Background of the invention

The invention relates to a distribution valve.

Specifically, but not exclusively, the invention can be used in the context of an operating machine for making a modular system with a series of modules or valve sections to connect a pump to a plurality of hydraulic actuators.

In particular, reference is made to a distribution valve provided with a pressure compensator.

Various modular valve systems with pressure compensation are already known for the hydraulic control of a plurality of actuators, such as, for example the modular systems shown in patent publications US 5579642, US 5890362, US 2008/0282691,

US 2009/0173067, EP 1610002, EP 1628018.

US 2008/000535 discloses a distribution valve as in the preamble of claim 1.

Summary of the invention

One object of the invention is to improve prior-art distribution valves with pressure compensators.

One advantage of the invention is to make a valve with relatively reduced dimensions. The valve may be advantageously compact and in particular it can be used, by way of example, for operating fluid flows up to 35 litres/minute with a pressure difference of ΔΡ = 8 bar.

Another advantage is to provide a constructionally simple and cheap valve.

A further advantage is to enable several actuators to be driven simultaneously.

Still another advantage is to permit substantially constant speed of the actuator, or of the actuators, also as the load varies, in particular by keeping constant the pressure difference through the valve, for example by means of a regulating choke.

Another advantage is to provide a distribution valve that integrates a pressure compensator and combines relatively high performance and relatively compact dimensions. Another advantage is to make available a valve that can be used in the context of control systems of hydraulic actuators and which for this purpose can be associated with already existing components, with a consequent reduction of costs. Another advantage is the reduced consumption of energy required to regulate the valve.

These objects and advantages and still others are all achieved by the valve according to one or more of the claims set out below.

Brief description of the drawings

The invention can be better understood and actuated with reference to the attached drawings that illustrate some non- limiting embodiments thereof.

Figure 1 is a perspective view of the valve.

Figure 2 is a side view of the valve in figure 1.

Figure 3 is the section III-III in figure 2.

Figure 4 is an enlarged detail in figure 3.

Figure 5 is the section V-V in figure 2.

Figure 6 is an enlarged detail in figure 5.

Figure 7 is a perspective view of a solid body that represents, negatively, the hollow parts of the valve body 2 of the valve in figure 1.

Figure 8 is a frontal view of the solid body in figure 7. Figure 9 is a view from the left of figure 8.

Figure 10 is a view from the right of figure 8.

Figure 11 is a bottom view in figure 8.

Figure 12 is a top view in figure 8.

Figure 13 is a frontal view of the distribution cursor 13 of the fluid flow.

Figure 14 is the section XIV-XIV in figure 13.

Figure 15 is a diagram of the operating fluid flow as a function of the position of the cursor 13.

Figure 16 is a fragmentary section that shows a detail of any of the two ports 10A or 10B supplying the operating fluid (in particular the port has been illustrated 10A) , the port comprising a flow-limiting device that in the specific case is of the type configured for use with magnets and cursor of the ON/OFF type.

Figure 17 is a hydraulic diagram of the valve in figure 1. Figure 18 is a diagram of a modular system of hydraulic control of a plurality of actuators that uses two or more valves like that in figure 1.

Detailed description

With reference to the above figures, with 1 a distribution valve is indicated overall having a valve body 2. The valve body 2 has externally a first face 3 and a second face 4 opposite the first face 3. The first face 3 and the second face 4 can be substantially flat, or at least partially flat, and parallel to one another.

The valve 1 can be used, as in this specific case, to make a module of a modular control system of a plurality of hydraulic actuators. The modular system, schematically illustrated in figure 18, comprises a plurality of valves 1 placed serially alongside one another (with a parallel hydraulic connection) , with the first face 3 of a valve coupled with the second face 4 of the adjacent valve such that one or more conduits obtained inside the valve body of a valve are in fluid communication with one or more conduits obtained inside the valve body of the adjacent valve. At least one corresponding hydraulic actuator (which is of known type and not illustrated) can be operationally associated with every valve 1.

The modular system of hydraulic control is used, in particular, on an operating machine of know type provided with various hydraulic actuators.

The valve body 2 can be optionally made by fusion of material, for example made of cast iron or of another (metal) material through casting. The valve body 2 has hollow portions inside that are configured for the passage of an operating fluid and/or for housing operating elements of the valve 1. For greater clarity, these hollow portions are shown for greater clarity as full portions (a solid body) in figures 7 to 12. These hollow portions are now disclosed in greater detail.

Internally, the valve body 2 has an inlet conduit 5 that, in the assembled configuration of the modular system, is optionally connected to a delivery of operating fluid (in the case in point it is collected to the delivery of a hydraulic pump) . The inlet conduit 5 optionally crosses the valve body 2 from one side to the other. In the specific case the inlet conduit 5 has opposite ends that end on two opposite faces (first face 3 and second face 4) of the valve body 2. The inlet conduit 5 can be substantially rectilinear, and, for example, perpendicular to the opposite faces.

