RU2562504C1 - Telescopic hydraulic cylinder and damper for telescopic hydraulic cylinder - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: telescopic hydraulic cylinder includes casing with hole for the work medium supply and removal, hollow rods with pistons installed in the casing one inside another, and creating straight stroke chamber and rod cavities, piston and dampers. At that the rods have at least two holes for the work medium supply and removal, located one above another on the longitudinal axis, on free ends of rods and in top end of the casing the lock rings are installed, and in the bottom part of each rod collars are made. Under the sealing elements of the lock rings the dampers are secured in form of the ring elements with collars, made in form of crown ring element, this ensures support of the drain holes in open state, and is necessary for operation of the system automatics for extension and stowage.

EFFECT: increased reliability of the telescopic hydraulic cylinder, simple design, impact exclusion at the end of stroke of each piston.

3 cl, 3 dwg

Description

The group of inventions relates to the field of engineering, in particular to long-stroke telescopic hydraulic cylinders for hydraulic drives of hoisting machines, which include mobile cranes, hoisting installations for the repair of oil and gas wells, etc.

In mechanical engineering, there is a large number of machines with hydraulic systems (tractors, excavators, track loaders, etc.), an integral part of which is a power hydraulic cylinder, consisting of a housing with cylindrical openings closed at the ends, a piston whose rod extends and connects to load, o-rings of the rod and piston, a hydraulic damper to eliminate shock at the end of the piston stroke (see Nikolsky L.N. Friction shock absorbers M .: Mechanical Engineering, 1964).

A disadvantage of the known technical solutions is the impact upon contact of the locking rings, excessive wear of the nodes of the movable structure, especially if it has a large mass and inertia, for example, in the case of freight elevators of large tonnage.

In addition, the prior art hydraulic cylinder with a damping device, consisting of a housing, a movable working element, consisting of a piston and rods, piston and rod seal assemblies, a packing follower with axially arranged holes and an annular groove for supplying to the working rod cavity and drain from it working fluid. An element is mounted on the rod concentrically to its axis, which compresses the piston seal assembly. The sleeve is made in the form of a glass with double concentric walls and is installed with the possibility of interaction with a spring-loaded sleeve (see AS USSR No. 1691578 A1, publ. 15.11.1991).

A disadvantage of the known device is also its low reliability, due to the complex design and the high probability of failure of individual structural elements.

Also known from the prior art is the use of plastic rings, springs, complex damping systems as damping devices for hydraulic cylinders (see Nikolsky L.N. Friction shock absorbers M: Mechanical Engineering, 1964).

The disadvantage of such devices is the complex design, as well as the high probability of an impact at the end of the piston stroke. In addition, from the prior art, a damper is known in the form of a spring-loaded sleeve in which radial throttling slots and axial holes are made, interconnected by an annular groove. When using a damper, throttling of the working fluid occurs, the pressure on the seal assemblies increases smoothly (see AS USSR No. 1691578 A1, publ. 15.11.1991).

A disadvantage of the known device is the complex design of the damper, as well as the presence of additional structural elements with a low lifetime.

The objective of this group of inventions is to eliminate the above disadvantages.

The overall technical result consists in increasing the reliability of the telescopic hydraulic cylinder, simplifying the design, as well as eliminating the occurrence of an impact at the end of the stroke of each piston segment of the telescopic hydraulic cylinder.

The technical result is ensured by the fact that the telescopic hydraulic cylinder includes a housing with a hole for supplying and discharging a working medium, hollow rods installed in the housing inside one another, forming a forward-running chamber and rod cavities, a piston and dampers. The rods have at least two drainage holes for supplying and discharging the working medium, the telescopic hydraulic cylinder contains lock rings. At the same time, dampers in the form of corona-shaped ring elements are fixed below the sealing elements of the lock rings. Bumps are made in the lower part of each rod, at the ends of which sealing elements are fixed. In addition, the damper makes it possible to leave open one of the drainage holes at the smallest stroke of the rod at the very end of its extension.

The sum of the areas of the drainage holes for supplying and discharging the working medium of each rod is equal to the area of the hole made in the housing for supplying and discharging the working medium.

The technical result is also ensured by the fact that the damper for the telescopic hydraulic cylinder is made in the form of a crown-shaped annular element, which makes it possible to maintain the drainage holes in the open state.

The essence of this group of inventions is illustrated by the following illustrations:

FIG. 1 shows a telescopic cylinder with the retracted position of the rods and piston;

FIG. 2 shows a telescopic cylinder with the extended position of the rods and piston;

FIG. 3 displays the damper.

