Hydraulic device including regenerative function

Abstract

To provide a hydraulic device that can maximize regeneration efficiency.SOLUTION: A hydraulic device (100) connected to a cylinder (V) having two chambers (C1, C2) separated by a piston (VP), includes two independent electrohydraulic modules (M1, M2) that are connected to the corresponding chambers (C1, C2), each of which has a directional control slide valve having main slide valves (1, 1') controlled by a control slide valve (2). A regeneration line (LR) connects chamber lines (L1, L2) via the directional control slide valve (1') of one (M2) of the modules (M1, M2).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hydraulic system with regeneration having an isolated directional control valve.

[0002] 2. Background of the Invention Hydraulic devices are already known in which the cross section regulating the inlet flow rate of the cylinder supplied by the hydraulic device and the cross section regulating the outlet flow rate are controlled relative to each other, as described in US 2010 / 0180761 A1, but devices for reducing the outlet flow rate are difficult to control and operate erratically.

[0003] In the device of DE 10 2008 064 064 A1, the two slide valves regulating the outflow rate receive a pilot pressure signal coming from a main slide valve in the other part of the device.

[0004] This complicates the design of the directional control valve, as the two parts of the device cannot be separated, one part connected to one chamber of the cylinder and the other part connected to the other chamber of the cylinder, since two additional pilot hydraulic lines would be required to connect the two main directional control valves.

[0005] In other words, the hydraulic devices currently supplying the cylinder, i.e. the chambers at the rear of the cylinder and at the rod side of the cylinder, are equipped with the same directional control slide valve, so that the outlet cross section of the cylinder as well as the inlet cross section varies with the stroke of the slide valve. Since the outflow rate of the cylinder does not depend only on the inflow rate, this means that the outlet cross section can be larger or smaller in size during normal use of the device.

[0006] Since the outlet flow rate also depends on the load on the cylinder and is related to the available flow rate delivered by the pump, the resulting back pressure is not constant and therefore the travel speed under load is not constant for the same input signal from the operator (movement of the control lever) under various loads. Restricting the cross section increases the stability of the operation but also increases the energy losses. The outlet cross section is in principle dimensioned to allow the load to be controlled in the worst case of movement. This causes restrictions in some applications, which increase the energy losses and the return flow directly reaches the tank conduit, resulting in energy losses.

[0007] Object of the invention The object of the present invention is to develop a hydraulic device connected to a cylinder, which allows the inlet and outlet cross sections of each of the two chambers of the cylinder to be distributed independently, thereby maximizing the efficiency of regeneration.

[0008] Disclosure and Advantages of the Invention To that end, the invention is directed to a hydraulic device connected to a cylinder having two chambers separated by a piston, a rod passing through one of the chambers being connected to the equipment, the device being characterized in that it has a control unit connected to a lever actuated by an operator to operate the equipment with the cylinder, a pump supplying the chamber of the cylinder via a pump line and a tank receiving hydraulic fluid returning from the cylinder via a tank line, the device being characterized in that it has two independent electro-hydraulic modules connected to the corresponding chamber, the pump line and the tank line via the chamber lines, each electro-hydraulic module having a directional control slide valve, each of which has a proportional hydraulic main slide valve connecting the conduits of the chamber to the pump line and the return line, a pilot chamber for hydraulically operating the main slide valve, and a directional control slide valve controlled by a proportional electro-hydraulic controlled slide valve connecting the pump line to the pilot chamber and receiving a control signal from the control unit, and a regeneration line connecting the chamber line via one of the directional control slide valves of the module.

[0009] This hydraulic device makes it possible to make the regeneration more efficient, since it is complete when it comes from the chamber of the cylinder through which the rod passes, and partial when it comes from the chamber of the cylinder head.

[0010] According to one feature, the slide valve of the proportional directional control slide valve to which the chamber line may be connected has a section connecting the ports of the lines, which section closes the ports of the pump line and allows access to the ports of the tank.

[0011] According to another advantageous feature, the slide valve of the directional control slide valve has a section which closes four ports: the chamber line, the regenerative line, the pump line and the tank line.