Internally, the valve body 2 has an outlet conduit 6, that, in the assembled configuration of the modular system, is optionally connected to a discharge of operating fluid (in the specific case the discharge is connected to the inlet of the hydraulic pump) . The outlet conduit 6 optionally crosses the valve body 2 from one side to the other. In the specific case the outlet conduit 6 has opposite ends that end on two opposite faces (first face 3 and second face 4) of the valve body 2. The outlet conduit 6 can be substantially rectilinear and, for example, perpendicular to the opposite faces. The outlet conduit 6 is optionally parallel to the inlet conduit 5. The longitudinal axis of the outlet conduit 6 and the longitudinal axis of the inlet conduit 5 are optionally coplanar and can define a plane that passes through these longitudinal axes and is transverse to the opposite faces 3 and 4. This transverse plane is optionally a substantially median plane of the valve body 2.

Internally, the valve body 2 has a distributor seat 7 that hosts a distributor that is configured for controlling the direction (distribution) of the operating fluid in relation to the actuator.

In the specific case the distributor is of the four-way and three-position type. It is possible to provide for the distributor being of another type, such as, for example of the four-way and two-position type. The distributor seat 7 comprises a cavity extending in length along a longitudinal axis that may be transverse (optionally perpendicular) to the plane passing through the longitudinal axes of the conduits 5 and 6. This cavity of the distributor seat 7 has some recesses that define the operating ways of the distributor. These recesses optionally comprise a first central recess 71, a second intermediate recess 72 and a third intermediate recess 73 arranged on opposite sides of the first recess 71, a fourth end recess 74 and a fifth end recess 75 arranged on a side of the second recess 72 and respectively of the third recess 73 opposite with respect to the first recess 71.

Internally, the valve body 2 has a compensator seat 8 that houses a pressure compensator configured for maintaining substantially constant the pressure difference between two zones of the hydraulic circuit, as will be better explained below. The compensator seat 8 comprises a cavity extending in length according to a longitudinal axis that may be transverse (optionally perpendicular) to the plane passing through the longitudinal axes of the conduits 5 and 6. The longitudinal axis of the compensator seat 8 can be, for example, substantially parallel to the longitudinal axis of the distributor seat 7.

Internally, the valve body 2 has a first user conduit Al and a second user conduit Bl that are connected respectively to the second recess 72 and to the third recess 73. In the use configuration the user conduits Al and Bl will be connected, in a known manner, to a hydraulic actuator, in particular to two sides (users A and B) of the actuator.

The valve body 2 has a third face 9 that may have, as in the specific case, two fluid ports 10A and 10B connected respectively to the first user conduit Al and to the second user conduit Bl . The two fluid ports 10A and 10B are substantially coplanar. The third face 9 can be, as in the specific case, transverse both to the first face 3 and to the second face 4. The third face 9 can connect, as in the specific case, the first face 3 to the second face 4. The fluid ports 10A and 10B are configured for connection (for example of removable type) to the actuator, in particular to the two operating sides A and B of the actuator.

The distance of each point (or the average distance of the various points) of the longitudinal axis of the distributor seat 7 from the third face 9 may be, as in the specific case, greater than the distance from each point (or the average distance of the various points) of the longitudinal axis of the inlet conduit 5 from the third face 9. The distance of each point (or the average distance of the various points) of the longitudinal axis of the outlet conduit 6 from the third face 9 can be, as in the specific case, greater than the distance of each point (or the average distance of the various points) of the longitudinal axis of the inlet conduit 5 from the third face 9, and/or greater than the distance of each point (or the average distance of the various points) of the longitudinal axis of the distributor seat 7 from the third face 9. The distance of each point (or the average distance of the various points) of the longitudinal axis of the compensator seat 8 from the third face 9 can be, as in the specific case, greater than the distance of each point (or the average distance of the various points) of the longitudinal axis of the inlet conduit 5 from the third face 9, and/or greater than the distance of each point (or the average distance of the various points) of the longitudinal axis of the distributor seat 7 from the third face 9, and/or greater than the distance of each point (or the average distance of the various points) of the longitudinal axis of the outlet conduit 6 from the third face 9.

