EP3862576A1 - Steuersystem für einen antriebszylinder eines krans - Google Patents

Steuersystem für einen antriebszylinder eines krans Download PDF

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Publication number
EP3862576A1
EP3862576A1 EP21155350.8A EP21155350A EP3862576A1 EP 3862576 A1 EP3862576 A1 EP 3862576A1 EP 21155350 A EP21155350 A EP 21155350A EP 3862576 A1 EP3862576 A1 EP 3862576A1
Authority
EP
European Patent Office
Prior art keywords
valve
conduit
supply conduit
pressure
pilot
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.)
Pending
Application number
EP21155350.8A
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English (en)
French (fr)
Inventor
Pierre Luigi Zaccarelli
Alberto PEDRAZZI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from IT102020000002506A external-priority patent/IT202000002506A1/it
Priority claimed from IT102021000000431A external-priority patent/IT202100000431A1/it
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP3862576A1 publication Critical patent/EP3862576A1/de
Pending legal-status Critical Current

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    • 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
    • F15B11/003—Systems with load-holding 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
    • 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
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/0413—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed in one direction only, with no control in the reverse direction, e.g. check valve in parallel with a throttle 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
    • 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
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
    • F15B11/0426—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in" by controlling the number of pumps or parallel valves switched on
    • 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
    • F15B2211/30505—Non-return valves, i.e. check 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
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F15B2211/3051—Cross-check 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
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F15B2211/30515—Load holding 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
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-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
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40576—Assemblies of multiple valves
    • F15B2211/40584—Assemblies of multiple valves the flow control means arranged in parallel with a check 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40576—Assemblies of multiple valves
    • F15B2211/40592—Assemblies of multiple valves with multiple valves in parallel flow paths
    • 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
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41527—Flow control characterised by the connections of the flow 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
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50563—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure
    • F15B2211/50581—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using counterbalance valves
    • F15B2211/5059—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using counterbalance valves using double counterbalance 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
    • 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
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members

