EP1188934A2 - Control device for an hydraulic volume flow - Google Patents

Control device for an hydraulic volume flow Download PDF

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Publication number
EP1188934A2
EP1188934A2 EP01121812A EP01121812A EP1188934A2 EP 1188934 A2 EP1188934 A2 EP 1188934A2 EP 01121812 A EP01121812 A EP 01121812A EP 01121812 A EP01121812 A EP 01121812A EP 1188934 A2 EP1188934 A2 EP 1188934A2
Authority
EP
European Patent Office
Prior art keywords
hydraulic
reducing valve
pressure reducing
control
pressure
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.)
Withdrawn
Application number
EP01121812A
Other languages
German (de)
French (fr)
Other versions
EP1188934A3 (en
Inventor
Joerg Siebert
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 to DE10045213 priority Critical
Priority to DE2000145213 priority patent/DE10045213A1/en
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1188934A2 publication Critical patent/EP1188934A2/en
Publication of EP1188934A3 publication Critical patent/EP1188934A3/en
Withdrawn legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/14Energy-recuperation means
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/003Systems with load-holding valves
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/028Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force

Abstract

The control device controls a pump with at least one hydraulic cylinder (12) under load, e.g. for raising and lower a load, with at least one locking valve (18) and at least one hydraulic motor (20). A pressure reducing valve (22) is fitted between the cylinder and the hydraulic motor to reduce the pressure on the hydraulic motor when the load is being lowered.

Description

State of the art

The invention relates to a control device for a volume flow flowing in a hydraulic system Hydraulic medium according to the preamble of claim 1.

A generic control device for lowering is known a load on a hydraulic cylinder. Here is the Hydraulic cylinder via a check valve and a hydraulic motor connected to a hydraulic fluid tank. Should the load be lowered the shut-off valve is opened and hydraulic fluid flows through the shut-off valve and the hydraulic motor to the hydraulic fluid tank. The hydraulic motor is driven by the pressure of the hydraulic fluid driven. Usually the function of the hydraulic motor from a reverse running hydraulic pump fulfilled, the supply pressure for the hydraulics in lifting operation provides. The hydraulic pump is mostly by one Electric motor driven. When lowering a load the electric motor is driven by the hydraulic motor and works in this operating state generator in the third quadrant. The lowering capacity exceeds the lifting capacity in lifting operation clear. The electric motor must therefore take up power be dimensioned larger than this in lowering operation would be necessary for pure lifting operation. This has higher costs disadvantageous for larger electric motors and requires above also a larger installation space.

Advantages of the invention

The invention relates to a control device for a volume flow flowing in a hydraulic system Hydraulic fluid of at least one loaded working fluid, especially for lifting and lowering a load, with at least a check valve and at least one hydraulic motor.

It is proposed that in the hydraulic system between the working medium and the hydraulic motor a pressure reducing valve so is arranged that when lowering the load on the hydraulic motor pending pressure is reduced. The pressure reducing valve increases high loads or high pressures in the hydraulic system, part of the hydrostatic energy of the work equipment on, the essentially of the potential Energy corresponds to the load when lowering it. That energy is partly due to the pressure reduction when flowing through of the hydraulic fluid through the pressure reducing valve converted into heat by internal friction. The heat output corresponds to the product of flow rate and pressure difference on the pressure reducing valve. The power consumption of the hydraulic motor and thus that of a generator driven by it working electric motor decreases accordingly Heat output. It can therefore be a smaller one Electric motor used and there can be thermal relief can be achieved. This leads to a cost reduction. The smaller design of the electric motor still leads to a Space reduction.

In an advantageous embodiment of the invention, this Pressure reducing valve biased in the opening direction Slider on through the outlet side of the pressure reducing valve hydraulic fluid under reduced pressure in Closing direction is displaceable. The higher the pressure on Pressure relief valve output is, the stronger the force is on the slide in the closing direction. The slider overcomes the Preload in the opening direction and closes the pressure reducing valve. The opening cross section of the pressure reducing valve increases and the pressure difference at the pressure reducing valve increases. at constant inlet pressure, therefore, the outlet pressure decreases. The force on the slide in the closing direction decreases, and the pressure reducing valve opens again. Finally poses a stable balance. The output side depends Pressure on the pressure reducing valve from the preload from. The design of the pressure reducing valve as a slide valve is characterized by a simple structure and reliability out.

