ES2234615T3 - INNOVATIVE OLEODYNAMIC PERCUSSION MACHINE THAT WORKS WITH CONSTANT HYDRAULIC PRESSURE. - Google Patents

Abstract

Oleodynamic percussion machine with a body (1) in which there is a piston (3) that transforms the hydraulic power of the power circuit into mechanical output power, a tool (5) that transfers said mechanical power, channels (7a) , (20), (6), control holes (19), (11), (15), control and thrust volumes (7), (16) that allow non-compressible process fluid, for example oil , transform the hydraulic power into mechanical power; including also a nitrogen-filled high pressure hydraulic accumulator (2) with the function of storing the hydraulic power supplied by the supply circuit (6) and returning it to the piston (3); said machine being characterized in that it comprises a modulating slide valve (4) that maintains the operating pressure at a constant value and controls the movement of the piston itself, varying its active displacement and the inlet and oil discharge control orifices ( 19), (11); not using said percussion machine, therefore, no external control element, such as a flow regulating valve, an OPEN-CLOSED check valve or the like, to control the operating pressure and / or active displacement or passive, and not using any mechanical stop of the piston stroke.

Description

Innovative oleodynamic percussion machine that It works at constant hydraulic pressure.

Technical field

The objective of the present invention is to an oleodynamic percussion machine whose basic characteristic is the absence of a hydraulic regulation device, valves retention or adjustment. Most percussion machines Oleodynamic alternatives known in the art work according to the same basic principle: a piston, operated by a fluid not compressible at high pressure, it is accelerated to a high speed and creates an impact on the tool that produces the demolition. The impact energy, in the form of pressure energy, is stored in a charged nitrogen (or other equivalent gas). The high pressure on the rear head is directly connected to the high pressure circuit that acts in the area intermediate piston, supporting the upward stroke of the piston.

Other mechanisms alternately connect the High and low pressure circuits with the piston head. In these mechanisms, the piston moves alternately to positions extremes called upper dead center and lower dead center. The impact energy is directly proportional to the race of the piston and the sum of the dynamic forces acting on East.

Therefore, the pressure of the oil in the rear head at the constant pressure value accumulator oleodynamics, since the energy value of Impact depends on it. Special valves, controlled by the accumulator pressure, regulate the discharge orifice to vary, as a result, the pressure drop between the pressure dynamics that is determined at the piston head and the pressure of the return circuit This means that the pressure value accumulator dynamics is inversely proportional to the piston lift speed.

A valve of this type is described in the European Patent No. 0085279, and is part of the apparatus disclosed in U.S.A. No. 4,380,901.

The drawback of these applications is the regulation of the pressure control valve. It's about a very unstable element, due to very short time constants, and to the difference between its control characteristic and what it does Reference to operating conditions.

This instability results in high peaks of pressure in the piston head that produce vibrations and rebounds on the percussion machine. Therefore, it is necessary to regulate the hydraulic system of the control machinery or that of the valves control, especially during installation. Due, improper regulation causes damage to the structure of the machine due to high mechanical stress or racing excessively powerful, greatly reducing the life of elements such as pumps, pipes, distributors, etc. Finally, another inconvenience is the hydraulic seal, which usually affects the machine / circuit system in working conditions, for any type of lamination that involve thermal stresses that reduce reliability and performance of the circuit This dynamic seal can only be formed using a special type of materials.

Description of the invention

The present invention resolves those mentioned technical problems and is characterized because the percussion machine it has no external control element such as a valve flow regulation, a check valve of the type OPEN-CLOSED or similar and, consequently, not It presents no high pressure dynamic seal. The advantage of it is that the neutral can be varied automatically upper piston, without any retention, regulation or control, thus allowing real-time displacement modulation active thrust chamber and device impact energy hydraulic on the tool; all this is carried out using the automatic oleodynamic control of an element called modulator In this way, the value of the pressure in the accumulator Gas / oil remains constant. This means that the working pressure and, consequently, the active force on the piston remain constant, improving system reliability of percussion, as well as the body frame and the circuit of hydraulic operation

