EP0216675A1 - Coaxial multifunctional insertable cartridge valves, and their use in the control of a double effect actuator - Google Patents

Abstract

The invention relates to a cartridge valve to insert multi-function coaxial hydraulic distribution comprising different inlet and outlet ports (P1, X1, R1, S1, s1, D1, B1), a first compensating slide (N1) biased towards a fully open position by a first spring (r1), a second internal drawer (J1) concentric with the first giving the main adjustment of the oil inlet flow requested by a second spring (r2) against the pressure control unit delivered by the inlet port (X1), to the closed position of the communication between the oil pressure inlet port (P1), and the outlet port (R1) delivering the pressure actuation, an isolation valve (C) and a make-up valve (G), biased by a third spring (r3) to return these two valves to the communication closed position towards (S1) for the valve (C) and towards (T1) for the valve (G), a third balancing slide (E1) biased by a fourth spring (r4) against the pressure delivered by the balancing pressure orifice (B1) and the pressure delivered by the actuation outlet orifice (R1) towards the closed position of the communication between the orifice (R1) for actuation outlet and orifice (T1) for oil return to the tank.

Description

The present invention relates to multi-function insert cartridge valves and their applications to the control of a double-acting cylinder.

These multi-function coaxial cartridges to be inserted constitute parallel distribution elements for oleo-hydraulic power circuits controlled by the load, often called: Load Sensing servo systems.

The hydraulic distribution circuits of public works and handling equipment, such as excavators, backhoe loaders, telescopic loaders, etc., are becoming more and more complex and expensive due to the greater demands of safety standards and the need to save energy.

A current distribution circuit on an excavator includes: manipulators for the remote control of distributors, distributors combining more and more functions (distribution, overpressure, recharge, throttling), large quantities of pipes that go to the receivers ( cylinders or motors), and finally increasingly complex safety and movement control valves incorporated into the cylinders without interposition of flexible.

A first object of the invention is to provide a cartridge valve to be inserted into the distribution blocks to facilitate construction and after-sales interventions, these cartridge valves comprising overpressure and vacuum safety devices, so as to meet current requirements safety and precision of movements in all pressure and flow conditions.

Our goal was to reduce the cost of building the device and its use and to make it compatible with a variable rate circuit dependent on the load (Load Sensing).

This first object is achieved by the fact that the cartridge valve to be inserted multifunctional coaxial hydraulic distribution is characterized in that it includes an oil inlet port, an oil return port, a valve control pressure inlet port, an outlet port delivering actuation pressure, a pressure reading port actuating oil, an orifice receiving this pressure information, a drainage orifice and an orifice for entering the balancing pressure, a first compensating slide urged towards a fully open position by a first spring, a second internal drawer concentric with the first one giving the main regulation of the oil inlet flow requested by a second spring against the control pressure delivered by the inlet of this pressure towards the closed position of communication between the oil pressure inlet port and the outlet port delivering the actuating pressure, an isolation valve and a make-up valve biased by a third spring to return these two valves to the f position communication shut-off towards the oil inlet port and pressure reading with regard to the isolation valve and towards the oil return port to the tank with regard to the make-up valve, a third balancer drawer biased by a fourth spring against the pressure delivered by the balancing pressure inlet port and the pressure delivered by the actuating outlet port towards the closed position of the communication between the actuation outlet port and the oil return port.

According to another characteristic, the various drawers and valves have their axes of coaxial symmetry and are arranged in a cylindrical jacket in two parts comprising on its periphery and spaced longitudinally from each other, the various orifices.

According to another characteristic, the cylindrical jacket is intended to be housed in a cavity having the respective bores corresponding to the dimensions of the jacket and the portion of the jacket located near the opening of the cavity has a thread external and internal thread.

According to another characteristic, a screw nut device for adjusting the force of the fourth spring is screwed into an internal thread.

According to another characteristic, the third drawer has external bores and an internal bore placing the return orifice in communication with the actuating outlet orifice when the drawer is released from its seat under the action of the pressures present in the bores external.

A final object of the invention was to apply these cartridge valves to the control of a double-acting cylinder in a distribution entirely incorporated in the cylinder to generate a simplification of the communications for the fluid between the different organs.

