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
• • 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
  • 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

Definitions

• the invention relates to a piston accumulator with an accumulator housing in which a separating piston is guided in a longitudinally displaceable manner, which separates two fluid chambers from one another, in particular a fluid chamber with a working gas from another fluid chamber with a liquid, such as hydraulic oil, and which has a damping piston with a check valve which can be moved into a fluid connection in the accumulator housing while forming a throttle gap.
• EP 0 286 777 A2 discloses a generic piston-cylinder unit with piston end position damping, which has a damping piston protruding on the end face of the piston, which can be moved into a damping chamber provided at the end of the cylinder facing towards it, forming a damping gap that tapers conically in the direction of the fluid connection and a flow path is provided for initiating a return stroke movement of the piston, which leads from the fluid connection for pressure oil, bypassing the damping gap, to the pressure chamber in the accumulator housing adjacent to the main piston surface of the piston and includes a check valve.
• This flow path which can be controlled by the check valve, extends inside the piston between an inlet opening at the front end of the damping valve, which is designed as a hollow sleeve. tion piston and a leading from the interior of this sleeve to the outside breakthrough in the form of a transverse channel.
• the check valve used in this respect has a solid valve plate that can be controlled by an energy store in the form of a compression spring, which controls a large opening cross section in the damping piston, which leads to leaks in the closed position and is associated with turbulence in the flow pattern when the valve is open. Furthermore, rapid opening and closing processes are excluded due to the inertia behavior of the valve plate.
• the invention is therefore based on the object of further improving the known solution in that a piston accumulator is created with improved end-position damping for the separating piston together with improved response behavior when fluid flows in and out of the hydraulic accumulator.
• the throttle gap is a cylindrical annular space formed from the adjacent wall parts of the accumulator housing and damping piston and that the check valve has a valve ball loaded with an energy accumulator, which in its closed position creates a fluid path between the fluid connection and a piston fluid chamber between the separating piston and the accumulator housing and releases it in its open position, a constant throttle gap width is achieved over the entire engagement length of the damping piston in the fluid connection, which leads to significantly improved end position damping.
• the engagement length for the damping piston in the flow can be selected to be extremely long within predeterminable limits, due to the geometry to be maintained for the hydraulic accumulator, so that in connection with the constant gap dimension over the entire length of engagement, a significantly improved piston end position damping is achieved.
• the valve ball of the check valve allows the realization of an improved valve seat geometry with improved tightness in the closed position and reduced turbulence during flow in the open position. Due to the low mass inertia of the correspondingly small dimensioned valve or closing ball, the fluid flows that occur when charging and discharging the hydraulic accumulator can also be reliably controlled in rapid succession. This has no equivalent in the prior art.
• the damping piston is formed from a hollow cylinder which, at least in one of its damping positions, creates a fluid path between the fluid connection and the check valve with its hollow cylindrical passage.
• the diameter of the hollow cylinder in the damping piston essentially corresponds to the diameter of the valve closing ball, so that when the accumulator is loaded with fluid, such as hydraulic oil, the valve ball flows centrally and can therefore lift off its valve seat in the associated valve housing without any obstacles.
• the damping piston viewed in the direction of the piston fluid chamber, transitions into an extension with an annular surface, forming a shoulder, which forms an annular gap when the separating piston rests on parts of the accumulator housing, such as a housing cover Gap size is larger than the gap size of the throttle gap.
• the annular surface is part of an insert body which accommodates the check valve and which is fixed in a receptacle of the separating piston, preferably by means of a snap ring between insert body and separating piston. Because the check valve is an integral part of the insert body, the damping device can be connected as a whole to the separating piston from a central point, in particular from the underside of the separating piston, which is extremely easy to assemble and involves few work steps. In this respect, the piston accumulator solution according to the invention can also be produced inexpensively.