It is necessary to highlight the difference between Innovative modulator of the present invention and a valve normal and known slide. In general terms, both pneumatic devices like hydraulic ones comprise a distributor or slide valve to provide pressure. This distributor or slide valve has a type control OPEN-CLOSED and is displaced by the fluid at extreme positions. In the patent EP-A-0085279 presents a similar device, mentioning in said document that it is of a part of the system that limits the upward stroke of the distributor anticipating the start phase of the piston with respect to the top dead center. These devices are combined with "others that allow the evacuation of compressed fluid to different speeds from the distributor boss, in the annular chamber (2C) that this same protuberance forms in the part upper slot (2) ". A similar device is described in U.S.A. No. 4,380,901, with a valve connected to the line of high pressure that determines the law of movement. At device disclosed in French Patent No. 8114043, a Single pass valve generates reciprocating piston movement. Therefore, from the literature and the current state of the technique, it is clear that neither the distributor's career nor Its speed can be regulated without the help of a device external or other means. With hydraulic slide modulator of the present invention, the opening of the exit holes of the hydraulic circuit is automatically controlled by position of the modulator. This constitutes an innovative evolution with respect to to the traditional reel distributor.

Another objective of the present invention is to in the easy installation in operation, due to the absence of procedures for adjusting and checking flow rates and of working pressure. Accordingly, the present invention solves the specific problem of hammer rental, in which it is difficult to perform daily repairs and maintenance, given that the oleodynamic percussion apparatus can be used in Different machines and circuits according to the needs.

These and other advantages will be described with more detailed description of the invention, making reference to tables 1/7, 2/7, 3/7, 4/7, 5/7, 6/7 and 7/7, which show some feasible diagrams as non-restrictive examples of the operation of the invention.

Embodiment of the invention

In reference to the tables above mentioned:

drawing 1 shows the invention in a sectioned elevation view;

drawings 2 and 3 show the same diagram in two different operating positions;

drawing 4 shows an enlarged detail of the piston head and the internal foundation of the modulator;

drawings 5 and 6 show the geometry and consequent regulation feature of the holes of lower and upper discharge;

drawing 7 shows a detail of the internal protection system;

• drawings 8 and 9 represent possible Piston geometry variations.

Referring to drawing 1, the machine Oleodynamic percussion comprises, according to the present invention, the following main components: the body (1), an accumulator Hydraulic (2) high-pressure nitrogen-filled, one piston (3), a modulating slide valve (4), a tool (5), a High pressure feed line (6), lifting volume (7) with the lift volume line (7a), the discharge line low pressure (8), the low pressure volume modulator (9), a hydraulic damper modulator (10), control holes (11) of the thrust volume, the crown ring volume (12), the lower discharge line (13) of the modulator and the discharge line bottom (13a) of the modulator, the modulator (14) of the volume of elevation, the volume control holes (15) of the modulator, the thrust volume (16), the hydraulic shock absorber (18) of the piston, high pressure outlet holes (19), the line of supply (20) of the accumulator, through holes (21) of the accumulator, overflow valve (22), shown in drawing 7, a pre-opening zone (A) of the piston, a pre-opening zone of the modulating sliding valve (3), the "meatus" of the seal superior dynamic (C) of the modulator, the "meatus" of the seal lower dynamic (D) modulator, the upper dynamic seal (E) of the body, the internal dynamic seal (F) of the box, the Hydraulic "meatus" (G) of the shock absorber and the inner zone calibrated (H) of the modulator.

The present invention comprises a component essential; a two chamber accumulator equipped with oil pressurized and nitrogen gas separated by a rubber diaphragm that keeps nitrogen locked. The oil-filled chamber is is connected to the high pressure line of the hydraulic circuit and to the central part of the piston to push the piston in the direction upward. The oil-filled chamber is also connected to the thrust chamber, in which the modulating slide valve supplies pressurized oil.