Definitions

  • the present invention relates to the field of a control system for controlling an actuator cylinder in a hydraulic application and in particular an actuator cylinder of a crane.
  • Control systems for actuator cylinders have evolved more and more over the years and require to satisfy an increasing number of functions. Firstly, they require a high level of safety so that, in the event of a pipe breakage, the system is able to control the actuator cylinder and stop it, preventing the load from falling. Secondly, a high level of system stability is required to ensure that the user can control the system without sudden jerks, which could cause the user discomfort. Last but not least, it is required that such systems are efficient in terms of consumption, so as to avoid waste such as bottlenecks, and that the costs of implementing such systems are low in terms of price.
  • FIG. 1 An example of a control system for a crane actuator cylinder known from the state of the art is shown in figure 1 and will be briefly described below.
  • the cylinder bottom is controlled during the ascent phase from 1 to 2 by opening valve 5.
  • valve 5 due to the spring-induced force, prevents the hydraulic fluid from passing through it.
  • the function of valve 6 is to prevent pressure peaks from inducing very high pressures in branch 2.
  • the fluid under pressure in 3 via valve 7, drives the control valve 5.
  • the cylinder on re-entry, causes a pressure increase in 2 which, if not controlled, could cause a sudden acceleration.
  • valve 5 always tends to close again, thus sacrificing the fluid-dynamic efficiency of the system.
  • valve 5 must also always be sized according to the flow rate of the machine.
  • the present invention addresses the problem of realising a control system for an actuator cylinder, preferably of an actuator cylinder of a crane, capable of solving the problems listed above.
  • the present invention relates to a control system according to the features listed in claim 1.
  • Such a configuration i.e. the positioning of two check systems having staggered openings in the downstream phase, has as an advantage the use of a rather small valve (the balancing valve 30), which allows to perform the initial control phase preventing jumps due to pressure differences between the upstream and downstream branches. Subsequently, most of the fluid is exchanged using a one-way valve, which is of very simple construction and easily adjustable.
  • Figure 2 shows a control system 1000 for an actuator cylinder 10 having a first chamber 11 and a second chamber 12, a piston 13 separating the first chamber 11 from the second chamber 12 and a piston rod 14 connected to the piston 13.
  • the control system 1000 of the present invention is controlled by a distribution valve 100.
  • Said distribution valve 100 comprises three positions which will be described in the course of the present description
  • the system 1000 comprises a first supply conduit 20 of the first chamber 11 of the cylinder 10 and a second supply conduit 21, 22 of the second chamber 12 of the cylinder 10.
  • the distribution valve 100 is connected to the first supply conduit 20 and the second supply conduit 21, 22 and is configured to alternately supply one between the first supply conduit 20 and the second supply conduit 21, 22 and discharge the other between the first supply conduit 20 and the second supply conduit 21, 22.
  • the distribution valve 100 connects the pressure source P to the first supply conduit 20 and, at the same time, connects the second supply conduit 21, 22 to a tank T. Conversely, in the right position of figure 2 the distribution valve 100 connects the pressure source P to the second supply conduit 21, 22 and, at the same time, connects the second supply conduit 20 to a tank T.
  • connection "Y" i.e. both the first supply conduit 20 and the second supply conduit 21, 22 are connected with the tank T.
  • the distribution valve 100 comprises an asymmetrical spool (not shown) configured in such a way that it is possible to start connecting the first supply conduit 20 with the pressure source P (left position of figure 2 ) while the connection between the supply conduit 21, 22 and the tank T is still closed.
  • the advantage of this feature will become clear in the following description.
  • the second supply conduit comprises a primary branch 21 along which a first check valve 30 is positioned, which acts as a pressurisation control valve, and a secondary branch 22 parallel to the primary branch 21 along which a check valve 40 is positioned.
  • the first check system 30 consists of a balancing valve 30, 30' whose characteristics are described in the following paragraph.
  • the balancing valve 30 is configured to open a passage for a fluid coming from the distribution valve 100 and directed towards the second chamber 12 if the pressure difference between the pressure in P (i.e. on the pressure acting on the basis of the first check valve 30) and the pressure in the second chamber 12 exceeds a first predetermined value.
  • the balancing valve 30 includes a pilot port 30 connected to the first supply conduit 20 by means of a first pilot conduit 201.
  • the balancing valve 30 is configured to open a passage for a fluid coming from the second chamber 12 and directed towards the distribution valve 100 when the pressure at the pilot port 30a reaches a first predetermined value.
  • the first pilot conduit 201 may comprise a restriction 201a, which allows the amount of fluid entering the first pilot conduit 201 to be reduced and to create a pressure difference between the first supply port 20 and the first pilot port 201 itself.
  • the check valve 40 which is positioned on the secondary branch 22, is configured to open a passage for a fluid coming from the distribution valve 100 and directed towards the second chamber 12 if the pressure difference between the pressure in P (i.e. on the pressure acting on the base of the check valve 40) and the pressure in the second chamber 12 exceeds a second predetermined value.
  • the values of the first and second predetermined values may be chosen as desired.
  • the two valves may be set to open simultaneously or one after the other.
  • the check valve 40 includes a pilot port 40a connected to the first supply conduit 20, and as shown, also to the first pilot conduit 201, by means of a second pilot conduit 202.
