EP0786598A1 - Einrichtung zur Betätigung einer hydraulischen Vorrichtung mit einer Betätigungsgeschwindigkeit, die unabhängig von der an der hydraulischen Vorrichtung wirkenden Last ist - Google Patents

Einrichtung zur Betätigung einer hydraulischen Vorrichtung mit einer Betätigungsgeschwindigkeit, die unabhängig von der an der hydraulischen Vorrichtung wirkenden Last ist Download PDF

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Publication number
EP0786598A1
EP0786598A1 EP97100802A EP97100802A EP0786598A1 EP 0786598 A1 EP0786598 A1 EP 0786598A1 EP 97100802 A EP97100802 A EP 97100802A EP 97100802 A EP97100802 A EP 97100802A EP 0786598 A1 EP0786598 A1 EP 0786598A1
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EP
European Patent Office
Prior art keywords
chamber
slider
branch
user apparatus
outlet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP97100802A
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English (en)
French (fr)
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EP0786598B1 (de
Inventor
Claudio Bovi
Renato Brevini
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Brevini Hydraulics SpA
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Brevini Hydraulics SpA
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Publication of EP0786598A1 publication Critical patent/EP0786598A1/de
Application granted granted Critical
Publication of EP0786598B1 publication Critical patent/EP0786598B1/de
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/028—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/0416—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor with means or adapted for load sensing
    • F15B13/0417—Load sensing elements; Internal fluid connections therefor; Anti-saturation or pressure-compensation valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F15B2211/3053—In combination with a pressure compensating valve
    • F15B2211/30535—In combination with a pressure compensating valve the pressure compensating valve is arranged between pressure source and directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3122—Special positions other than the pump port being connected to working ports or the working ports being connected to the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/321—Directional control characterised by the type of actuation mechanically
    • F15B2211/324—Directional control characterised by the type of actuation mechanically manually, e.g. by using a lever or pedal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6055—Load sensing circuits having valve means between output member and the load sensing circuit using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/76—Control of force or torque of the output member

