EP1306562B1 - Hydraulic actuator with retainer - Google Patents
Hydraulic actuator with retainer Download PDFInfo
- Publication number
- EP1306562B1 EP1306562B1 EP20020022504 EP02022504A EP1306562B1 EP 1306562 B1 EP1306562 B1 EP 1306562B1 EP 20020022504 EP20020022504 EP 20020022504 EP 02022504 A EP02022504 A EP 02022504A EP 1306562 B1 EP1306562 B1 EP 1306562B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- push rod
- bellows
- housing
- actuator
- 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.)
- Expired - Lifetime
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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
- F15B15/26—Locking mechanisms
- F15B15/261—Locking mechanisms using positive interengagement, e.g. balls and grooves, for locking in the end positions
Definitions
- This invention relates to hydraulic actuators and in particular, though not exclusively, to an actuator for use as a master cylinder for the operation of a vehicle clutch.
- the object of the present invention to provide an improved form of hydraulic actuator which is particularly easy to install as a clutch operating master cylinder.
- Such an hydraulic actuator is known from document US-A-2001/0010188: it comprises a housing with a piston slideable in the housing and a push rod extending from one end of the housing; a bellows encircles the push rod and is secured at one perimeter to the housing and at a second perimeter to a formation on the push rod.
- An additional retainer is foreseen for shipment and installation in a predetermined extended position.
- the hydraulic actuator is characterised in that the second perimeter of the bellows engages the formation on the push rod such that it retains the push rod in the predetermined extension position relative to the housing during delivery of the actuator from the manufacturer to the end user, and the actuation of the actuator after connection to an associated hydraulic circuit will disengage the second periphery of the bellows from the formation on the push rod to allow free movement of the push rod relative to the housing thereafter.
- the bellows retains the push rod in a concentric arrangement with the piston bore so that the push rod can be easily connected with its mating portion of the clutch actuation system for example, the push rod may be provided with a ball end which snaps into a ball socket associated with an associated operating pedal.
- the bellows may also be arranged to hold the push rod either in an extended or in a retracted position depending on the design parameters of the clutch actuating system.
- a hydraulic master cylinder 10 for use in the operation of a vehicle clutch comprises a body 11 having a bore 12 in which a piston 13 is in sealed sliding contact. Piston 13 is connected with an associated clutch pedal shown diagramatically at 14 by a push rod 15 having a part-spherical head portion 15a which bears on a complementary part-spherical portion 13a of piston 13. A working chamber 16 is provided ahead of piston 13 which has an outlet 17 connected via a conduit (not shown) with a clutch operating slave cylinder.
- the master cylinder also has an inlet 18 which is connected with a fluid reservoir (not shown) and also a larger diameter portion 19 of bore 12 via a passage 20.
- Piston 13 carries a main seal 21 which is of plastics material being an integral part of an annular component 22 (see figure 3).
- the plastics main seal 21 is energised against bore 12 by an elastomeric (e.g. rubber) annulus 23 which ensures that the seal 21 remains in contact with the associated bore etc.
- This sealing arrangement is the subject of the Applicant's co-pending European Patent Application No. EP 0894687 A1.
- a normal separate rubber seal can alternatively be used to seal piston 13 to bore 12.
- the component 22 and rubber annulus 23 are held in place on the remainder of the piston by a central member 24 which is pressed into, welded or otherwise secured to the main body 25 of the piston 13.
- the central member 24 has an axial bore 26 which is provided for manufacturing reasons (to reduce shrinkage) since the central member 24 is produced by an injection moulding technique from plastics material.
- the central member may alternatively, for example, be of a shorter construction which may not necessarily include the shrinkage bore 26.
- both the body 11 and piston 13 etc. are all formed from plastics material by injection moulding techniques.
- annular sleeve 27 is provided in the larger diameter portion 19 of bore 12.
- Sleeve 27 includes axially extending grooves 28 which in combination with bore portion 19 define passages which emerge into the smaller diameter portion 29 via openings 30 (see figure 3).
- Sleeve 27 also includes an annular shoulder 31 against which a return spring 32 reacts. The other end of spring 32 reacts against a shoulder 33 provided on piston 13 to ensure that the piston always returns to the fully extended position shown in figures 1 and 2 when the associated pedal is released.
- an elastomeric sealing bellows 40 has an outer bead 41 which engages in a groove 42 in housing 11 and also has an inner bead 43 which engages in a groove 44 formed in a larger diameter d2 of push rod 15 when the master cylinder is in the retracted position.