  • the check valve 40 is configured to open a passage for a fluid coming from the second chamber 12 and directed towards the distribution valve 100 when the pilot port 40a is pressurised.
  • the balancing valve 30 and the check valve 40 are sized such that the maximum fluid flow that can pass through the check valve 40 is at least twice as large as the maximum fluid flow that can pass through the balancing valve 30, preferably at least three times as large, more preferably at least four times as large, even more preferably at least five times as large, even more preferably at least six times as large.
  • the check valve 40 in particular the check valve system 40
  • the check valve 40 may be replaced by a plurality of check valves. However, it is important that the sum of the flow rates of the plurality of valves is at least twice the maximum flow rate of the balancing valve 30.
  • both the pilot port 30a of the balancing valve 30 and the pilot port 40a of the check valve 40 may each comprise a piston 30b, 40b which is configured to amplify the pilot pressure at the pilot port 30a, 40a, so as to facilitate the opening of the valves.
  • a two-way two-position control valve 50 is positioned along the second pilot conduit 202 to control the pilot flow to the check valve 40.
  • FIGS 2 and 3 show two alternative embodiments of the control valve 50.
  • control valve 50 With reference to figure 2 , a first embodiment of the control valve 50 will first be presented. Subsequently, with reference to figure 3 a second form of embodiment of the control valve 50 will be presented.
  • the control valve 50 when the pressure in the second pilot conduit 202 is less than a second threshold value, the control valve 50 closes a fluid passage to the pilot port 40a of the check valve 40. Conversely, when the pressure in the second pilot conduit 202 is greater than the second threshold value, the control valve 50 opens a fluid passage to the pilot port 40a of the check valve 40. As shown in figure 2 , and in particular in the left portion of said figure, the control valve 50 may be either perfectly tight 50', or with a slight leakage.
  • control valve 50 is connected to a first portion 21a of the second supply conduit 21 included between the second chamber 12 and the balancing valve 30 and to a second portion 21b of the second supply conduit 21 included between the balancing valve 30 and the distribution valve 100.
  • control valve 50 When the pressure difference between the first portion 21a and the second portion 21b of the primary branch of the second supply conduit 21 is greater than a third predetermined value, the control valve 50 is configured to close a passage of fluid to the pilot port 40a of the check valve 40. On the other hand, when the pressure difference between the first portion 21a and the second portion 21b of the second supply conduit 21, 22 is less than the third predetermined value the control valve 50 is configured to open a fluid passage to the pilot port 40a of the check valve 40.
  • the positioning in series of the control valve 50 and the check valve 40 acts as a balancing valve, analogous to the balancing valve 30 described above.
  • the check valve 40 and the balancing valve 30 may be replaced by a balancing valve 40', shown in the figure, having larger dimensions than the balancing valve 30 so as to allow a large part of the flow between the second chamber 12 and the distribution valve 100 to pass through it.
  • the system 1000 further comprises a first drainage conduit 203 configured to connect a portion of the second pilot conduit 202 between the control valve 50 and the check valve 40 with the first supply conduit 20.
  • a check valve 203b and a restriction 203a said first drainage conduit 203 is configured to allow fluid to be released to the first supply conduit 20 in the event that the pressure difference between the pressure at said portion of the second pilot conduit 202 and the pressure in the first supply conduit 20 exceeds a predetermined value, and also so as to prevent reverse flow.
  • the first drainage conduit 203 thus allows an overpressure generated in the area between the control valve 50 and the check valve 40 to be discharged to the first supply conduit 20.
  • the system 1000 may further comprise a second drainage conduit 204 that connects a portion of the second pilot conduit 202 between the first pilot conduit 201 and the control valve 50 to the second supply conduit 21, 22.
  • a drain valve 205 is positioned along said second drainage conduit 204 and is configured to drain fluid through it until the balancing valve 30 is fully open. This arrangement will then allow the opening of balancing valve 30 to be dampened by draining fluid through drain valve 205, thereby allowing a gradual opening of balancing valve 30. This function is fully described in the applicant's Italian patent application number 10 2018 000002172 .
  • This solution of the drain valve 205 could be particularly useful, in case the dimensions of the balancing valve 30 require it.
  • the dimensions of the balancing valve 30 cause the direct flow from the second chamber 12 to the distribution valve 100 to cause a forward jerk of the actuator cylinder 10, such a drain valve 205 would make it possible to diminish this undesirable effect.
  • control system can preferably be used as a control system for controlling an actuator cylinder in a hydraulic application and in particular an actuator cylinder of a crane. Therefore, the present invention can be used in a crane comprising such a control system.
  • the control of the actuator cylinder 10 is by means of the distribution valve 100. Therefore, by going to operate the distribution valve 100, the positioning of the actuator cylinder 10 will be controlled.
  • the control of the cylinder bottom 10 takes place by bringing the distribution valve 100 to the position on the right of figure 2 , thus connecting the pressure source P with the second supply conduit 21, 22 and at the same time connecting the first supply conduit 20 with the outlet T, for example with an external tank. Thanks to the pressure of the pressure source P, both the balancing valve 30 and the non-return valve 40 will open and give a thrust to the piston 13 which will cause an expansion of the second chamber 12. The fluid contained within the second chamber 12 will then be conveyed through the distribution valve 100 to the tank T.
