Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
• • 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
  • F15B2211/21—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
  • F15B2211/30—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
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/615—Filtering 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
  • F15B2211/60—Circuit components or control therefor
  • F15B2211/62—Cooling or heating 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
  • F15B2211/60—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

Definitions

• the invention relates to a device for providing a pressure for a hydraulic consumer and a method for providing a pressure for a hydraulic consumer.
• Hydraulic consumers for example. Spraying cylinder, lock cylinder or screw motors must be supplied with a hydraulic fluid having a predetermined pressure. Especially when such consumers each require a short time large quantities of pressure medium, the regulation of the pressure provided must respond accordingly quickly.
• the accumulator assembly is controlled by an actual pressure in the pressure accumulator is compared with a desired pressure and, accordingly, the speed of a drive motor is changed.
• the regulation of the pressure is still slow, so that a relatively large accumulator must be provided.
• a device for providing pressure to a hydraulic consumer comprising a tank for providing a hydraulic fluid and a hydraulic pump fed from the tank and adapted to provide pressure at its outlet.
• An electric motor is provided for driving the hydraulic pump and a pressure transducer for indicating the output from the hydraulic pump pressure.
• the frequency converter receives the signal indicated by the pressure transducer and is set to control the pressure provided by the hydraulic pump by controlling the speed of the electric motor.
• the frequency converter for sensorless control of the electric motor is set up by means of a vector control.
• sensorless is used synonymously with the term encoderless, with an encoder being understood as a device that measures the speed of the electric motor.
• the electric motor is designed as an asynchronous motor, since an asynchronous motor is particularly suitable for sensorless or encoderless control.
• a forced cooling fan is provided to the radiator of the electric motor, eliminating the need to provide a separate fan that changes the load behavior of the induction motor.
• an accumulator is additionally provided for storing the pressure provided by the hydraulic pump.
• a minimum amount can be set at low speeds in order to avoid low speeds.
• the pressure can be stably controlled over a wide speed range.
• a filter is provided between the outlet of the hydraulic pump and the hydraulic filter, whereby clogging of the throttle valve can be avoided.
• the hydraulic pump is operated in a speed range with speeds n> 2 Hz, because in this higher speed range, the engine models of the vector control are carried out very close to reality.
• a constant pump is used in the preferred form.
• a constant pump is characterized by a constant displacement volume; the flow rate essentially results from the product of displacement volume and speed. A change in the flow rate is thus adjusted by a change in the speed.
• the invention also relates to a method for providing a pressure with the following steps: first, a device according to the invention is provided, after which the actual value of the pressure provided by the hydraulic pump is compared with a desired value.
• the speed of the electric motor is controlled sensorless by means of a vector control.
• variable-speed pump drive is created, which is composed of inexpensive components.
• FIG. 1 shows a hydraulic system with a device according to the invention for generating a pressure
• FIG. 2 shows a further embodiment of a hydraulic system
• FIG 3 shows a third embodiment of a hydraulic system with a device according to the invention for generating a pressure.
• FIG. 1 shows a hydraulic system with a hydraulic consumer 2 and a device 1 for generating a pressure for the electrical load 2.
• the device comprises a tank 4, a hydraulic pump 3, a throttle valve 15, a check valve 12, a pressure transducer 9, and a control device 11.
• the control device 11 includes a frequency converter 8, an electric motor 6 and a forced cooling fan 10.
• the forced cooling fan 10 has the task of cooling the electric motor 6.
• the tank 4 contains a hydraulic fluid, for example a hydraulic oil, with which the hydraulic pump 3, which is designed as a constant displacement pump according to the displacement principle, is supplied.
• a pressure p 0 is provided at the output of the pump 5, which serves to operate the hydraulic consumer 2.
• a check valve 12 is provided between the output 5 of the hydraulic pump 3 and the designated by the reference P terminal of the hydraulic consumer 2. This check valve is arranged so that a return flow of hydraulic fluid from the hydraulic consumer 2 is prevented in the hydraulic pump 3. The check valve 12 thus protects the hydraulic pump 3 from the system pressure generated by the hydraulic consumer 2.
• the pressure p 0 is received by the pressure transducer 9, which outputs an electrical signal I whose characteristics are dependent on the pressure p 0 .
