FR3054007A1 - HYDRAULIC DISTRIBUTOR INSTALLATION WITH SCANNING VALVE - Google Patents

Abstract

Installation comprising control modules (Mi) connected to receivers (Ri), a pump (1) of liquid under pressure (Pr) by a pump line (P), a control line (LS) connected to the modules (Mi ) transmits the control pressure (Pc) to the pump (1). A sweep valve (4) has an inlet (42) connected to the pump line (P) and an outlet (43) connected to the return (T). Its piston (45) is subjected to the pressure of the pump line (P) in the opening direction and to the pressure (Pc) of the control line (LS) and to the thrust of a setting spring (46) in the direction of closing. The piston (45) has a continuously adjustable passage (451) connecting the pump line (P) to the return (T) and a second input (42) connected by an auxiliary line (L2) to the control line ( LS). The piston (45) has a continuously adjustable passage (452) connecting the second inlet (42) to the outlet (43) when the piston (45) is in the open position.

Description

(57) Installation comprising control modules (Mi) connected to receivers (Ri), a pump (1) of pressurized liquid (Pr) by a pump line (P), a control line (LS) connected to the modules (Mi) transmits the control pressure (Pc) to the pump (1). A sweep valve (4) has an inlet (42) connected to the pump line (P) and an outlet (43) connected to the return (T). Its piston (45) is subjected to the pressure of the pump line (P) in the opening direction and to the pressure (Pc) of the control line (LS) and to the thrust of a calibration spring (46) in the closing direction. The piston (45) has a continuously adjustable passage (451) connecting the pump line (P) to the return (T) and a second inlet (42) connected by an auxiliary line (L2) to the control line ( LS). The piston (45) has a continuously adjustable passage (452) connecting the second inlet (42) to the outlet (43) when the piston (45) is in the open position.

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Field of the invention

The present invention relates to a hydraulic distributor installation for supplying at least two hydraulic receivers comprising:

a control module connected to each receiver, a pump supplying hydraulic fluid at a regulated pressure, a pump line connecting the pump to the modules, a control line connected to the modules for transmitting the control pressure applied to the pump, and a return connected to the pump reservoir, a sweep valve having an inlet connected to the pump line and an outlet connected to the return and of which the piston is subjected:

in the opening direction, at the pressure of the pump line, in the closing direction, at the pressure of the control line and at the push of a calibration spring, the piston having an adjustable passage in continuous to connect, in the opening direction, the pump line to the return.

State of the art

Such an installation is known, represented in FIG. 5. The known hydraulic distributor installation is composed of control modules Mi, associated with receivers Ri for their supply of hydraulic liquid under controlled pressure Pr, supplied by a pump 1 controlled by a adjustment member 3. The pump 1 supplies the hydraulic fluid to the pump line P connected to the modules Mi. These are connected to a control line LS applying a control pressure Pc to the adjustment member 3. This control pressure Pc is obtained by a known processing from the operating pressure of the various modules Mi working in LS mode or in LUDV mode. A return line T receives the hydraulic liquid returned by the receivers Ri through the modules Mi to the tank 2 supplying the pump 1.

The supply line P is connected to the return T by a scanning valve 71 controlled by the set pressure Pr and the control pressure Pc.

The control line LS is connected to the return T by a pressure limiter 72 limiting the control pressure Pc and also by a flow regulator 73.

At rest, when the receivers Ri are all stopped, the pump 1 continues to operate with a minimum flow rate through the scanning valve 71; the liquid is then at a pressure fixed by the calibration spring 711 of this valve. Residual circulation is necessary to filter the liquid and cool it.

But when all the Mi modules are at rest, the pressure in the line LS must be eliminated so that the pump pressure returns to the low level which is that of the standby mode pressure ensuring only this circulation of liquid.

In this installation, the pressure in the LS line can only be reduced with a leak which is then permanent and also exists in normal mode when one or more receivers are activated. This permanent leak represents a significant loss of performance of the installation.

When a receiver is then activated, the pressure of the receiver load is added to the thrust of the spring 711 and the sweep valve 71 closes.

Purpose of the invention

The present invention aims to avoid permanent leakage to the tank to improve the efficiency and operation of the installation while simplifying the installation and reducing its cost.

Presentation and advantages of the invention

To this end, the subject of the present invention is an installation of the type defined above, characterized in that the scanning valve has a second inlet connected by an auxiliary line to the control line, and the piston of the scanning valve has a continuously adjustable passage, connecting the second inlet to the outlet towards the return when the piston is in the open position.