The inlet conduit 5 is connected to the distributor seat 7. In particular, the inlet conduit 5 can be connected to the distributor seat 7 by the compensator seat 8. The compensator seat 8 can be interposed between the inlet conduit 5 and the distributor seat 7 in such a manner that the passage of the operating fluid between the inlet conduit 5 and the distributor seat 7 can occur only via the passage of the fluid through at least one part of the compensator seat 8. For this purpose it is possible to set up a first conduit 11 that connects the inlet conduit 5 to the compensator seat 8, and a second conduit 12 that connects the compensator seat 8 to the distributor seat 7. The first conduit 11 may have an end that terminates in an inlet recess 81 of the cavity of the compensator seat 8. The second conduit 12 may have an end that terminates in an outlet recess 82 of the cavity of the compensator seat 8. The inlet recess 81 and the outlet recess 82 can be arranged next to one another at a mutually axial distance. The second conduit 12 may have an end that terminates in the distributor seat 7, in particular, as in the illustrated example, in the first central recess 71 of the seat.

The outlet conduit 6 is connected to the distributor seat 7. For this purpose, internally the valve body 2 can have a first outlet branch 61 and a second outlet branch 62 that connect the outlet conduit 6 respectively to the fourth recess 74 and to the fifth recess 75.

The distributor seat 7 can be situated at least partially in a region of the valve body 2 comprised between the inlet conduit 5 and the outlet conduit 6.

The outlet conduit 6 can be situated at least partially in a region of the valve body 2 comprised between the distributor seat 7 and the compensator seat 8.

The outlet conduit 6 can be situated at least partially in a region of the valve body 2 comprised between the first conduit 11 and the second conduit 12.

The outlet conduit 6 can be situated at least partially in a region of the valve body 2 comprised between the compensator seat 8 and the inlet conduit 5.

The distributor seat 7 can be situated at least partially in a region of the valve body 2 comprised between the inlet conduit 5 and the compensator seat 8.

The distributor, which is optionally of the proportional type and can be, as in the specific case, of the four-way (delivery, discharge and two users) and three-position type, comprises a cursor 13 that is axially slidable in the distributor seat 7. The cursor 13 is configured so as to be able to assume at least three operating configurations in which it respectively locks the actuator (preventing fluid communication between the four paths, i.e. between the various recesses 71, 72, 73 and 74/75), drives the actuator in one direction by supplying one of the two users (enabling fluid communication between the recesses 71 and 72 and between the recesses 73 and 75) , drives the actuator in the opposite direction by supplying the other user (enabling fluid communication between the recesses 71 and 73 and between the recesses 72 and 74) . It is possible to provide, as a non-illustrated example, for the cursor being optionally configured in such a manner that, in the central position of the cursor, the recess 71 is locked and moreover that the recess 73 is placed in communicate with the recess 75 and the recess 72 is placed in communication with the recess 74.

The distributor comprises driving means, of known type, for example of electric type (solenoid) for controlling the axial sliding of the cursor 13 in one direction and/or in the opposite direction. The distributor may comprise two elastic elements (springs) that operate on the cursor 13 with opposite actions.

The cursor 13 comprises an external surface that has various seal zones that are slidingly coupled with the internal surface of the distributor seat 7 to make a fluid seal in a known manner in the zones of the seat comprised between the various recesses and in the zones most outside the recesses. The seal zones optionally have a cylindrical shape (with, optionally, one or more circumferal grooves) . The seal zones optionally terminate in a chamfered (for example frustum- conical) surface to promote the operating linearity of the distributor. The seal zones may have at the ends (for example in the chamfered surface, if it exists, as in the specific case) a niche or, as in the specific case, two niches 14 (situated diametrically opposite one another) , or more than two niches, to promote the operating linearity of the distributor. The niche 14 can be bounded at least partially by a tilted surface (for example with a frustum conical sector shape) . The maximum width of the niche 14 may be a fraction (for example comprised between 20% and 80%) of the diameter of the seal zone. It is possible, as in the specific case, to set up at least one niche 14 arranged on the edge of the seal zone that operates between the fifth recess 75 and the third recess 73, and/or at least a niche 14 arranged on the edge of the seal zone that operates between the first recess 71 and the third recess 73, and/or at least one niche 14 arranged on the edge of the seal zone that operates between the first recess 71 and the second recess 72, and/or at least one niche 14 arranged on the edge of the seal zone that operates between the fourth recess 74 and the second recess 72.

The diagram in figure 15, that shows the operating fluid flow as a function of the position of the cursor 13, shows the operating linearity of the distributor. This linearity may be promoted and/or obtained, in particular, owing to a specific conformation of the cursor 13 provided with niches 14 (for example as illustrated in figures 13 and 14) .

The diagram refers to a situation in which the pressure difference ΔΡ between the valve inlet and outlet is 8 bar. In the diagram the position of the cursor is given as a percentage on the horizontal axis, where the position 0 (zero) indicates the cursor 13 in central position and the position 100 (cent) indicates the cursor 13 in any of the two possible end positions (with the operating fluid directed towards the user A or to the user B) .