• the check valve designed as a valve cartridge is screwed with its valve housing into the insert body and that the valve ball is guided in the valve housing under permanent pressure from an energy store, preferably in the form of a compression spring.
• an energy store preferably in the form of a compression spring.
• the valve housing preferably has at least one transverse channel which can be controlled by the valve ball of the check valve in the direction an associated transverse channel in the insert body.
• the valve housing preferably has a groove on the outer circumference, preferably in the form of an annular valve chamber, into which the respective transverse channel of the valve housing opens from one side and the respectively assigned transverse channel in the insert body from the other, opposite side.
• the separating piston delimits a hollow chamber-like recess on its side facing the fluid connection, which opens out in a slope in the direction of the snap ring and that the bore axis of the respective transverse channel in the insert body is aligned with a wall of the separating piston , which at least partially delimits the recess in the floating piston and at which the bevel opens into the recess.
• the snap ring for fixing the insert body in the separating piston can be securely positioned via the mentioned, preferably circumferential bevel, and the bevel can also serve as an inflow aid to directly convert a lateral force introduction of the fluid flow into a lifting movement for the separating piston as part of an accumulator charging process.
• the axial length of the damping piston is greater than the comparable height of the piston fluid space in the separating piston, through which the insert body at least partially passes. It has been shown in practical tests that the pertinent length-height design results in particularly good damping properties during the discharge process of the accumulator result and in the reverse direction with the loading of the accumulator, the separating piston moves without hindrance in the direction of the fluid space with the working gas and is thereby prestressed.
• the invention also relates to a method for operating a piston accumulator with the following method steps:
• Throttling of the volume flow when discharging the piston accumulator by forming a hollow-cylindrical throttling gap between the damping piston and parts of the accumulator housing, - bypassing the throttling gap when charging the piston accumulator
• the figure shows the lower part of a piston accumulator with a hollow-cylindrical wall part 8 of an accumulator housing designated as a whole with 10, in which a separating piston 12 is guided in a longitudinally displaceable manner, which separates two fluid chambers 14, 16 from one another, in particular a fluid chamber 14 with a working gas, such as nitrogen, from a further fluid chamber 16 with a liquid such as hydraulic oil.
• the separating piston 12 has a damping piston 18 with a damping piston at its free front end Check valve 20 on.
• the damping piston 18 can move into a fluid connection 24 in the accumulator housing 10, forming a throttle gap 22, with the figure showing the maximum lowermost position for the separating piston 12 in the accumulator housing 10, with maximum throttling of the fluid flow from the side of the fluid space 16 in the direction of the fluid connection 24.
• the position of the separating piston 12 shown in the figure corresponds to the maximum discharge situation for the hydraulic accumulator as a whole.
• the piston accumulator can be connected in the usual way by means of a tubing, not shown, to a hydraulic circuit of a conventional design, not shown.
• the throttle gap 22 is a cylindrical annular space or a hollow cylinder filled with fluid, formed from the adjacent wall parts 28 of the accumulator housing 10 in the form of a housing cover 30 and the adjacent wall parts 32 of the damping piston 18 arranged opposite.
• the housing cover 30 is screwed as part of the accumulator housing 10 into its hollow-cylindrical wall part 8 on the bottom side and sealed in an annular groove 31 with respect to the rest of the accumulator housing 10 by means of an annular seal, not shown in detail.
• the separating piston 12 has two annular grooves 33 on the outer circumference for receiving sealing rings and guide bands, not shown in detail, of which only the upper one is denoted by 33 .
• Check valve 20 has a valve ball 36 that is permanently loaded with an energy storage device in the form of a compression spring 34 and that, in its closed position shown in the figure, blocks a fluid path between fluid connection 24 and a piston fluid chamber 38 between separating piston 12 and accumulator housing 10 or housing cover 30 and in an open position against the action of the compression spring 34 releases this fluid path.