[0012] In this hydraulic device, the control unit is connected to the lever, * the inlet cross section of the unit that receives the inflow of the cylinder, *Outlet cross section of the unit that receives the cylinder's outflow Generates an electrical signal that controls the

[0013] In particular, the set cross section of the orifice through which the outflow passes is given by the simplified Bernoulli equation:

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[0014] The set pressure Pcp is -predetermined fixed value, - Variable value according to lever operation, -Value obtained from pressure sensor measurements is selected from.

[0015] The present invention is directed to a hydraulic device for managing the operation of a hydraulic machine as illustrated in the accompanying drawings. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram of the hydraulic mechanism of the device for mounting hydraulic machines such as cylinders. [Diagram 2] FIG. 2 is a detailed hydraulic diagram of one of the two modules of the hydraulic device. [Diagram 3] FIG. 2 is a diagram of the hydraulic system of the device according to the invention operating in full regenerative mode. [Figure 4] FIG. 2 is a diagram of the hydraulic system of the device according to the invention operating in partial recuperation mode.

[0017] Description of the Preferred Embodiments of the Invention As a general convention, the terms "line" and "conduit" are used in the claims synonymously and describe a fluid connection.

[0018] 1, the object of the invention is an electrohydraulic device 100 associated with a cylinder V connected to equipment for manipulating a load. The cylinder V has two chambers C1, C2 separated by a piston VP associated with a cylinder rod VT connected to the equipment.

[0019] The volumes of the two chambers C1, C2 change with the movement of the piston according to the ratio of the free cross sections S1, S2 of the two chambers, the cross section SB of the chamber VB through which the rod VT passes is a cross section of the bore, and the cross section S2 of the chamber C2 through which the rod VT passes is a cross section of the bore reduced by the cross section of the rod VT.

[0020] According to the commanded operation of the cylinder V, one of the chambers C1, C2 receives an inflow Qin, while the other chamber C2, C1 provides an outflow Qout. The flow rates are the ratio of the cross-sectional areas of the chambers as well as the change in their volumes: Ql / Q2=Sl / S2.

[0021] The electrohydraulic device 100 associated with the cylinder V consists of two separate electrohydraulic modules M1, M2, independently controlled by a control unit UC, which are interconnected and connect each one of the chambers to a pump line LP coming from the pump P and to a tank line LT for returning the hydraulic fluid to a tank T.

[0022] Each module M1, M2 has a directional control slide valve 1, 1' whose throttle cross section can be adjusted independently, this cross section being determined by an electric signal Σ(Ses) generated by a control unit UC receiving a signal Sm of a lever Mn operated by the driver, and the following parameters: - Fixed or variable setting back pressure PCP assigned to output chamber -Tank pressure PT - Flow rate Qin into the input chamber (C1 or C2) Each module is controlled separately by

[0023] These parameters enable the control unit UC to calculate the throttle outlet cross section Ses for the outlet flow rate Qout, which is thus determined by the theoretical inlet flow rate related to the position of the lever Mn.

[0024] The central unit UC applies the simplified Bernoulli equation to obtain the outlet cross section Ses for the outflow rate Qout.

[0025]

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[0026] In this device, the set pressure is -predetermined fixed value, - a variable value according to the operation of the lever; -Value obtained from pressure sensor measurements is selected from.

[0027] The outlet cross section for the defined flow rate is the set outlet cross section Sec of the module receiving the outflow flow Qout, this cross section being issued by the central unit UC in the form of a control electrical signal Σ(Sec).

[0028] The inlet flow rate Qin is a flow rate that depends, among other things, on the position of the lever. This set inlet flow rate determines the outlet flow rate Qout that is used to calculate the set outlet cross section Sec.

[0029] The device 100 is supplied with pressurized hydraulic fluid by a pump P regulated on the basis of a specific supply pressure, which is supplied by return of hydraulic fluid from a tank T. The output line LP of the pump is connected to the inlets of two modules M1, M2, the outlets of which are connected to a tank line LT.

[0030] According to FIG. 1, the module M1 comprises a directional control valve with a proportional directional control main slide valve, which is controlled by a pilot chamber 11 that moves the slide valve 1 from the rest position shown in FIG. 1, and the module M1 is connected to the line L1 of the chamber C1, to the pump line LP and to the tank line LT, to which it is connected in the rest position returned by a spring 12.