The installation according to the invention has the advantage of allowing the pump to operate with a minimum flow rate when no receiver is activated. This minimum flow passes through the sweep valve. At the same time, the sweep valve releases pressure from the control line so that the control pressure decreases and its control member thus reduces the flow rate of the pump. This reduction continues until the minimum flow.

In the simplest case, the pump controller operates as a closed control loop and the pump pressure will be equal to the pressure of the control line increased by a predefined pressure difference.

In this installation in normal operation, there will be no leakage of liquid to the return, which increases the yield. At rest, it also reduces energy loss.

According to another advantageous characteristic, the auxiliary line comprises a pressure limiter downstream of its connection to the second inlet and to the bypass connected to the piston.

This pressure relief valve advantageously supplements the sweep valve to relieve the control line in the event of overpressure therein.

According to another advantageous characteristic, the auxiliary line has a throttle upstream of the connection of its branch connected to the piston to absorb pressure shocks in the control line, in combination with the sweep valve.

This constriction allows the sweep valve to function as a pressure shock absorber in the control line.

According to another advantageous characteristic, the sweep valve, its sweep line, its bypass, its auxiliary line, its taps and the pressure limiter as well as the throttle are produced in a module crossed by lines and connected to the other modules, for example the input module.

The sweep valve is thus very easily integrated into the combination of modules constituting the hydraulic distributor installation which is generally constituted by a stack of modules in the form of plates, associated with the various receivers.

More specifically, the sweep valve is formed by a bore in the body of a module through which the pump, control pressure and return lines to the tank, these lines being connected to the inputs and to the output of the bore which receives a piston formed by a sleeve open at one end and the other end of which is closed by a bottom, this piston continuing at one end provided with a narrowing forming the first passage, holes in the sleeve performing the second passage of the piston.

This embodiment of the valve is particularly simple to carry out and of a reduced bulk.

Drawings

The present invention will be described below in more detail using different embodiments of a hydraulic distributor installation for supplying receivers, represented in the drawings in which:

Figure 1 is a simplified block diagram of a hydraulic distributor installation according to the invention, Figure 2 is a simplified diagram of a variant of the installation of Figure 1, Figure 3 is a simplified diagram of another variant of the installation of FIG. 1, FIGS. 4 and 4B show an embodiment of a scanning valve in the closed state in FIG. 4A and in the open state in FIG. 4B, FIG. 5 is a diagram of a known hydraulic distributor installation.

Description of embodiments of the invention

According to Figure 1, the invention relates to a hydraulic distributor installation for supplying at least two hydraulic receivers Ri with hydraulic liquid under controlled pressure Pr, supplied by a pump 1.

The installation consists of Mi control modules (i = l, 2 ...) each associated with a Ri receiver (i = l, 2 ...) to control its operation by supplying it with hydraulic fluid from the pump line P. The pressure of the hydraulic fluid at the level of the modules Mi is used to form the pressure of com3054007 demand Pc regulating the operation of the pump 1 by means of an adjustment member 3 not detailed.

The installation comprises, in addition to the pump line P which supplies the modules Mi, a control line LS (control pressure) which collects the pressure of the liquid treated at the level of the modules Mi, according to a procedure not described here, to form the pressure Pc command transmitted by the LS command line to the regulating member 3 of the pump 1. The operating principle of the Mi modules of the installation is for example that of load sensing usually called LS mode or that of the flow distribution (usually called LUDV mode).

The Mi modules are connected to the return line T and to the reservoir 2. This line T receives the hydraulic liquid leaving the receivers Ri through the Mi modules or directly a part of the liquid flow from the pump P according to the operating modes of the different Mi modules (intentional leak).

Usually, the Mi modules are elements in the form of stacked plates comprising different hydraulic passages and a distributor drawer connecting the passages to supply the associated receiver Ri in a controlled manner, from the supply line P and in return from the receiver to the return line T. The modules are also crossed by the command line LS.

These different lines are generally aligned passages, crossing all the modules and thus constituting a pipe. This is true for the pump line P but also for the LS control line and the return line T (or more simply the return T).

The command line LS transmits the control pressure Pc to the regulating member 3 of the pump 1 so that the latter supplies, in response to this command, the flow rate of hydraulic fluid required, at the set pressure Pr.

The pump line P is connected to the return line T by a scanning line L1 equipped with a scanning valve 4.

The scanning valve 4 has a first inlet 41 connected to the scanning line L1 and an outlet 43 connected to the return line T. It also has a second inlet 42 connected to the control line LS by an auxiliary line L2. The scanning valve 4 has a piston 45 having a cut-off segment S1 closing the connection between the inputs 41, 42 and the output 43 and an active segment S2 opening this connection.

