EP0601736A1 - Verbesserungen an Zylindern - Google Patents

Verbesserungen an Zylindern Download PDF

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Publication number
EP0601736A1
EP0601736A1 EP93309366A EP93309366A EP0601736A1 EP 0601736 A1 EP0601736 A1 EP 0601736A1 EP 93309366 A EP93309366 A EP 93309366A EP 93309366 A EP93309366 A EP 93309366A EP 0601736 A1 EP0601736 A1 EP 0601736A1
Authority
EP
European Patent Office
Prior art keywords
cylinder
head
barrel
cap
piston
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Withdrawn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
EP93309366A
Other languages
English (en)
French (fr)
Inventor
Peter Tovey
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.)
Parker Hannifin Manufacturing Ltd
Original Assignee
Parker Hannifin PLC
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 Parker Hannifin PLC filed Critical Parker Hannifin PLC
Publication of EP0601736A1 publication Critical patent/EP0601736A1/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Withdrawn legal-status Critical Current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
    • F15B15/08—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

  • This invention concerns improvements relating to cylinders.
  • a pneumatic or hydraulic cylinder essentially comprises a piston, a piston rod, a cylinder cap, a cylinder head and a cylinder barrel between the cap and the head. Machining the cap, the head and the barrel in one piece from solid material is prohibitively expensive except in very special circumstances.
  • the barrel is advantageously formed from stock tube and there are basically three different methods of securing it to the head and the cap.
  • a first method is by welding, that is to say forming a peripheral weld to join a forged or cast and machined head to one end of the barrel and a forged or cast and machined cap to the other end of the barrel. Distortion is likely to be caused by the heat of the welding and once put together the components cannot thereafter be separated. This first method is only used for low precision applications.
  • a second method comprises pulling the head and cap onto opposite ends of the barrel by means of four longitudinally extending tie rods which pass through apertures in the head and cap and cooperate with nuts.
  • tie rods By selective angular positioning of the head and the cap prior to insertion of the tie rods, inlet and outlet ports in the head and the cap can be provided at a required alignment or 90° or 180° misalignment without such relative rotation of the head and cap affecting the stroke of the cylinder.
  • the third method comprises screw threading the ends of the barrel and screwing the cap and head thereto. This is increasingly popular since modern CNC machine tools can readily screwthread quite large diameter work pieces.
  • a cylinder head and a cylinder cap are each joined by a respective screw thread to a cylinder barrel but the stroke length is set by a member inserted into a free end of the cylinder head whereby a relative twisting movement of the cylinder head and cylinder cap need not affect stroke length.
  • the cylinder head and cylinder cap can thus be preported, that is to say provided with ports prior to their engagement with the cylinder barrel, and can be screwed with respect to the cylinder barrel until the ports are at a desired alignment or degree of misalignment and at a desired spacing.
  • the piston and piston rod can then be inserted in the cylinder and said member, preferably a gland screwed into the free end of the cylinder head, inserted to set by its inner end, or by the inner end of a spacer which precedes it, the precise length of stroke which can be effected by the piston.
  • All components of the hydraulic cylinder can thus be firmly locked with all internal faces pressed into contact, i.e. not spaced apart with gaps therebetween.
  • cushioning at the head end can be provided in the spacer which precedes the gland rather than in the head. This can permit delicate machining operations necessary to form cushioning passages to be effected on small low cost relatively otherwise unmachined parts rather than as a final machining operation on large expensive components which require considerable previous machining, whereby if the cushioning machining goes wrong, only an inexpensive component is scrapped.
  • a cylinder formed according to this aspect of the invention can be relatively inexpensive to manufacture since the barrel, the cap, the gland and the spacer can all be formed from standard tube and require only relatively small amounts of machining.