The slide is preferably in the opening direction and in Closing direction with surfaces that differ in size Hydraulic fluid can be applied. One after this so-called Differential surface principle built pressure reducing valve offers the advantage of a weaker dimensionable biasing element. For example, a spring can be used who need a smaller installation space, because the in Direction of opening of the pressure reducing valve thus supports the preload. The resulting total force results from the pressure of the hydraulic medium multiplied with the difference of the two areas.

The slide advantageously has the shape of a sleeve on, which is closed on one axial end face and on the other is open to drain hydraulic fluid. The Sleeve is slidable in a housing of the pressure reducing valve. In its outer surface it has at least one radial one Opening as hydraulic fluid inlet on that with a hydraulic medium supply channel in the housing of the pressure reducing valve Regulation of the reduced pressure of the hydraulic fluid in changeable Extent can be brought into overlap. By size The hydraulic fluid flow rate becomes the cover area and thus regulates the pressure reduction. The larger the cross section the overlap between the opening in the sleeve and the opening of the hydraulic medium supply channel, the larger is the hydraulic fluid flow and the smaller it is the pressure drop at this point. At constant Inlet pressure thus increases the pressure on the outlet side of the Pressure reducing valve. The pressure in the sleeve causes one Force on the inner surface of the closed face. There the opposite end face is open, there is this Pressure force no hydraulic counterforce. But the pod is biased against this force. The radial opening in the The sleeve and the opening of the hydraulic fluid supply channel are in their arrangement chosen such that with increasing displacement the sleeve against the bias, the coverage of Openings and thus the inlet cross-section decreases. It puts the equilibrium described above. This Construction of the pressure reducing valve with control movements of the sleeve perpendicular to the hydraulic fluid flow has the advantage that no back pressure effects occur. The pressure reducing valve shows thus a simple control behavior. Furthermore, with a proposed sleeve a light and dirt-resistant Construction can be achieved. The sleeve can also have several radial Have openings that connect to the hydraulic fluid supply channel connected annular, enclosing the sleeve Groove on the inside of the housing to cover can be brought.

A spring preferably exerts a spring acting in the opening direction Force on the sleeve, the pressure force of the hydraulic fluid on an inner surface of a closed face of the Counteracts sleeve. In this way, the bias of the Slider against the hydraulic force in the simplest way be designed.

In an advantageous embodiment of the invention, a Part of the outer surface of the closed face of the sleeve for partial compensation of the closed on the inner surface Frontal pressure force also with hydraulic fluid applied. The pressure force on this part of the outer surface acts in the opening direction of the pressure reducing valve and thus supports the preload. The resulting total force results from the pressure of the hydraulic medium multiplied with the difference between the inner surface and the outer Part of the face of the sleeve. The above Differential surface principle can be simple with such a sleeve will be realized.

For this purpose, the closed end face preferably has a hydraulic medium duct for hydraulic fluid loading part of the outer surface of the closed face of the Sleeve on. This hydraulic fluid loading can be done in the simplest Way be designed as a hole and is very inexpensive.

The pressure reducing valve is advantageously by means of a Leakage line connected to a hydraulic fluid tank. Hydraulic fluid, that through a seal from a press pressurized valve chamber of the pressure reducing valve into one depressurized part of the pressure reducing valve, such as a spring chamber that emerges is in via this leakage line the hydraulic fluid tank can be removed. In this way, a Leakage loss from hydraulic fluids can be avoided, the environment spared and in particular an undesirable pressure build-up be avoided in a depressurized room.

A check valve is preferably parallel to the pressure reducing valve connected. This check valve forms in Lift operation of the work equipment or a bypass for the Hydraulic fluid. This can be beneficial in the event of a regulated hydraulic pump the work equipment hydraulic fluid can be applied quickly and easily.

In an advantageous embodiment of the invention works the hydraulic motor in the lifting operation of the work equipment or as Hydraulic pump. With possible double-sided operation of the hydraulic motor a separate hydraulic pump can be saved.

drawing

Further advantages result from the following description of the drawing. In the drawing, an embodiment of the Invention shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will also expediently use the features individually consider and combine them into meaningful further combinations.

