WO2019166695A1 - Power unit for controlling a pressure medium for load control - Google Patents

Power unit for controlling a pressure medium for load control Download PDF

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Publication number
WO2019166695A1
WO2019166695A1 PCT/FI2019/050153 FI2019050153W WO2019166695A1 WO 2019166695 A1 WO2019166695 A1 WO 2019166695A1 FI 2019050153 W FI2019050153 W FI 2019050153W WO 2019166695 A1 WO2019166695 A1 WO 2019166695A1
Authority
WO
WIPO (PCT)
Prior art keywords
power unit
pressure medium
pressure
actuator
drive circuit
Prior art date
Application number
PCT/FI2019/050153
Other languages
French (fr)
Inventor
Juha ELONEN
Original Assignee
Fiellberg Oy
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
Application filed by Fiellberg Oy filed Critical Fiellberg Oy
Publication of WO2019166695A1 publication Critical patent/WO2019166695A1/en

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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
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/027—Installations or systems with accumulators having accumulator charging devices
    • F15B1/0275—Installations or systems with accumulators having accumulator charging devices with two or more pilot valves, e.g. for independent setting of the cut-in and cut-out pressures
    • 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
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/027—Installations or systems with accumulators having accumulator charging devices
    • F15B1/033—Installations or systems with accumulators having accumulator charging devices with electrical control means
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/08—Superstructures; Supports for superstructures
    • E02F9/0858—Arrangement of component parts installed on superstructures not otherwise provided for, e.g. electric components, fenders, air-conditioning units
    • E02F9/0875—Arrangement of valve arrangements on superstructures
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
    • 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
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • 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
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/027—Installations or systems with accumulators having accumulator charging devices
    • 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/14—Energy-recuperation 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
    • F15B2201/00—Accumulators
    • F15B2201/30—Accumulator separating means
    • F15B2201/31—Accumulator separating means having rigid separating means, e.g. pistons
    • 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
    • F15B2201/00—Accumulators
    • F15B2201/50—Monitoring, detection and testing means for accumulators
    • F15B2201/51—Pressure detection
    • 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
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/212—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being accumulators
    • 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
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/214—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being hydrotransformers
    • 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
    • F15B2211/305—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
    • F15B2211/30575—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 in a Wheatstone Bridge arrangement (also half bridges)
    • 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/61—Secondary circuits
    • F15B2211/611—Diverting circuits, e.g. for cooling or filtering
    • 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
    • F15B2211/625—Accumulators
    • 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
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/632—Electronic controllers using input signals representing a flow rate
    • F15B2211/6323—Electronic controllers using input signals representing a flow rate the flow rate being a pressure source flow rate
    • 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
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/88—Control measures for saving energy
    • 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
    • F15B3/00—Intensifiers or fluid-pressure converters, e.g. pressure exchangers; Conveying pressure from one fluid system to another, without contact between the fluids