The compensator comprises a movable compensating element 15 that can slide axially within the compensator seat 8. An elastic element (spring) pushes axially on a side of the compensating element 15 at a preset force. The compensating element 15, for example the aforesaid side of the compensating element 15 where the elastic element operates, can be set up for being placed in selective communication with the first user conduit Al or with the second user conduit Bl, according to whether the user conduit Al or Bl is connected to the delivery (see hydraulic diagram in figure 17) . This communication may optionally comprise a three-way valve with a movable shutter that selectively shuts a first way (connected to the first port 10A) or a second way (connected to the second port 10B) , according to which way is connected to the port connected in that moment by means of the distributor to the discharge, and which leaves a third way (connected to the compensator and/or to an auxiliary conduit 16) in fluid communication with the one between the first way and the second way that is not closed but connected by the distributor to the delivery of the pump P. This communication may comprise, for example, a conduit having a local pressure drop (for example an adjustable or fixed throttle) . It is in fact possible that, in particular if the distributor is of the proportional type, the means for defining the local pressure drop (for example the throttle) is adjustable, for example for varying the pressure drop as a function of the position of the cursor of the distributor. It is possible that, particularly if the distributor is of the type with magnets and an ON/OFF cursor, the throttling and therefore the local pressure drop can be fixed in a preset manner, as in the illustrated example in which the pressure drop is determined by the drilled screw 18, in which the dimensions of the hole in the screw is chosen on the basis of conditions of use, for example as a function of the features of the system in which the valve is used.

The side of the compensating element 15 opposite the side facing the inlet recess 81 (i.e. opposite the delivery) is subjected to a reference pressure that depends on the supply pressure of the actuator (for example it is the same as this pressure less local apart from distributed and/or local pressure losses), i.e. of the pressure at the fluid door 10A or 10B that, at that moment, supplies the operating fluid to the actuator.

In use, the movable compensating element 15 of the pressure compensator is subjected, on an end side, to the supply pressure at the valve inlet, and, on the opposite end side, to the sum of the force due to the elastic element and the force due to the reference pressure (taken from the way of the distributor that at that moment is connected to the supply of the actuator), to the object of maintaining the pressure drop substantially constant between the inlet of the valve and the (inlet) supply of the actuator.

The operating fluid flow that first passes through the pressure compensator and then through the distributor, and then supplies the actuator, remains substantially constant as the load on the actuator changes.

The valve optionally comprises an auxiliary conduit 16 that is connected to the user conduits Al and Bl so as to be selectively in fluid communication with the user conduit Al or Bl that delivers the operating fluid to the user A or B. The auxiliary conduit 16 is configured for the passage of a pressure signal coming from the user conduit Al or Bl connected to the delivery. This pressure signal can be used to control the pump that supplies the operating fluid. The auxiliary conduit 16 optionally crosses the valve body from one side to the other, for example with a longitudinal axis substantially parallel to the longitudinal axis of the distributor seat 7.

In figure 18 a modular system is schematically shown, comprising two or more modules or sections, each comprising a valve 1 of the type disclosed above. The modular system comprises a pump P that supplies the operating fluid at delivery pressure and a discharge T that receives the operating fluid leaving the actuators and which is connected to the inlet of the pump P. Each valve 1 (module) of the modular system is connected to the two users A and B, which may be the opposite sides of a corresponding hydraulic actuator .

The various valves 1 (modules or sections) are placed alongside one another and can be fixed together by locking elements, such as, for example, tie rods, inserted into holes 17. The various valves 1 are clamped in a block such that the inlet conduit 5 and the outlet conduit 6 of each valve are in fluid communication (in particular aligned) with the inlet conduit 5 and the outlet conduit 6 of the adjacent valves. It is possible to provide for the various auxiliary conduits 16 of the valves being in reciprocal communication (for example co-aligned) to transmit to the pump a signal indicating the supply pressure of the actuator that works at greatest pressure .

The valve can be controlled electrically, for example with reels of the on/off and of the proportional type, or manually. It is optional to set up a device for determining the maximum flow that is dispensable from the valve, for example a device comprising a drilled screw 18 operating on one or both the fluid ports 10A and 10B to limit the flow (in the specific case illustrated here of a distributor with assembly of the magnets and ON/OFF cursor type) .

Legend

1 distribution valve

2 valve body

3 first face

4 second face

5 inlet conduit

6 outlet conduit

61 first outlet branch

62 second outlet branch

7 distributor seat

71 first recess

72 second recess

73 third recess

74 fourth recess 75 fifth recess

8 compensator seat

81 inlet recess

82 outlet recess

9 third face

10A, 10B fluid ports

11 first conduit

12 second conduit

13 cursor

14 niches

15 compensating element

16 auxiliary conduit

17 holes for tie rods

18 drilled screw

Al first user conduit

Bl second user conduit

A first user

B second user

P pump

T discharge