Show it:

Fig. 1
a schematic diagram of a control device according to the invention and
Fig. 2
a pressure reducing valve in the open state.
Description of the embodiment

In Fig. 1 is a schematic diagram of an inventive Control device shown. A working cylinder 12 will to the piston stroke to lift a load from a hydraulic pump 10 supplied with hydraulic fluid from a hydraulic fluid tank 14. The hydraulic pump 10 is preferably used by one in both Directions driven variable speed electric motor 16. The lowering of the piston in the working cylinder 12 for lowering the load is controlled by a check valve 18. Should the load is held, the check valve 18 is closed. It is opened to lower the load. hydraulic fluid flows through the check valve 18 and the hydraulic pump 10 to the hydraulic fluid tank 14. The hydraulic pump 10 runs backwards in the mode of action of a hydraulic motor 20 and drives the electric motor 16. The electric motor 16 works in this operating state generator in the third quadrant. The hydraulic fluid pressure is the weight of the Load determined. At high loads or high pressures in the Hydraulic fluid, the lowering capacity could increase the lifting capacity significantly exceed.

To the electric motor 16 in its power consumption in this Relieving the generator operating state is between Check valve 18 and hydraulic motor 20, a pressure reducing valve 22 interposed. The hydraulic motor 20 and thus the electric motor 16 is then driven by the reduced pressure, so that its power consumption is limited by this. Thereby the electric motor 16 can be made smaller. During the lifting operation of the working cylinder 12, the check valve 18 and bypass the pressure reducing valve 22 by means of a bypass 24, in which a check valve 26 is arranged. By the latter shuts off the bypass 24 in lowering mode.

The pressure reducing valve 22 is shown in detail in FIG. 2. The pressure reducing valve 22 has one in the opening direction 28 by means of a spring 30 preloaded slide 32, the through the output side of the pressure reducing valve 22 below reduced pressure hydraulic fluid in the closing direction 34 is displaceable. The slider 32 has the shape a sleeve 36, which is closed on one axial end face 38 and on the other to drain hydraulic fluid is open. This sleeve 36 is in a housing 40 of the Pressure reducing valve 22 slidable. The sleeve 36 has in her Shell surface 42 two radial openings 44, 46 in the form of Bores as hydraulic fluid inlet, which with an annular, the groove 36 comprising the sleeve 36 on the inside of the housing 40 can be brought to cover. The annular groove 48 is with a hydraulic fluid supply channel 50 connected in the housing 40 of the pressure reducing valve 22.

The spring 30 exerts a force acting in the opening direction 28 on the sleeve 36, the pressure force of the hydraulic fluid counteracts the inner surface 52 of the closed end face 38. With increasing pressure in the sleeve 36, the Force on the inner surface 52 of the closed face 38. The sleeve 36 is thus counteracted in the illustration according to FIG. 2 the spring force increasingly shifted to the left. The coverage cross section between the radial openings 44, 46 and the groove 48 comprising the sleeve 36 or the hydraulic medium supply channel 50 decreases. The coverage cross section determines the inlet cross-section of the pressure reducing valve 22. Since the discharge cross-section of the pressure reducing valve 22 is constant with decreasing inlet cross-section of the pressure reducing valve 22 at constant inlet pressure the outlet side Pressure in the pressure reducing valve 22. With that the Closing direction 34 force acting on the inner surface 52 of the closed end 38 and the pressure reducing valve 22nd opens again. Finally, it turns out to be stable Balance one. The output pressure depends on Pressure reducing valve 22 from the bias of the spring 30 in the opening direction 28 from. In this way the output side Pressure in the pressure reducing valve 22 through the overlap cross section between the radial openings 44, 46 and the Sleeve 36 comprising groove 48 or the hydraulic fluid supply channel 50 regulated. An end stop 68 prevents the sleeve 36 by the force of the spring 30 so far in the opening direction 28 is shifted from the stable regulatory equilibrium into an unstable equilibrium that with increasing displacement of the sleeve 36 in the opening direction 28 the overlap cross section between the radial Openings 44, 46 and the groove 48 or sleeve 36 of the hydraulic medium supply channel 50 decreases again.