The illustrations show the following features:

1 - housing;

2 - hole in the housing;

3 - stock;

4 - stock;

5 - stock;

6 - the piston;

7 - damper - crown-shaped ring element;

8 - drainage hole;

9 - a lock ring;

10 - shoulder;

11 - camera forward motion;

12 - sealing element shoulder;

13 - a sealing element of a lock ring;

14 - teeth;

15 - stock cavity;

16 - rod cavity;

17 - stock cavity;

18 - compensation cavity.

The telescopic hydraulic cylinder includes a housing 1 with an opening 2 for supplying and discharging a working medium, hollow rods 3, 4, 5 and a piston 6 installed in the housing one inside the other. Dampers 7 are installed in the device and are made in the form of ring-shaped ring elements. The rods 3,4, 5 have at least two drainage holes 8 for supplying and discharging the working medium. The rods have an equal number of drainage holes 8. In the retracted position of the rods, the drainage holes 8 are located one above the other on the longitudinal axis, that is, in steps. Moreover, above all (that is, at the greatest distance from the lower part of the housing 1) are openings 8 of the rod 5 having the smallest diameter. The sum of the areas of the holes 8 for supplying and discharging the working medium of each rod 3, 4, 5 is equal to the area of the hole 2 for supplying and discharging the working medium made in the housing 1. Locking rings 9 are installed on the free ends of rods 3, 4 and in the upper part of the housing; collars 10 are made in the lower part of each rod. The device contains three rods 3, 4, 5 installed in the housing 1 inside one another, while the rod 5 is smaller the diameter is made in the form of an open hollow cylinder having a base.

At the ends of the shoulders 10, sealing elements 12 are fixed. In addition, in the housing 1 and in two rods there are 3 and 4 sealing elements 13 fixed in the location of the locking rings 9. In the housing 1 there is a forward-running chamber 11. In addition, the device has rod cavity 15,16, 17 and the compensation cavity 18. The rod cavity 15 is formed by the inner wall of the housing 1 and the outer wall of the rod 3, the rod cavity 16 is formed by the inner wall of the rod 3 and the outer wall of the rod 4, the rod cavity 17 is formed by the inner wall of the rod 4 and the outer th wall of the rod 5. The rod cavity 15 communicates with at least two radial holes 8 with the rod cavity 16, the rod cavity 16 communicates with at least two drainage holes 8 with the rod cavity 17, which using at least two drainage holes 8 is connected to a compensation cavity 18 formed inside the cylinder, it allows you to divert the working medium from the rod cavities 15, 16, 17. The damper 7 for the telescopic hydraulic cylinder is made in the form of a crown-shaped annular element, that is, has the shape an inverted crown with protrusions in the form of teeth 14 around the circumference. The damper is fixed under the sealing element 13 of the retaining ring 9. The damper ensures that one of the drain holes is left open at the smallest stroke of the rod at the very end of its extension, which is necessary for the automation of the extension and folding of the rods. The device operates as follows.

A telescopic hydraulic cylinder with hydraulic damping (hereinafter referred to as the GTCH) resembles telescopic hydraulic cylinders of double-acting force with single-sided rods 3,4,5, containing several concentrically arranged pistons moving relative to each other.

In the piston cavity 11, the fluid is supplied through an opening in the housing 2 in the wall of the housing 1. In the rod cavity 15, 16, 17, the fluid is supplied / discharged through two (or more) drainage holes (DO) 8 located in the lower part of each of the rods.

The rod of the smallest diameter 5 is made by a hollow cylinder, a piston 6 without a rod runs inside it, allowing fluid to be drained from the cascade of rod cavities 15, 16, 17 into the formed cavity 18 (compensation cavity - KP). Or, the piston 6 with the rod - then this rod also does the job, increasing the operating range of the HZ. The volume of the gearbox is equal to the sum of the displaced volumes of the cascade of rod cavities.

