EP0258712B1 - Lightweight linear hydraulic actuator - Google Patents

Lightweight linear hydraulic actuator Download PDF

Info

Publication number
EP0258712B1
EP0258712B1 EP19870111802 EP87111802A EP0258712B1 EP 0258712 B1 EP0258712 B1 EP 0258712B1 EP 19870111802 EP19870111802 EP 19870111802 EP 87111802 A EP87111802 A EP 87111802A EP 0258712 B1 EP0258712 B1 EP 0258712B1
Authority
EP
European Patent Office
Prior art keywords
barrel
hydraulic actuator
members
linear hydraulic
fitting
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
EP19870111802
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0258712A3 (en
EP0258712A2 (en
Inventor
Ralph L. Vick
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.)
Honeywell International Inc
Original Assignee
AlliedSignal Inc
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 AlliedSignal Inc filed Critical AlliedSignal Inc
Publication of EP0258712A2 publication Critical patent/EP0258712A2/en
Publication of EP0258712A3 publication Critical patent/EP0258712A3/en
Application granted granted Critical
Publication of EP0258712B1 publication Critical patent/EP0258712B1/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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/149—Fluid interconnections, e.g. fluid connectors, passages
    • 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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1423—Component parts; Constructional details
    • F15B15/1438—Cylinder to end cap assemblies

Definitions

  • the present invention relates to lightweight linear hydraulic actuators and more particularly to such an actuator which is comparatively simple in construction and inexpensive to manufacture.
  • Usual linear actuators as disclosed, for example, in DE-A-2846027 particularly for operating aircraft control surfaces include a cylindrical barrel which may be cast or forged to include a head end with a structure for fastening the actuator to a stationary part of the aircraft or other vehicle.
  • the head end may include a separate structure fastened to the barrel, but in either case the end structure usually will include a passage to allow hydraulic fluid to flow into and out of the cylinder.
  • a piston attached to a rod is moveable in the cylinder.
  • a separate rod end gland is fastened to the barrel and this gland includes one or more seals surrounding the rod which passes through the barrel and usually also will include a passage to allow hydraulic fluid to flow into and out of the cylinder.
  • Such passages may also be cast into the barrel if the barrel is cast.
  • the piston and rod may be cast or forged in one piece, or formed of separate pieces which are then secured together. Actuators incorporating such cast or forged components are usually quite expensive both because of the cost of castings and forgings but also of the required machining. These casts are further escalated by whatever losses or scrap are caused by the machining operations.
  • the port fittings can sometimes be welded or brazed in place. On comparatively thin wall tubing, this sometimes results in high scrap and rework, at least partially because of distorting of the barrel.
  • Another known possibility is to add separate outer glands surrounding the barrel. This technique leaves much to be desired because the extra glands must be capable of withstanding pressure hoop stress and must seal on two extra and rather large diameter seals which adversely affects size, weight and reliability.
  • a lightweight linear hydraulic actuator including a cylindrical barrel, head end and rod end gland members on opposite ends of said barrel, a piston in said barrel dividing said barrel into first and second chambers, a rod attached to said piston and extending through said rod end gland member, and means connecting a source of hydraulic fluid under pressure to said actuator on opposite sides of said piston
  • said means including a first port in the sidewall of said barrel communicating with said first chamber, a second port in the sidewall of said barrel communicating with said second chamber, a first fitting member having a passageway communicating with said first port, and a second fitting member having a passageway communicating with said second port, characterised by grooves and seals in said grooves surrounding said first and second ports; said fitting members each having hoop supports surrounding said barrel and arcuate surfaces mating with the surface of said barrel in contact with said seals, and fastening means fastening said fitting members to said barrel.
  • the pre-characterising clause of the subject invention is based upon DE-A-2846027.
  • a cast or forged fitting including a thin hoop support structure surrounds the barrel and provides a channel with a threaded connection to a fluid source which channel registers with a port in the barrel.
  • a small circular groove in the surface of the cylinder surrounds the port and receives an O-ring seal which seals against a curved surface of the fitting which mates with the curvature of the barrel.
  • a suitable threaded fastener maintains the fitting securely in place.
  • the present inventor has found, however, that the localised force and resultant strain on the fitting is less than the barrel hoop strain (at the same pressure) if the fitting is designed properly. Therefore, the initial face seal annular gap will tend to decrease with pressure rather than the reverse.
  • the fitting can be lightweight, has only one seal (potential leak path) and is readily removeable and replaceable even with the actuator assembled.
  • the single figure is a cross sectional drawing of an actuator according to this invention.
  • the hydraulic actuator is shown generally at numeral 10, including a barrel section 12 which typically is formed of steel tubing material.
  • the barrel is closed at its head end by means of a head end gland 14 which is securely fastened to the barrel member 10 by means of a feedthrough wire 16.
  • a conventional seal 18 is located in the surface of the head end gland and seals against the inside wall of the barrel 12.
  • a clevis member 20 which may be a part of gland member 14 is provided for attachment of the actuator to a stationary member, not shown.
  • the opposite end of the actuator 10 is closed by means of a rod end gland 22 having an opening 24 through which passes an actuating rod 26 driven by a piston 28, which separates the interior of barrel 12 into chambers 29 and 30.
  • Rod end gland 22 is secured to the inside surface of barrel 12 by means of a feedthrough wire 31 and piston 28 is similarly secured to rod 26 by means of a feedthrough wire 32.
  • Conventional seals 34 and 36 which may be O-ring seals, prevent communication across the piston between the piston 28 and rod 26 and piston 28 and the inside surface of the barrel 12, respectively.
  • Similar seals 38 and 40 prevent high pressure fluid within chamber 30 from leaking along the surface of rod 26 to the exterior of rod end gland 22.
  • Chambers 29 and 30 are each supplied with hydraulic fluid under high pressure from an external source not shown. Chamber 29 communicates with a port 46 through the sidewall of barrel 12 which in turn communicates with the interior channel 48 of a fitting member 50.
  • Chamber 30 communicates with a port 52 which communicates with a channel 54 in a fitting member 56 which is similar to fitting member 50.
  • Members 50 and 56 are forged or cast as ring-shaped members which surround the barrel 12 and include bosses 58 and 60, respectively, which receive screws 62 and 64, respectively, which are threadedly engaged with the sidewall of barrel 12, and as shown may also penetrate into the head and rod end glands 14 and 22.
  • a pair of face seal grooves 66 and 68 are formed in the sidewall of barrel 12 by electrical discharge machining, multi-axis conventional machining, or other suitable method such that they surround the ports 46 and 52.
  • the fitting members 50 and 56 have internal diameters such that they afford approximately 0.05-0.13mm (0.002 to 0.005 inch) clearance around the barrel 12 and grooves 66 and 68 may contain conventional O-type ring seals for preventing the high pressure fluid in chambers 29 and 30 from leaking laterally along the outside surface of the barrel 12.
  • the fitting can be lightweight, has only one seal or potential leak path and is a removable and replaceable part even with the actuator assembled.
  • the seals 66 and 68 would normally be of the type utilizing an O-ring of elastomeric material having an outer diameter backup ring of polytetraflorethylene (Teflon) or similar material.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
EP19870111802 1986-09-02 1987-08-14 Lightweight linear hydraulic actuator Expired EP0258712B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US90253386A 1986-09-02 1986-09-02
US902533 1986-09-02