  • Trunnions can be provided on the cylinder barrel by forming the trunnions on a split block which can be clamped around the cylinder barrel, forming annular projections on the bore of the clamp block, forming annular grooves in the wall of the cylinder barrel and engaging the annular projections in the annular grooves before tightening clamp means of the split block thereby to lock the split block axially on the cylinder barrel.
  • a hydraulic cylinder 1 comprises a cylinder cap 2 with a mounting 3 welded thereto at a position 4, a cylinder barrel 5, a cylinder head 6, a piston 7, a piston rod 8 secured to a mounting 9, a gland 10 and an axial spacer 11.
  • the cylinder cap 2 can be formed from a length of bar stock, has a blind bore 12 therein to receive a cushioning spear 13 of the piston rod 8, has a main port 14 in communication with the bore 12 and a pilot bore 15 in communication with the bore 12 and thus the port 14 by way of an adjustable cushioning valve 16 and a radial port 17.
  • On its outer face the cylinder cap 2 is screwthreaded at 18 so that it can be screwed into the end of the cylinder barrel 5 with the provision of an environmental seal 19.
  • the cylinder barrel 5 is formed of standard tube only the bore of which needs to be finished machined and at its other end to the screwthread 18 is provided with an external screwthread 20 by means of which it is screwed into the cylinder head 6 with provision of an environmental seal 21.
  • the cylinder head 6 has a main port 22 which as shown is offset 90° from the port 14 of the cylinder cap 2, the port 22 being connected to a circumferential gallery 23 in the head 6 and the head 6 including a pilot bore 24, an adjustable cushioning valve 25 and a radial bore 26. At its free outer end the cylinder head 6 is internally screwthreaded at 27.
  • the piston 7 is an annular piston screwed onto a portion 28 of the piston rod 8 by a screwthread 29 and including piston seals 31 and bearings 32.
  • a cushioning sleeve 33 is received on a portion 34 of the piston rod 8 so as to be axially and radially moveable thereon.
  • the gland 10 is screwed into the cylinder head 6 by means of the screwthread 27 with the provision of an environmental seal 35 and is provided with sealing rings 36, seals 37 and bearings 38 which contact the outer face of the piston rod 8 and seal thereagainst.
  • the axial spacer 11 is located between the inner end face 39 of the gland 10 and the cylinder head end 40 of the cylinder barrel 5 .
  • a radially inner face 41 of the spacer 11 cooperates with the radially outer face of the sleeve 33 to effect cushioning upon final movements of expansion of the cylinder 1 by closing off the communication between a radial bore 42 in the spacer 11, which radial bore 42 is in communication with the gallery 23, and a space 43 in the barrel 5 provided between the spacer 11 and the piston 7.
  • fluid in the space 43 can only be ejected from the cylinder by way of a cutaway 44 formed by flats at the sides of the end of the spacer 11, the radial bore 26, the valve 25 and the bore 24, a sealing ring 45 being provided in the outer face of the spacer 11 to cooperate with the bore of the cylinder head 6.
  • One parameter of a fluid cylinder which is usually required to be accurately determined is the maximum stroke and this is the distance S indicated in Figure 2 and is the travel of the piston between the position at which it is hard up against the cylinder cap 2 to a position where it is hard up against the end face of the spacer 11 which abuts the end face 40 of the cylinder barrel 5 minus the piston width. If in a previously proposed fluid cylinder formed by screwing the components together, adjustment is made in the alignment of the ports, the cylinder head moves axially towards or away from the cylinder cap 2 and thus the length of the stroke of the piston is changed.
  • the stroke length is unaffected by the angular position of the cylinder head 6 which can be rotated a whole turn if desired to obtain the required relative angular positions of the ports 14 and 22 without in any way affecting the stroke of the piston and thus of the cylinder.
  • the stroke can be adjusted if required by rotating the cap 2 with respect to the barrel 5.
  • the spacer 11 need not be a separate component to the gland 10 ie it could be a forward projection thereof but it is more convenient for it to be a separate component.
  • the construction of the cylinder shown can have the advantage that without disturbing the relative axial or relatively rotated positions of the cap 2, barrel 5 and head 6 nor pipework connected to the ports 14 and 22, the piston rod 8 and the piston 7 can be removed from within the barrel 5 and head 6, for example to replace the seals 31 and bearings 32 on the piston, merely by unscrewing the gland 10 from the head 6 and sliding out the spacer 11.