The pressure in the oil chamber depends on the relationship between the input flow and the impulse output flow. The discharge rate is a function of the following parameters:

a) the ascending speed of the piston that determines the oil discharge time through the circuit discharge, depending on the pressure drop that has taken place. The exit holes are automatically controlled by the point top dead modulator slide valve that modulates the opening;

b) the variation of the upward stroke of the piston, which defines the amount of oil in the passive cycle or return;

c) the variation of the valve stroke sliding modulator, which sequentially determines the position from the top dead center of the piston and also from its stroke;

d) pressure spikes in the thrust chamber due to the return impact waves from the piston. The The present invention eliminates these pressure peaks by opening the exit hole before impact;

e) characteristics of hydraulic slowdown during the last part of the upward movement of the modulator;

f) the full duration of a work cycle active passive.

The modulating valve interacts with the piston, automatically determining the sequential control of previous parameters.

Example

Referring to Figure 1, the valve modulating reel (4) is in the inactive position, and the piston (3) is in the bottom dead center. The line of Bottom discharge (13) and (13a) of the modulator is closed. From the High pressure feed circuit line (6), oil flows to the upward thrust volume (7) through the circuit (7a), and from the thrust chamber (16) through the hole of high pressure oil inlet (9). The oil pushes nitrogen present in the high pressure gas / oil accumulator (2) at secondary power circuit (20), through the holes (twenty-one). The hydraulic seal from high pressure to low pressure It is secured by coupling between the modulator and the body. Under these conditions, the high pressure feed acts on the piston head (3) and upward thrust volume (7). Considering the difference between the areas, high pressure pushes the piston down in contrast to the reaction movement of the tool.

At the same time, high pressure feed acts on the exposed surface of the slide valve modulator (4), which has a volume (9) connected to the circuit low pressure (8) through the holes (11) of the volume of thrust and discharge circuit (8) of the spool valve modulator The difference between the thrust areas, along with the static pressure differential between the supply pressure and the discharge pressure, determine the rising force that raises the modulating spool valve (4) to the maximum of its stroke permitted; in this way, the closure of the orifice of inlet (19) and opening of the hole (11) of the thrust volume. At the end of its run, the modulating spool valve (4) is slowed by a hydraulic damper (10) of the modulator, and the oil contained in the volume (14) is discharged through the hole (15).

In this way, the static pressure value in volume (16) decreases, allowing force to be imposed upward thrust volume (7), starting the movement ascending piston (3) that provides the oil discharge residual volume (16), towards the low discharge circuit pressure (8) through the control hole (11).

In this phase, the entrance hole (19) of high pressure oil is closed, and the oil coming from the high pressure oil feed circuit fills the gas / oil accumulator (2) through the circuit line (20) and the holes (21), up to the dynamic pressure of the circuit feeding.

The piston (3), free to ascend (figure 2), is Insert the modulating spool valve (4) and exert pressure against the rising volume (14) of the slide valve modulator through the holes (15), constituting a force descending modulator (4) that pushes the piston down, the lower discharge circuit (13), (13a) of the modulator

The dynamic interaction between the movement alternative piston (3) and the opposite movement of the valve Sliding modulator (4) ends when the slide valve modulator opens the inlet hole (19) of high oil pressure (reaching the extreme forward position) and when, at close the hole (11), recreate the dynamic "meatus" seal (D). From the high pressure feed circuit (6), the oil enters both the thrust volume (16) and the volume upward thrust (7), thanks to the volume of compressed oil by the nitrogen contained in the accumulator (2). Therefore the same pressure value acts on the top of the piston (3) and on the lower part of the volume (7), generating a downward force proportional to the difference between both areas. The resulting force is equal to a sudden downward thrust that acts on the piston (3), providing a uniform acceleration movement.

