EP0197911A2 - An hydraulic accumulator and an hydraulic impacting device with same - Google Patents

An hydraulic accumulator and an hydraulic impacting device with same Download PDF

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Publication number
EP0197911A2
EP0197911A2 EP86850119A EP86850119A EP0197911A2 EP 0197911 A2 EP0197911 A2 EP 0197911A2 EP 86850119 A EP86850119 A EP 86850119A EP 86850119 A EP86850119 A EP 86850119A EP 0197911 A2 EP0197911 A2 EP 0197911A2
Authority
EP
European Patent Office
Prior art keywords
tube
elastic wall
accumulator
hydraulic
hydraulic accumulator
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Withdrawn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
EP86850119A
Other languages
German (de)
English (en)
French (fr)
Inventor
Per Staffan Göte Gustafsson
Kurt Östen Brännström
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.)
Atlas Copco AB
Original Assignee
Atlas Copco AB
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
Application filed by Atlas Copco AB filed Critical Atlas Copco AB
Publication of EP0197911A2 publication Critical patent/EP0197911A2/en
Withdrawn legal-status Critical Current

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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
    • 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
    • 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
    • F15B2201/315—Accumulator separating means having flexible separating means
    • F15B2201/3151—Accumulator separating means having flexible separating means the flexible separating means being diaphragms or membranes
    • 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
    • F15B2201/405—Housings
    • F15B2201/4053—Housings characterised by the material
    • 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
    • F15B2201/41—Liquid ports
    • F15B2201/413—Liquid ports having multiple liquid ports

Definitions

  • This invention relates to an hydraulic accumulator that has an accumulator chamber that is at least partly defined by an elastic wall.
  • the invention relates also to an hydraulic impact device that comprises such an acculmulator. It relates also to a method of accumulating a pressure liquid.
  • the liquid used for operating the impact device usually hydraulic oil, has a certain compressibility and, by US-A 3620312 and 4282937,impact devices are known which utilizes this inherent compressibility of the liquid, Then, the accumulator chambers have . large volume and are confined by steel walls. Often, the accumulator chambers can not be made as large as desirable..
  • Fig 1 is a longitudinal section through an hydraulic jack hammer on which the invention is applied.
  • Fig 2 shows at a larger scale a seal shown in Fig 1.
  • the hydraulic impact device in the form of a jack hammer as shown in Fig 1 has a plural part housing 11 with two handles that are in an angle to each other so that only one of the handles 12 can be seeen on the figure.
  • a work tool in the form of a chisel has a hexagonal shank 13 that is inserted in the front portion of the housing 11 and it is retained there by means of a non-illustrated conventional chisel holder.
  • a non-illustrated collar on the chisel 13 takes support on the housing 11 in a conventional way so that a feed force can be transmitted from the housing 11 to the chisel 13 and so that the chisel will have a defined axial position in the housing 11.
  • the housing 11 forms a cylinder for an axially movable lining 15 which in its turn forms a cylinder for a hammer piston 16 that is axially movable in the lining 15.
  • the hammer piston 16 is arranged to periodically impact on the end face 17 of the chisel shank. The end face 17 forms thus an anvil surface for the hammer piston 16.
  • the housing has an inlet 18 for the pressure liquid, usually hydraulic oil, and an outlet 19.
  • An inlet chamber 23 can be pressurized by means of a valve 21 that is controlled by means of a trigger 22.
  • the cylinder 15 has the function of a valve that alternately couples a cylinder chamber 27 between the cylinder 15 and the hammer piston 16 to the inlet chamber 23 and to an outlet chamber 28.
  • the impact motor is not described in detail but reference is made to EP-A-133609 that describe an impact motor of this kind.
  • the housing 11 has two annular walls 30, 31 with grooves for annular seals 32, 33 as is best shown in Fig 2.
  • a tube 34 of glass fibre reinforced plastics is supported by these seals 3 2, 33 and the tube is axially affixed by means of shoulders 35, 36 of the housing 11.
  • the tube 34 should not be axially clamped but should preferably have a small axial play to the housing 11.
  • Inside the tube 34 an accumulator chamber 37 is formed which is constantly coupled to the inlet chamber 23 by means of a bore 38.
  • the tube 34 itself can be considered as a part of the housing 11.
  • the accumulator chamber 37 and the tube 34 are arranged both around a part of the cylinder 16 for the hammer piston 15 and around a part of the cylinder for the cylinder 16.
  • the cylinder for the cylinder 16 is formed by the housing 11.
  • the tube or cylinder 34 has a filament winding, e.g. glass fibre, with a small pitch and the matrix comprises a thermoset for example epoxy or vinyl esther.
  • a tube will have high linear strain tangentially at fatigue strength which is the characteristic that makes a large accumulator capacity.
  • the wall thickness of the tube 34 should be chosen such that, in operation, the stress will be at a suitable level below the fatigue strenth.
  • the accumulating capacity that results from the compressibility of the hydraulic fluid will then be smaller than the accumulator capacity that results from the elasticity of the tube 34; the quotient will be less than 1 or even less than 1.
  • the elasticity of the wall of the tube will provide for the main portion of the accumulating capacity.
  • the tube 34 can have an outer protective layer 40 of unreinforced wear resistant resin or plastics.
  • the tube 34 can also have an unreinforced sealing layer of resin or plastics on its inner side. These two layers are probably not necessary but one or both of them can be omitted. They need not be of the same resinous material as the reinforced part of the tube wall.
  • a sealing rubber layer can be vulcanized to the tube 34 on the interior of the tube wall. It might be a risk that an unsealed tube can transpire oil, which has no effect on the function but may be unpleasant. Since the ends of the tube 34 are not clamped but they are only supported by the seals 32, 33, the tube is comparatively evenly stressed and fatigue breakdown is avoided. Also other ways of mounting-the tube 34 may work, for example clamping of the ends.
  • the tube 34 can be manufactured in a continuous mode and then cut into suitable pieces.
  • a glass fibre filament winding with a small pitch seems to be preferable since it will provide a tube with very high strain at fatigue strength.
  • the strain will exceed 0.2% or even exceed 0.5%. Any other material having this property could be used as an alternative.
  • another tube can be arranged outside the tube 34 spaced therefrom.
  • the elastic wall of the accumulator is shown as a tube 34 with a circular cross section. Such a design seems preferable.
  • the elastic wall could, however, have another form. It could for example be a circular plate that is sealed off around its periphery, or it could be in the form of a bubble for example a sphere.
  • the accumulator is continuously pressurized in operation since it is continuously coupled to the inlet 18, and it reduces the cyclical pressure fluctuations in the inlet.
  • An accumulator of the kind described can also be used in an impact device that has an accumulator that is alternately coupled to the supply and to the outlet, for example an impact device of the kind described in US-A-3620312.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Percussive Tools And Related Accessories (AREA)
  • Pipe Accessories (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
EP86850119A 1985-04-12 1986-04-09 An hydraulic accumulator and an hydraulic impacting device with same Withdrawn EP0197911A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8501793A SE8501793L (sv) 1985-04-12 1985-04-12 Vetskeackumulator och hydrauliskt slagverk med en sadan
SE8501793 1985-04-12