This latter goal is achieved by the fact that the control of the double-acting cylinder is ensured by two valves, the oil inlet ports of which are connected by the pipe made to the pump, the oil return ports are connected to the return circuit to the tank, the control pressure inlet ports of each of the valves are connected to the outputs of the control manipulator, the drainage ports are connected together and join the return pipe to the tank, the reading ports are each connected on the one hand to an input of a pressure priority selector, the output of which is connected to the pipe of the flow and pressure control mechanism of the pump, on the other hand with the balancing pressure input of the other valve, the outlet of the first valve being connected to a first chamber actuating the rod of the cylinder towards the outside, while the outlet of the second valve is connected to a second chamber actuating the tig e of the cylinder inwards.

According to another characteristic of the invention, the valve housing cavities can be incorporated into the jacks and the connecting pipes are also incorporated into the jacks.

According to another characteristic of the invention, the valves can be connected to the cylinders by flexible or rigid pipes.

Other characteristics and advantages of the present invention will appear more clearly on reading the description below made with reference to the single figure representing two cartridge valves associated so as to actuate a jack, each of the cartridge valves being represented by a half -cup along its axis of symmetry and an external view in the body of the jack in which this valve is incorporated.

For the sake of convenience, we will assimilate in the description which follows the body of the valve block with the body of the jack whether the body of the block is flanged on the body of the jack or whether it forms with it a one-piece assembly.

Each inlet or element designated by a letter will subscribe the number of the valve. Thus the control port X1 belongs to the valve 1, while the control port X2 belongs to the valve 2. A pipe 5 formed in the body 3 of the control cylinder A connects an outlet port of the manipulator to the orifice X1 for arriving at the control pressure of the valve 1. Likewise, the pipe 6 also formed in the body of the actuator A connects another outlet orifice of the manipulator to the orifice X2 arriving at the control pressure of the valve 2. The pipe 7 formed in the body of the jack A connects the outlet of the pump to the oil inlet orifices P1, P2 of each of the two valves 1 and 2. The pipe 8 also made in the body of the jack A connects the reservoir to the oil return orifices T1, T2 of each of the two valves 1 and 2 on the one hand, and on the other hand to the drainage orifices D1, D2 by the pipes 80. The orifices S1, S2 of reading of the actuating oil pressure are each connected to the inputs of a selector 4 whose s Nettle is connected to line 9 connected to the pump flow control input. The actuation oil pressure reading port S1 is also connected by a pipe 90 to the inlet port B2 of balancing pressure of the second valve 2, while the orifice S2 for reading the actuating oil pressure of the second valve is connected by a pipe 91 to the orifice B1 for entering the pressure of balancing of the first valve. Finally, the pressure reading ports S1 and S2 are also respectively connected to s1 and s2 bringing the oil pressure information to the pressure compensator of each valve. An outlet orifice R1 of the first valve delivers the actuating pressure to the first chamber A1 actuating the rod A3 of the jack towards the outside, indicated by the direction of the arrow. In another operating phase, an outlet orifice R2 of the second valve 2 also delivers the actuating pressure to a second chamber A2 of the jack actuating the rod A3 of the jack inward. Each of the valves 1, 2 is housed in the body 3 of the jack and more particularly in cavities formed by the succession of bores 29 to 36 co-axial and spaced longitudinally in the body of the jack. The bore 36 includes a thread in which is screwed an external thread F2 of the jacket 100 of the cartridge valve.

This jacket 100 in two parts assembled between the levels of the bores 33 and 34 has the orifices indicated above with the exception of the orifice D1 which is placed at the bottom of the cavity intended to receive the valve. This jacket 100 includes the bores intended to receive the various drawers and valves constituting the valve and a channel H putting the orifice R1 in communication with the orifice S1 or the orifice P1 according to the position of the second drawer J1.

