EP1074750A2 - Druckmittelzylinder mit Enddämpfung und Geschwindigkeitssteuervorrichtung - Google Patents

Druckmittelzylinder mit Enddämpfung und Geschwindigkeitssteuervorrichtung Download PDF

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Publication number
EP1074750A2
EP1074750A2 EP00116651A EP00116651A EP1074750A2 EP 1074750 A2 EP1074750 A2 EP 1074750A2 EP 00116651 A EP00116651 A EP 00116651A EP 00116651 A EP00116651 A EP 00116651A EP 1074750 A2 EP1074750 A2 EP 1074750A2
Authority
EP
European Patent Office
Prior art keywords
piston
damping
chamber
actuator according
bush
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Withdrawn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
EP00116651A
Other languages
English (en)
French (fr)
Other versions
EP1074750A3 (de
Inventor
Sergio c/o Univer S.P.A. Favotto
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.)
Univer SpA
Original Assignee
Univer SpA
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 Univer SpA filed Critical Univer SpA
Publication of EP1074750A2 publication Critical patent/EP1074750A2/de
Publication of EP1074750A3 publication Critical patent/EP1074750A3/de
Withdrawn legal-status Critical Current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
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
    • F15B15/222—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having a piston with a piston extension or piston recess which throttles the main fluid outlet as the piston approaches its end position
    • 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
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
    • F15B15/223—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having a piston with a piston extension or piston recess which completely seals the main fluid outlet as the piston approaches its end position

