RU2153464C1 - Double-acting telescopic hydraulic cylinder - Google Patents

Abstract

FIELD: materials handling machinery; power positive-displacement hydraulic mechanisms. SUBSTANCE: hydraulic cylinder has coaxial set of piston stages, each with rod spaces, and piston space. One of hydraulic cylinder stages has double-side rod whose ends differ in section areas. Working areas of piston sides also differ in size. Piston space of hydraulic cylinder is formed by piston spaces of each stage installed for getting into opposite phases in extreme positions of hydraulic cylinder. Unlike spaces of hydraulic cylinder are hydraulically connected in pairs to form united spaces so that at maximum volumes of piston spaces united spaces of hydraulic cylinder are connected with pressure head and at maximum volume of piston space of one of stages, united space formed by corresponding space is connected with pressure head, and other united space is connected with drain. Cylinder of double-side rod stage can be made in form of rod-and-step sleeve mated with ends of different diameter rod for axial displacement. Its mated surfaces can be made in form of different diameter cylinders. Invention makes it possible to dispense with flexible lines for delivering working liquid owing to provision of hydraulic coupling of hydraulic cylinder spaces ensuring delivery of working liquid to any stationary part of hydraulic cylinder with guaranteed successive and independent action of hydraulic cylinder stages. EFFECT: enhanced operation reliability. 4 cl, 4 dwg

Description

 The invention relates to power volumetric hydraulic motors with rectilinear reciprocating movement of double-acting (with power extension and retraction at full speed) and can be used in shipbuilding, engineering and other industries.

 Known double-acting telescopic hydraulic cylinders with one-way rods for implementing large strokes in conditions of insufficient space to accommodate a conventional translational hydraulic motor, the stroke of which is limited by the length of the assembled cylinder, and in these conditions cannot provide the required stroke length (Bashta T.M. Volumetric pumps and hydraulic hydraulic system engines. - M.: Mechanical Engineering, 1974, p. 516-518, Fig. 216a). Such multi-cylinder hydraulic cylinders comprise a large cylinder in which a large diameter piston is located with a rod having an internal cavity in which a smaller diameter piston with its rod is located. The large cylinder, pistons and rods are concentric and have the possibility of relative and sequential movement, and the sum of their moves is equal to the total stroke of the output link. The supply (withdrawal) of the working fluid is simultaneously carried out both to the movable and to the stationary elements, namely to the common piston cavity and individual rod cavities. The disadvantages of the known telescopic hydraulic cylinders are the necessity of using flexible pipelines, which ensure the passage of the working medium to the moving parts of the hydraulic cylinders, as well as the lack of functionality, which is due to the lack of support, apart from the sequential, also independent action of the stages of the hydraulic cylinders.

 Known telescopic double-acting hydraulic cylinder with one-sided rods, providing simultaneous extension of all stages (Podgorny, Yu.P. Hydraulic drives for ground handling aircraft. - M.: Transport, 1980, p. 63, 65, Fig. 4.8). The hydraulic cylinder consists of a casing and three cylinders, which form three direct pressure chambers and three counterpressure chambers, while the counterpressure chamber of the cylinder of the previous stage and the direct pressure chamber of the cylinder of the next stage are pairwise connected with the formation of a closed joint cavity, which have two cylinders. The fluid from the pump in the forward stroke is fed into the direct pressure chamber in the housing. To fill the hydraulic cylinder with liquid, check valves mounted in the piston heads (except for the piston rod) are used. From the backpressure chamber of the rod, liquid is discharged through the rod.

 For the return stroke, the fluid is supplied through the rod to the stem counter-pressure chamber, and from the direct pressure chamber formed by the housing, the working fluid is drained into the oil tank.

 With forward and reverse strokes, all cylinders of the hydraulic cylinder are extended (retracted) simultaneously.

 The disadvantages of the known double-acting telescopic hydraulic cylinder with the simultaneous extension of all stages is the need to use flexible pipelines that ensure the passage of the working medium to the moving part of the hydraulic cylinder, as well as the lack of functionality, which is caused by the impossibility of providing, in addition to the simultaneous, also independent action of the hydraulic motor stages.

 Known telescopic hydraulic cylinders of bilateral power action with one-sided rods containing several concentrically arranged pistons (with rods) moving one relative to the other, while the stroke of the output link is equal to the sum of the strokes of each (Marutov VA, Pavlovsky SA Hydraulic cylinders. - M .: Engineering, 1966, p. 8, fig. 3, p. 97, 99, fig. 86a). Both in the piston and in the rod cavity, the liquid is supplied through the rod. Both in the extended and retracted positions of the pistons, the piston cavity is a single (combined) cavity of the hydraulic cylinder. In the retracted position of the pistons, all the rod cavities between themselves form a separate united cavity, and in the extended position of the pistons the rod cavities are connected to the combined piston cavity, except for the rod cavity of the rod through which the working fluid is supplied (withdrawn). Thus, the rod cavity during the relative movements of the moving parts alternately sequentially switch from one united cavity to another. When fluid is supplied to the piston cavity, the pistons successively extend, starting from a large diameter to a smaller one. When fluid is supplied to the rod cavity, the piston of the smallest diameter is first drawn in, and then the “telescope” is successively folded in the reverse order - from the piston of the smallest diameter to the largest.