The oil coming from the pressure inlet orifice P1 first crosses the flow control orifices of the first pressure compensating slide N1 which is biased towards a position of full opening of the passage by a first preload spring r1 , for example three or six bars. The pressure arrives in the groove of the drawer J1 and tends to compress the opening spring of the compensator in order to reduce the oil flow. On the other hand, after the throttle through the throttle due to the modulated position of the main spool J1, the pressure reading made in S1 will be brought back to s1 to help the preload spring r1 of the pressure compensator to reduce the throttle . The second drawer J1, in the order of passage of the oil arriving through the pressure inlet orifice, is permanently biased by a second spring r2 towards a rest position in which the chamber formed by the diameter 10 of the back of drawer J1 and the internal bore of the compensating drawer is reduced to its minimum volume. In this position the drawer J1 prevents the communication of the orifice P1 with on the one hand the orifice S1 and on the other hand the orifice R1. This drawer J1 also has an internal bore 15 which makes it possible to put the orifice S1 in communication with the orifice D1. In the pipe H internal to the jacket of the valve, a valve C is urged permanently by a third spring r3 towards a closed or insulating position in which this valve C rests on the seat 101 belonging to the jacket of the valve .

The liner 100 has in its internal bore Q an internal thread F1 on which a threaded screw L is mounted, itself supporting a screw system U and lock nut V, at the end of which are mounted a ball Y and a stop plate Z. This stop plate Z sealed on its outside diameter with the bore of the screw L, serves as a fulcrum for a fourth spring r4 which permanently urges a third drawer E1 called a balancing drawer towards a rest position in which the end 16 opposite the end receiving the spring r4 bears on the seat 102 of the make-up valve G. In this position of the balancing drawer E1, the orifice T1 is in communication with the internal bore 14 of the balancing drawer E1 but any communication of this bore with the orifice R1 is prevented. In the rest position, the orifice B1 is in communication with a chamber formed by the external bore 11 of the balancing slide E1 and the internal bore of the jacket 100, this chamber having in this position its minimum volume. The balancing slide E1 also has, near its end 16, a second external bore 12 of diameter smaller than the bore in which it is housed and making it possible to have an annular section, in general, of one third or one fifth of the section annular corresponding to bore 11.

In operation, when the output of the rod A3 of the jack is controlled by the manipulator, the pressure of the piloting circuit modulated by the manipulator between 0 and 20 bars for example arrives at the orifice X1 and ensures between these two values of pressure a displacement of the first slide J1 between a zero stroke and a maximum stroke modulating the oil inlet flow rate between zero and the maximum. The oil then moves from the inlet port P1 to the actuation outlet port R1, connected with the chamber A1 of the jack situated at the bottom of the latter to bring out the rod A3.

In passing, the port S1 provides a pressure reading which will be used by the circuit selector 4, the line 9 and the inlet port of the oil flow control regulator of the self-regulating pump to adjust the '' flow-pressure assembly on demand. Thus, the flow will be adjusted according to the position of the manipulator, position chosen by the operator of the machine and the pressure will be adjusted according to the positive or negative charge. When the drawer J1 puts the orifice P1 in communication with the pipe H, the pressure exerted on the isolation valve C pushes the latter and the spring r3 so as to put the pipe H in communication with the outlet orifice R1 .

If the flow of oil used is stopped by returning the manipulator to position 0, the spring r2 of the drawer J1 brings the latter back to flow closure and puts the reading orifice S1, isolated from the outlet orifice R1 and the cylinder by the isolation valve C, in communication with the drainage orifice D1. The pump no longer receiving via line 9 a pressure indication on its regulator, will stall in zero flow and will no longer consume energy.

The oil which leaves the outlet orifice R1 of the first valve 1 delivering the actuating pressure therefore tends to bring out the rod A3 from the jack in the direction indicated by the arrow. When this occurs, the oil on the other side of the piston is expelled from the chamber A2 towards the line 81 then towards the orifice R2 of the second valve 2 and, when the pressure is sufficient to push the third drawer E2 by the second valve 2, towards the return T2.

Closing of the return of the oil to the reservoir is therefore ensured by the seal between the balancer E2 on the seat 102 of the make-up valve G2 of the second valve 2. This makes it possible to ensure sufficient back pressure to control the movements and ensure that a variable load never becomes motive whatever the input flow.