When the area (A) of the piston (3) reaches the position (B) of the modulating spool valve (4) before due (with respect to the position of impact on the tool, which has previously closed the circuit -13-, -13a-), eliminates the Dynamic "meatus" (A) / (B) and allows the active oil to high pressure fully pressurize the modulating spool valve (4) which presents a volume (9) at low pressure. Volume down pressure (9) of the modulating slide valve (4), multiplied by the difference between the pressure set in the accumulator (2) and that of the download, preexisting in volume (9), determines a force proportional to the dynamic pressure generated in the volume (16). This force causes the modulator to close in the direction ascending the high pressure oil inlet hole (19) in the direction of the lift volume control (14) of the modulator

The modulating slide valve (4) transforms the kinetic energy introducing at high speed the volume of elevation control (14) of the modulator, creating a "meatus" dynamic (E), (F) that puts pressure on the control volume (14) of the modulator and, by partially opening the holes (11) of the thrust volume, forces the oil (trapped in the volume -14-) to flow through the holes (15), with Exponential type regulation characteristics.

If the dynamic pressure in the volume (16) is very high, with the oil volume (14) completely discharged, the modulating slide valve (4) will stop at the point dead superior. On the contrary, if the dynamic pressure generated it is very low, the modulating slide valve (4) will end its run when you enter the volume (14) and start pressurize it. In the same way, when the slide valve modulator (4) has a greater load, will open a larger fraction of the control hole (11) of the thrust volume, causing a smaller hydraulic discharge resistance; the piston (3) will accelerate thanks to the lower pressure differential in the oil discharge de-energized through the lower holes (11) of the volume of thrust. Therefore, when the discharge time is reduced, the pressure in the accumulator (2) it will tend to decrease.

The piston (3) hits with the tool (5) and amounts to a speed that is a function of the difference between the upward thrust and that of the discharge pressure existing in the chamber (16), multiplied by the area of thrust of the piston (3). During the upward stroke, the piston enters the valve modulating slider (4) in its variable top dead center, pressurizing its upper part in volume (14). The bottom of the piston is connected to the open discharge circuit (12), (13), (13a), descend by opening the holes (19) and resetting the operating cycle This allows to keep constantly the average values of the preset operating pressure.

The degree of accuracy in defining the geometry of the dynamic fluid passage to optimize the fine adjustment and valve times of Sliding modulator (4). The goal is to have no areas with different speeds: consequent pressure variations they can influence the time constant of the modulation system. Therefore, the route to be traveled must be optimized. oil through the crown hole and the thrust volume (16) definite.

The cone-shaped piston head (3) inverted forms an entry step with the inner curve and the base Conical of the modulating slide valve (4) (figure 4). He objective of this special geometry is to transform into real time the kinetic energy of the fluid in a pressure energy snapshot that instantly moves the slide valve modulator (4). After that, the fluid passes through the holes control (11) of the volume, modulating the stop position of the modulator These holes (11) can have different shapes, as described in figure 5: circular, rectangular section or trapezoidal according to the law to use.

Similarly, the discharge holes (15) (figure 6) that define the variable position of the neutral upper modulator slide valve (4) present different ways. In general terms, these holes have a characteristic of exponential regulation as a function of The elevation. For short races, regulations may be used linear (adjustments) with considerable design simplification and less accuracy of the neutral control position top modulator

The percussion machine according to another embodiment advantageous is characterized by having a hydraulic shock absorber (10) that protects the slide valve from mechanical stress modulator (4). This prevents accidental knocking of the valve Sliding modulator (4). Once the slide valve modulator (4) has risen to its upper position, the volume (10), formed between the maximum top dead center of the modulator (4) and the "meatos" (C) and (G), allows the transformation of the inertia energy of the modulator in thermal energy.

The percussion machine, according to another embodiment, It is characterized by having an internal protection system (figure 7) to maintain the internal pressure level of operation and, as a consequence, of the impact energy of the piston against the tool, within the mechanical stress level planned in the design phase.

This internal protection system will be activated in the case of an abnormal operation of the hydraulic circuit that involve excessive flow problems or unexpected fluctuations.