 If it is impossible to supply the working fluid to any of the combined cavities through the stem, it is necessary to use flexible pipelines that ensure the passage of the working fluid to the moving parts of the hydraulic cylinder.

 The well-known double-acting telescopic hydraulic cylinders provide sequential movement of the pistons, however, the independent action of the steps is impossible to realize, which can be considered a drawback of the device in terms of design optimization and expansion of functionality.

 The well-known double-acting telescopic hydraulic cylinder is selected as the closest analogue.

 The objective of the invention is to optimize the design to eliminate flexible pipelines, providing a working fluid to moving parts, as well as to expand the functionality by providing in these conditions a consistent and independent action of the stages of the hydraulic cylinder.

 The problem is solved in that in a double-acting telescopic hydraulic cylinder including a coaxial set of piston stages with rod cavities each, as well as a piston cavity, in accordance with the invention, one of the hydraulic cylinder stages has a two-sided rod, the ends of which have different cross-sectional areas, and the working areas of the sides are different while the piston cavity of the hydraulic cylinder is composed of piston cavities of each stage, which are installed with the possibility of coming in opposite phases in the extreme positions of the hydrocyclone ndra, while the opposite cavity of the hydraulic cylinder is pairwise hydraulically connected with the formation of the joint cavities so that at the maximum volumes of the piston cavities the combined cavities of the hydraulic cylinder are connected with the pressure, and with the maximum volume of the piston cavity of one of the stages, the combined cavity formed by the corresponding piston cavity is connected to the pressure, and the other joint cavity is connected to the drain.

 In addition, the opposite phases in the position of the steps are the phases "The volume of the piston cavity is maximum" and "The volume of the piston cavity is minimum."

 In addition, the stage cylinder with a two-sided rod is made in the form of a rod-stepped sleeve, mating with the ends of the rod of different diameters with the possibility of axial movement.

 In addition, the surfaces of the sleeve mating with the double-sided rod are cylindrical and have different diameters.

 The technical result of the invention is the exclusion of flexible lines for supplying a working fluid due to the hydraulic connection of the cavities of the hydraulic cylinder, which provides a supply of working fluid to any of the stationary parts of the hydraulic cylinder. In addition, a consistent and independent movement of the pistons of the hydraulic cylinder stages is ensured.

 Thus, in the extreme positions of the telescopic hydraulic cylinder, the resulting displacement of the stages of the hydraulic cylinder is determined by summing the displacements of both elements, and if the middle part is attached to the fixed element, this possibility is excluded.

 The invention is illustrated in FIG. 1, which shows a telescopic double-acting hydraulic cylinder in the retracted (initial) position; FIG. 2 - the same in the extended position; FIG. 3 - the same in an intermediate fixed position; FIG. 4 is a particular example of a telescopic double-acting hydraulic cylinder in an extended position.

 A double-acting telescopic hydraulic cylinder (Fig. 1-3) contains a telescopic set of piston stages, which includes a cylinder 1 of a small stage, a cylinder 2 of a large stage, a piston rod 3 of a small stage with channels 4.5 for supplying and discharging a working fluid. The cylinder 1 of the small stage is combined with a two-sided rod of the large stage, containing the piston 6, lower 7 (cylindrical) and upper 8 parts, the last of which is equipped with a landing neck. The telescopic set of steps is made so that it forms a small rod 9 and a large piston 10 cavity of a small stage, a small 11 and a large 12 cavity of a large stage, while the cavity 9 communicates with the cavity 12 through the channel 13, and the cavity 10 communicates with the cavity 11 through the channel 14 with the formation of joint cavities. The small cavity 11 of the large stage according to the functional purpose corresponds to the rod cavity of this stage, and the piston cavity of the hydraulic cylinder is composed of the piston cavities of each stage, respectively, the large piston cavity 10 of the small stage and the large cavity 12 of the large stage. The piston of the two-sided rod of the large stage is made with unequal working (effective) areas so that the working area of the piston from the side of the cavity 12 exceeds the working area of the piston from the side of the cavity 11, while the diameter (cross-sectional area) of the seating neck of the upper part 8 of the two-sided rod exceeds the diameter ( the cross-sectional area) of its lower part 7. The cylinder 2 of the large stage is made in the form of a stock-step sleeve, mating with the possibility of axial movement and with the ends of the rod of different diameters (parts 7.8). The surfaces of the cylinder liner 2 mating with the double-sided rod are made in the form of a cylindrical neck mating with the cylinder of the lower part 7 of the rod, as well as in the form of a cylinder mating with the neck of the upper part 8 of the rod having different diameters in accordance with the diameters of the rod.