Definitions

  • the present invention relates to a hydraulic control device for actuating a hydraulic user apparatus with an actuation speed that is independent of the resisting load affecting the hydraulic user apparatus. More particularly, the device according to the present invention is meant to be used in hydraulic systems for the actuation of user apparatuses constituted by double-action fluid-actuated cylinders, or of hydraulic motors, or of user apparatuses with two actuation branches selectively connected to a pressurized branch of the hydraulic circuit and to the discharge branch, for example in machines for lifting or moving a load.
  • Conventional hydraulic circuits are generally supplied by a single pump of adequate capacity and are meant to actuate a plurality of user apparatuses which usually have different loads or require mutually different pressures for their actuation.
  • each user apparatus is usually controlled by a pilot valve or directional valve, which selectively connects the two hydraulic supply branches of the corresponding user apparatus to the pressurized branch of the main circuit or to the discharge branch, or closes the two supply branches of the user apparatus being considered.
  • a pressure compensation unit is arranged on the branch of the circuit connecting the pressurized branch, i.e., the delivery of the pump, to the pilot valve of each user apparatus.
  • the pressure compensation unit has the purpose of maintaining a constant pressure difference between the pressurized branch of the hydraulic circuit, which is connected to the delivery of the pump, and the operating pressure that overcomes the load, by means of the ⁇ P which forms across the valve gear or slider of the pilot valve.
  • the operating pressure that overcomes or brakes the load acts, together with a spring, so as to increase the opening of the compensation unit in contrast with the pressure acting on the feed branch of the pilot valve.
  • the two feed branches of the user apparatus are connected respectively to the pressurized branch that enters the pilot valve and to the discharge branch of the circuit; the branch of the user apparatus connected to the pressurized branch is also connected, by means of said pilot valve, to a duct that enters the pressure compensation unit and wherethrough the operating pressure is transmitted to the pressure compensation unit.
  • the pressure transmitted along said duct from the user apparatus branch to the pressure compensation unit constitutes a hydraulic signal known as "load sensing" or LS, which accordingly drives the pressure compensation unit.
  • the actuation of the user apparatus being considered must be interrupted when the pressure along an actuation branch of said user apparatus reaches a preset maximum value.
  • the LS duct is connected to a maximum-pressure valve, which connects the LS duct and therefore the corresponding user apparatus actuation branch to the discharge branch of the circuit, or more generically to a discharge, when said preset maximum pressure is reached.
  • German patent DE-38.41.507 Said device comprises a double-acting three-position pilot valve, which respectively connects a user apparatus actuation branch to the pressurized branch of the hydraulic circuit whilst it connects the other user apparatus actuation branch to the discharge, or vice versa, or simultaneously closes the two user apparatus feed branches when no actuation is required.
  • the device comprises also two different ducts for the LS signals, LS A and LS B respectively, which are connected by the same pilot valve to the user apparatus actuation branches A and B when the branches A and B are connected to the pressurized branch of the hydraulic circuit.
  • the duct LS A or LS B that is not used, i.e., the one corresponding to the user apparatus actuation branch connected to the discharge, is closed by the gear or slider of the pilot valve.
  • a maximum-pressure valve is arranged along each duct LS A and LS B ; the two maximum-pressure valves provided have maximum pressures for intervention different from each other.
  • the two ducts LS A and LS B downstream of the maximum-pressure valves, merge into a single duct entering the pressure compensation unit, on the spring side, in order to drive it.
  • the two ducts LS A and LS B are merged by means of a switching or selector valve, which connects the duct LS A or LS B that is at the highest pressure to the duct leading into the pressure compensation unit, whilst the other duct LS B or LS A is closed.
  • a device of the type described in patent DE-38.41.507 allows to stop the actuation of the user apparatus when two different maximum pressures are reached on the two branches A or B for the actuation of the user apparatus, but it entails drawbacks.
  • Unwanted leakages of liquid from the duct LS A or LS B under pressure towards the closed duct LS B or LS A can in fact occur during operation in the switching or selector valve. These leakages increase the pressure along the closed duct LS B or LS A until said pressure reaches the same value as the pressure in the pressurized duct LS A or LS B . When this occurs, the switching valve cannot operate correctly, and if along the unused or closed duct LS a maximum-pressure valve is provided that is set to a lower pressure than the maximum-pressure valve arranged on the duct LS being used, the two ducts LS are connected to the discharge by the opening of said maximum-pressure valve, causing an unwanted halting of the actuation of the user apparatus.