The piston 45 is subjected to the pressure Pr of the supply line P through a bypass Lll of the line L1 applied to one of the faces of the piston 45. The piston is also subjected, on its other face, to the pressure control unit Pc or at a pressure deducted therefrom, transmitted via the auxiliary line L2 and a branch L21.

The pressure Pr of the line L1 acts in the direction of the opening of the communication through the scanning valve 4 towards the return line T, putting the segment S2 in communication with the inputs 41, 42 and the output 43.

The pressure Pc on line L2 acts in the direction of closing the communication to the return line T.

The thrust exerted on the piston 45 by the auxiliary line L2 is supplemented by the thrust exerted by a calibration spring 46.

The active segment S2 of the piston 45 has a first passage 451 for connecting the first inlet 41 to the outlet 43 and a second passage 452 for connecting the second inlet 42 to the outlet 43. The passages 451, 452 are continuously adjustable by displacement piston 45.

The sweep valve 4 is activated when no receiver Ri is working and thus the flow of hydraulic liquid in the supply line P to the modules Mi is stopped. The pressure Pr transmitted by the lines L1, L12 is then sufficient to move the piston 45 in the direction of opening while exceeding the control pressure transmitted by the lines L2, L21 and the thrust of the spring 46 so that the line LS begins to empty towards the return line T through the second passage 452. The pressure Pc decreases and as it is applied to the regulating member 3, the pump 1 reduces the flow rate to a fixed minimum flow rate.

When one of the Mi modules is actuated to control its receiver Ri, the Mi module communicates the pump line P and the pressure line LS so that the pressure in this line increases and as this pressure is applied to the member setting 3, the pump 1 supplies a flow at a pressure which increases progressively up to the flow necessary for the operation of the module (s) Mi. This increase in pressure results in an increase in the control pressure of the line LS which closes valve 4. There is then no longer any leakage of liquid towards the return T.

FIG. 2 shows a variant of the embodiment of the installation, generally presented in FIG. 1. According to this variant, the auxiliary line L2 is connected to the return T beyond the branch L21 by a pressure limiter 5 one side of the piston 55 of which is subjected to the pressure of the line LS by a branch L22 and the other side of which is subjected to the thrust of a spring 56 which fixes the triggering threshold of the pressure limiter 5.

FIG. 3 shows another variant of the embodiments of FIGS. 1 and 2 by supplementing the embodiment of FIG. 2 with a throttle 6 upstream of the connection of the sweep valve 4.

Under normal conditions, this embodiment operates like that of FIG. 2 but in the event of a pressure shock, if the pressure limiter 5 opens, the flow of hydraulic liquid thus generated produces a pressure drop in the throttle 6 so that the pressure applied to the second face of the piston 45 decreases and allows the brief opening of the scanning valve 4 which evacuates the pressure shock which could have been transmitted to the control line LS.

After this brief phase of absorbing the hydraulic shock, the sweep valve 4 and the pressure relief valve 5 close; the normal regime resumes its course and there is no longer any leakage of liquid towards the return T.

FIGS. 4A, 4B show an embodiment of a scanning valve according to the invention, installed in the body 100 of the module Mi. The scanning valve will be described below using, if possible, the references of FIG. 1.

Thus, the scanning valve 4 has a piston 45 housed in a bore 110 of the body 100 of the module Mi. The pump line P is connected by the scanning line Ll to the bore 110 by opening into the first inlet 41. The pressure line LS is connected to bore 110 by line L2 and opens there through the second inlet 42. The return line T to the reservoir is connected by outlet 43 to bore 110.

The piston 45 carries out the passage 451, 452 between the inputs 41, 42 and the output 43 or the interruption of this communication.

To simplify the description, the piston will bear here the new reference 120 as well as its parts, the equivalences with the references in FIG. 1 will be given during the description.

The valve 4 consists of a bore 110 closed by a plug 111 and receiving the piston 45/120. The piston 45/120 is a cylindrical sleeve 121 closed by a bottom 122 and provided with holes

123 passing through the sleeve 121. Beyond the bottom 122, the piston is extended by one end 125 with a narrowing 124 thus constituting the equivalent of the bypass line L11 to apply the pressure of the pump line P to the section of the piston. This end 125 is crossed by a bore 126 connecting the face 127 to the narrowing

124 and allowing the exchange of liquid with the cavity terminating the bore 110 by creating a hydraulic damping by a throttle 128 integrated in the bore 126. A return spring 46 housed in the plug 111 and in the sleeve 121 pushes the piston 45 / 120 to its closed position (low position) (Figure 4A).