Definitions

  • Power unit for controlling a pressure medium for load control
  • the present invention relates to a power unit for controlling a pressure medium for load control, in connection with which power unit is arranged in use both a supply circuit for supplying pressure medium under pressure into the power unit and a drive circuit, in connection with which is arranged an actuator, into which the pres- sure medium is to be supplied for loading said actuator, the pressure being created by control means arranged to the power unit, and in connection with which power unit is arranged a discharge circuit for discharging pressure medium from the drive circuit.
  • Power units according to that presented above are used specifically for controlling actuators intended for moving working machines, such as forklift hoists, excavator scoops and their arms. While directing the pressure medium required for load con- trol, the energy required by such arrangements, in other words fuel consumption, is relatively high, and their placement, specifically the placement of the power units in connection with the actuators, is often challenging. Often, the apparatus related to operation of the power unit, such as the valves and the connections between them for supplying pressure medium, must be positioned scattered apart from each other, which, in turn, disadvantageously increases energy requirements and, consequently, fuel consumption in power units of this type.
  • FI 125918 A system more precise in its adjustment characteristics is presented in FI 125918, which includes a system connected directly to the actuator, into its many working chambers.
  • the actuator generates the total force affecting the load.
  • the structure of the actuator is, however, quite restricted, at least for achieving a precise total force affecting the load.
  • the object of the present invention is to obviate or at least substantially decrease above said disadvantages, which thus relate to the adjustability of the power unit and the energy efficiency of the structure.
  • the present invention is characterized by that, which is specified in the characterizing part of independent claim 1.
  • the invention in prior known arrangements is achieved the advantage that the pressure medium control means and the transfer channels required for load control can be integrated into a very small space in the module frame and such that there is no need for separate channels or pipes causing control means pressure losses.
  • the directional control valves, the cylinders and a pressure accumu- lator included in the control means can be fitted into the module frame in such a required amount that provides for loading the actuator an exceptionally precise and energy-saving control of the pressure medium between the control means arranged in connection with the actuator and the module frame. That which is presented above thus provides a plug-and-play type power unit between the supply circuit and the drive circuit, which is even more energy-efficient and more precise in its ad- justments than in prior known solutions.
  • Fig. 1 shows a diagrammatic view of a power unit according to a preferred embodiment of the invention, as well as the supply and drive circuits arranged in connection with it,
  • Fig. 2 shows an axonometric projection of a power unit according to Fig. 1, and
  • Fig. 3 shows diagrammatically the application of a power unit according to
  • Fig. 2 for controlling the load of a hydraulic cylinder.
  • Fig. 1 thus illustrates diagrammatically a power unit according to the present inven- tion, which is designated by reference numeral 10.
  • the control means included in the power unit are inside the box designated by reference numeral 10a representing the module frame and shown by a dashed line.
  • a supply circuit 50 In connection with the power unit 10 is arranged a supply circuit 50, through which the pressure medium is supplied under pressure into the power unit 10.
  • the supply circuit 50 includes a tank 51, from which the pressure medium is pumped by a pump 53 (motor 53a) along the flow path 52 into the power unit 10.
  • the pressure medium is a hydraulic pressure medium, but the pressure medium can also be, for example, air or other fluid pressure medium.
  • the supply circuit 50 can also be formed in some other manner for supplying pres- sure medium under pressure into the power unit 10. In other words, the presented embodiment is just one of many preferred examples of supplying a pressure medi- urn.
  • Fig. 2 shows a power unit 10 according to the invention, which comprises a module frame designated by reference numeral 11, as well as control means arranged im- movably in relation to the module frame 11 and presented in more detail in the fol- lowing.
  • the control means include at least one pressure accumulator 12, which is, for ex- ample, a piston pressure accumulator. From the supply means 50 is arranged via a connection 12a into the module frame 11 a first flow path 20, which is directly con- nected to the pressure accumulator 12 for supplying pressure medium thereto.
  • a flow path 20a or flow paths 20a which are in connection with the cylinders 14 included in the control means.
  • the cylinders 14 are four units, and they are designated by refer- ence numerals 14a, 14b, 14c and 14d.
  • the number of cylinders can generally vary according to the application. Flowever, there must be at least two, preferably how- ever 3 - 5 units. In Fig. 2 they are encased within the space defined by the protec- tive casing 10a.
