Classifications

• • 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
  • E02F9/2221—Control of flow rate; Load sensing arrangements
• • 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
  • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
  • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
  • F15B11/165—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for adjusting the pump output or bypass in response to demand
• • 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
  • E02F9/2058—Electric or electro-mechanical or mechanical control devices of vehicle sub-units
  • E02F9/2062—Control of propulsion units
  • E02F9/207—Control of propulsion units of the type electric propulsion units, e.g. electric motors or generators
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B7/00—Special methods or apparatus for drilling
  • E21B7/02—Drilling rigs characterised by means for land transport with their own drive, e.g. skid mounting or wheel mounting
  • E21B7/022—Control of the drilling operation; Hydraulic or pneumatic means for activation or operation
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F3/00—Dredgers; Soil-shifting machines
  • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
  • E02F3/96—Dredgers; Soil-shifting machines mechanically-driven with arrangements for alternate or simultaneous use of different digging elements
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B7/00—Special methods or apparatus for drilling
  • E21B7/02—Drilling rigs characterised by means for land transport with their own drive, e.g. skid mounting or wheel mounting
  • E21B7/025—Rock drills, i.e. jumbo drills
• • 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
  • F15B2211/205—Systems with pumps
  • F15B2211/20507—Type of prime mover
  • F15B2211/20515—Electric motor
• • 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
  • F15B2211/205—Systems with pumps
  • F15B2211/2053—Type of pump
  • F15B2211/20538—Type of pump constant capacity
• • 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
  • F15B2211/255—Flow control functions
• • 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
  • F15B2211/26—Power control functions
• • 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
  • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line