However, as will be seen below, the balancing slide E2 of the second valve makes it possible to play the role of maximum pressure valve and of balancing valve. Indeed, the balancing drawer E2 tends to move away from the seat 102 by fighting against its calibration spring r4 under the effect of two forces (a) and (b) which add up. The first force (a) is due to the pressure brought to the orifice R2 and applying to the annular section of the end opposite to the spring of the balancing drawer E2 of the valve 2, this pressure tending to spread the drawer balancing E2 of the support of its seat 102 and ensures the maximum pressure valve function. The second force (b) is constituted by the pressure which applies to the annular section corresponding to the bore 11 of the balancing slide E2 of the second valve. This section is normally three to five times greater than the annular section corresponding to the pressure relief valve located at the part opposite the calibration spring and helps to open the communication between the ports R2 and T2. This force (b) resulting from the pressure delivered to the opening B2 from the reading opening pressure S1 is the balancing valve function. Indeed, in normal operation, the back pressure in the chamber A2 and in the pipe 81 is low, but if the load tends to become motive, there is no more pressure in the chamber A1 and, consequently, more of pressure either at the reading orifice S1 of the valve A1 and at the balancing orifice B2 of the valve 2. The annular section of the pressure relief valve at the end opposite to the spring of the balancing drawer as well as the spring r4 are calculated so that the maximum pressure induced by the load, when the latter tends to become motive, cannot cause the displacement of the balancing slide E2 in its valve overpressure valve function, and the movement tends to stop. As the pump continues to flow, its flow is blocked by the piston of the jack itself retained by the oil in the chamber A2, blocked by the balancing slide E2. The pressure rises in the chamber A1 and this pressure is reflected by the orifice S1 towards the balancing orifice B2 of the valve 2 and by this orifice B2 towards the opening assistance section, called the balancing section corresponding to bore 11. This action of pressures acting on the throttle of the return line, thus ensures a constantly modulated back pressure. This is called the balancing function.

In the event of an abrupt stop to a movement, the kinetic energy of the moving load is transformed into pressure which will be reduced to a progressive stop of the movement by the maximum pressure valve function of the balancing slide E2.

In the event of a hose rupture connecting the manipulators or the pump to the cylinders and to the distributors constituted by the valves, there is no longer any oil pressure on the ports R1 and S1 and, consequently, no more oil pressure on the balancing orifice B2 providing assistance in opening the valve in outlet control; in this case the movement is stopped and this complies with safety standards.

In the case of an action on the manipulator for the retraction of the rod, the operation is identical but the valve 2 becomes the control valve while the valve 1 becomes the balancing valve.

Finally, when an external force forces a cylinder normally stopped, to move (take out its rod, for example) the balancing slide E2 allows, in its pressure relief valve function, to evacuate the oil between the orifices R2 and T2 in the direction of movement, but this displacement causes a depression in the chamber A1 and, consequently, on the orifice R1. In this case, the make-up valve G1 is then unbalanced and causes its spring r2 to move back so as to allow passage between the orifices T1 and R1 of the valve 1 to fill the vacuum.

Other modifications within the reach of the skilled person are also part of the spirit of the invention. Thus, the two input and output control elements constituted respectively by the first drawer J and the second balancing drawer E, are normally designed to operate together in a single cartridge to be inserted, but they can be adapted to be dissociated and then constitute independent insert cartridges ensuring, one the input control function, the other the output control function. In particular, the cartridge valve, as described, can be used in the case where the regulation of the inlet flow is ensured by a potentiometric control transformed into a hydraulic control at modulated pressure by means of an electro-valve.

Claims (12)

