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
  • F15B1/04—Accumulators
  • F15B1/08—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor
  • F15B1/24—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor with 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
  • F15B2201/20—Accumulator cushioning means
  • F15B2201/205—Accumulator cushioning means using gas
• • 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
  • F15B2201/312—Sealings therefor, e.g. piston rings
• • 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
  • F15B2201/32—Accumulator separating means having multiple separating means, e.g. with an auxiliary piston sliding within a main piston, multiple membranes or combinations thereof
• • 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
  • F15B2201/40—Constructional details of accumulators not otherwise provided for
  • F15B2201/41—Liquid ports
  • F15B2201/411—Liquid ports having valve means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2201/00—Accumulators
  • F15B2201/40—Constructional details of accumulators not otherwise provided for
  • F15B2201/415—Gas ports
  • F15B2201/4155—Gas ports having valve means

Definitions

• the invention relates to a device for saving energy in hydraulically actuated tools with a piston accumulator.
• the invention is based on the object of creating a device for saving energy in hydraulically actuated work tools with expanded application options which does not have the disadvantages described above.
• a corresponding object is achieved by a device having the features of claim 1.
• a piston accumulator is used with a housing in which at least two pistons which can be moved longitudinally are arranged, each with an adjacent piston opposite one another Coupling part are connected to each other, which is guided in a longitudinally movable manner on a partition wall of the housing, which delimits two fluid spaces with the two adjacent pistons, at least one of the pistons at least partially next to a fluid space on the opposite side, a prestressing space with a predeterminable gas pressure limited.
• the pistons which are positively coupled to one another allow an increase in the internal gas pressure in one direction of travel with a decreasing preload space, which decreases in the sense of relaxation as soon as the pistons move in the other direction of travel with an increase in the volume of the preload space.
• the amount of gas enclosed in the prestressing space thus forms a type of energy store comparable to a mechanical spring, and the kinetic energy introduced into the store by the movement can be called up again.
• the piston accumulators used in the energy saving device belong to the family of hydraulic accumulators, which also include bladder accumulators and membrane accumulators.
• One of the main tasks of these hydraulic accumulators is to take up certain volumes of a pressurized liquid in a hydraulic system and to return them to the system if necessary.
• the known piston accumulators consist of a liquid and a gas part with a piston as a gas-tight separating element, the gas side being filled with nitrogen.
• the liquid side of the piston accumulator is connected to the hydraulic circuit, so that when the pressure rises, the piston accumulator absorbs more liquid and the gas is compressed on its gas side. When the pressure drops, the compressed gas expands and displaces the stored hydraulic fluid in the hydraulic circuit.
• Piston accumulators can basically work in any position, whereby a vertical arrangement with the gas side up is preferred, so that contamination from the liquid on the piston seals is avoided.
• the piston accumulator does not have a flexible separating element in the form of a rubber membrane or rubber bladder, but rather a rigid piston which is hardly subject to wear and, like the device according to the invention, can also function without failure over very long periods of time.
• the energy saving device need not be limited to working machines, but can also be used in hydraulic brake systems, in elevators and in hydraulic motors or the like. In these cases, it is expedient to provide a large volume for the prestressing space in order to achieve a low spring constant. In order to achieve this, it can be provided to connect the prestressing space to a further gas supply device, in particular in the form of a nitrogen storage as a buffer.
• FIG. 3 shows a longitudinal section through a second embodiment of a piston accumulator applicable according to FIG.
• the piston accumulator according to FIG. 2 has a housing designated as a whole by 10.
• the housing 10 is designed in the form of a cylinder tube, but can also form other cross-sectional shapes (square, elliptical).
• two longitudinally movable pistons 12, 14 are arranged, which are connected to one another via a coupling part in the form of a solid coupling rod 16.
• the coupling rod 16 is guided longitudinally in a partition 18 of the housing 10, which is designed in the manner of a cylindrical intermediate section of the housing 10 and which delimits two fluid spaces 20, 22 with the two pistons 12, 14 located opposite one another.
• the circumferential partition wall 18 has corresponding round seals 24.
• the housing 10 is delimited at the end by two end walls 26, 28 which form the closure cover of the piston accumulator. Between the left-hand end wall 26, as seen in FIG. 2, and the piston 12 located opposite one another, a preload space 30 is delimited by these parts, to which a predeterminable gas internal pressure is assigned.
• the respective fluid space 20, 22 widens in diameter from the dividing wall 18 to the respectively assigned piston 12, 14 by one step, the coupling between the pistons 12, 14 being designed such that in the case of a fluid space 20 with a small volume the other fluid space 22 by the amount of the reduced volume is increased accordingly.
• the coupling rod 16 is of solid construction and at the end by means of screws 32 on the end face in fixed contact with the respectively associated pistons 12, 14.
• the pistons 12, 14 have corresponding sliding seals in the known design on the outer circumference.
• the partition wall 18 is part of a tubular center connector 34, to which the housing tubes 36 of the housing 1 0 connect on both sides, which serve for the longitudinal guidance of the pistons 1 2, 14.
• connection points 40 and 42 run in the center connector 34 and open into the respectively assigned fluid spaces 20 and 22.
• the H-shaped central connector 34 viewed in the direction of the longitudinal axis 38 in cross-section and looking in the direction of FIG. 1, is sealingly guided at both ends by a sealing ring 44 in the two housing tubes 36 and the fluid spaces 20, 22 from the surroundings .
• the two end walls 26, 28 each have a sealing ring 46 on the outer circumference.
• end sleeves 50 each screwed into the free ends of the two housing tubes 36, holding the end walls 26, 28 in question in their position shown in FIG.
• the respective connection point 40, 42 opens into a cylindrical transverse channel 52, which is penetrated by the coupling rod 16 in each travel position of the pistons 12, 14 and runs parallel to the longitudinal axis 38 of the piston accumulator.
• the two pistons 12 and 14 have a hollow cylindrical central recess 56 to accommodate the screws 32 and to enlarge the prestressing space 30 and an opposite surrounding space 54.
• the fixed end wall 26 of the housing 10, which limits the pretensioning space 30 to the outside, has a connection point 58 which can be sealed in a sealing manner by means of a sealing plug (not shown).
• the prestressing space 30 can be connected via the connection point 58 to a gas supply device (cf. FIG. 1), in particular in the form of a nitrogen reservoir 62.