  • the aim of the present invention is to solve the above described problems by providing a hydraulic control device for the actuation of a user apparatus with a speed that is independent of variations in the resisting load which, even when it must be possible to stop the load when different maximum pressures are reached on the two user apparatus actuation branches, is free from instability problems, i.e., is not affected by pressure pulses or instabilities.
  • an object of the present invention is to provide a device that can use a same pilot valve for different system configurations, such as to fully meet the most disparate operating requirements.
  • Another object of the invention is to provide a control device with a pilot valve providing extremely easy and precise actuation.
  • Another object of the invention is to provide a device wherein the pilot valve is structurally simple and easy to access during maintenance.
  • a hydraulic control device for the actuation of a hydraulic user apparatus with an actuation speed that is independent of the resisting load affecting said hydraulic user apparatus, comprising a double-acting pilot valve that can be actuated so as to connect a user apparatus actuation branch to a pressurized branch of a hydraulic circuit and the other user apparatus actuation branch to a discharge branch of the hydraulic circuit and a pressure compensation unit arranged on the pressurized branch of the hydraulic circuit entering said pilot valve, characterized in that said pilot valve has: a first inlet connected to the pressurized branch of the hydraulic circuit; at least one second inlet connected to the discharge branch of the hydraulic circuit; a first outlet connected to a first user apparatus actuation branch; a second outlet connected to the second user apparatus actuation branch; a first outlet port connected to a first monitoring duct; a second outlet port connected to a second monitoring duct; a third outlet port connected to a control duct which is connected to said pressure
  • the device according to the invention comprises a double-acting pilot valve, generally designated by the reference numeral 1, which can be actuated so as to connect an actuation branch A or B of a hydraulic user apparatus to a pressurized branch P of a hydraulic circuit and the other actuation branch B or A of the user apparatus to a discharge branch T of the hydraulic circuit.
  • the device comprises also, in a per se known manner, a pressure compensation unit 2 arranged along the pressurized branch of the hydraulic circuit entering the pilot valve 1.
  • the portion of the pressurized branch running from the pressure compensation unit 2 to the pilot valve 1 has been designated by P 1 .
  • the pilot valve 1 has: a first inlet 3 connected to the pressurized branch P 1 ; at least one second inlet 4a and 4b (two second inlets in the illustrated case) connected to the discharge branch T of the hydraulic circuit; a first outlet 5 connected to the first branch A for the actuation of the user apparatus; a second outlet 6 connected to the second branch B of the user apparatus to be actuated; a first outlet port 7 connected to a first monitoring duct 8 (LS A ); a second outlet port 9 connected to a second monitoring duct 10 (LS B ); and a third outlet port 11 connected to a control duct 12 that enters the pressure compensation unit 2 on the side of the spring 13, so that the pressure of the liquid transmitted along the control duct 12 acts, together with the force of the spring 13, on the moving part 14 of the pressure compensation unit in contrast with the action applied by the pressure of the liquid along the branch P 1 , which acts on the moving part 14 of the pressure compensation unit on the opposite side.
  • the pilot valve 1 has a slider 15 that can move on command into three positions: a first position, wherein it connects the first inlet 3 to the first outlet 5, to the first port 7, and to the third port 11 whilst it connects the second inlet 4b to the second outlet 6 and to the second port 9; a second position, wherein it connects the first inlet 3 to the second outlet 6, to the second port 9, and to the third port 11 whilst it connects the second inlet 4a to the first outlet 5 and to the first port 7; and a third position, or idle position, wherein it closes the first inlet 3, the first outlet 5, and the second outlet 6.
  • the slider 15 conveniently connects the ports 7 and 9 to the second inlets 4a and 4b, i.e., it connects the monitoring ducts 8 and 10 to the discharge branch T of the hydraulic circuit.
  • the pilot valve 1 as shown in particular in figures 1 to 5, comprises a body 16 wherein a substantially cylindrical seat 17 is provided which accommodates the slider 15 so that it can slide axially; the slider is also substantially cylindrical and has narrower regions spaced one from the other.
  • a first chamber 18 is formed in the body 16 at a median region of the seat 17 and is connected to the first inlet 3.
  • a second chamber 19 and a third chamber 20 are formed laterally to the first chamber 18, and on opposite sides with respect to it, in the body 16 and again at the seat 17; chambers 19 and 20 are connected to the first outlet 5 and to the second outlet 6 respectively.