  • the flow paths 20a leading to the cylinders lead into their spaces on the side of the piston shaft.
  • Each cylinder is preferably of different size. In this case, the diameters of the piston shaft are different, wherein from each cylinder is obtained, through the directional control valves presented below, different pressures for the actuator 100.
  • the piston-side spaces of the cylinders 14a, 14b, 14c and 14d are, in turn, via other flow paths 21a, 21b, 21c and 21d, in connection with the directional control valves arranged immovably into the module frame 11.
  • the group of directional control valves is designated by reference numerals 15 and 16, and their number can vary depending on the number of the cylinders and/or the size of the valves, preferably being 9 - 30 units.
  • the pressure medium can be directed through the first directional con- trol valves 15 from the actuator 100 back to the cylinders 14a 14b, 14c and 14d.
  • the pressurized pressure medium to be discharged from the actuator 100 can still be used for charging the pressure accumulator 12.
  • the transfer of the pressure medium occurs thus through the connections (channels) integrated into the power unit.
  • control means include second directional control valves, i.e. auxiliary valves 16, through which the pressure medium can be directed from the supply circuit 50 directly though the power unit 10 to the drive circuit 60 and, fur- ther, to the actuator 100.
  • auxiliary valves include directional control valves 16' between the drive circuit 60 and the first directional control valves 15, through which the pressure medium to be discharged from the actuator can be directed directly through the power unit 10 (12b) to the discharge circuit 70 in con- nection with the tank 51.
  • the actuator 100 is a double-acting piston cylinder.
  • the directional control valves 15 and 16 are further divided in two such groups that the pressure medium can be directed through the supply channels 61 and 62 of the drive circuit 60 onto both sides of the piston of the piston cylinder.
  • Such an ar- rangement can be adapted, for example, in an arrangement according to Fig. 3, in which the actuator 100 is adapted for turning the bucket arm of a shovel loader or the arm parts 81 of the arm 80 of a crane.
  • Another example of the many applica tions for a power unit according to the invention is, for example, the forks of devic- es intended for lifting things, such as forklifts.
  • the actuator 100 is preferably equipped with detection means 110, on the basis of the data detected by which the control means are to be controlled to create the pressure required by the actuator 100.
  • the detection means 110 can be, for example, pressure sensors arranged into the pressure spaces of the actuator 100, the detections of which sensors can be sent electronically along the data transmis- sion means 111 and 112 to the control unit 17, which is an integral part of the con- trol means of the power unit.
  • the detection means can be used to detect directly or indirectly also other parameters required for the control, such as force, position and/or station.
  • from the control unit 17 can be sent, on the basis of detections, electronic control commands for controlling the control means.
  • control means which preferably include, for example, the above-described pressure accumulator 12, four cylinders 14a, 14b, 14c and 14d and twenty-four units of grouped direc- tional control valves 15, 16, 16', is already achieved as such a very precise control of loading in the presented embodiments.
  • the inven- tion is not limited to these numbers of cylinders and directional control valves, as has already been specified earlier. This also involves that the control means achiev- ing precise control are arranged immovably in connection with the module frame 11 of the power unit 10.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The invention relates to a power unit (10) for controlling a pressure medium for load control. In connection with it is arranged a supply circuit (50) for supplying pressure medium under pressure into the power unit (10) and a drive circuit (60), in connection with which is arranged an actuator (100), into which the pressure medium is to be supplied for loading said actuator (100). Loading is achieved by control means (12, 14, 15, 16, 16') ar- ranged to the power unit (10). In connection with the power unit (10) is arranged a discharge circuit (70) for discharging pressure medium from the drive circuit (60). Arranged immovably in relation to the module frame (11) are the control means (12, 14, 15, 16) including at least: a pressure accumulator (12), into which the pres- sure medium is to be supplied from the supply circuit (50); at least two parallel connected cylinders (14), into which the pressure medium is to be supplied from the circuit (50), the pressure accumulator (12) and/or the drive circuit (60); directional control valves (15, 16, 16') arranged in connection with the cylinders (14) and through which the pressure medium supplied from the supply circuit (50) and/or from the cylinders (14) is to be directed to the external drive circuit (60) of the power unit (10) and further to the actuator (100), or through which said directional control valves (15, 16,160 the pressure medium returning from the drive circuit (60) is to be directed to the cylinders (14) for charging the pressure accumulator (12) and/or to the discharge cir- cuit (70); connections for the pressure medium are formed to the module frame (11), wherein the control unit (10) is to be placed as one unit between the supply circuit (50) and the drive circuit (60).