Definitions

  • the present invention relates to pressure fluid actuators comprising a reciprocable piston member into a piston chamber, and more particularly relates to a hydraulic, pneumatic or hydra-pneumatic cylinder provided with a flow damping device acting at the end of each working stroke of the piston, and to achieve a rapid starting movement of the same piston upon each reversal of its stroke.
  • the damping systems used in hydraulic or conventional pneumatic cylinders require a small-diameter spigot at each end of the piston, to penetrate into a damping chamber in a corresponding closing head, or alternatively require a tubular member having a restricted path for discharging the fluid, which extends from each head to tightly penetrate into a corresponding dead hole in the piston; linear actuators provided with damping systems of this kind are described, for example, in EP-A-0,005,407, EP-A-0,082,829 and EP-A-0,648,941.
  • the piston begins to move slowly at the starting owing to the inadequate thrust exerted by the pressure fluid on the spigot inside the damping chamber, and then suddenly speed up when the spigot has been substantially withdrawn and the load connected to the cylinder is already moving.
  • the main object of the present invention is to provide a linear pressure fluid actuator provided with a suitable damping system which subsequently allows a rapid movement of the piston at the starting of each working stroke.
  • a further object of the present invention is to provide a linear actuator of the above mentioned kind, provided with a damping system for achieving damping and fast starting movement, suitable for universal use, in both hydraulic and pneumatic cylinders, i.e. independently of the type of fluid used.
  • Yet another object of the present invention is to provide a linear actuator as defined above, in particular for double-acting hydraulic or pneumatic cylinders, provided with a damping system for damping and achieving a fast starting movement of the piston, of the same type on both side ends of the piston stroke.
  • Yet another object of the present invention is to provide a linear actuator as defined above which is constructionally simplified, more cost-effective and easy to assemble, such that it may be sold in disassembled condition and packaged in kit form.
  • a pressure fluid actuator has been provided with flow damping device, the actuator comprising:
  • the actuator denoted in its entirety by reference 10, comprises a tubular body 11 and two closing heads 12 and 13 to define a chamber 14 inside which a piston 15 reciprocates.
  • Each closing head 12 and 13 is provided with an inlet/outlet port 16, 17, for supplying and discharging a pressurised fluid, for example oil or air, which communicates with a damping chamber 18 and 19 coaxially arranged inside each head 12, 13 and opening towards the piston chamber 14, as shown.
  • a pressurised fluid for example oil or air
  • the left-hand head 13 in Figure 1 also comprises a guide sleeve 20 for the rod 21 of the piston 15, suitable seats being provided for annular seals 22, for example of the lip type, as shown.
  • Each end head 12 and 13, on the side opposite to the inlet/outlet port 16 and 17, is provided with a branched duct 24A, 24B comprising a needle valve 23 - also called a flow throttling valve - which defines a restricted path for discharging the fluid, which on the side 24A opens into the piston chamber 14, while on the opposite side 24B opens into the damping chamber 18 or the damping chamber 19, respectively.
  • the two needle valves 23, the narrow passages 24A, 24B and the damping chambers 18 and 19 in both end heads 12 and 13 form part of a damping system for damping the speed of the piston 15, at each end of a working stroke, and for controlling the starting speed of the piston at the beginning of each working stroke.
  • each side of the piston 15 is provided with a damping bush 25 having an external cone-shaped surface so as to tightly close each of the two damping chambers 18 and 19, causing a gradual sealing action during the insertion into the damping chamber 18, 19 at the end of each stroke of the piston 15.
  • Each damping bush 25, as shown for the left-hand bush in Figure 1, has a thick end wall 26 bearing against the end face of the piston 15 and having a peripheral wall 27 delimited by a cylindrical internal surface having a diameter greater than the diameter of the rod 21 so as to form an annular space 28 open towards the piston chamber 14.
  • the piston rod 21 also has an extension 22A of smaller-diameter which passes through axially aligned holes in the end walls 26 of two bushes 25 and in the central piston 15, and provided with a threaded end for screwing engagement with a nut 29 which keeps the assembly consisting of the piston 15, the rod 22 and the two damping bushes 25 in the assembled condition shown in Figure 1.
  • each damping bush 25 has one or more longitudinal holes or flow passages 30 which extend from the rear end of the bush, i.e. the end facing the central piston 15, towards the internal cavity 28.
  • each passage 30 open to the chamber 14 via one or more recesses 31, at the rear side and directly at the front side.
  • Each longitudinal passage 30 in the bushes 25 comprises a pressure actuated unidirectional valve, for example consisting of a ball valve 32 having a diameter smaller than that of the hole defining the passage 30 and designed to seal against a conical seat 33 on the side facing the annular space 28 in each bush 25.
  • the ball valve 32 has the function of preventing the fluid from flowing from the piston chamber 14 into the damping chamber 18 and 19 when the said damping bush 25 extends inside the respective damping chamber 18 and 19, so as to gradually reduce the speed of the piston 15 in an usual manner at the end of its stroke, as shown for example in the enlarged detail according to Figure 3, and to allow the fluid to flow in the opposite direction, as shown in the enlarged detail of Figure 2 and as explained further below.
  • each passage 30 in the damping bush 25 on one side leads into the front-open cavity 28 inside the bush and on the other side communicates with the piston chamber 14, via a recess 31 on the end face of the piston 15; however, it is also possible to form this recess on the rear end face of the bush.
  • the recess 31 may be formed in any manner; for example it may consist of a simple radial slot or having a circular shape as shown in the cross-sectional view according to Figure 4, or a helical shape or other suitable shape as shown in the cross-sectional view of Figure 5.
  • the solution according to Figure 5 tends to increase further the thrust surface, compared to the solution according to Figure 4, since the helical recess 31' extends as far as the peripheral edge of the piston 15 so that most of the front surface of the latter is immediately acted on by the pressurised fluid, increasing the thrust so as to impart a fast starting movement of the piston.
  • each sealing bush 25 with several longitudinal passages 30, each with its own non-return valve, so as to increase the quantity of fluid supplied at the start of each working stroke, thereby increasing the initial thrust and the starting speed of the piston 15 depending on the load to be controlled or the work requirements envisaged.
  • FIGs 4 and 5 show two different solutions as regards the form and arrangement of the slots or recesses 31, 31' in the piston 15 or in the said bush 25.
  • Figure 4 shows a single circular slot 31 which is coaxial with the piston 15 and into which two passages 30 in the damping bush lead
  • Figure 5 shows the use of two helical slots 31' which extend from a respective passage 30 in the bush 25 to the peripheral edge of the piston 15.
  • Figure 6 in the drawings shows a further solution which differs from that of Figure 1 as regards the formation of the fluid supply path in the two damping bushes 25 and the piston 15, together with the associated non-return valve.
  • the cylinder according to Figure 6, which is only partially shown, is substantially similar to that shown in Figure 1; therefore, in this case also, the same reference numbers have been used to indicate similar or equivalent parts.
  • the solution according to Figure 6 differs from the solution according to Figure 1 in that now the non-return valve consists of an annular element 35 seated in a corresponding annular recess 36 at the rear end of each bush 25, leading both into the cavity 28 inside the said bush by means of a plurality of holes 37 and to the piston 15; as regards the rest, the cylinder according to Figure 6 is similar to and operates in a manner entirely identical to that of the cylinder according to Figure 1.
  • the invention provides a linear actuator actuated by a fluid under pressure, in particular a hydraulic or pneumatic cylinder or an air-hydraulic cylinder provided with a system for damping and controlling the speed of deceleration and initial movement of the piston, which uses a non-return valve actuated so as to open and close by the same pressurised fluid which flows into the piston chamber and by means of which it is possible to achieve the desired objects.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Vibration Prevention Devices (AREA)
EP00116651A 1999-08-04 2000-08-02 Druckmittelzylinder mit Enddämpfung und Geschwindigkeitssteuervorrichtung Withdrawn EP1074750A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT1999MI001751A IT1313145B1 (it) 1999-08-04 1999-08-04 Attuatore lineare con dispositivo di smorzamento e di controllo dellavelocita'
ITMI991751 1999-08-04