• the piston fluid chamber 38 is in the present case from a chamber-like recess formed on the underside of the separating piston 12, which is surrounded on the outer circumference at the height of the sealing ring system in the annular groove 33 of wall parts of the separating piston 12.
• the damping piston 18 is formed from a hollow cylinder which, at least in one of its damping positions, in the figure in a fully damped position, with its hollow-cylindrical passage 40 the fluid path between the fluid connection 24 and the check valve 20 its valve ball 36 produces.
• the annular surface 44 is part of an insert body 48 which accommodates the check valve 20 as a whole and which is held in a hollow-cylindrical receptacle 50 of the separating piston 12 by means of a snap ring 52 between the insert body 48 and the separating piston 12 .
• the check valve 20 is designed as a valve cartridge, which is screwed with its valve housing 54 into the insert body 48 using a hexagon socket 55 and according to the representation in the figure, the valve ball 36 is seat-tight under the action of the compression spring 34 on a valve seat 56 in the valve housing 54 held in their closed position.
• the pertinent valve housing 54 has a transverse channel 58 diametrically opposite one another in relation to the longitudinal axis 60 of the hydraulic accumulator, which channel connects directly to the valve ball 36 and can be controlled by the latter.
• a transverse channel 58 diametrically opposite one another in relation to the longitudinal axis 60 of the hydraulic accumulator, which channel connects directly to the valve ball 36 and can be controlled by the latter.
• a transverse channel 58 instead of a pair of transverse channels 58, a different number of transverse channels 58 can also be provided, in particular only a single transverse channel 58.
• the respective lige transverse channel 58 opens out in the valve housing 54 in the direction of a further assignable transverse channel 62 in the insert body 48 .
• the valve housing 54 has a groove 64 on the outer circumference, preferably in the form of an annular valve chamber, into which the respective transverse channel 58 of the valve housing 54 opens from one side, as does the respectively associated transverse channel 62 in the insert body 58 from the other, opposite side.
• the separating piston 12 delimits a hollow, chamber-like recess as part of the piston fluid space 38, which opens out in the direction of the snap ring 52 into a bevel 66 in the separating piston 12, which tapers conically upwards in the direction of the longitudinal axis 60.
• the bore axis of the respective transverse channel 62 in the insert body 48 is aligned with the upper wall delimitation of the recess in the separating piston 12, with the bevel 66, which is guided circumferentially in the separating piston 12, opening onto the pertinent upper delimiting wall.
• the axial length of the damping piston 18, if it is in engagement with parts of the fluid connection 24, is in any case greater than the comparable height of the piston fluid chamber 38, formed by the recess in the separating piston 12, which is insofar at least partially penetrated by the insert body 46 .
• the piston accumulator shown in the figure can then be operated as follows with the equipment according to the invention:
• a damping valve designated as a whole with 68 with a longitudinally movable valve plate 70 in which a throttle bore 72 is introduced coaxially to the longitudinal axis 60 of the hydraulic accumulator.
• the valve plate 70 in question is in a valve housing 74, preferably designed as a tripod was added, which is screwed flush into the fluid connection 24 along the internal thread 26 .
• valve plate 70 moves from its upper position shown in the figure to a lower closed position in which the valve plate 70 is seated on the inside of the valve housing 74 and a fluid passage is then only over the throttle bore 72 is given in the valve plate 70, so that the fluid flow is also throttled in this respect in addition to the throttle measures 22, 46 already described by the damping valve 68. Further details on the function of the pertinent damping valves can be found in DE 103 37 744 B3, for example.

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• 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)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Citations (5)

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• 2022
  • 2022-01-12 DE DE102022000098.9A patent/DE102022000098A1/de active Pending
  • 2022-12-20 WO PCT/EP2022/086999 patent/WO2023134978A1/de not_active Ceased
  • 2022-12-20 EP EP22840718.5A patent/EP4463635A1/de active Pending
  • 2022-12-20 CN CN202290000841.0U patent/CN222277059U/zh active Active
  • 2022-12-20 CN CN202422870990.6U patent/CN223075862U/zh active Active
  • 2022-12-20 US US18/712,360 patent/US20250003428A1/en active Pending
  • 2022-12-20 JP JP2024541793A patent/JP2025500673A/ja active Pending

Patent Citations (5)

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