1.- Cartridge valve to be inserted multifunctional co-axial hydraulic distribution characterized in that it comprises an oil inlet orifice (P1), an oil return orifice (T1), an orifice (X1) d valve control pressure inlet, an outlet orifice (R1) delivering the actuating pressure, an orifice (S1) for reading the actuating oil pressure, an orifice (s1) receiving the information pressure of (S1), a drainage orifice (D1), and an orifice (B1) for entering the balancing pressure, a first pressure compensation slide (N1) biased in the position for maintaining full passage by a first spring (r1), a second slide (J1) for adjusting the oil inlet flow rate, biased by a second spring (r2) against the control pressure delivered by the inlet orifice ( X1), towards the closed position of the communication between the oil pressure inlet port (P1) and the outlet port (R1) delivering the actuation pressure ement, an isolation valve (C) and a make-up valve (G), biased by a third spring (r3) against the flow delivered by the oil inlet orifice (P1), towards a closed position of the communication between the outlet orifice (R1) and the oil pressure reading orifice (S1), a third balancing slide (E1) biased by a fourth spring (r4) against of the pressure delivered by the balancing pressure orifice (B1), and of the pressure delivered by the actuation outlet orifice (R1) towards the closed position of the communication between the orifice (R1) of actuation outlet and the oil return port (T1) to the tank. 2.- Valve according to claim 1, characterized in that different drawers and valves have their axes of co-axial symmetry and are arranged in a cylindrical jacket (100) having on its periphery and spaced longitudinally from each other, the different orifices (P1, T1, X1, R1, S1, s1, B1). 3.- Valve according to claim 1 or 2, characterized in that the cylindrical jacket (100) is intended to be housed in a cavity comprising the respective bores (29 to 36) corresponding to the different diameters of the jacket and the portion of the jacket located near the opening of the cavity includes fixing means. 4.- Valve according to one of claims 2 to 3, characterized in that the jacket (100) has a communication channel (H), connecting the part of the internal bore (0) of the shirt and accommodating the first drawer (N) and the second drawer (J), with the internal bore (Q) accommodating the valves (C and G), and the balancing drawer (E). 5.- Valve according to one of the preceding claims, characterized in that the pressure compensating slide (N1) receiving at its two ends of equal sections the pressures upstream and downstream of the modulated orifice established by the conductor of the machine at the main distribution drawer (J1) and responsible for maintaining a constant pressure drop at this orifice thanks to its preload spring (r1) is mounted concentric with the main drawer (J1) and directly in contact with it. 6.- Valve according to one of the preceding claims, characterized in that the second drawer (J1) has an internal bore (15) connecting the drainage orifice (D1) with the orifice (S1) for reading actuating oil pressure. 7.- Valve according to one of the preceding claims, characterized in that the two isolation valves (C) and make-up (G) are mounted in a co-axial manner and in direct contact with one other and are biased in the opposite direction by a single spring (r3). 8.- Valve according to one of the preceding claims, characterized in that the third drawer (E) has external diameters (11 and 12) and an internal bore (14), the latter placing the orifice in communication oil return (T1) with the actuation outlet orifice (R1) when the slide (E1) is released from its seat (G) under the action of the pressures present around the diameters (12 and 11). 9.- Application of two valves (1 and 2) according to one of the preceding claims to the control of a double-acting cylinder (A), characterized in that the oil supplied by the pump on the pipe (7) arrives at the oil inlet ports (P1 and P2), the oil return ports (T1 and T2) are connected to the pipe (8) returning to the tank, the inlet ports (X1 and X2) control pressure of each of the valves are connected to the pipes (5 and 6) connected respectively to the orifices of the manipulator corresponding to the rod exit and rod reentry commands of the jack (A), the drainage ports (D1 and D2) are connected to the pipe (8) returning to the tank, the pressure reading orifices (S1 and S2) are each connected on the one hand to an input of a selector (4) whose output is connected to the pipe ( 9) controlling the pump flow, on the other hand with the balancing pressure input of the other valve respectively (B2, B1) as well as respectively to the orifices (s1) and (s2) supplying the oil pressure information to the pressure compensator, the outlet orifice (R1) of the first valve (1) being connected to a first chamber (A1) actuating the rod of the cylinder towards the outside, while the outlet orifice (R2) of the second valve (2) is connected to a second chamber (A2) actuating the rod of the cylinder towards the inside. 10.- Application according to claim 9, characterized in that the valve housing cavities are incorporated in the body 3 of the jack or in a removable block as well as the connecting pipes (5, 6, 7, 8, 9, 80, 81, 90, 91). 11.- Application according to claim 9, characterized in that the valves and valve holder blocks are connected to the cylinders by rigid pipes. 12.- Application according to claim 9, characterized in that the two oil inlet and outlet control elements respectively comprising one, the compensation drawers (N1) and for adjusting the inlet orifice of oil provided by the drawer (J1) as well as the orifices (P1, S1, s1, X1, and D1) and the other, the balancing drawer (E1) as well as the orifices (R1, T1 and B1) , are either combined in a single cartridge to operate together, or dissociated according to independent cartridges ensuring one the function of controlling the oil inlet, the other the function of controlling the return of oil to the reservoir.

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