  • Figures 3 and 4 show that the cushioning sleeve 33 at the head end is relatively axially movable on the portion 34 of the piston rod on which it is mounted so that when the piston rod is moving from right to left as indicated in Figure 3 and the cushioning sleeve 33 overlaps with the spacer 11, hydraulic pressure applied to the righthand end of the sleeve 33 as indicated by arrows 46 will press the lefthand end (as viewed in Figures 3 and 4) of the sleeve 33 against a shoulder 8 a of the piston rod 8 to form a seal so that the fluid can only exit the space 43 through the cutaway 44, the radial bore 26, the cushioning valve 25 and the bore 24.
  • the force of the fluid applied through the port 22 acts on the cushioning sleeve 33 to move it rightwardly to open up a gap 47 between the shoulder 8 a and lefthand end of the cushioning sleeve 33, such fluid then flowing through a spiral duct 48 formed by a spiral groove in the bore of the cushioning sleeve 33 to pass outwardly through a cutaway 49 at the righthand end of the sleeve so that the recompression of the cylinder 1 can be more rapidly effected than it would be if the compressing fluid had to pass solely through the cushion valve 25 and between the cushion sleeve 33 outside diameter and the cushion bore of the spacer 11.
  • the cushioning sleeve 33 thus in conjunction with the piston 7 and the shoulder 8 a acts as a check valve.
  • a cushioning ring 50 is engaged in a recess in the cap 2 and is axially movable by fluid pressure applied to its opposite sides so that a face 51 of the ring 50 cooperates with a face of the cap 2 to form a seal therewith after the spear 13 of the piston rod 8 enters the ring 5 so that there is effective cushioning but the face 51 moves away from the abutting face of the cap 2 to open up a space for rapid expansion of the cylinder when pressure is applied to the port 14.
  • the ring 50 has vanes 52 at its radially outer part which are retained by a securing ring 53 screwed into the recess in the cap 2 in which the ring 50 is mounted so as to allow free flow of fluid past the ring 50 when it is not in its sealing position.
  • Figure 6 shows that the seals 36 on the gland 10 can be replaced by a chevron-type seal 54 and a cast iron bearing ring 55 if desired.
  • a modified spacer 11 a is provided which includes a longitudinal bore in two parts 56, 57 with an adjustable cushioning valve 58 between the portions 56 and 57.
  • a circumferential seal 59 is provided additionally to the seal 45 and spaced therefrom with the valve 58 located between the seals 45 and 59 and also located in axial and circumferential alignment with a radial bore 60 in the head 6.
  • Means (not shown) is provided to prevent relative rotation between the head 6 and the spacer 11 a .
  • a tool such as a Allen key 61
  • an adjusting screw of the valve 58 can be inserted to engage an adjusting screw of the valve 58 to adjust the size of an aperture therein and thus the rate at which fluid can flow therethrough.
  • One advantage of providing the relatively small bore 56, 57 in two parts in the spacer 11 a rather than the bores 24 and 26 in the head 6 is that a somewhat risky operation of drilling small bores, which operation may result in the component being drilled having to be scrapped can be effected in the small spacer 11 a rather than the large head 6.
  • Figures 8 and 9 show a trunnion clamp 62.
  • the trunnion clamp 62 can be provided comprising two halves 62 a and 62 b boltable together with a joint line 63 by bolts 64 and having trunnions 65 thereon.
  • the cylinder barrel 5 is machined on its outer surface to form at least one circumferential groove 66 therein and a bore 67 of the trunnion clap 62 is formed with a matching number of projections extending circumferentially therearound and to engage in the at least one groove 66.
  • the bolts 64 can be tightened to clamp the trunnion clamp around the barrel 5 and mount the trunnions at an accurately determined axial position on the cylinder with only a very small reduction in wall thickness of the barrel 5 and virtually no reduction in strength due to the banding of the trunnion clamp 62 therearound.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
EP93309366A 1992-12-11 1993-11-24 Verbesserungen an Zylindern Withdrawn EP0601736A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9225925 1992-12-11
GB929225925A GB9225925D0 (en) 1992-12-11 1992-12-11 Improvements relating to cylinders