Publications (2)

Publication Number Publication Date
EP1074750A2 true EP1074750A2 (de) 2001-02-07
EP1074750A3 EP1074750A3 (de) 2003-06-04

Family

ID=11383498

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00116651A Withdrawn EP1074750A3 (de) 1999-08-04 2000-08-02 Druckmittelzylinder mit Enddämpfung und Geschwindigkeitssteuervorrichtung

Country Status (3)

Country Link
EP (1) EP1074750A3 (de)
CA (1) CA2314958A1 (de)
IT (1) IT1313145B1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008089804A1 (de) * 2007-01-23 2008-07-31 Festo Ag & Co. Kg Aktor mit aktorglied
EP3258117A4 (de) * 2015-02-10 2018-10-17 KYB Corporation Flüssigkeitsdruckzylinder

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0005407A1 (de) 1978-05-05 1979-11-14 Climax France S.A. Einrichtung zur Endlagenbremsung und/oder -beschleunigung für abwechselnd hin- und hergehende Elemente
EP0082829A1 (de) 1981-12-22 1983-06-29 AB Mecman Vorrichtung an einem mit Druckflüssigkeit beaufschlagten Zylinder ohne Kolbenstange
EP0648941A1 (de) 1993-10-18 1995-04-19 UNIVER S.p.A. Pneumatisches Stellorgan mit einstellbarer Endlagen- und Dämpfungseinrichtung

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1039844B (de) * 1957-05-23 1958-09-25 Pumpenfabrik Urach Hydraulischer Arbeitszylinder mit Daempfungseinrichtung
DE2027395A1 (de) * 1970-06-04 1971-12-09 Hennecke E Doppelt wirkender druckmittelbeaufschlagter Arbeitszylinder mit Endlagendämpfung
FR2410756A1 (fr) * 1977-11-30 1979-06-29 Outillage Air Comprime Dispositif de demarrage d'un verin a piston amorti
JPS57114003A (en) * 1980-12-29 1982-07-15 Showa Mfg Co Ltd Hydraulic shock absorber
DE3712671A1 (de) * 1987-04-14 1988-10-27 Hydraulik Zubehoer Ges Fuer Kolben-zylinder-einheit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0005407A1 (de) 1978-05-05 1979-11-14 Climax France S.A. Einrichtung zur Endlagenbremsung und/oder -beschleunigung für abwechselnd hin- und hergehende Elemente
EP0082829A1 (de) 1981-12-22 1983-06-29 AB Mecman Vorrichtung an einem mit Druckflüssigkeit beaufschlagten Zylinder ohne Kolbenstange
EP0648941A1 (de) 1993-10-18 1995-04-19 UNIVER S.p.A. Pneumatisches Stellorgan mit einstellbarer Endlagen- und Dämpfungseinrichtung

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008089804A1 (de) * 2007-01-23 2008-07-31 Festo Ag & Co. Kg Aktor mit aktorglied
EP3258117A4 (de) * 2015-02-10 2018-10-17 KYB Corporation Flüssigkeitsdruckzylinder

Also Published As

Publication number Publication date
CA2314958A1 (en) 2001-02-04
ITMI991751A0 (it) 1999-08-04
IT1313145B1 (it) 2002-06-17
ITMI991751A1 (it) 2001-02-04
EP1074750A3 (de) 2003-06-04

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