Publications (3)

Publication Number Publication Date
EP0258712A2 EP0258712A2 (en) 1988-03-09
EP0258712A3 EP0258712A3 (en) 1989-10-04
EP0258712B1 true EP0258712B1 (en) 1992-01-29

Family

ID=25415990

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19870111802 Expired EP0258712B1 (en) 1986-09-02 1987-08-14 Lightweight linear hydraulic actuator

Country Status (3)

Country Link
EP (1) EP0258712B1 (ja)
JP (1) JPS6362903A (ja)
DE (1) DE3776465D1 (ja)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001208001A (ja) * 2000-01-21 2001-08-03 Nippon Accumulator Co Ltd アキュムレータ

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2645513A (en) * 1947-12-31 1953-07-14 Vance C Sterrett Cylinder construction
DE6913740U (de) * 1969-04-05 1977-04-14 Christian Buerkert Arbeitszylinder.
DE2158720C2 (de) * 1971-11-26 1982-12-16 Indramat Gesellschaft für Industrie-Rationalisierung und Automatisierung mbH, 8770 Lohr Kolben-Zylindereinheit
US4211150A (en) * 1977-10-26 1980-07-08 Abex Corporation Air cylinder
SE439818B (sv) * 1983-06-13 1985-07-01 Osa Ab Kolvstangsstyrning for hydraulcylindrar

Also Published As

Publication number Publication date
EP0258712A3 (en) 1989-10-04
EP0258712A2 (en) 1988-03-09
DE3776465D1 (de) 1992-03-12
JPS6362903A (ja) 1988-03-19

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