[0031] The pilot chamber 11, controlled by hydraulic fluid supplied by the control slide valve 2, moves the main slide valve 1 to place the supply section 113 between the conduits LP and L1, supplying chamber Cl with hydraulic fluid (incoming flow Qin). In the reverse operation, section 111 connects line L1 to the tank line LT for the outgoing flow Qout from chamber C1.

[0032] The two compartments 111 and 113 are separated by an intermediate compartment 112 which blocks communication through the slide valve 1 .

[0033] The pilot chamber 11 associated with the main slide valve 1 is controlled by a control slide valve 2. This control slide valve is a proportional slide valve and is actuated by an electric control device 21 which receives a control signal Σ(Se) from a control unit UC. The control slide valve 2 is returned by a spring 22 to a rest position in which the line of the pilot chamber 11 is connected to the tank line LT.

[0034] To regulate the inlet flow rate Qin, the control slide valve 2 receives a signal Σ(Se) from the control unit UC and connects the pump line LP to an outlet towards the pilot chamber 11, which proportionally operates the main slide valve 1 while adjusting the throttle cross section Se in response to the signal Σ(Se).

[0035] The module M1, previously described as an input unit of the function of adjusting the inlet cross section of the cylinder, works in the same way as the output module, but by inverting the calculation of the outlet cross section: the control signals Σ(Se)Σ(Sec) are inverted.

[0036] The module M2 comprises a directional control valve with a proportional main directional control slide valve 1', the pilot chamber 11 being controlled by moving the slide valve 1' from the rest position shown in Figure 1, and the module M2 is connected to the line L2 of the chamber C2, to the pump line LP and to the tank line LT. The slide valve 1' is placed by a spring 12 in the position of the compartment 111 connected to the tank line LT. In this position, the line L2 is blocked.

[0037] The pilot chamber 11, controlled by hydraulic fluid from the control slide valve 2, moves the main slide valve 1 to connect the conduits LP and L2 via the supply section 113 and supply hydraulic fluid (inlet flow Qin) to the chamber C2. In the reverse operation, the section 111 connects the line L2 to the tank line LT for the outlet flow Qout from the chamber C2.

[0038] More specifically, according to FIG. 2 in conjunction with FIG. 1, module M2 is connected to line L1 of module M1 via a regenerative conduit LR, which makes it possible to connect conduit L2 to conduit L1 through section 114 of slide valve 1′ and to redirect part or all of the outflow flow Qout from chamber C2 to chamber C1, where it merges with the flow arriving from pump line LP.

[0039] Compartment 114 is shown with the connection between ports PL2 and PLR of lines L2 and LR of slide valve 1', the connection between ports PLP and PLT of lines LP and LT is shown disconnected.

[0040] However, in this figure, the proportional movement of the slide valve 1' distributes the outflow Qout of the line L2 between the regeneration lines LR and LT to allow partial regeneration by the port PLT, while the port PLP remains blocked whether the outflow Qout from the line L2 to the line LR is total or partial.

[0041] The two compartments 111 and 113 are separated by an intermediate compartment 112' which blocks the communication, via the slide valve 1', between the ports PL2, PLR of the lines L2, LR and the ports PLP, PLT of the lines LP, LT.

[0042] As in the module M1, the pilot chamber 11 associated with the main slide valve 1 is controlled by a proportional control slide valve 2 which is actuated by an electric control device 21 which receives a control signal ΣSec from the control unit UC. The control slide valve 2 is returned by a spring 22 to its rest position, in which the line connected to the pilot chamber 11 is connected to the tank line LT.

[0043] The two independent modules M1, M2 of the device 100 are connected to the lines LP, LT via interfaces A1, A2, respectively, which are connected in series to the two lines LP, LT. The interfaces A1, A2 are directly incorporated into one of the modules M1, M2.

[0044] The modules M1, M2 are supplemented with a safety valve 3 that opens when the lines L1, L2 are pressurized, and an on-off valve 4 that combines the function of preventing backflow (section 41) and the function of allowing flow (section 42) between the main slide valve 1. The valve 4 is controlled by an electrical signal from the unit UC, independently of the control of the slide valves 1, 1'.