  • the distribution valve 100 will be brought to the central position shown in figure 2 , so neither the first supply conduit 20 nor the second supply conduits 21, 22 are connected with the pressure source P and, thanks to the force of the internal spring of the balancing valve 30 and the check valve 40, a flow of fluid through them is prevented.
  • the displacement of the distribution valve 100 towards the left position of figure 1 thanks to the presence of the asymmetrical coil, allows to start supplying fluid under pressure to the first supply conduit 20 while the connection between the second supply conduit 21, 22 and the tank T is still closed.
  • the inlet pressure of the first supply conduit 20 will be applied to the balancing valve 30 by means of the first pilot conduit 201 at the pilot port 30a. Once a certain predetermined pressure has been reached, the balancing valve 30 will open so as to open a passage for the fluid coming from the second chamber 12 and directed towards the distribution valve 100. However, since there is not yet a connection between the second supply conduit 21, 22 and the tank T, the balancing valve 30 will allow the pressure upstream and downstream of the balancing valve 30 to be equalized so as to prevent a possible "hopping" of the cylinder 10. This pressure difference is due to a possible leakage of the distribution valve 100 or to the load induced on the cylinder 10.
  • control valve 50 will open the section of the second pilot conduit 202 between the control valve 50 and the check valve 30 and therefore the check valve 40 will also be opened accordingly.
  • This subsequent opening of the valves 30, 40 is due to the fact that, as described above, the setting of the control valve 50 causes the pressure of the first supply conduit 20 to be transferred initially to the balancing valve 30 which will progressively open and only after a certain pressure has been reached, thanks to the opening of the control valve 50, will it be transferred to the check valve 40, which will open.
  • This opening of the balancing valve 30 makes it possible to equalise the pressure upstream and downstream of it, so as to prevent leaps.
  • the distribution valve 100 will create the connection between the second supply conduit 21, 22 and the tank T in such a way as to be able to discharge the fluid contained inside the second chamber 12 towards the tank T.
  • the balancing valve 30 and the check valve 40 are dimensioned in such a way that the maximum fluid flow which can pass through the check valve 40 is greater than the maximum flow passing through the balancing valve 30, it will be the case that most of the flow will pass through the check valve 40.
  • the present configuration of the control system 1000 has as an advantage the use of a rather small valve (the balancing valve 30), which allows to carry out the initial control phase which prevents jumps due to pressure differences between the branches upstream and downstream of the same. Subsequently, most of the fluid is exchanged using a one-way valve, which is of very simple construction and easily calibrated. Control of the cylinder is, as mentioned above, delegated to the full distributor.
  • the control system 1000 of figure 3 is completely analogous to the one described above.
  • the only difference is the mode of opening of the control valve 50 which, in this particular case, is controlled by the pressure in the two portions 21a and 21b of the primary branch 21 of the second supply line.
  • the control valve 50 when the pressure difference between the two portions 21a and 21b is less than a third predetermined value, that is, when the balancing valve 30 has gone to reduce said pressure difference, the control valve 50 will go to open the second pilot conduit 202.
  • said pressure difference is greater than said third predetermined value, the control valve will close the connection and therefore the check valve will be closed.
  • This solution may, for example, be useful in the event of a rupture of the portion 21b of the second supply conduit 21. In fact, the sudden drop in pressure of said portion due to the rupture of the conduit will allow to close the check valve 40 and to safely descend with only the balancing valve.
  • a control system 1000 for an actuator cylinder 10 according to a further embodiment of the present invention is shown in figure 6 .
  • the distribution valve 100 again comprises an asymmetric spool (not shown) configured in such a way that it is possible to start connecting the first supply conduit 20 with the pressure source P (left position of figure 2 ) while the connection between the supply conduit 21, 22 and the reservoir T is still closed.
  • the advantage of this feature will become clear in the following description.
  • the second supply conduit comprises a primary branch 21 along which a first non-return system 30 is positioned and a secondary branch 22 parallel to the primary branch 21 along which a non-return valve 40 is positioned.
  • the first check system is completely analogous to that described with reference to the other embodiments.
  • the check valve 40 which is positioned on the secondary branch 22, is configured to open a passage for a fluid coming from the distribution valve 100 and directed towards the second chamber 12 if the pressure difference between the pressure in P (i.e. on the pressure acting on the base of the check valve 40) and the pressure in the second chamber 12 exceeds a second predetermined value.
  • the values of the first and second predetermined values may be chosen as desired.
  • the two valves may be set to open simultaneously or one after the other.
  • the check valve 40 includes a pilot port 40a connected to the primary branch 21 and by means of a second pilot port 211.
  • the check valve 40 is configured to open a passage for a fluid coming from the second chamber 12 and directed towards the distribution valve 100 when the pilot port 40a is subjected to pressure, in particular when the pressure at the pilot port 40a reaches a second threshold value.
  • the first opening threshold value of the balancing valve 30 may be chosen as desired and may be greater than, less than or equal to the second opening threshold value of the check valve 40.
  • the reason for this is that the operations of the two valves are independent of each other.