In the retracted position of the pistons, the piston cavity 11 represents the working cavity of the hydraulic cylinder, and all rod cavities (including gearboxes), united by a cascade by DO between themselves, form a separate united cavity. The total cross-section of each pair of drainage holes is equal to the cross-section of the supply hole 2 in the wall of the sleeve 1. When filling the forward-flow chamber 11 from the supply line, the rod package 3, 4, 5 is extended (the rods have a hierarchy of lower collar areas from a larger area (for rod 3), to a smaller one (rod 5), respectively, the rod 3 having the largest cross section of the base is put forward first) and, as a result, the first rod cavity 15 contracts: it creates increased fluid pressure, which through the cascade of drainage holes 8 and the rod cavities is unloaded into the compensation cavity 18. In the almost extended position of the first link (rod 3), the first drainage hole 8 of the rod cavity 15 of the first link is blocked by the sealing ring of the previous link (in this case, in the upper part of the sleeve), which reduces the section of the drainage holes by half the first rod cavity 15, creating increased pressure in the first rod cavity 15, thereby slowing down the speed of movement of this link and, consequently, provoking the beginning of the movement of the next link (rod 4 with the package ex upstream rods) before stopping the previous link (here - rod 3). With the beginning of the movement of the next link (here, rod 4), the second UP 8 of the previous rod cavity 15 ceases to communicate with the cascade of rod cavities 16 and 17 and opens for communication with the combined piston cavity 11, the pressure in the first rod cavity 15 is aligned with the pressure of the piston cavity 11, the link stops. Each of the following links works in a similar way, while due to the deceleration of the course of each previous link (with the subsequent stop focusing on the hydraulic cushion) with the simultaneous start of the stroke and acceleration of the next link, there is no hard contact of the locking elements of the HZ, there is no shock load.

Thus, the rod cavities in the process of relative movements of the moving parts alternately sequentially switch from one united cavity to another.

When the fluid is supplied into the piston cavity 11, the rods are sequentially extended, starting from a large diameter to a smaller one.

When the supply of fluid to the piston cavity is stopped and the supply valve in the wall of the sleeve 1 is closed, the extension of the rods stops. When switching the supply valve to drain the fluid from the piston cavity 11 under the influence of gravity and the weight of the load simultaneously with the downward movement of the piston 6, the rod 5 of the smallest diameter is first drawn in, the rod cavity 17 is filled with oil through the drain holes by drawing oil from the compensation cavity 18 - first through one drain hole 8 - the slow movement of the rod, and after the release of the second hole 8 (it is obscured by the sealing element of the retaining ring) - through both DOs - a quick movement of the rod ka. The upper rod 5 moves down until it has passed the second (lower) drainage hole 8 of the next rod cavity 16. The passage of this drainage hole by the bottom of the rod 5 overlaps the connection of the rod cavity 16 with the common piston cavity 11 and ensures the start of oil flow into the rod cavity 16 in a cascade of gearboxes (from the previous rod cavity 17 in a cascade of gearboxes) - the next stock 4 starts moving and starts moving downward (however, at a lower speed than the previous stock 5). Immediately after the start of the movement of this rod 4, the upper drainage hole 8 of the rod cavity 16 is unlocked - oil from the compensation cavity 18 begins to flow into the rod cavity 16 unhindered, the speeds of the rods 5 and 4 down are aligned - right before the collision of the shoulders of these rods (or other locking devices) - the impact from the collision does not occur, or it is reduced by the decomposition of the speeds of the two rods. Further folding of the links occurs similarly, with the upper piston and each subsequent moving simultaneously with different speeds, which reduces the contact effect of each link when fully folded with the next link due to the difference in the speeds of movement (the lower speed is subtracted from the higher speed, which is the collision speed of the links , in contrast to the usual scheme, when the moving part of the links meets the stationary subsequent link). The sequential folding of the "telescope" occurs in the reverse order - from the piston of the smallest diameter to the largest.

The crown-shaped damping element with the folded hydraulic cylinder is located in the upper part of the rod cavity with the sealing element 13 of the retaining ring 9.

Overheating of the oil and its increase in volume due to the expansion that occurs during friction when the holes flow from one rod cavity to another is compensated by the free stroke of the piston 6 and slightly larger than the volume of the cascade of rod cavities by the volume of the compensation cavity 18 - with cooling the piston 6 itself gradually lowers in its cylinder.

Claims (3)

1. Telescopic hydraulic cylinder, comprising a housing with a hole for supplying and discharging a working medium, hollow rods installed inside the housing inside the housing, forming a forward-stroke chamber and rod cavities, a piston and dampers, characterized in that the rods have at least two drainage holes for the inlet and outlet of the working medium, the telescopic hydraulic cylinder contains locking rings, while below the sealing elements of the locking rings are fixed dampers in the form of crown-shaped ring elements, in the lower part of each rod Execute the clamps at the ends of which are fixed sealing elements, moreover, the damper allows the possibility of leaving open one of drainage holes at the low speed shaft at the end of deployment. 2. The telescopic hydraulic cylinder according to claim 1, characterized in that the sum of the areas of the drainage openings for supplying and discharging the working medium of each rod is equal to the area of the opening made in the housing for supplying and discharging the working medium. 3. Damper for a telescopic hydraulic cylinder according to any one of paragraphs. 1-2, made in the form of a crown-shaped annular element, which makes it possible to maintain drainage holes in the open state.

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