EP0313539B1 - A device for neutralizing metal chips in a pressure liquid accumulator - Google Patents

A device for neutralizing metal chips in a pressure liquid accumulator Download PDF

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Publication number
EP0313539B1
EP0313539B1 EP88850356A EP88850356A EP0313539B1 EP 0313539 B1 EP0313539 B1 EP 0313539B1 EP 88850356 A EP88850356 A EP 88850356A EP 88850356 A EP88850356 A EP 88850356A EP 0313539 B1 EP0313539 B1 EP 0313539B1
Authority
EP
European Patent Office
Prior art keywords
piston
metal chips
scraper ring
pressure liquid
liquid 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.)
Expired
Application number
EP88850356A
Other languages
German (de)
French (fr)
Other versions
EP0313539A1 (en
Inventor
Olof Älund
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.)
GKN Aerospace Sweden AB
Original Assignee
Volvo Flygmotor 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 Volvo Flygmotor AB filed Critical Volvo Flygmotor AB
Publication of EP0313539A1 publication Critical patent/EP0313539A1/en
Application granted granted Critical
Publication of EP0313539B1 publication Critical patent/EP0313539B1/en
Expired 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/04—Special measures taken in connection with the properties of the fluid
    • F15B21/041—Removal or measurement of solid or liquid contamination, e.g. filtering
    • 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
    • F15B2201/40—Constructional details of accumulators not otherwise provided for
    • F15B2201/41—Liquid ports

Definitions

  • the present invention refers to a device for neutralizing or rendering metal chips harmless, which occur at a scraper ring of a piston in a cylinder of a pressure liquid accumulator.
  • pressure accumulators in the form of a cylindrical chamber, in which a pressurized liquid, conventionally hydraulic oil, is confined by means of a piston under counter-pressure from a gas body.
  • a pressurized liquid conventionally hydraulic oil
  • the piston is moved in the emptying direction under the action of the gas body pressure, while when the accumulator is loaded, said piston moves in the opposite direction in the cylinder and compresses the gas body.
  • metal chips arise which accompany the pressure liquid.
  • DE-A 3 638 640 there is disclosed a pressure accumulator of the type defined in the preamble of claim 1.
  • the scraper ring thereof is provided for pushing the abrasive particles which accumulate in the hydraulic chamber in a collecting chamber located in an end plate of the housing. Ingress of the particles between ring and cylinder wall may still occur.
  • a rotary vane-type actuator is furthermore known from US-A 4 345 509, which includes in the actuator housing internal sump cavities that collect abrasive particles from the fluid and which hold such contaminants away from the path of movement of the vane.
  • a magnetic element at each sump attracts and holds ferromagnetic particles.
  • the object of the present invention now is to remedy said problem and this object is reached substantially in that radially inwardly of said scraper ring is mounted an annular strip of magnetic material for collecting the metal chips thereon. If, according to a preferred embodiment of the invention a free space is formed in the piston at the side of the scraper ring and strip closest to the head of the piston, the metal chips might be collected and retained there in a very advantageous manner.
  • a hydraulic pressure accumulator 1 has a cylindrical casing 2, which at one end is closed by means of an end plate 3.
  • a piston 4 which defines between itself and the end plate 3 a pressure liquid chamber 5.
  • the piston 4 defines a gas- filled space 6 within the cylindrical casing 2.
  • the piston 4 is sealed against the cylinder wall of the casing 2 by means of conventional piston rings 7 located in ring grooves.
  • a scraper ring 8 is located in a groove in a similar manner.
  • said scraper ring is formed with a front edge, which is inclined obliquely forwardly-outwardly as illustrated.
  • an annular strip 9 of magnetic material In order to render metal chips, i.e. of steel and similar materials which might be attracted by magnetic forces, harmless and prevent them from penetrating into the space between the scraper ring 8 and the cylinder wall of the casing 2 and cause damages of the aforementioned kind, which chips possibly occur in the pressure liquid, there is according to the invention radially inwardly of the scraper ring 8 arranged an annular strip 9 of magnetic material.
  • said magnetic strip 9 might be made in the form of a plastic-pressed elastic ring of e.g. samarium and cobalt.