The closed end face 38 of the sleeve 36 has a bore as hydraulic medium bushing 54. This hole connects the interior 58 of the sleeve 36 with an annular space 60 between the housing 40 and the end face 38 of the sleeve 36. In this annulus 60 there is the same pressure as in Interior 58 of the sleeve 36. The annular space 60 encloses one cylindrical extension 62 of the end face 38 of the sleeve 36, which extends into a bore 64 of the housing 40. The the extension 62 of the end face 38 as an annular surface Part of the outer surface 56 of the closed end 38 becomes thus also acted upon by hydraulic fluid pressure. On Part of the closed face on the inner surface 52 38 acting pressure force is compensated in this way. The Pressure force on this part of the outer surface 56 acts in the opening direction 28 of the pressure reducing valve 22 and supported thus the preload of the spring 30. The resulting total force results from the pressure of the hydraulic medium multiplied with the difference between the inner surface 52 and the outer Partial surface of the end face 38 of the sleeve 36. This corresponds the product of the pressure and the cross-sectional area of the extension 62 of the end face 38. This after this so-called Differential surface principle built pressure reducing valve 22 has the advantage that the spring 30 is dimensioned weaker can be. Otherwise, the spring would be 30 significantly larger installation space required.

The bore 64 of the housing 40, in which the cylindrical Extension 62 of the end face 38 of the sleeve 36 extends, and in which the spring 30 is received, is by means of a Leakage line 66 connected to the hydraulic fluid tank 14. Hydraulic fluid through a seal, not shown from the pressurized annulus 60 of the pressure reducing valve 22 in the unpressurized space of the bore 64 of the pressure reducing valve 22 emerges, is via this leakage line 66 discharged into the hydraulic fluid tank 14.

The level of the pressure at the hydraulic motor 20 is determined by the bias of the spring 30 is set. The pressure is allowed should not be chosen too small, otherwise in the generator Operation of the electric motor 16 of the hydraulic motor 20 no longer starts and thus the volume flow of the hydraulic medium is interrupted is.

Claims (11)

  1. Control device for a volume flow of a hydraulic medium of at least one loaded working medium (12) flowing in a hydraulic system, in particular for lifting and lowering a load, with at least one shut-off valve (18) and at least one hydraulic motor (20), characterized in that in the hydraulic system between the Working means (12) on the hydraulic motor (20), a pressure reducing valve (22) is arranged so that it reduces the pressure on the hydraulic motor (20) when lowering the load.
  2. Control device according to Claim 1, characterized in that the pressure reducing valve (22) has a slide (32) which is biased in the opening direction (28) and which can be displaced in the closing direction (34) by the hydraulic medium under reduced pressure on the outlet side of the pressure reducing valve (22).
  3. Control device according to Claim 2, characterized in that the slide (32) can be acted upon by hydraulic fluid in the opening direction (28) and in the closing direction (34) via surfaces (56, 52) which differ in size.
  4. Control device according to claim 2 or 3, characterized in that the slide (32) has the form of a sleeve (36) which is closed on one axial end face (38) and on the other is open for the discharge of the hydraulic medium, and in that the Sleeve (36) in a housing (40) of the pressure reducing valve (22) is displaceable and has at least one radial opening (44, 46) as a hydraulic medium inlet in its outer surface (42), which has a hydraulic medium supply channel (50) in the housing (40) of the Pressure reducing valve (22) for regulating the reduced pressure of the hydraulic medium can be brought into overlap to a variable extent.
  5. Control device according to claim 4, characterized in that a spring (30) exerts a force acting in the opening direction (28) on the sleeve (36), which forces the pressure force of the hydraulic medium on an inner surface (52) of a closed end face (38) of the sleeve ( 36) counteracts.
  6. Control device according to claims 3 and 5, characterized in that a part of the outer surface (56) of the closed end face (38) of the sleeve (36) for the partial compensation of the pressure force acting on the inner surface (52) of the closed end face (38) is also acted upon by hydraulic medium becomes.
  7. Control device according to claim 6, characterized in that the closed end face (38) has a hydraulic medium feed- through (54) for applying hydraulic fluid to part of the outer surface (56) of the closed end face (38) of the sleeve (36).
  8. Control device according to one of the preceding claims, characterized in that the pressure reducing valve (22) is connected to a hydraulic medium tank (14) by means of a leakage line (66), via which hydraulic medium emerging from the pressure reducing valve (22) through a seal into the hydraulic medium tank (14) is dissipatable.
  9. Control device according to one of the preceding claims, characterized in that a check valve (26) is connected in parallel to the pressure reducing valve (22), which forms a bypass (24) for the hydraulic medium during the lifting operation of the working means (12).
  10. Control device according to claim 9, characterized in that the check valve (26) is connected in parallel to the shut-off valve (18) which is in series with the pressure reducing valve (22).
  11. Control device according to one of the preceding claims, characterized in that the hydraulic motor (20) operates as a hydraulic pump (10) in the lifting mode of the working means (12).
EP01121812A 2000-09-13 2001-09-11 Control device for an hydraulic volume flow Withdrawn EP1188934A3 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE10045213 2000-09-13
DE2000145213 DE10045213A1 (en) 2000-09-13 2000-09-13 Control device for a hydraulic volume flow