  • check valve 40 can open at a pressure of just under 10 bar, while balancing valve 30 can open at a pressure of, for example, between 5 and 10 bar.
  • the balancing valve 30 and the check valve 40 are dimensioned in such a way that the maximum fluid flow that can pass through the check valve 40 is at least twice as high as the maximum fluid flow passing through the balancing valve 30, preferably at least three times as high, more preferably at least four times as high, even more preferably at least five times as high, even more preferably at least six times as high.
  • both the pilot port 30a of the balancing valve 30 and the pilot port 40a of the check valve 40 may each comprise a piston 30b, 40b which is configured to amplify the pilot pressure at the pilot port 30a, 40a, so as to facilitate the opening of the valves.
  • a restriction 212 is also positioned along the primary branch 21 of the second supply conduit.
  • the second pilot conduit 211 is connected to the primary branch 21 of the second supply conduit at an intermediate position between the bottleneck 212 and the second chamber 12. This allows, in the phase of descent of the load, to be able to create a pressure downstream of the balancing valve 30 in such a way as to guarantee the opening of the check valve (from which substantially all the fluid contained in the second chamber 12 passes).
  • the restriction 212 may also be omitted since the opening of the check valve 40 via the second pilot conduit 211 may be ensured by the asymmetrical spool of the distributor 100 (which has been described above)
  • the system 1000 further comprises a pressure relief valve 99 positioned along a channel connecting the first supply conduit 20 to the second supply conduit, and configured to open a connection between the first supply conduit and second supply conduit if the pressure in either supply conduit exceeds a predetermined value.
  • the pressure relief valve can open at pressures between 280 and 380 bar, for example.
  • the control of the actuator cylinder 10 is by means of the timing valve 100. Therefore, by actuating the distribution valve 100, the positioning of the actuator cylinder 10 will be controlled.
  • the control of the cylinder bottom 10 takes place by bringing the distribution valve 100 to the position on the right of figure 2 , thus connecting the pressure source P with the second supply conduit 21, 22 and at the same time connecting the first supply conduit 20 with the outlet T, for example with an external tank. Thanks to the pressure of the pressure source P, both the balancing valve 30 and the non-return valve 40 will open and give a thrust to the piston 13 which will cause an expansion of the second chamber 12. The fluid contained within the second chamber 12 will then be conveyed through the distribution valve 100 to the tank T.
  • the distribution valve 100 will be brought to the central position shown in figure 2 , so neither the first supply conduit 20 nor the second supply conduits 21, 22 are connected with the pressure source P and, thanks to the force of the internal spring of the balancing valve 30 and the check valve 40, a flow of fluid through them is prevented.
  • the displacement of the distribution valve 100 towards the left position of figure 1 allows to start supplying fluid under pressure to the first supply conduit 20 while the connection between the second supply conduit 21, 22 and the tank T is still closed.
  • the inlet pressure of the first supply conduit 20 will be applied to the balancing valve 30 by means of the first pilot conduit 201 at the pilot port 30a. Once a certain predetermined pressure has been reached, the balancing valve 30 will open so as to open a passage for the fluid coming from the second chamber 12 and directed towards the distribution valve 100. However, since there is not yet a connection between the second supply conduit 21, 22 and the tank T, the balancing valve 30 will allow the pressure upstream and downstream of the balancing valve 30 to be equalized so as to prevent a possible "hopping" of the cylinder 10. This pressure difference is due to a possible leakage of the distribution valve 100 or to the load induced on the cylinder 10.
  • the opening of the check valve 40 can take place by means of the second pilot line 211.
  • the task of allowing the opening of the check valve 40 can alternatively be performed by the asymmetry of the distribution valve 100 (as described in the previous paragraph) or by the presence of the restriction 212. It is clear that in a preferred embodiment such as that shown in the figure, both the asymmetry of the spool of the distribution valve 100 and the bottleneck 212 may be present.
  • the distribution valve 100 will create the connection between the second supply conduit 21, 22 and the tank T so as to be able to discharge the fluid contained inside the second chamber 12 towards the tank T.
  • the balancing valve 30 and the check valve 40 are sized in such a way that the maximum fluid flow that can pass through the check valve 40 is greater than the maximum fluid flow passing through the balancing valve 30, it will be the case that most of the flow will pass through the check valve 40.
  • the present configuration of the control system 1000 has as an advantage the use of a rather small valve (the balancing valve 30), which allows to carry out the initial phase which prevents jumps due to pressure differences between the branches upstream and downstream of the same. Subsequently, most of the fluid is exchanged using a one-way valve, which is of very simple construction and easily calibrated.
  • the control of the cylinder is, as mentioned above, left to the full distributor.
  • the present invention has been described with particular reference to a crane, the present invention can be applied in any other field where hydraulic control is required in moving a load. For example, in operating machines.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
EP21155350.8A 2020-02-10 2021-02-05 Steuersystem für einen antriebszylinder eines krans Pending EP3862576A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT102020000002506A IT202000002506A1 (it) 2020-02-10 2020-02-10 Sistema di controllo per un cilindro attuatore di una gru
IT102021000000431A IT202100000431A1 (it) 2021-01-12 2021-01-12 Sistema di controllo per un cilindro attuatore di una gru