Description

  • The present invention refers to a device for neutralizing or rendering metal chips harmless, which occur at a scraper ring of a piston in a cylinder of a pressure liquid accumulator.
  • In hydraulic drive and contro Isystems it is often used pressure accumulators in the form of a cylindrical chamber, in which a pressurized liquid, conventionally hydraulic oil, is confined by means of a piston under counter-pressure from a gas body. When the accumulator is emptied, the piston is moved in the emptying direction under the action of the gas body pressure, while when the accumulator is loaded, said piston moves in the opposite direction in the cylinder and compresses the gas body. During the piston movement and moreover during operation of e.g. hydrostatic transmissions metal chips arise which accompany the pressure liquid. Particularly in a pressure accumulator such metal chips might cause great harm since the piston at its pressure liquid side often is provided with a scraper ring where the metal chips might be clamped between said ring and the cylinder wall. By this, the cylinder wall might be scratched as the piston and its associated scraper ring moves. Such scratch damages might occur not only in the cylinder wall but also on the scraper ring and the piston.
  • Sometimes oil filters are included in hydraulic systems but since the oil often has to travel a long distance to such a filter in which metal chips present might be removed, they still manage many times to cause great harm prior thereto. Thus, there is a great need of an improved device to render such metal chips harmless and particularly in connection with the most vital portion of the system, namely the pressure accumulator.
  • In DE-A 3 638 640 there is disclosed a pressure accumulator of the type defined in the preamble of claim 1. The scraper ring thereof is provided for pushing the abrasive particles which accumulate in the hydraulic chamber in a collecting chamber located in an end plate of the housing. Ingress of the particles between ring and cylinder wall may still occur.
  • A rotary vane-type actuator is furthermore known from US-A 4 345 509, which includes in the actuator housing internal sump cavities that collect abrasive particles from the fluid and which hold such contaminants away from the path of movement of the vane. A magnetic element at each sump attracts and holds ferromagnetic particles.
  • The object of the present invention now is to remedy said problem and this object is reached substantially in that radially inwardly of said scraper ring is mounted an annular strip of magnetic material for collecting the metal chips thereon. If, according to a preferred embodiment of the invention a free space is formed in the piston at the side of the scraper ring and strip closest to the head of the piston, the metal chips might be collected and retained there in a very advantageous manner.
  • By way of example, the invention will be further described below with reference to the accompanying drawing, in which is illustrated a partial longitudinal section of a pressure accumulator having a scraper ring-provided piston according to the invention.
  • A hydraulic pressure accumulator 1 has a cylindrical casing 2, which at one end is closed by means of an end plate 3. In the cylindrical casing 2 is axially movably mounted a piston 4, which defines between itself and the end plate 3 a pressure liquid chamber 5. At its opposite side, the piston 4 defines a gas- filled space 6 within the cylindrical casing 2.
  • At its peripheral surface the piston 4 is sealed against the cylinder wall of the casing 2 by means of conventional piston rings 7 located in ring grooves. At the portion of the peripheral surface located closest to the head of the piston a scraper ring 8 is located in a groove in a similar manner. Preferably said scraper ring is formed with a front edge, which is inclined obliquely forwardly-outwardly as illustrated.
  • In order to render metal chips, i.e. of steel and similar materials which might be attracted by magnetic forces, harmless and prevent them from penetrating into the space between the scraper ring 8 and the cylinder wall of the casing 2 and cause damages of the aforementioned kind, which chips possibly occur in the pressure liquid, there is according to the invention radially inwardly of the scraper ring 8 arranged an annular strip 9 of magnetic material. Preferably, said magnetic strip 9 might be made in the form of a plastic-pressed elastic ring of e.g. samarium and cobalt.
  • When the piston 4 moves within the cylindrical casing 2 metal chips possibly existing in the pressure liquid and located in the vicinity of the scraper ring 8 will be pulled towards the magnetic strip 9 by the magnetic forces therefrom and hence carried away from the cylinder wall of the casing 2 and the scraper ring 8. The chips get stuck onto the magnetic strip 9 and can then no longer hurt the cylinder wall and the scraper ring and/or the piston 4.
  • It is also advantageous to provide at the side of the scraper ring 8 and the strip 9 closest adjacent the head of the piston a free space 10 in the piston 4 for housing the metal chips collected. Said space then also remains when the piston 4 reaches its end position into abutment against the end plate 3 such that the metal chips collected onto the magnetic strip 9 will not be dislodged and again discharged into the hydraulic liquid.