  • a fourth chamber 21 and a fifth chamber 22 are formed laterally to the second chamber 19 and to the third chamber 20, on the opposite side with respect to the first chamber 18, and are respectively connected to the inlet 4a and to the inlet 4b.
  • a sixth chamber 23 and a seventh chamber 24 are formed laterally to the fourth chamber 21 and to the fifth chamber 22, on the opposite side with respect to the first chamber 18, and are connected to the third port 11.
  • An eighth chamber 25 and a ninth chamber 26 are also formed laterally to the sixth chamber 23 and to the seventh chamber 24, on the opposite side with respect to the first chamber 18, and are connected to the first port 7 and to the second port 9 respectively.
  • the chambers 18-26 are delimited by the slider 15 towards the axis of the seat 17.
  • the sixth chamber 23 and the seventh chamber 24 are connected one to the other by a channel 27 which is formed in the body 16 and is connected to the third port 11.
  • the slider 15, as mentioned, has a substantially cylindrical shape with four circumferential narrower regions 28, 29, 30, and 31, which divide the active region of the slider 15, i.e., the region located in the seat 17, into a central portion 32, two middle lateral portions 33 and 34, and two end lateral portions 35 and 36.
  • the various portions of the slider 15 are sized and arranged so that when the slider 15 is in the first position, shown in figure 3, the middle lateral portion 33 closes the fourth chamber 21 whilst the other middle lateral portion 34 closes the seventh chamber 24; when the slider 15 is in the second position, shown in figure 4, the middle lateral portion 34 closes the fifth chamber 22, whilst the middle lateral portion 33 closes the sixth chamber 23; when the slider 15 is in the third position, shown in figure 5, the central portion 32 closes the first chamber 18, whilst the two middle lateral portions 33 and 34 close the second chamber 19 and the third chamber 20.
  • the end lateral portions 35 and 36 provide the hydraulic tightness of the seat 17 at its axial ends.
  • the slider 15 has also recesses 37 that are located astride the narrower regions 28 and 29, affecting the central portion 32 and the two middle lateral portions 33 and 34. Said recesses 37 are cusp-shaped and widen away from the axis of the slider 15, from the middle lateral portions 33 and 34, and from the central portion 32 towards the narrower regions 28 and 29.
  • the recesses 37 connect the second chamber 19 to the first chamber 18 and the third chamber 20 to the fifth chamber 22 when the slider 15 is in the first position (figure 3) and connect the first chamber 18 to the third chamber 20 and the second chamber 19 to the fourth chamber 21 when the slider 15 is in the second position (figure 4).
  • the recesses 37 provide no connection.
  • a first passage 38 and a second passage 39 are formed inside the slider 15, on opposite sides with respect to the central portion 32.
  • the first passage 38 has at least one opening 38a at the narrower region 30 and at least one opening 38b in a region of the middle lateral portion 33 of the slider 15.
  • the second passage 39 has at least one opening 39a at the narrower region 31 and at least one opening 39b in a region of the middle lateral portion 34 of the slider 15.
  • the openings 38a, 38b and 39a, 39b are spaced from each other so that when the slider 15 is in the first position (figure 3) the first passage 38 connects the second chamber 19 to the sixth chamber 23 whilst the second passage 39 connects the fifth chamber 22 to the ninth chamber 26 and so that when the slider 15 is in the second position (figure 4) the first passage 38 connects the eighth chamber 25 to the fourth chamber 21 whilst the second passage 39 connects the third chamber 20 to the seventh chamber 24.
  • the first passage 38 connects the fourth chamber 21 to the eighth chamber 25 whilst the second passage 39 connects the fifth chamber 22 to the ninth chamber 26.
  • the narrower regions 28-31 are meant to provide connections in the various positions of the slider 15.
  • the narrower region 30 connects the sixth chamber 23 to the eighth chamber 25; when the slider 15 is in the second position (figure 4), the narrower region 31 connects the seventh chamber 24 to the ninth chamber 26; when the slider 15 is in the third position (figure 5), the narrower region 30 connects the sixth chamber 23 to the eighth chamber 25 whilst the narrower region 31 connects the seventh chamber 24 to the ninth chamber 26.
  • the chambers 18-26 are arranged symmetrically with respect to a median plane lying at right angles to the axis of the seat 17, and the active region of the slider 15 is also symmetrical with respect to a median plane which is perpendicular to the axis of the slider 15, so that said slider 15 can be inserted in the seat 17 in one direction or in the opposite direction depending on the intended position of the actuation unit of the slider 15, which in the illustrated embodiment is constituted by a lever 40 whereby the slider 15 is moved along the axis of the seat 17 in contrast with the action of a return spring 41.
  • the actuation unit of the slider 15 can anyway be constituted also by an automatic actuation device of a conventional type, which is not shown for the sake of simplicity.
  • the device according to the invention provided with the pilot valve 1 described so far, can be completed by other components according to requirements.