Publications (1)

Publication Number Publication Date
EP0197911A2 true EP0197911A2 (en) 1986-10-15

Family

ID=20359841

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86850119A Withdrawn EP0197911A2 (en) 1985-04-12 1986-04-09 An hydraulic accumulator and an hydraulic impacting device with same

Country Status (7)

Country Link
EP (1) EP0197911A2 (pt)
JP (1) JPS62251501A (pt)
BR (1) BR8601683A (pt)
DK (1) DK164086A (pt)
FI (1) FI861533A (pt)
SE (1) SE8501793L (pt)
ZA (1) ZA862762B (pt)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0947293A2 (en) * 1998-03-30 1999-10-06 Sandvik Tamrock Oy Hydraulically operated impact device
WO2003093680A1 (en) 2002-04-30 2003-11-13 Groep Stevens International, Naamloze Vennootschap Fluid accumulator
US6789388B1 (en) * 2000-07-20 2004-09-14 Automotive Products (Usa), Inc. Triple action damper for hydraulic clutch actuator
US8701398B2 (en) 2012-03-20 2014-04-22 Robert Bosch Gmbh Strain energy accumulator
US8991433B2 (en) 2009-10-05 2015-03-31 Robert Bosch Gmbh Energy storage system including an expandable accumulator and reservoir assembly

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0947293A2 (en) * 1998-03-30 1999-10-06 Sandvik Tamrock Oy Hydraulically operated impact device
EP0947293B1 (en) * 1998-03-30 2004-10-27 Sandvik Tamrock Oy Hydraulically operated impact device
US6789388B1 (en) * 2000-07-20 2004-09-14 Automotive Products (Usa), Inc. Triple action damper for hydraulic clutch actuator
WO2003093680A1 (en) 2002-04-30 2003-11-13 Groep Stevens International, Naamloze Vennootschap Fluid accumulator
BE1014807A5 (nl) * 2002-04-30 2004-04-06 Groep Stevens International Na Fluidumaccumulator en werkwijze voor het vervaardigen ervan.
US7048009B2 (en) 2002-04-30 2006-05-23 Groep Stevens International, Naamloze Vennootschap Fluid accumulator
EP2299126A1 (en) 2002-04-30 2011-03-23 Groep Stevens International, Naamloze Vennootschap Fluid accumulator
US8991433B2 (en) 2009-10-05 2015-03-31 Robert Bosch Gmbh Energy storage system including an expandable accumulator and reservoir assembly
US8701398B2 (en) 2012-03-20 2014-04-22 Robert Bosch Gmbh Strain energy accumulator

Also Published As

Publication number Publication date
JPS62251501A (ja) 1987-11-02
BR8601683A (pt) 1986-12-16
SE8501793D0 (sv) 1985-04-12
DK164086D0 (da) 1986-04-11
DK164086A (da) 1986-10-13
ZA862762B (en) 1986-12-30
FI861533A (fi) 1986-10-13
SE8501793L (sv) 1986-10-13
FI861533A0 (fi) 1986-04-10

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Inventor name: BRAENNSTROEM, KURT OESTEN

Inventor name: GUSTAFSSON, PER STAFFAN GOETE