Publications (1)

Publication Number Publication Date
EP0601736A1 true EP0601736A1 (de) 1994-06-15

Family

ID=10726488

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93309366A Withdrawn EP0601736A1 (de) 1992-12-11 1993-11-24 Verbesserungen an Zylindern

Country Status (2)

Country Link
EP (1) EP0601736A1 (de)
GB (1) GB9225925D0 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0684391A1 (de) * 1994-04-26 1995-11-29 Robert Bosch Gmbh Druckmittelbetätigbarer Arbeitszylinder
DE29602088U1 (de) * 1996-02-07 1996-04-04 Buemach Engineering Internatio Verschraubbarer druckmittelbetätigter Arbeitszylinder mit Verschlußteilen zur Kopplung des Zylinderrohres
EP0735280A3 (de) * 1995-03-29 1997-03-05 KOREA INSTITUTE OF MACHINERY & METALS Pneumatikzylinder
GB2322417A (en) * 1996-11-08 1998-08-26 Ognibene Spa Cylinder-piston unit with through rod particularly for vehicle power steering devices
EP1677009A1 (de) * 2004-12-31 2006-07-05 Bosch Rexroth Teknik AB Zapfenelement, insbesondere für einen Antriebzylinder
EP2829742A4 (de) * 2012-03-23 2015-12-02 Kayaba Industry Co Ltd Hydraulikzylinder
CN109667806A (zh) * 2018-12-29 2019-04-23 浙江亿日气动科技有限公司 带后摆尾带锁气缸

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2557307A1 (de) * 1975-12-19 1977-06-30 Guenter Neumann Aus kolben und zylinder bestehender druckmitteltrieb
US4384511A (en) * 1980-10-17 1983-05-24 Mefferd Roy J Hydraulic cylinder
EP0135386A1 (de) * 1983-09-06 1985-03-27 Delibes Pty. Ltd. Hydraulik-Zylinderanordnung

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2557307A1 (de) * 1975-12-19 1977-06-30 Guenter Neumann Aus kolben und zylinder bestehender druckmitteltrieb
US4384511A (en) * 1980-10-17 1983-05-24 Mefferd Roy J Hydraulic cylinder
EP0135386A1 (de) * 1983-09-06 1985-03-27 Delibes Pty. Ltd. Hydraulik-Zylinderanordnung

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0684391A1 (de) * 1994-04-26 1995-11-29 Robert Bosch Gmbh Druckmittelbetätigbarer Arbeitszylinder
EP0735280A3 (de) * 1995-03-29 1997-03-05 KOREA INSTITUTE OF MACHINERY & METALS Pneumatikzylinder
DE29602088U1 (de) * 1996-02-07 1996-04-04 Buemach Engineering Internatio Verschraubbarer druckmittelbetätigter Arbeitszylinder mit Verschlußteilen zur Kopplung des Zylinderrohres
US6196112B1 (en) 1996-02-07 2001-03-06 Buemach Engineering International B.V. Screw-on pressure medium-actuated working cylinder with closure components for coupling the cylinder tube
CN1088806C (zh) * 1996-02-07 2002-08-07 比马赫国际工程公司 具有用于连接缸衬套的封闭件的可旋紧的用压力介质操纵的工作缸
GB2322417A (en) * 1996-11-08 1998-08-26 Ognibene Spa Cylinder-piston unit with through rod particularly for vehicle power steering devices
GB2322417B (en) * 1996-11-08 2000-08-23 Ognibene Spa Cylinder-piston unit with through rod particularly for vehicle power steering devices
EP1677009A1 (de) * 2004-12-31 2006-07-05 Bosch Rexroth Teknik AB Zapfenelement, insbesondere für einen Antriebzylinder
EP2829742A4 (de) * 2012-03-23 2015-12-02 Kayaba Industry Co Ltd Hydraulikzylinder
CN109667806A (zh) * 2018-12-29 2019-04-23 浙江亿日气动科技有限公司 带后摆尾带锁气缸
CN109667806B (zh) * 2018-12-29 2023-10-24 浙江亿日气动科技有限公司 带后摆尾带锁气缸

Also Published As

Publication number Publication date
GB9225925D0 (en) 1993-02-03

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