  • Figures 6 to 8 illustrate a first embodiment of the device according to the invention, meant to be used when it must be possible to stop the actuation of the user apparatus during the pressurized feeding of the branch A and during the pressurized feeding of the branch B when the pressure in the branches A and B reaches a preset maximum value, with the possibility of differentiating the maximum allowable pressure along the branch A from the maximum allowable pressure along the branch B.
  • the device shown in figures 6 to 8 allows also to stop the actuation of the user apparatus independently on the two branches A and B by means of an external control.
  • the first monitoring duct 8 wherealong the pressurized hydraulic signal LS A is transmitted, is connected to the discharge branch T of the hydraulic circuit across a maximum-pressure valve 42, which connects the duct 8 to the discharge branch T when a pressure at least equal to the set pressure of the valve 42 occurs along the duct 8.
  • the second monitoring branch 10, wherealong the pressurized hydraulic signal LS B is transmitted, is also connected to the discharge branch T of the hydraulic circuit by means of a maximum-pressure valve 43, which connects the duct 10 to the discharge branch T when a pressure at least equal to the set pressure of the valve 43 occurs along the duct 10.
  • each monitoring duct 8 and 10 has a branch which is connected to the discharge branch T by means of respective controllable electric valves 44 and 45.
  • the electric valves 44 and 45 are energized, i.e. closed, and therefore prevent the connection of the ducts 8 and 10 to the discharge branch T, and can be de-energized in order to provide this connection when conditions occur requiring an interruption in the actuation of the user apparatus during actuation on the branch A or on the branch B.
  • the circuit shown in figures 6 to 8 is completed by a choke 46 arranged along the control duct 12 and by a branch 12a of the control duct 12 that enters a switching or selector valve 47.
  • the outlet of the switching valve 47 is connected to the pump so as to send to the pump an LS signal for driving said pump.
  • antishock valves are provided, designated by the reference numerals 48 and 49, in the device shown in figures 6 to 8.
  • the branch P 1 is connected to the branch A. It should be noted that when the slider 15 is in this position, the branch A and the branch P 1 are connected to the control duct 12 and to the first monitoring duct 8, wherealong the hydraulic signal LS A is transmitted.
  • the branch B and the second monitoring duct 10, wherealong the hydraulic signal LS B is transmitted, are connected to the discharge branch T.
  • the branch P 1 is connected to the branch B, to the control duct 12, and to the second monitoring duct 10.
  • the operating pressure of the user apparatus along the branch B affects the actuation of the pressure compensation unit 2 on the side of the spring 13 and is transmitted simultaneously to the second monitoring duct 10.
  • the branch A and the first monitoring duct 8 are connected to the discharge branch T.
  • connection of the monitoring duct which corresponds to the branch of the user apparatus that is not connected to the branch P 1 , to the discharge branch T in the device according to the invention is performed directly across the pilot valve 1 used to provide the other connections, as described above for the actuation of the user apparatus.
  • one or both of the maximum-pressure valves 42 and 43, as well as one or both of the electric valves 44 and 45, can be omitted.
  • the device has the appearance shown schematically in figure 9.
  • the device has the appearance shown schematically in figure 10.
  • connection of the monitoring ducts 8 and 10, and therefore of the user apparatus branch connected to said ducts, to the discharge by means of the electric valves 44 or 45 instead of the maximum-pressure valves 42 or 43 is faster.
  • the embodiment illustrated in figure 11 shows a device that uses only the electric valve 44.
  • the actuation of the user apparatus along the branch A is controlled by means of said electric valve 44, whilst the actuation of the user apparatus along the branch B is controlled by the maximum general set pressure of the system. Nonetheless, even in this case it is possible to differentiate the maximum allowable pressures on the two branches A and B of the user apparatus. Of course, a similar operation, with reversal of the type of control on the two branches A and B of the user apparatus, would be achieved with a device that used only the electric valve 45.
  • the device according to the invention has the electric valve 44 and the maximum-pressure valve 42, whilst the valve 43 and the electric valve 45 are not present with respect to the diagram of figures 6 to 8.
  • the actuation of the user apparatus along the branch A is controlled by the valve 42 and by the electric valve 44, whilst the actuation of the user apparatus along the branch B is controlled simply by means of the general maximum set pressure of the system, which is of course higher than the intervention pressure of the valve 42. Similar operation would be achieved by using only the valve 43 and the electric valve 45, with a reversed type of control between the branches A and B with respect to what has been described above with reference to figure 12.