[0045] Module M2 differs from module M1 in the directional control slide valve 1'. This asymmetry of the two modules is due to the asymmetrical construction of the cylinder chambers C1, C2, the change in the volume of the chambers due to the piston movement depends on the ratio of the free cross sections of the chambers (the cross section without the piston rod and the cross section through which the piston rod passes).

[0046] 3 is a hydraulic circuit diagram of modules M1, M2 in full regeneration mode between chamber C2 and chamber C1 of cylinders via lines L2, LR, L1 passing through section 114 of slide valve 1' of module M2. Since the flow rate Qout out of chamber C2 is less than the flow rate into chamber C1, the amount of regeneration through line LR is supplemented by the amount from pump line LP passing through module M1. Section 111 of slide valve 1 of module M1 therefore connects pump line LP to chamber line L1 to supplement the flow rate of regeneration entering chamber C1.

[0047] 4 shows the hydraulic system operating in partial recuperation mode, where the partial recuperation is from chamber C1 of the cylinder to chamber C2. The flow rate out of chamber C1 is greater than the flow rate into chamber C2, so that the excess of the flow rate out of line LR going to chamber C2 that is not recuperated is discharged in tank line LT.

[0048] In the two operating modes of FIG. 3 and FIG. 4, module M2 constitutes a regeneration module which performs full or partial regeneration depending on the chamber of the cylinder which supplies the outflow flow.

[0049] Thus, a hydraulic device enabling regeneration between the outflow and inflow chambers requires only one regeneration module including a slide valve 1 ′ with a regeneration section 114 .

[0050] In conclusion, to summarize, the invention relates to a hydraulic device 100 connected to a cylinder V having two chambers C1, C2 separated by a piston VP, a rod VT passing through one of the chambers C1, C2, C2, connected to a machine, The device is a control unit UC connected to a lever Mn actuated by an operator to operate the equipment O by means of a cylinder V; a pump P for supplying the chambers C1, C2 of the cylinders via a pump line LP and a tank T for receiving the hydraulic fluid returning from the cylinders V via a tank line LT; having The device is * Two independent electro-hydraulic modules M1, M2, each connected to a corresponding chamber C1, C2, pump line LP and tank line LT via chamber lines L1, L2, - directional control slide valves 1D, 1'D, each of which * proportional hydraulic main slide valves 1,1' connecting the chamber conduits L1,L2 to the pump line LP and the return line LT; * a pilot chamber 11 for actuating the main slide valve 1 by hydraulic connection, and * Proportional electrohydraulic controlled slide valve 2, connecting the pump line LP to the pilot chamber 11 and receiving the control signal ΣSec from the control unit UC A directional control slide valve 1D, 1'D, which is controlled using a regeneration line LR connecting the chamber lines L1, L2 via a directional control slide valve 1' of one of the modules M1, M2; Two independent electrohydraulic modules M1, M2 The present invention relates to a hydraulic device 100 having the following features.

[0051] According to one feature, the proportional directional control slide valve 1', which may connect the chamber lines L1, L2, has a section 114 which connects the ports of the lines L1, L2, closes the port PLP of the pump line and allows access to the port PLT of the tank LT.

[0052] According to another feature, the slide valve 1' of the directional control slide valve 1, 1'D has a section 112' closing off the four ports PL2, PLR, PLP, PLT of the chamber line L2, the regeneration line LR, the pump line LP and the tank line LT.

[0053] According to another characteristic, a control unit UC is connected to the lever Mn and controls the parameters -Set back pressure Pcp at the outlet of cylinder V, - Set pressure of tank PT, - Inflow flow rate Qin of cylinder V Depending on * the inlet cross section Se of units M1 and M2 receiving the inlet flow Qin of cylinder V, * The outlet cross section Sec of units M1 and M2 that receive the outflow Qout of cylinder V The control circuit generates electrical signals ΣE and ΣS that control the

[0054] According to another feature, the set cross section (Sec) of the throttle through which the outflow (Qout) passes is given by the simplified Bernoulli equation:

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[0055] According to another feature, the set pressure Pcp is -predetermined fixed value, - variable value according to the operation of the lever Mn, -Value obtained from pressure sensor measurements is selected from. [Explanation of symbols]