• This electrical signal I is applied to a first input of the frequency converter 8, which receives at a second input an electrical signal S representing a desired value for the pressure.
• At its output of the frequency converter 8 outputs the electrical sinusoidal signals U, V, W, with which the stator windings of the induction motor are acted upon.
• the signals U, V, W are each phase shifted by 120 degrees and thus provide a three-phase current available.
• the magnitude of the voltage, the magnitude of the current and the frequency of the electrical signals U, V, W determine the rotational speed of the asynchronous motor 6.
• the hydraulic pump 3 is preferably designed as an internal gear pump or external gear pump.
• the rotary motion generated by the asynchronous motor 6 rotates the gears of the hydraulic pump 3, so that the pressure p 0 at the output 5 of the hydraulic pump 3 is generated.
• the manipulated variable for the regulation of the pressure is the speed of the asynchronous motor 6, resulting in the speed of the gears and the flow rate of the hydraulic pump 3 results.
• the assembly of hydraulic pump 3, electric motor 6 and frequency converter 8 form a unit of a variable-speed pump drive.
• the frequency converter 8 controls the asynchronous motor 6 only.
• the frequency converter 8 uses as a control method no U / f control, but a sensorless current or voltage vector control.
• the control loop is closed via the pressure transducer 9.
• the frequency converter 8 contains an image of the asynchronous machine, the image of the asynchronous machine corresponding to a replacement circuit diagram of complex resistors.
• Speeds ⁇ 2 Hz is mathematically complex to calculate and may be inaccurate given the computing power. For this reason, the image is usually in the frequency ter 8 only implemented from 2 Hz and in some versions from 4 Hz.
• the throttle valve 15 may, for example, be designed as a nozzle o as a switching valve.
• a PI or a PID controller is integrated, which regulates the pressure p 0 on the basis of the actual signal I and the desired signal S.
• the output signals of the frequency converter 8 are changed, the change taking place due to the values for the engine speed stored in the frequency converter.
• a frequency converter 8 with an integrated vector control for example, under the product name "IndraDrive Fc" from Bosch Rexroth can be used for distributed frequency converters.
• the sensorless vector control has the advantage that it can respond quickly to a target-actual difference.
• FIG. 2 shows a further embodiment of a hydraulic system 1; in which the pressure p 0 is provided according to the invention for the hydraulic consumer 2.
• the device 1 for generating a pressure additionally has a filter 20 and a cooler 21.
• the filter 20 is connected behind the output 5 of the hydraulic pump 3, so that the hydraulic fluid, which flows to the throttle valve 15, the check valve 12 or the pressure transducer 9, also called pressure transducer 9, first passes the filter 20.
• the filter 20 ensures that the so-called by-pass amount, d. H. , the amount of hydraulic fluid flowing through the throttle valve 15 is ensured by preventing clogging of the throttle valve.
• the radiator 21 is provided for reflux to the tank 4 to cool the by-pass amount.
• FIG. 3 shows a further exemplary embodiment of a device 1 for generating a pressure for a hydraulic consumer 2.
• the device 1 has a throttle check valve 16 and a reservoir 17. If the hydraulic consumer 2 short-term requires a large amount of hydraulic fluid can these are provided by the memory 17 for a short time by the biased in the memory 17 amount.
• the memory covers the dynamic requirements of the system, which increases the dynamics of the system, ie that even large changes in consumption can be compensated quickly.
• the throttle check valve 16 is provided between the reservoir 17 and the inlet P of the hydraulic consumer 2. In the direction from the memory 17 to the port P of the hydraulic consumer 2, the volume flow is free. In the opposite direction he is throttled against it.
• the memory 17 can be quickly discharged into the system. However, the throttling causes the memory 17 can be loaded defined and thus a reaction of the membranes or the bubbles of the memory 17 is prevented to the pressure control. The disturbance function of the vibrating element in the memory 17 is thus largely linearized or eliminated.
• the throttle check valve 16 can also be replaced by a check valve with nozzle bore in the valve.
• the memory is provided directly at the input P of the hydraulic consumer 2 see.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
• Fluid-Pressure Circuits (AREA)
• Control Of Positive-Displacement Pumps (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
• Motor Or Generator Cooling System (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=41328954

Family Applications (1)

Country Status (5)

Cited By (4)

Families Citing this family (10)

Citations (2)

Family Cites Families (15)

• 2008
  • 2008-08-20 DE DE200810038520 patent/DE102008038520A1/de not_active Withdrawn
• 2009
  • 2009-08-14 WO PCT/EP2009/005901 patent/WO2010020376A1/de active Application Filing
  • 2009-08-14 JP JP2011523338A patent/JP2012500370A/ja active Pending
  • 2009-08-14 EP EP09777880A patent/EP2315950A1/de not_active Withdrawn
  • 2009-08-14 CN CN2009801322029A patent/CN102124232A/zh active Pending

Patent Citations (2)

Also Published As

Similar Documents

Legal Events