Description

Power unit for controlling a pressure medium for load control
The present invention relates to a power unit for controlling a pressure medium for load control, in connection with which power unit is arranged in use both a supply circuit for supplying pressure medium under pressure into the power unit and a drive circuit, in connection with which is arranged an actuator, into which the pres- sure medium is to be supplied for loading said actuator, the pressure being created by control means arranged to the power unit, and in connection with which power unit is arranged a discharge circuit for discharging pressure medium from the drive circuit.
Power units according to that presented above are used specifically for controlling actuators intended for moving working machines, such as forklift hoists, excavator scoops and their arms. While directing the pressure medium required for load con- trol, the energy required by such arrangements, in other words fuel consumption, is relatively high, and their placement, specifically the placement of the power units in connection with the actuators, is often challenging. Often, the apparatus related to operation of the power unit, such as the valves and the connections between them for supplying pressure medium, must be positioned scattered apart from each other, which, in turn, disadvantageously increases energy requirements and, consequently, fuel consumption in power units of this type.
Such hydraulic control devices are presented, for example, in EP 1253327, in which for each actuator is arranged one directional control valve and its adjustment char- acteristics are also not very precise.
A system more precise in its adjustment characteristics is presented in FI 125918, which includes a system connected directly to the actuator, into its many working chambers. Herein, the actuator generates the total force affecting the load. Herein, the structure of the actuator is, however, quite restricted, at least for achieving a precise total force affecting the load.
The object of the present invention is to obviate or at least substantially decrease above said disadvantages, which thus relate to the adjustability of the power unit and the energy efficiency of the structure. In order to achieve the above-stated object, the present invention is characterized by that, which is specified in the characterizing part of independent claim 1. Using the invention, in prior known arrangements is achieved the advantage that the pressure medium control means and the transfer channels required for load control can be integrated into a very small space in the module frame and such that there is no need for separate channels or pipes causing control means pressure losses. Further, the directional control valves, the cylinders and a pressure accumu- lator included in the control means can be fitted into the module frame in such a required amount that provides for loading the actuator an exceptionally precise and energy-saving control of the pressure medium between the control means arranged in connection with the actuator and the module frame. That which is presented above thus provides a plug-and-play type power unit between the supply circuit and the drive circuit, which is even more energy-efficient and more precise in its ad- justments than in prior known solutions.
The preferred embodiments of the invention are presented in the accompanying dependent claims.
In the following, the invention is described in more detail by referring to the accom- panying drawings, in which:
Fig. 1 shows a diagrammatic view of a power unit according to a preferred embodiment of the invention, as well as the supply and drive circuits arranged in connection with it,
Fig. 2 shows an axonometric projection of a power unit according to Fig. 1, and
Fig. 3 shows diagrammatically the application of a power unit according to
Fig. 2 for controlling the load of a hydraulic cylinder. Fig. 1 thus illustrates diagrammatically a power unit according to the present inven- tion, which is designated by reference numeral 10. The control means included in the power unit are inside the box designated by reference numeral 10a representing the module frame and shown by a dashed line.
In connection with the power unit 10 is arranged a supply circuit 50, through which the pressure medium is supplied under pressure into the power unit 10. Preferably, the supply circuit 50 includes a tank 51, from which the pressure medium is pumped by a pump 53 (motor 53a) along the flow path 52 into the power unit 10. In the presented embodiment, the pressure medium is a hydraulic pressure medium, but the pressure medium can also be, for example, air or other fluid pressure medium. The supply circuit 50 can also be formed in some other manner for supplying pres- sure medium under pressure into the power unit 10. In other words, the presented embodiment is just one of many preferred examples of supplying a pressure medi- urn.
Fig. 2 shows a power unit 10 according to the invention, which comprises a module frame designated by reference numeral 11, as well as control means arranged im- movably in relation to the module frame 11 and presented in more detail in the fol- lowing.
The control means include at least one pressure accumulator 12, which is, for ex- ample, a piston pressure accumulator. From the supply means 50 is arranged via a connection 12a into the module frame 11 a first flow path 20, which is directly con- nected to the pressure accumulator 12 for supplying pressure medium thereto.