  • Figure 13 illustrates another embodiment of the device according to the invention, wherein only the maximum-pressure valve 42 is provided on the first monitoring duct 8.
  • the actuation pressure along the branch A of the user apparatus is controlled by means of the valve 42, whilst the actuation along the branch B of the user apparatus depends on whether the general maximum allowable pressure of the hydraulic system, which is obviously higher than the set pressure of the valve 42, is exceeded or not. Similar operation, with a reversed control mode between the two branches A and B, would occur by using only the maximum-pressure valve 43 on the second monitoring duct 10.
  • FIGS 9 to 13 illustrate several embodiments of the device according to the invention, already preset to be completed by simply adding one or more valves or electric valves until the embodiment of the device illustrated in figures 6 to 8 is achieved; of course this presetting may also not be provided.
  • the two monitoring ducts 8 and 10 enter a switching or selector valve 51, wherefrom a combined monitoring duct 52 exits; said duct 52 is connected to the discharge branch T of the hydraulic system by means of a maximum-pressure valve 53 or by means of an electric valve 54, or also by means of both the maximum-pressure valve 53 and the electric valve 54, as shown.
  • the branch A of the user apparatus is connected to the branch P 1 , to the monitoring duct 8, and to the control duct 12.
  • the pilot valve 1 also connects the branch B and the second monitoring duct 10 to the discharge branch T of the system. In this manner, the pressure along the branch A of the user apparatus is transmitted along the control duct 12 to the pressure compensation unit 2, along the first monitoring duct 8, and to the combined monitoring duct 52 across the switching valve 51.
  • the pressure occurring along the duct 52 which is correlated to the pressure along the branch A, is higher than the set pressure of the maximum-pressure valve 53, the combined monitoring duct 52 and, through said duct, the duct 12 and the branch A of the user apparatus are connected to the discharge branch T of the system, halting the actuation of the user apparatus.
  • the electric valve 54 is de-energized; the electric valve thus connects the combined monitoring duct 52 and therefore the duct 12 and the branch A of the user apparatus to the discharge branch T of the system.
  • the branch B of the user apparatus, the second monitoring duct 10, and the control duct 12 are connected to the pressurized branch P 1 , whilst the branch A and the first monitoring duct 8 are connected to the discharge branch T of the system.
  • the pressure along the branch B is transmitted to the control duct 12, driving the pressure compensation unit 2, as already described, and to the combined monitoring duct 52 across the switching valve 51.
  • the combined monitoring duct 52 which is correlated to the pressure in the branch B, is higher than the set pressure of the maximum-pressure valve 53, the combined monitoring duct 52 and, through said combined monitoring duct, the duct 12 and the branch B of the user apparatus are connected to the discharge branch T, halting the actuation of the user apparatus.
  • the device according to the invention fully achieves the intended aim, since by virtue of the fact that the monitoring duct, i.e., the "load sensing" signal transmitted along it, which corresponds to the branch of the user apparatus connected to the discharge, is also connected to the discharge, said device effectively avoids instabilities even in the presence of pressure instabilities or pulsations and facilitates also the actuation of the pilot valve and makes it more precise.
  • the monitoring duct i.e., the "load sensing" signal transmitted along it, which corresponds to the branch of the user apparatus connected to the discharge
  • said device effectively avoids instabilities even in the presence of pressure instabilities or pulsations and facilitates also the actuation of the pilot valve and makes it more precise.
  • a further advantage is that it is possible to use a same pilot valve for several types of application.
  • Another advantage is that the device has a pilot valve which is structurally simple, without the need to insert valve elements inside the slider of the pilot valve.
  • the device thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; thus, for example, if required, the pilot valve 1 can be modified so that when the slider 15 is in the third position, the branches A and B, instead of being closed, are connected to the inlets 4a or 4b, i.e., to the discharge branch T of the circuit.
  • the materials employed, as well as the dimensions, may be any according to the requirements and the state of the art.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Control Of Transmission Device (AREA)
EP97100802A 1996-01-24 1997-01-20 Einrichtung zur Betätigung einer hydraulischen Vorrichtung mit einer Betätigungsgeschwindigkeit, die unabhängig von der an der hydraulischen Vorrichtung wirkenden Last ist Expired - Lifetime EP0786598B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITMI960117 1996-01-24
IT96MI000117A IT1281708B1 (it) 1996-01-24 1996-01-24 Dispositivo per l'azionamento di un'utenza idraulica con una velocita' di azionamento indipendente dal carico resistente gravante su tale