• the already addressed ambient space 54 which is delimited by the other end wall 28 and by the piston 14, can be connected to a supply line 66 via a passage point 64.
• the housing 10 delimits the fluid spaces 20, 22 on the outer circumference with its two housing tubes 36
• the biasing chamber 30 is filled with a working gas, for example in the form of nitrogen, and is assigned an internal gas pressure.
• a working gas for example in the form of nitrogen
• the sealing plug can be provided with a valve device 68 (see FIG. 1) which allows gas to pass in the direction of the prestressing space 30 but blocks the outlet in the sense of a check valve.
• the gas located in the prestressing chamber 30 with a predeterminable internal gas pressure thus forms a type of gas or pressure cushion with, provided a mechanical comparison model is used, a given spring constant Pistons 1 2, 14 seen in the direction of FIG. 2 are in their extreme right-hand driving position, the piston 12 abuts the facing end of the center connector 34 and the piston 14 comes into contact with the end wall 28.
• the prestressing space 30 then takes up its largest volume, as does the fluid space 22, which can be filled with a fluid via the connection point 42.
• the gas located in the prestressing space 30 is then compressed and prestressed accordingly, which is equivalent to the tensioning of a mechanical spring.
• the gas or spring energy stored in this way can then be called up in order to assist, as will be explained in more detail, a hydraulic work tool or the like.
• even more pistons can be used for other control processes, which may increase the number of fluid spaces as well as the preload spaces and other gas spaces.
• a plurality of piston accumulators could also be connected in series or in parallel with one another.
• FIG. 1 shows the use of the piston accumulator according to FIG. 2 in a device for saving energy in the case of hydraulically actuated working tool shafts in the form of two hydraulic working cylinders 70.
• the two hydraulic cylinders 70 have the same effect with one of their respective piston rods 72
• Boom 74 connected, for example in the form of a crane or excavator arm.
• the boom 74 can, however, also represent a lifting platform, such as is used in goods and passenger lifts and lifting platforms, provided that these can be moved with hydraulic cylinders.
• a suitably designed hydraulic motor can also be used to actuate a work tool.
• the two hydraulic working cylinders 70 are connected in a fluid-conducting manner to a fluid control 78 via a connecting line 76, which can have, for example, a controllable valve unit in the form of directional valves or the like.
• a motor-operated hydraulic pump 80 is also connected to the fluid control 78, as well as Tank line 82 for the tank 84.
• the fluid control 78 has a further fluid-carrying connection line 86 which flows into the second connection point 42.
• the first connection point 40 of the fluid space 20 is to the supply line 66 in the embodiment shown in FIG.
• the fluid space 20 is not filled with air but with hydraulic fluid and, like the supply line 66, is connected to the hydraulic work tool via a branch 66a in the form of the two hydrozy Linder 70 in fluid connection
• the secondary branch 66a can also be omitted and the connection point 40 can flow into the surroundings, the fluid space 20 then having ambient air and ambient air pressure.
• the pistons 12, 14 are moved in the direction of the surrounding space 54, it can then occur Compression processes of the air and consequently undesired heating occur, which is avoided via the connection in the secondary branch 66a. In the latter case, the amounts of fluid to be controlled for carrying out a working stroke can be reduced.
• the supply line 66 and the secondary branch 66a flow as shown in FIG 1 in a further fluid-carrying connecting line 88, which bifurcates in the direction of the hydraulic cylinders 70 and which is connected to the hydraulic cylinders 70 on the piston ridges 90.
• the energy-saving device is now set in such a way that with a middle load or boom position of the boom 74 in the prestressing chamber 30 there is an increased, if possible maximum internal gas pressure which corresponds to a prestressed mechanical compression spring.
• the hydraulic pump 80 is switched on and, via the fluid control 78, fluid passes under pressure via the connecting line 86 and the second connection point 42 into the fluid space 22, with the direction of view of FIG .1 seen the piston 1 2 and 14 move to the right.
• the fluid stored in the fluid space 20 of the piston accumulator is then discharged together with the fluid from the surrounding space 44 via the secondary branch 66a or the connecting line 66 and the further connecting line 88 to the piston side 90 of the hydraulic cylinder 70, whereby the pressure cushion in the pretensioning space 30 supports this movement process and the energy stored in the pretensioning space 30 is delivered to the boom 74 via the fluid guide.
• the fluid quantities displaced in this way are depressurized via the connecting line 76 and the fluid control 78 to the tank 84 via the connecting line 82.
• Hydraulic energy is then stored in the pretensioning space 30 when the boom 74 is lowered, the fluid stored on the piston side 90 being returned to the fluid space 20 and the surrounding space 54 with the result that in the direction of view of FIG. 1 seen, the pistons 1 2 and 14 move to the left and the preload in the preload chamber 30 increases.
• the boom 74 is moved about a central position, an upcoming lifting operation can be supported in a particularly energy-efficient manner. If the boom 74 can be moved in the case of working machines, the gas supply device 62 in the form of the nitrogen store shown can be omitted.
• the chamber volume of the prestressing space 30 is increased by the connection of the accumulator 62. Furthermore, by switching the fluid control 78 on the rod side, the hydrocycline the 70 is filled under pressure via the hydraulic pump 80, which facilitates the lowering process and the increase in the gas pressure in the prestressing space 30
• FIG. 3 shows a further piston accumulator which, like the piston accumulator design according to FIG. 2, is suitable for being used in an energy saving device according to the circuit diagram in FIG. 1.
• the same components of the piston accumulator are shown in FIG .3 denoted by the same reference numerals but increased by 100, as described above according to the illustration in FIG. 2.
• What has been said for the embodiment in accordance with FIG. 2 therefore applies accordingly to the embodiment of the piston accumulator in accordance with FIG. 3, which is described in the following only insofar as it differs substantially from the previously described embodiment according to FIG.
• the end walls 126, 128 are formed in one piece and are each screwed to the interior of the housing tubes 136.
• the connection points 140, 142 flow in one direction, that is, as seen in the direction of view of FIG. 3, downward from the interior of the housing 110.
• the two-part partition 18 again has the character of a hollow cylindrical intermediate piece 34 and engages with one another , wherein the fixed bond is realized via a screw connection 1 92, which extends through the flange-like widenings of the two-part intermediate piece.
• the cylindrical center recesses 156 made in the pistons 1 12, 1 14 are arranged coaxially to the longitudinal axis 1 38 and face one another. The volume of the fluid spaces 120 and 1 22 is therefore increased.
• Both embodiments of a piston accumulator both according to FIG. 2 and according to FIG. 3 essentially show a symmetrical arrangement of parts with respect to a central axis and to its longitudinal axis 38, 138, which allows cost-effective inexpensive to manufacture and offer the piston accumulator in a variety as an inexpensive standard component.