[0056] 1,1' Main Slide Valve 11 Pilot Chamber 111 Return Section 112 Stop Section 112' Middle Section 113 Supply Section 114 Regenerative Section 12 Spring 2 Control slide valve 21 Electromechanical control system 22 Return spring 3. Overpressure valve 4. On-off valve 41 Backflow prevention section 42 Passing Function Area 5 Buffer 51 Expanded Cell 52 Actuating Slide Valve 6 Pressure Sensors 7. Check valve C1, C2 Cylinder chamber VP Piston VT piston rod O Loaded equipment UC Control Unit Mn Lever Signal from Sm lever P-Pump LP Pump Line T Tank LT Tank Line LR Regenerative line UA Electric Hydraulic Unit M1,M2 Electro-hydraulic Module L1, L2 chamber line S1, S2 chamber cross section Se entrance cross section Sec setting exit cross section Ses exit cross section Σ(Se) Inlet cross section control electrical signal Σ(Ses) Control electrical signal for outlet cross section Σ(Sec) Control electrical signal for set cross section Qin inflow flow rate Qout Outflow flow rate Al Module M1 Interface A2 Module M2 Interface LR Regenerative line

Claims

1. A hydraulic device (100) connected to a cylinder (V) having two chambers (C1, C2) separated by a piston (VP), a rod (VT) passing through one (C2) of said chambers (C1, C2) being connected to a machine, The device is a control unit (UC) connected to a lever (Mn) actuated by an operator to operate the equipment (O) by means of said cylinder (V); a pump (P) for supplying the chambers (C1, C2) of the cylinders via a pump line (LP); and a tank (T) for receiving hydraulic fluid returning from the cylinders (V) via a tank line (LT). having The device is Two independent electro-hydraulic modules (M1, M2) connected to a corresponding chamber (C1, C2), said pump line (LP) and said tank line (LT) via chamber lines (L1, L2), each electro-hydraulic module comprising: A directional control slide valve (1D, 1'D), each of which comprises: a proportional hydraulic main slide valve (1,1') connecting the conduits (L1,L2) of the chamber with the pump line (LP) and with the return line (LT); a pilot chamber (11) for actuating the main slide valve (1) by means of a hydraulic connection; a proportional electrohydraulic controlled slide valve (2) connecting said pump line (LP) to said pilot chamber (11) and receiving a control signal (ΣSec) from said control unit (UC); A directional control slide valve (1D, 1'D) controlled using a regeneration line (LR) connecting the chamber lines (L1, L2) via the directional control slide valve (1') of one (M2) of the modules (M1, M2); Two independent electrohydraulic modules (M1, M2) having A hydraulic device (100) comprising:

2. 2. The hydraulic system (100) according to claim 1, characterized in that the slide valve (1') of the proportional directional control slide valve to which the chamber lines (L1, L2) can be connected has a compartment (114) which connects the ports of the lines (L1, L2), closes the port (PLP) of the pump line and allows access to the port (PLT) of the tank (LT).

3. The hydraulic system (100) according to claim 1, characterized in that the slide valve (1') of the directional control slide valve (1, 1'D) has a section (112') that closes four ports (PL2), (PLR), (PLP), (PLT) of the chamber line (L2), the regeneration line (LR), the pump line (LP) and the tank line (LT).

4. The control unit (UC) is connected to the lever (Mn) and controls the parameters: The set back pressure (Pcp) at the outlet of the cylinder (V), The set pressure of the tank (PT), The inflow flow rate (Qin) of the cylinder (V) Depending on the inlet cross section (Se) of the unit (M1, M2) receiving the inlet flow (Qin) of the cylinder (V), the outlet cross section (Sec) of the unit (M1, M2) receiving the outlet flow (Qout) of the cylinder (V); Generate electrical signals (ΣE) and (ΣS) that control The hydraulic system (100) of claim 1 .

5. The set cross section (Sec) of the throttle through which the outflow (Qout) passes is given by the simplified Bernoulli equation: [0010] ΔP=Pcp−PT where:

5. The hydraulic system (100) of claim 4, wherein K=CT√ρ, a coefficient that varies with section modulus Cd and density (ρ) of the liquid.

6. The set pressure (Pcp) is A predetermined fixed value, A variable value according to the operation of the lever (Mn), Value obtained from pressure sensor measurement The hydraulic device (100) according to any one of claims 1 to 5, characterized in that the hydraulic device (100) is selected from the group consisting of:

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