Definitions

• the invention relates to a hydraulic system of a working vehicle .
• the hydraulic system i provided with a fixed displacement pump , and a speed and torque controlled electric motor for producing hydraulic power .
• the electric motor i s controlled by means of an electric controller .
• the invention further relates to a working vehicle and to a method of producing hydraulic power to a hydraulic system of a working vehicle .
• the field of the invention is defined more specif ically in the preambles of the independent claims .
• the working vehi cles may comprise hydraulic actuators connected to hydraulic systems of the vehicles .
• These types of systems have several advantage s .
• the known solutions have shown to have some disadvantages especially in special situations when there i s a need for pre s sure with no requirement for fluid flow .
• An obj ect of the invention i s to provide a novel and improved hydraulic system, a working vehicle equipped with such hydraulic system and a method for producing hydraulic power to a hydraulic system of a working vehicle .
• the hydraulic system according to the invention is characterized by the characteriz ing feature s of the first independent apparatus claim .
• the working vehicle according to the invention is characterized by the characteriz ing features of the second independent apparatus claim .
• the method according to the invention is characterized by the characterizing features of the independent method claim .
• a hydraulic system of a working vehicle comprise s one or more fixed displacement hydraulic pumps which are powered by one or more speed and torque controlled electric motors .
• the motors are controlled by means of one or more electric controllers for adj usting the speed of the electric motor and to thereby adj usting produced hydraulic fluid flow and pres sure in the hydraulic system .
• the hydraulic system is provided with one or more by-pas s f low channels comprising one or more throttle elements for directing limited continuous discharge fluid flow from the hydraulic system .
• the hydraulic system is provided with the throttle element arranged parallel to the hydraulic pump whereby there is a small hydraulic leak flow out of the hydraulic system to a hydraulic reservoir or tank .
• Purpose of the throttle element is to keep magnitude of the flow in the by-pas s flow channel low so that energy consumption is not increased due to the by-pa ss flow .
• advantages of the disclosed arrangement comprising the f ixed displacement pump and speed and torque controlled electric motor are that hydraulic system pres sure can be controlled fast and accurately by means of the electrical controller .
• the system can keep the system pres sure accurately on controlled values and can adapt quick and automatically to different flow demands of the system by speed adaption of the motor and pump.
• the flow supplied to the system is always in accordance with need. Then the system can be energy efficient and provides accurate pressure control.
• the internal leakage is so small that the hydraulic pump is not rotated continuously which causes unsmooth drive and pressure fluctuations in the system pressure.
• the disclosed by-pass flow channel and the continuous by-pass flow through it will provide the system with smooth drive .
• the magnitude of the by-pass flow is dimensioned so that rotation of the hydraulic pump is always at least 30 - 200 rpm.
• the magnitude of the by-pass flow is dimensioned to be small by means of the throttle element, whereby no relevant power and energy consumption occurs due to the caused constant rotation of the pump-motor arrangement.
• low speed rotation of the motor and pump is implemented in situations when no fluid flow is needed in the system, but pressure request is on for the electric controller.
• the magnitude of the rotation speed may be dependent on power output grade of the hydraulic pump, for example.
• the disclosed by-pass arrangement is adapted to generate slow speed rotation of the pump 150 rpm when no fluid flow request occurs in the electric controller. Then electric consumption of idle run of the motor may be low, for example 250 - 300 W.
• the throttle element is an adjustable element whereby magnitude of the by-pass flow is adjustable.
• the throttle element may be a valve or orifice comprising an adjustable through opening for the fluid flow passing through it.
• the throttle element is a pressure compensated element whereby magnitude of the bypass flow is configured to be adjusted automatically in response to magnitude of pressure prevailing in the hydraulic system.
• the by-pass flow system can adapt to different output pressure situations and can thereby keep the output of the pump stable in different operational situations.
• An advantage of this solution is that the pressure compensated throttle element can take care of that the by-pass flow stays low also at high pressures and thereby ensures good energy efficiency.
• the electric controller is a variable frequency drive serving as an electrical motor control device for controlling torque and rotation speed of the electric motor.
• the disclosed solution aims to stabilize pressure of an inverter controlled hydraulic system.
• the electric controller is configured to control the torque and speed of the motor to adapt the speed of the hydraulic pump in accordance with needed fluid flow at requested pressure level.
• the disclosed solution relates to a working vehicle.
• the working vehicle comprises: a movable carrier; one or more work devices mounted on the carrier; and at least one hydraulic system.
• the hydraulic system is in accordance with the features and embodiments disclosed in this document.
• the working vehicle is a mining vehicle comprising at least one hydraulically operable mining actuator connected to the hydraulic system.
• the above mentioned mining vehicle is a rock drilling rig, a loading vehicle, or a hauling vehicle.
• the working vehicle is alternatively a forest machine, earth moving machine, or mobile crane.
• the carrier of the working vehicle is provided with a brake system comprising spring loaded brakes openable with hydraulic brake actuators.
• the brakes are of normally on type.