Publications (1)

Publication Number Publication Date
EP3862576A1 true EP3862576A1 (de) 2021-08-11

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EP21155350.8A Pending EP3862576A1 (de) 2020-02-10 2021-02-05 Steuersystem für einen antriebszylinder eines krans

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT202100009539A1 (it) * 2021-04-15 2022-10-15 Bosch Gmbh Robert Sistema per un cilindro attuatore di una gru
IT202100023543A1 (it) * 2021-09-13 2023-03-13 Bosch Gmbh Robert Dispositivo per il rientro controllato di un cilindro

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0867567A2 (de) * 1997-03-24 1998-09-30 Oyodo Komatsu Co., Ltd. Öldruck-Regler
EP1387089A2 (de) * 2002-07-30 2004-02-04 Kobelco Construction Machinery Co., Ltd. Schaltkreis eines hydraulischen Stellglieds
US20180066681A1 (en) * 2016-09-08 2018-03-08 Lippert Components, Inc. Hydraulic stabilizing system
IT201800002172A1 (it) 2018-01-30 2019-07-30 Bosch Rexroth Oil Control S P A Circuito di alimentazione con pilotaggio a pressione regolabile.
WO2019210341A1 (de) * 2018-05-04 2019-11-07 Palfinger Ag Hydrauliksystem

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0867567A2 (de) * 1997-03-24 1998-09-30 Oyodo Komatsu Co., Ltd. Öldruck-Regler
EP1387089A2 (de) * 2002-07-30 2004-02-04 Kobelco Construction Machinery Co., Ltd. Schaltkreis eines hydraulischen Stellglieds
US20180066681A1 (en) * 2016-09-08 2018-03-08 Lippert Components, Inc. Hydraulic stabilizing system
IT201800002172A1 (it) 2018-01-30 2019-07-30 Bosch Rexroth Oil Control S P A Circuito di alimentazione con pilotaggio a pressione regolabile.
EP3527833A1 (de) * 2018-01-30 2019-08-21 Bosch Rexroth Oil Control S.p.A. Zufuhrkreislauf mit steuerung mit regulierbarem druck
WO2019210341A1 (de) * 2018-05-04 2019-11-07 Palfinger Ag Hydrauliksystem

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT202100009539A1 (it) * 2021-04-15 2022-10-15 Bosch Gmbh Robert Sistema per un cilindro attuatore di una gru
IT202100023543A1 (it) * 2021-09-13 2023-03-13 Bosch Gmbh Robert Dispositivo per il rientro controllato di un cilindro
EP4148014A1 (de) * 2021-09-13 2023-03-15 Robert Bosch GmbH Vorrichtung zum kontrollierten wiedereintritt eines zylinders

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