In the operating position, the pressure Pc of the line LS and the thrust of the spring 46 push the piston 120 into the low closed position; in this position, the supply line P is cut from the return T as well as the control line LS (FIG. 4A).

Under the effect of the thrust of the hydraulic fluid from line P and the reduced pressure in line LS, the piston 220 is gradually raised to the high position; it then releases:

the passage between the line P and the return T, the holes 123 which then connect the line LS (42, L2) through the sleeve 221 to the return T (43) (FIG. 4B).

As already indicated, the Mi modules are elements similar to plates traversed by passages and by the bore receiving the distributor valve controlling the flow of hydraulic fluid to the ports to which the receivers are connected. The different passages in the plate are integrated therein and are independent of those of the other module plates. The only elements common to the different plates (modules) are the holes crossing the plates perpendicular to their plane and forming the lines P, LS, T.

The stacking of the plates of the Mi modules is completed by an end plate closing the holes opening into the lines P, LS, T and the plate of the input module integrating the lines Ll, Lll, L2, L21, L22, la sweep valve 4, pressure relief valve 5 and throttle 6.

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NOMENCLATURE

Pump

Tank

Pump regulator

Sweep valve

First entry

Second entry

Exit

Piston

451 First pass

452 Second pass

Taring spring

Pressure limiter

Piston

Taring spring

Choking

100 Module body

110 Bore

111 Plug

120 Piston

121 Cylindrical sleeve

122 Background

123 Drilling

124 Narrowing

125 Piston end

126 Drilling

127 Face

128 Strangulation

P Pump line

LS Pressure line

T Return / return line

Mi control module

Ri Receiver associated with the Mi module L1 Scan line Lll Derivation of line L1 L2 Auxiliary line L21 L2 auxiliary line bypass L22 L2 auxiliary line bypass IF Cut-off segment S2 Active segment

Claims (4)

1 °) Installation of a hydraulic distributor to supply at least two hydraulic receivers comprising: a control module (Mi) connected to each receiver (Ri), a pump (1) supplying hydraulic fluid at regulated pressure (Pr), a pump line (P) connecting the pump (1) to the modules (Mi), a control line (LS) connected to the modules (Mi) to transmit the control pressure (Pc) applied to the pump (1), a return (T) connected to the reservoir (2) of the pump (1), a valve sweep (4) having an inlet (41) connected to the pump line (P) by a sweep line (Ll) and an outlet (43) connected to the return (T), and of which the piston (45) is subject : in the opening direction, at the pressure (Pr) of the pump line (P), in the closing direction, at the pressure (Pc) of the control line (LS) and at the thrust of a calibration spring (46), the piston (45) having a continuously adjustable passage (451) for connecting, in the opening direction, the pump line (P) to the return (T), installation characterized in that that the scanning valve (4) has a second inlet (42) connected by an auxiliary line (L2) to the control line (LS), and the piston (45) of the scanning valve (4) has a passage ( 452) infinitely adjustable, connecting the second inlet (42) to the outlet (43) towards the return (T) when the piston (45) is in the open position. 2) installation of a hydraulic distributor according to claim 1, characterized in that the auxiliary line (L2) connecting the control line (LS) to the second inlet (42) of the sweep valve (4) comprises a pressure limiter (5) downstream of this connection to the second inlet (42) and to the bypass (L21) connected to the piston (45) of the scanning valve (4). 3 °) installation of hydraulic distributor according to claim 2, characterized in that the auxiliary line (L2) has a throttle (6) upstream of the connection of its branch (L21) connected to the piston (45) to absorb pressure shocks in the command line (LS), in combination with the valve 5 scan (4). 4 °) installation of hydraulic distributor according to any one of claims 1 to 3, characterized in that the scanning valve (4), its scanning line (L1), its bypass (Lll), its auxiliary line (L2 ), its branches (L21, L22) and the pressure limiter (5) as well as the throttle (6) are produced in a module crossed by the lines (P, LS, T) and connected to the other modules (Mi). 5) installation of a hydraulic distributor according to claim 1, characterized in that the scanning valve (4) is formed by a bore (110) in the body (100) of a module (Mi) crossed by the lines (P, LS, T) connected to the inputs (41, 42) and to the output (43) of the bore (110), and 20 the piston (45/120) is formed by a sleeve (121) open at one end and the other end of which is closed by a bottom (122) and continuing at one end (125) provided with a narrowing ( 124) forming the first passage (451), holes (123) in the sleeve (121) providing the second passage (452) of the piston (45). y / 4 co