From the first flow path 20 shown in Fig. 1 branches also a flow path 20a or flow paths 20a, which are in connection with the cylinders 14 included in the control means. Flerein, the cylinders 14 are four units, and they are designated by refer- ence numerals 14a, 14b, 14c and 14d. The number of cylinders can generally vary according to the application. Flowever, there must be at least two, preferably how- ever 3 - 5 units. In Fig. 2 they are encased within the space defined by the protec- tive casing 10a. The flow paths 20a leading to the cylinders lead into their spaces on the side of the piston shaft. Each cylinder is preferably of different size. In this case, the diameters of the piston shaft are different, wherein from each cylinder is obtained, through the directional control valves presented below, different pressures for the actuator 100.
The piston-side spaces of the cylinders 14a, 14b, 14c and 14d are, in turn, via other flow paths 21a, 21b, 21c and 21d, in connection with the directional control valves arranged immovably into the module frame 11. The group of directional control valves is designated by reference numerals 15 and 16, and their number can vary depending on the number of the cylinders and/or the size of the valves, preferably being 9 - 30 units. The first directional control valves 15, which in the case of four cylinders are sixteen units, are divided here into groups of four directional control valves, of which each valve group is in such a connection with a corresponding cyl- inder such that the pressure medium directed from the corresponding cylinder can be directed through each directional control valve of the group to the external drive circuit 60 of the power unit 10 and to the actuator 100 in connection with it. Corre- spondingly, the pressure medium can be directed through the first directional con- trol valves 15 from the actuator 100 back to the cylinders 14a 14b, 14c and 14d. Hence, at least a portion of the pressurized pressure medium to be discharged from the actuator 100 can still be used for charging the pressure accumulator 12. The transfer of the pressure medium occurs thus through the connections (channels) integrated into the power unit.
In addition to this, the control means include second directional control valves, i.e. auxiliary valves 16, through which the pressure medium can be directed from the supply circuit 50 directly though the power unit 10 to the drive circuit 60 and, fur- ther, to the actuator 100. Correspondingly, the auxiliary valves include directional control valves 16' between the drive circuit 60 and the first directional control valves 15, through which the pressure medium to be discharged from the actuator can be directed directly through the power unit 10 (12b) to the discharge circuit 70 in con- nection with the tank 51.
Shown in Fig. 2, as the actuator 100 is a double-acting piston cylinder. Preferably, the directional control valves 15 and 16 are further divided in two such groups that the pressure medium can be directed through the supply channels 61 and 62 of the drive circuit 60 onto both sides of the piston of the piston cylinder. Such an ar- rangement can be adapted, for example, in an arrangement according to Fig. 3, in which the actuator 100 is adapted for turning the bucket arm of a shovel loader or the arm parts 81 of the arm 80 of a crane. Another example of the many applica tions for a power unit according to the invention is, for example, the forks of devic- es intended for lifting things, such as forklifts.
The actuator 100 is preferably equipped with detection means 110, on the basis of the data detected by which the control means are to be controlled to create the pressure required by the actuator 100. Herein, the detection means 110 can be, for example, pressure sensors arranged into the pressure spaces of the actuator 100, the detections of which sensors can be sent electronically along the data transmis- sion means 111 and 112 to the control unit 17, which is an integral part of the con- trol means of the power unit. Depending on the application, the detection means can be used to detect directly or indirectly also other parameters required for the control, such as force, position and/or station. Hence, from the control unit 17 can be sent, on the basis of detections, electronic control commands for controlling the control means.
In relation to prior art for loading an actuator, such an arrangement combines ex- ceptionally precise control as well as compact structure, using which new kind of combination a significant energy savings is achieved. Using the control means, which preferably include, for example, the above-described pressure accumulator 12, four cylinders 14a, 14b, 14c and 14d and twenty-four units of grouped direc- tional control valves 15, 16, 16', is already achieved as such a very precise control of loading in the presented embodiments. However, let it be noted that the inven- tion is not limited to these numbers of cylinders and directional control valves, as has already been specified earlier. This also involves that the control means achiev- ing precise control are arranged immovably in connection with the module frame 11 of the power unit 10. As a result of this, a great number of the flow paths connect- ing the control means, also in terms of length, are obtained as a single compact module in connection with a mobile power unit. This structure significantly shortens the length of the flow paths connecting the control means. This, in combination with precise adjustment of loading, has a direct reductive influence on the energy re- quirement needed for loading the actuator, for example the fuel consumption of a working machine. This provides also the possibility of a plug-and-play type control unit, the installation and maintenance of which is significantly simpler than in the past. The present invention is not limited to only the presented embodiments, rather many various modifications are possible within the protective scope of the claims.