As described above, the law for adjusting the volume control holes (14) towards the Volume (16) has a type regulation feature exponential; therefore, the time constant must be reduced from such that the modulating slide valve (4) achieves the maximum elevation in the minimum possible time, favoring a operating condition at maximum displacement (maximum process oil consumption). For this reason, the volume of lift control (14) of the modulating slide valve is has provided a second circuit with regulations of the type OPEN-CLOSED that can work in this case extreme. This second circuit has a simple DERIVATION connected directly to the accumulator and to a check valve (22) that has the priority function as described above and shown in figure 7. Finally, they should stand out two important aspects for the right sizing of the invention: the first is that the impact efficiency increases as the speed of impact, and the second is that the speed of impact, being the constant acceleration in the piston, it tends to increase as the piston stroke increases. It is also known that the impact energy is proportional to the square of the velocity of impact; therefore, in the design phase, in order to have in your due consideration what has been shown here, the values of the piston stroke must be maintained within certain criteria Preset

The consequence of this is that the diameter of active piston thrust (DV16) on which the High pressure should be reduced proportionally.

The percussion machine can be modified according to different models or sizes, while maintaining the same operating principle.

Figures 8 and 9 show two variations of the piston geometry (3) in which the thrust diameter is reduced active.

Claims (10)

1. Oleodynamic percussion machine with a body (1) in which there is a piston (3) that transforms the hydraulic power of the power circuit into mechanical output power, a tool (5) that transfers said mechanical power, channels ( 7a), (20), (6), control holes (19), (11), (15), control and thrust volumes (7), (16) that allow non-compressible process fluid, by oil example, transform the hydraulic power into mechanical power; including also a nitrogen-filled high pressure hydraulic accumulator (2) with the function of storing the hydraulic power supplied by the supply circuit (6) and returning it to the piston (3); said machine being characterized in that it comprises a modulating slide valve (4) that maintains the operating pressure at a constant value and controls the movement of the piston itself, varying its active displacement and the inlet and oil discharge control orifices ( 19), (11); not using said percussion machine, therefore, no external control element, such as a flow regulating valve, an OPEN-CLOSED check valve or the like, to control the operating pressure and / or active displacement or passive, and not using any mechanical stop of the piston stroke. 2. Modulating sliding valve (4) of an oleodynamic percussion machine characterized in that it moves exclusively through the hydraulic and hydraulic interaction with the piston (3). 3. Modulating sliding valve according to the preceding claim, characterized in that its geometry, its particular shape together with the positions of said inlet (15) and discharge (11) holes, and together with the thrust and control volumes (16 ), (14), are very important as regards the variation of the piston stroke (3), the active displacement and also for the operating frequency. 4. Modulating slide valve, according to any of claims 2 or 3, characterized in that it automatically controls its own position, dissipating kinetic energy in the volume (14) and in the meats (E) and (F), said characterization being also characterized Modulating sliding valve for internal and external calibrated surfaces that, together with the calibrated body parts (1), create the meatballs (E), (F). 5. Modulating slide valve according to any one of claims 2 to 4, characterized in that it can control all the operating parameters by means of which the pressure of the gas / oil accumulator (2) and the energy can be maintained at a constant value of impact. 6. The oleodynamic percussion machine according to claim 1, characterized in that the oil routes inside the machine optimize the sensitivity and timing of said modulating slide valve. 7. Oleodynamic percussion machine according to any one of claims 1 or 6, characterized in that the upper (15) and lower (11) discharge holes are governed by particular regulating characteristics. 8. An oleodynamic percussion machine according to any one of claims 1, 6 or 7, characterized in that it comprises a hydraulic damper (10) that prevents the impact between the body (1) and the modulating slide valve (4) when said valve Modular slide is near its top dead center. 9. The oleodynamic percussion machine according to any one of claims 1, 6, 7 or 8, characterized by a secondary branch circuit (22) which, in the case of excessive and unexpected flow rates in the high pressure supply circuit, allows , by opening, the system reduces the pressure in the accumulator. 10. The oleodynamic percussion machine according to any of claims 1, 6, 7, 8 or 9, characterized in that the rapid opening of the discharge holes (11) and the rapid closure of the oil discharge holes (19) in said volume (16) prevents any type of energy recovery, and consequently, any pressure peak in the thrust volume (16).