Landscapes

• Engineering & Computer Science (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
• Fluid-Pressure Circuits (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Optical Head (AREA)
• Percussive Tools And Related Accessories (AREA)
• Confectionery (AREA)
• Pretreatment Of Seeds And Plants (AREA)
• Bakery Products And Manufacturing Methods Therefor (AREA)
• Separation By Low-Temperature Treatments (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7793343

Family Applications (1)

Country Status (8)

Cited By (2)

Families Citing this family (36)

Family Cites Families (13)

• 1996
  • 1996-05-04 DE DE19617950A patent/DE19617950A1/de not_active Withdrawn
• 1997
  • 1997-03-29 SK SK1481-98A patent/SK284792B6/sk unknown
  • 1997-03-29 AT AT97915466T patent/ATE220766T1/de not_active IP Right Cessation
  • 1997-03-29 CZ CZ19982992A patent/CZ295658B6/cs not_active IP Right Cessation
  • 1997-03-29 EP EP97915466A patent/EP0897480B1/fr not_active Expired - Lifetime
  • 1997-03-29 WO PCT/EP1997/001613 patent/WO1997042417A1/fr not_active Ceased
  • 1997-03-29 DE DE59707734T patent/DE59707734D1/de not_active Expired - Lifetime
  • 1997-03-29 JP JP53946197A patent/JP3857321B2/ja not_active Expired - Lifetime
  • 1997-03-29 US US09/155,484 patent/US6266959B1/en not_active Expired - Lifetime

Non-Patent Citations (1)

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