Publications (2)

Publication Number Publication Date
EP1188934A2 true EP1188934A2 (en) 2002-03-20
EP1188934A3 EP1188934A3 (en) 2004-01-21

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Family Applications (1)

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EP01121812A Withdrawn EP1188934A3 (en) 2000-09-13 2001-09-11 Control device for an hydraulic volume flow

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EP (1) EP1188934A3 (en)
DE (1) DE10045213A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1369377A3 (en) * 2002-06-05 2006-07-05 BT Industries Control method for lift truck
EP1628020A3 (en) * 2004-08-17 2008-09-03 Jungheinrich Aktiengesellschaft Fluid circuit and industrial truck with fluid circuit
DE102007027567B4 (en) 2007-06-15 2018-03-01 Robert Bosch Gmbh Control arrangement with pipe rupture function

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Publication number Priority date Publication date Assignee Title
US2493111A (en) * 1945-02-01 1950-01-03 Weatherhead Co Pressure regulator
US2594626A (en) * 1946-09-09 1952-04-29 Clarence E Earle Safety valve
CH405851A (en) * 1963-11-27 1966-01-15 Gunzenhauser Ag J & R Pressure reducing valve
DE2618046A1 (en) * 1976-04-24 1977-11-10 Sven O I Jonsson Stored energy utilisation system - has hydraulic motor driven by lowering pressure coupled to dynamo recharging battery
SU735560A1 (en) * 1978-09-19 1980-05-25 Горьковский Институт Инженеров Водного Транспорта Electric hydraulic drive of floor-mounted load-handling device
AU7232781A (en) * 1981-02-13 1982-08-19 Groh West Pty. Ltd. Dual circuit pressure equalising valve
JPS6068410A (en) * 1983-09-22 1985-04-19 Nachi Fujikoshi Corp Reversible reducing valve
JP2628397B2 (en) * 1990-04-25 1997-07-09 回生工業株式会社 Speed control method of hydraulic elevator using inverter power supply
DE4140408A1 (en) * 1991-12-07 1993-06-09 Robert Bosch Gmbh, 7000 Stuttgart, De Electrohydraulic control of linear hydraulic actuator - has proportional flow control valve responding to pressure feedback to provide load compensating action
JP3376263B2 (en) * 1997-12-05 2003-02-10 仁科工業株式会社 Hydraulic devices in battery-powered industrial vehicles

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1369377A3 (en) * 2002-06-05 2006-07-05 BT Industries Control method for lift truck
EP1628020A3 (en) * 2004-08-17 2008-09-03 Jungheinrich Aktiengesellschaft Fluid circuit and industrial truck with fluid circuit
DE102007027567B4 (en) 2007-06-15 2018-03-01 Robert Bosch Gmbh Control arrangement with pipe rupture function

Also Published As

Publication number Publication date
DE10045213A1 (en) 2002-03-28
EP1188934A3 (en) 2004-01-21

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