• the disclosed solution is implemented for powering the hydraulic brake actuator keeping the brakes off during transfer drives. Then high pressure is needed for the brake actuators without a need for fluid flow since normal working actuators are not operable during the transfer drives.
• the disclosed solution relates to a method of producing hydraulic power to a hydraulic system of a working vehicle.
• the method comprises: rotating a fixed displacement hydraulic pump by means of a speed and torque controlled electric motor; and controlling the rotation of the motor by means of an electric controller for adjusting the speed of the hydraulic pump and to thereby adjusting the produced hydraulic fluid flow and pressure in the hydraulic system.
• the method further comprises directing limited continuous discharge fluid flow via a by-pass flow channel and through a throttle element from an output side of the hydraulic pump to a reservoir whereby the hydraulic pump is driven continuously, and output of the hydraulic pump is stabilized.
• the method comprises stabilizing pressure fluctuations in operational situations when pressure is needed for the output of the hydraulic pump and fluid flow is not.
• the method comprises restricting magnitude of the by-pass flow by means of the throttle element for limiting hydraulic energy consumption.
• the method comprises adj usting magnitude of the by-pa s s f low by means of the throttle element to correspond low speed rotation of the hydraulic pump at 30 - 200 rpm in situation where one or more hydraulic actuators connected to the hydraulic system require no fizid f low but require pres sure .
• Figure 1 is a schematic side view of working vehicle provided with a hydraulic system
• Figure 2 is a schematic diagram showing some pos s ible working vehicle s wherein the dis closed solution can be implemented
• Figure 3 is a s chematic view of a hydraulic diagram of the disclosed hydraulic system
• Figure 4 is a schematic view of an alternative hydraulic diagram of the disclosed hydraulic system
• Figure 5 is a schematic view of two graphs for illustrating sensed pres sures as a function of time .
• Figure 6 is a schematic view of two graphs for illustrating sensed rotation speeds of a hydraulic pump as a function of time .
• FIG. 1 For the sake of clarity, the figure s show some embodiments of the disclosed solution in a simplified manner .
• like reference numerals identify li ke element s .
• Figure 1 di scloses a working vehicle 1 which comprises a movable carrier 2 and one or more work devices 3 .
• the working vehicle 1 is a rock drilling rig for drilling drill holes to a rock surface.
• the rock drilling rig comprises one or more rock drilling units 4 arranged on one or more drilling booms 5.
• the drilling unit 4 comprises a rock drilling machine 6 which serves as a hydraulic actuator Ha connected to a hydraulic system Hs.
• There may be also other hydraulic actuators such as a feed device 7 and boom cylinders 8.
• Other hydraulic actuators on the carrier are also possible, such as breaking actuators.
• the hydraulic system Hs comprises a hydraulic pump Hp, an electric motor M and an electric controller Ec for controlling the motor M.
• Figure 2 discloses a listing of some possible working vehicles wherein the hydraulic system according to this document can be implemented. As it is disclosed in Figure
• the working vehicle may be a loading vehicle, or a haling vehicle used for transporting removed broken rock material in mines.
• the working machine may be an earthmoving machine or vehicle, such as an excavator, a wheel loader, a bulldozer, or a dumper.
• the disclosed solution can be utilized also in forest machines, such as in harvesters and forwarders.
• Different mobile cranes and container handling apparatuses may be provided with the disclosed hydraulic system.
• One more working apparatus to be mentioned, as an example of the working machine, is a pile-driving machine. All the mentioned working vehicles may have operational situations wherein the hydraulic system is subjected to requests for high fluid pressure with no fluid flow.
• Figure 3 discloses a hydraulic system Hs comprising a fixed displacement hydraulic pump Hp rotatable with a speed and torque controlled electric motor M.
• the electric motor M is controlled by means of an electric controller Ec.
• the pump-motor combination generates hydraulic power for powering one or more hydraulic actuators Ha. For simplicity reasons only one hydraulic actuator Ha is presented.
• there is a by-pass flow channel By comprising at least one throttle element Te for directing limited continuous di scharge fluid flow to a reservoir Re .
• Figure 4 differs f rom the solution of Figure 3 only in that the throttling element Te is adj ustable and that the electric controller Ec is a variable frequency drive Vdf .
• Figures 5 and 6 show first curve s E of a hydraulic system with the dis closed solution , and second curves D of a substantially similar kind of hydraulic system without the by-pa s s flow system .
• first curve E is stabili zed .
• the stabili zing effect of the disclosed solution can also be seen when comparing curves E and D in Figure 6 showing the rotation speed of the hydraulic pump . Stabile and controlled rotation of the hydraulic pump i s clearly shown by the curve E .
• the curves E are flat or almost flat .

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• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Fluid Mechanics (AREA)
• Geology (AREA)
• General Engineering & Computer Science (AREA)
• Geochemistry & Mineralogy (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Mechanical Engineering (AREA)
• Fluid-Pressure Circuits (AREA)
• Operation Control Of Excavators (AREA)
• Motor Power Transmission Devices (AREA)
• Control Of Fluid Gearings (AREA)

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• 2021
  • 2021-12-10 EP EP21213736.8A patent/EP4194617A1/en active Pending
• 2022
  • 2022-12-09 CN CN202280080389.8A patent/CN118302581A/zh active Pending
  • 2022-12-09 WO PCT/EP2022/085194 patent/WO2023105048A1/en not_active Ceased
  • 2022-12-09 CA CA3238004A patent/CA3238004A1/en active Pending
  • 2022-12-09 JP JP2024534277A patent/JP2025503403A/ja active Pending
  • 2022-12-09 AU AU2022407149A patent/AU2022407149A1/en active Pending
  • 2022-12-09 US US18/717,465 patent/US12331763B2/en active Active

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