 The double-acting telescopic hydraulic cylinder is installed in such a way that in the initial position (Fig. 1) the volume of the large cavity 10 of the small stage is minimum, and the volume of the large cavity 12 of the large stage is maximum, therefore, the extreme positions of both stages are opposite in phase, while the opposite cavity of the hydraulic cylinder is pairwise hydraulically connected to form joint cavities.

 In the initial position (Fig. 1), all landing surfaces are structurally covered and protected from any external influences.

 It is essential for the inventive double-acting telescopic hydraulic cylinder to be attached to a fixed element, which can be carried out either by a piston rod 3 of a small stage, or by a cylinder 1 of a small stage combined with a two-sided rod of a large stage, or by a cylinder 2 of a large stage.

 The modification of a double-acting telescopic hydraulic cylinder (Fig. 4) differs from the hydraulic cylinder (Fig. 1-3) by the execution of a large stage 2 cylinder - it has half the length due to the fact that the surfaces of the cylinder sleeve 2 mating with a two-sided rod are made in the form cylindrical necks, and the ends of the two-sided rod, respectively, are made in the form of cylinders of different diameters, while the total length of the telescopic links in the extended position is one quarter less, although the sum of the moves of the steps remains unchanged. At the same time, in the initial (retracted) position, the landing surface of the upper part 8 of the double-sided rod is open and not protected from external influences.

 The telescopic hydraulic cylinder operates as follows.

 The working fluid under pressure is fed through the channel 4 into the cavity 10 and through the channel 14 into the cavity 11, and the cavity 12 through the channel 13 together with the cavity 9 is connected to the drain channel 5 (Fig. 1). Under liquid pressure, cylinder 2 and cylinder 1 from the initial (retracted) position are successively forced upward. The hydraulic cylinder is installed in the extreme extended position, while the volume of the large cavity 10 is maximum — the combined cavity 10,11 is connected to the pressure, and the other combined cavity 9,12 is connected to the drain, and the volume of the large cavity 12 is minimal, i.e. the extreme positions of both steps are opposite in phase (Fig. 2).

 The working fluid under pressure is fed through channels 4 and 5 in the cavity 9 and 10, as well as in the cavity 12 and 11 due to the corresponding hydraulic connections - channels 13 and 14 (Fig. 1,2). Under fluid pressure, the hydraulic cylinder is installed in an intermediate fixed position, with only cylinder 1 being extended, the volumes of large cavities 10 and 12 are maximum, the combined cavities are connected with the pressure, i.e. the extreme positions of both stages are single-phase (Fig. 3).

 The working fluid under pressure is fed through the channel 5 into the cavity 9 and through the channel 13 into the cavity 12, and the cavity 11 through the channel 14 together with the cavity 10 is connected to the drain channel 4 (Fig. 2,3).

 Under the pressure of the liquid, the hydraulic cylinder is set to its original (retracted) position, while the cylinders 1 and 2 are removed, the volume of the large cavity 12 is maximum - the combined cavity 9,12 is connected to the pressure, and the other combined cavity 10, 11 is connected to the drain, and the volume of the large cavity 10 is minimal, i.e., the extreme positions of both steps are opposite in phase (Fig. 1).

 For passive lowering from any position that presents such an opportunity, it is enough to inform the combined cavities 9,12 and 10,11 with a drain through channels 4,5 (Fig. 2,3), while the hydraulic cylinder goes into a retracted position under the influence of an external load ( Fig. 1).

 The operation of the steps and the supply of hydraulics for special cases of the telescopic cylinder (Fig. 4) are identical to those discussed above.

 The inventive telescopic hydraulic cylinder makes it easy to optimize the design by eliminating flexible pipelines providing a supply of a working medium to moving parts, as well as expanding the functionality by providing in these conditions both sequential and independent action of the hydraulic cylinder stages.

Claims (4)

 1. A double-acting telescopic hydraulic cylinder, comprising a coaxial set of piston stages with rod cavities each, as well as a piston cavity, characterized in that one of the stages of the hydraulic cylinder has a two-sided rod, the ends of which have different cross-sectional areas, and the working areas of the piston sides are different, while the piston cavity of the hydraulic cylinder is composed of piston cavities of each stage, which are installed with the possibility of coming in opposite phases in the extreme positions of the hydraulic cylinder, the hydraulic cylinder cavities are pairwise hydraulically connected to form the united cavities so that at the maximum volumes of the piston cavities, the combined hydraulic cylinder cavities are connected with the pressure, and at the maximum volume of the piston cavity of one of the stages, the combined cavity formed by the corresponding piston cavity and the other combined cavity are connected to the pressure connected to the drain.  2. The hydraulic cylinder according to claim 1, characterized in that the opposite phases in the position of the steps are the phase "The volume of the piston cavity is maximum" and "The volume of the piston cavity is minimum."  3. The hydraulic cylinder according to claim 1, characterized in that the cylinder of the stage with a double-sided rod is made in the form of a stock-step sleeve, mating with the ends of the rod of different diameters with the possibility of axial movement.  4. The hydraulic cylinder according to claim 3, characterized in that the surfaces of the liner mating with the two-sided rod are cylindrical and have different diameters.

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