Publications (2)

Publication Number Publication Date
EP0786598A1 true EP0786598A1 (de) 1997-07-30
EP0786598B1 EP0786598B1 (de) 2000-09-27

Family

ID=11373006

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97100802A Expired - Lifetime EP0786598B1 (de) 1996-01-24 1997-01-20 Einrichtung zur Betätigung einer hydraulischen Vorrichtung mit einer Betätigungsgeschwindigkeit, die unabhängig von der an der hydraulischen Vorrichtung wirkenden Last ist

Country Status (4)

Country Link
EP (1) EP0786598B1 (de)
DE (1) DE69703166T2 (de)
DK (1) DK0786598T3 (de)
IT (1) IT1281708B1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1106839A2 (de) * 1999-11-25 2001-06-13 Brevini Hydraulics S.p.A. Hydraulische Steuereinheit
WO2002066842A1 (de) * 2001-02-17 2002-08-29 Bosch Rexroth Ag Wegeventil zur lastunabhängigen steuerung eines hydraulischen verbrauchers hinsichtlich richtung und geschwindigkeit
WO2009062572A1 (de) * 2007-11-14 2009-05-22 Hydac Filtertechnik Gmbh Hydraulische ventilvorrichtung
EP2157319A1 (de) 2008-08-20 2010-02-24 HAWE Hydraulik SE Hydrauliksteuerung für einen Hydromotor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0224936A2 (de) * 1985-12-06 1987-06-10 Karl-Thomas Dipl.-Ing. Rhody Proportionalwegeventil mit Einzeldruckwaage
DE3841507C1 (de) 1988-01-22 1989-06-29 Danfoss A/S, Nordborg, Dk
DE4324177A1 (de) * 1992-08-10 1994-02-17 Heilmeier & Weinlein Hydraulische Steuervorrichtung

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0224936A2 (de) * 1985-12-06 1987-06-10 Karl-Thomas Dipl.-Ing. Rhody Proportionalwegeventil mit Einzeldruckwaage
DE3841507C1 (de) 1988-01-22 1989-06-29 Danfoss A/S, Nordborg, Dk
DE4324177A1 (de) * 1992-08-10 1994-02-17 Heilmeier & Weinlein Hydraulische Steuervorrichtung

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1106839A2 (de) * 1999-11-25 2001-06-13 Brevini Hydraulics S.p.A. Hydraulische Steuereinheit
EP1106839A3 (de) * 1999-11-25 2002-07-24 Brevini Hydraulics S.p.A. Hydraulische Steuereinheit
WO2002066842A1 (de) * 2001-02-17 2002-08-29 Bosch Rexroth Ag Wegeventil zur lastunabhängigen steuerung eines hydraulischen verbrauchers hinsichtlich richtung und geschwindigkeit
US6994116B2 (en) 2001-02-17 2006-02-07 Bosch Rexroth Ag Distributing valve for the load-independent control of a hydraulic consumer in terms of direction and speed
WO2009062572A1 (de) * 2007-11-14 2009-05-22 Hydac Filtertechnik Gmbh Hydraulische ventilvorrichtung
US20100300552A1 (en) * 2007-11-14 2010-12-02 Rueb Winfried Hydraulic valve device
US8464757B2 (en) 2007-11-14 2013-06-18 Hydac Filtertechnik Gmbh Hydraulic valve device
EP2157319A1 (de) 2008-08-20 2010-02-24 HAWE Hydraulik SE Hydrauliksteuerung für einen Hydromotor

Also Published As

Publication number Publication date
IT1281708B1 (it) 1998-02-26
DE69703166T2 (de) 2001-05-17
ITMI960117A0 (de) 1996-01-24
DE69703166D1 (de) 2000-11-02
DK0786598T3 (da) 2000-12-27
ITMI960117A1 (it) 1997-07-24
EP0786598B1 (de) 2000-09-27

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