Claims

Claims
1. A power unit (10) for controlling a pressure medium for load control, in connec- tion with which power unit (10) is arranged in use a supply circuit (50) for supplying pressure medium under pressure into the power unit (10) and a drive circuit (60), in connection with which is arranged an actuator (100), into which the pressure medi- um is to be supplied for loading said actuator (100), the loading of which is achieved by control means (12, 14, 15, 16, 16') arranged to the power unit (10), and in connection with which power unit (10) is arranged a discharge circuit (70) for discharging pressure medium from the drive circuit (60), characterized in that the power unit (10) includes a module frame (11), which includes the control means (12, 14, 15, 16) arranged immovably in relation to the module frame (11) and in- cluding at least: - a pressure accumulator (12), into which the pressure medium is to be supplied from the supply circuit (50),
- at least two parallel connected cylinders (14), into which the pressure medium is to be supplied from the supply circuit (50), the pressure accumulator (12) and/or the drive circuit (60),
- directional control valves (15, 16, 16') arranged in connection with the cylinders (14) and through which the pressure medium supplied from the supply circuit (50) and/or cylinder (14) is to be directed to the external drive circuit (60) of the power unit (10) and further to the actuator (100), or through which said directional control valves (15, 16,16') the pressure medium returning from the drive circuit (60) is to be directed to the cylinders (14) for charging the pressure accumulator (12) and/or to the discharge circuit (70), and that the connections of the pressure accumulator (12), the cylinders (14) and the direc- tional control valves (15) for the pressure medium are formed to the module frame (11), wherein the power unit (10) formed thus is to be placed as one unit between the supply circuit (50) and the drive circuit (60).
2. A power unit according to claim 1, characterized in that the actuator (100) is equipped with detection means (110), on the basis of the data detected by which the control means (12, 14, 15, 16) are to be controlled in order to create the pres- sure required by the actuator (100).
3. A power unit according to claim 1 or 2, characterized in that the directional control valves (15, 16, 167) are 9 - 30 units and, correspondingly, the cylinders (14) are 3 - 5 units.
4. A power unit according to any one of the preceding claims 1 - 3, characterized in that the directional control valves (15, 16, 167) are at least twenty-four units, which provide the use of at least four cylinders (14a, 14b, 14c, 14d) in order to cre- ate the pressure required by the actuator (100).
5. A power unit according to claims 1 - 4, characterized in that each of the cylin- ders (14; 14a, 14b, 14c, 14d) is connected to a group formed by the first four direc- tional control valves (15), depending on the state of which first directional control valves (15) the pressure medium is to be supplied at least from the respective cylin der to the drive circuit (60) in order to create the pressure required by the actuator (100) or, alternatively, from the drive circuit (60) to the corresponding cylinder for charging the pressure accumulator (12) and/or to the discharge circuit (70).
6. A power unit according to any one of the preceding claims 1 - 5, characterized in that the power unit (10) includes auxiliary valves (16, 16') included in the direc- tional control valves (15, 16, 16'), through which auxiliary valves the pressure medi- um is to be supplied directly from the supply circuit (50) to the drive circuit (60), and from the drive circuit (60) to the discharge circuit (70).
7. A power unit according to any one of the preceding claims 2 - 6, characterized in that the cylinders (14) and the directional control valves (15, 16, 16') are to be controlled electronically, and that their electronic control is achieved on the basis of electronically detected data obtained from the detection means (110).
8. A power unit according to any one of the preceding claims 2 - 7, characterized in that the detection means (110) are a load-detecting sensor of the power unit (100) and/or a sensor detecting the prevailing pressure of the pressure medium in the actuator.
9. A power unit according to any one of the preceding claims 1 - 8, characterized in that the actuator (100) is a hydraulic cylinder, and that a portion of the direction- al control valves (15,16) is arranged to direct the hydraulic pressure medium into the space on the side of the piston shaft of the hydraulic cylinder (100) and a por- tion of the directional control valves (15, 16) is arranged to direct the pressure me- dium into the piston-side space of the hydraulic cylinder (100).
10. A power unit according to any one of the preceding claims 1 - 7, characterized in that the cylinders (14) are, in comparison to each other, of different size.
PCT/FI2019/050153 2018-02-27 2019-02-26 Power unit for controlling a pressure medium for load control WO2019166695A1 (en)

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Application Number Priority Date Filing Date Title
FI20185181 2018-02-27
FI20185181A FI20185181A1 (en) 2018-02-27 2018-02-27 Power unit for controlling a pressure medium for load control

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130081385A1 (en) * 2011-09-30 2013-04-04 Patrick Opdenbosch Meterless hydraulic system having multi-actuator circuit
CN104728329A (en) * 2013-12-24 2015-06-24 大连浦州航空科技有限公司 Hydraulic wheel handling and damping system of amphibian vehicle
CN103807239B (en) * 2014-03-12 2015-09-16 南通恒力重工机械有限公司 A kind of shear plate synchronous control hydraulic system based on Dual-output shaft motor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130081385A1 (en) * 2011-09-30 2013-04-04 Patrick Opdenbosch Meterless hydraulic system having multi-actuator circuit
CN104728329A (en) * 2013-12-24 2015-06-24 大连浦州航空科技有限公司 Hydraulic wheel handling and damping system of amphibian vehicle
CN103807239B (en) * 2014-03-12 2015-09-16 南通恒力重工机械有限公司 A kind of shear plate synchronous control hydraulic system based on Dual-output shaft motor

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