are connected by a crank pin, the connecting rod with the swing axis in the housing is opposedly located in the direction opposite to the working cylinder from the main shaft axis, the connecting rod axis at the top dead center and bottom dead center is located on the continuation of the straight line of the cylinder axis, the cranks of the main shaft are connected by axes of rotation to the cranks of the coaxial axes, and the length of the connecting rod exceeds the radius of the main shaft crank by more than two times.

[0018] The applicant has not identified any sources containing information on technical solutions whose set of features coincides with the set of distinctive features of the declared technical solution, which allows us to conclude that it meets the “novelty” (N) condition.

[0019] The claimed set of essential features of the invention ensures the achievement of a technical result, which consists in the mutual transformation of the rotary and reciprocating motion required to implement working processes in piston machines with double-acting cylinders, in which the piston with the rod is one link having one generalized coordinate corresponding to the translational motion. This is achieved due to the opposite arrangement of the connecting rod with the swing axis in the housing in the direction opposite to the working cylinder from the main shaft axis, the formation of moments of the pair of forces and the formation of a self-aligning mechanism, leading to the balancing of the mechanism as a whole, as well as to an increase in load-bearing capacity due to the supports on the housing of the connecting rod axis and the support journals of the main shaft.

[0020] This technical result is not a consequence of known properties, manifested by a number of separately known features from other technical objects, such as a support bed, but is a property of only the entire set of essential features set out in the independent claim of the formula of the claimed invention. This allows the claimed invention to be recognized as corresponding to the condition of "inventive step" (IS).

[0021] Best use of the invention

[0022] The essence of the claimed technical solution is explained by a drawing, which shows a kinematic diagram of the claimed mechanism.

[0023] The opposed crank mechanism structurally consists of a piston 1 rigidly fixed with a forked rod 2 passing through the seal of the cylinder cover 3. The horns 4 and 5 of the forked rod 2 are fixed with the outer rings of two bearings installed parallel to the axis of the main shaft. The inner rings of the bearings in the axial direction have two diametrically opposite cranks 6 and 7, which together with the inner rings of the bearings form one solid-cast part. The cranks 7 installed in the middle part of the mechanism are connected by a crank journal 8. The connecting rod 9 is installed opposite to the swing axis 10 in the housing of the piston machine equipped with the mechanism of the claimed design. The axis of the connecting rod 9 at the top dead center and the bottom dead center is located on the continuation of the straight line of the axis of the working cylinder 3 oppositely on the other side from the axis of the main shaft. The length of connecting rod 9 exceeds the radius of the main shaft crank by more than twice.Cranks 6 and 7, installed diametrically opposite to the middle cranks forming the connecting rod journal of the crankshaft 12, are cantilever-connected by bearings of sliding bodies with the cranks of the crankshaft in both axial directions from the plane of swing of the connecting rod 9. Balancing of the crankshaft 12 by correcting masses of counterweights 11 is performed in a manner known from the prior art.

[0024] The declared opposite crank mechanism works as follows.

[0025] When the crankshaft 12 rotates, its rotational motion is transmitted by the cranks 13 through the rotational kinematic pair to the cranks 6. In this case, the axis of rotation of the cranks 6 and 7, which form the moments of the pair of forces, performs a complex translational-rotational motion, which is facilitated by the rocking motion of the connecting rod 9 along an arc of a circle with a radius equal to the length of the connecting rod 9.

[0026] Thus, the rotational movements of the crankshaft 12, the complex translational-rotational movement of the axis of the diametrically opposite, axially spaced cranks 6 and 7, and the rocking movements of the connecting rod 9 are one movement.

[0027] This ensures the achievement of the following advantages over known technical solutions:

[0028] - mechanical efficiency and service life are increased due to the formation of moments of a pair of forces and the creation of a self-aligning mechanism, leading to the balancing of the mechanism as a whole;

[0029] - shock and vibration effects are reduced and damped jointly by the crankshaft and the oppositely mounted connecting rod with the swing axis in the machine body, located on the continuation of the straight line of the cylinder axis on the other side of the intersection point of this straight line with the perpendicular line of the main shaft axis. At the same time, torsional vibrations are eliminated and the reactive overturning moment is reduced;

[0030] - the weight and dimensions of the piston machine are reduced due to the reduction of the radial dimensions, the weight of the parts of the declared opposite crank mechanism, performing a reciprocating motion. The specified advantages of the declared mechanism ensure the possibility of its effective operation in piston machines with double-acting cylinders, in trunk engines and other crank mechanisms.

[0031] Industrial applicability

[0032] The claimed invention, as described in the claims, can be industrially implemented using known equipment, technical and technological means.

Claims

7 Invention formula An opposed crank-connecting rod mechanism comprising a cylinder with a piston and a rod, characterized in that the piston is rigidly fixed with a forked rod, the horns of the forked rod are connected to coaxial axes capable of performing a complex translational-rotational motion, the coaxial axes have two diametrically oppositely directed cranks spaced apart in axial directions, wherein the middle cranks are connected by a crank pin, the connecting rod with the swing axis in the housing is opposedly located in the direction opposite to the working cylinder from the main shaft axis, the connecting rod axis at the top dead center and bottom dead center is located on the continuation of the straight line of the cylinder axis, the cranks of the main shaft are connected by axes of rotation to the cranks of the coaxial axes, and the length of the connecting rod exceeds the radius of the main shaft crank by more than two times.

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