Claims (2)

1. A device for neutralizing metal chips occurring at a scraper ring (8) of a piston (4) in a cylinder (2) of a pressure liquid accumulator, characterized in that radially inwardly of said scraper ring (8) is mounted an annular strip (9) of magnetic material for collecting the metal chips thereon.
2. A device according to claim 1, characterized in that at the side of the scraper ring (8) and strip (9) located closest to the piston head is formed a free space (10) in the piston (4) for housing metal chips collected.
EP88850356A 1987-10-23 1988-10-21 A device for neutralizing metal chips in a pressure liquid accumulator Expired EP0313539B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8704137 1987-10-23
SE8704137A SE459275B (en) 1987-10-23 1987-10-23 DEVICE FOR UNFAMILYING OF METAL TIPS IN A PRESSURE FLUID CUMULATOR

Publications (2)

Publication Number Publication Date
EP0313539A1 EP0313539A1 (en) 1989-04-26
EP0313539B1 true EP0313539B1 (en) 1990-05-16

Family

ID=20369990

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88850356A Expired EP0313539B1 (en) 1987-10-23 1988-10-21 A device for neutralizing metal chips in a pressure liquid accumulator

Country Status (4)

Country Link
EP (1) EP0313539B1 (en)
JP (1) JPH01158201A (en)
DE (1) DE3860156D1 (en)
SE (1) SE459275B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022000197A1 (en) 2022-01-20 2023-07-20 Hydac Technology Gmbh hydraulic accumulator
DE102022000382A1 (en) 2022-02-01 2023-08-03 Hydac Technology Gmbh hydraulic accumulator
DE102022000511A1 (en) 2022-02-10 2023-08-10 Hydac Technology Gmbh hydraulic accumulator

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19740150A1 (en) * 1997-09-12 1999-03-25 Hydac Technology Gmbh Piston accumulator with depth filtration seal
GB2420380A (en) * 2004-11-18 2006-05-24 Parker Hannifin Plc Twin piston gas filled hydraulic actuator
CN109538545A (en) * 2018-12-25 2019-03-29 山东华阳众能动力科技有限公司 A kind of fuel tank and the hydraulic system with the fuel tank
CN110374962A (en) * 2019-06-24 2019-10-25 宁波海天金属成型设备有限公司 A kind of fuel tank Filtrierapparatus of hydraulic system

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4345509A (en) * 1980-06-23 1982-08-24 Caterpillar Tractor Co. Contaminant trap for fluid operated rotary actuator
SE447296B (en) * 1985-11-25 1986-11-03 Stromsholmens Mek Verkstad Cylinder flip device and axially movable piston

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022000197A1 (en) 2022-01-20 2023-07-20 Hydac Technology Gmbh hydraulic accumulator
DE102022000382A1 (en) 2022-02-01 2023-08-03 Hydac Technology Gmbh hydraulic accumulator
DE102022000511A1 (en) 2022-02-10 2023-08-10 Hydac Technology Gmbh hydraulic accumulator

Also Published As

Publication number Publication date
SE8704137L (en) 1989-04-24
SE8704137D0 (en) 1987-10-23
JPH01158201A (en) 1989-06-21
DE3860156D1 (en) 1990-06-21
EP0313539A1 (en) 1989-04-26
SE459275B (en) 1989-06-19

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