- the bead 43 on bellows 40 serves to hold the piston 13 in its fully retracted condition and also holds the push rod 15 in axial alignment within the housing 11 thus facilitating the attachment of the push rod to the associated operating pedal 14 via a snap-in ball joint or other suitable attachment.
- the present invention has been described above in relation to a particular master cylinder design the basic concept of using the protective bellows to hold the pushrod and piston in their retracted condition can be used on any type of pushrod master cylinder. Also, although described above in relation to a construction in which the pushrod/piston is held in its retracted (figure 1) condition the bellows arrangement of the invention can also be used to hold the pushrod/piston in its extended (figure 2) condition by appropriately axially positioning groove 44 in pushrod 15.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
Description
- This invention relates to hydraulic actuators and in particular, though not exclusively, to an actuator for use as a master cylinder for the operation of a vehicle clutch.
- The object of the present invention to provide an improved form of hydraulic actuator which is particularly easy to install as a clutch operating master cylinder.
- Such an an hydraulic actuator is known from document US-A-2001/0010188: it comprises a housing with a piston slideable in the housing and a push rod extending from one end of the housing; a bellows encircles the push rod and is secured at one perimeter to the housing and at a second perimeter to a formation on the push rod. An additional retainer is foreseen for shipment and installation in a predetermined extended position.
- According to the present invention the hydraulic actuator is characterised in that the second perimeter of the bellows engages the formation on the push rod such that it retains the push rod in the predetermined extension position relative to the housing during delivery of the actuator from the manufacturer to the end user, and the actuation of the actuator after connection to an associated hydraulic circuit will disengage the second periphery of the bellows from the formation on the push rod to allow free movement of the push rod relative to the housing thereafter.
- With such a solution, the additional retainer according to the prior art is then not needed anymore.
- Preferably the bellows retains the push rod in a concentric arrangement with the piston bore so that the push rod can be easily connected with its mating portion of the clutch actuation system for example, the push rod may be provided with a ball end which snaps into a ball socket associated with an associated operating pedal.
- In addition to ensuring axial alignment of the push rod with the piston bore the bellows may also be arranged to hold the push rod either in an extended or in a retracted position depending on the design parameters of the clutch actuating system.
- One embodiment of the present invention will now be described, by way of exarnple only, with reference to the accompanying drawings in which:-
- Figure 1 shows, partially diagramatically, in section a master cylinder embodying the present invention in its retracted condition;
- Figure 2 shows the cylinder of figure 1 in its extended condition; and
- Figure 3 shows details of part of figure 1 on a larger scale.
-
- Referring to the drawings a hydraulic master cylinder 10 for use in the operation of a vehicle clutch comprises a
body 11 having abore 12 in which apiston 13 is in sealed sliding contact. Piston 13 is connected with an associated clutch pedal shown diagramatically at 14 by apush rod 15 having a part-spherical head portion 15a which bears on a complementary part-spherical portion 13a ofpiston 13. A workingchamber 16 is provided ahead ofpiston 13 which has anoutlet 17 connected via a conduit (not shown) with a clutch operating slave cylinder. - The master cylinder also has an
inlet 18 which is connected with a fluid reservoir (not shown) and also alarger diameter portion 19 ofbore 12 via apassage 20. Piston 13 carries amain seal 21 which is of plastics material being an integral part of an annular component 22 (see figure 3). The plasticsmain seal 21 is energised againstbore 12 by an elastomeric (e.g. rubber)annulus 23 which ensures that theseal 21 remains in contact with the associated bore etc. This sealing arrangement is the subject of the Applicant's co-pending European Patent Application No. EP 0894687 A1. A normal separate rubber seal can alternatively be used to sealpiston 13 to bore 12. - The
component 22 andrubber annulus 23 are held in place on the remainder of the piston by acentral member 24 which is pressed into, welded or otherwise secured to themain body 25 of thepiston 13. In the construction shown thecentral member 24 has anaxial bore 26 which is provided for manufacturing reasons (to reduce shrinkage) since thecentral member 24 is produced by an injection moulding technique from plastics material. The central member may alternatively, for example, be of a shorter construction which may not necessarily include theshrinkage bore 26.
In a preferred arrangement both thebody 11 andpiston 13 etc. are all formed from plastics material by injection moulding techniques. - An
annular sleeve 27 is provided in thelarger diameter portion 19 ofbore 12.Sleeve 27 includes axially extendinggrooves 28 which in combination withbore portion 19 define passages which emerge into thesmaller diameter portion 29 via openings 30 (see figure 3).Sleeve 27 also includes anannular shoulder 31 against which areturn spring 32 reacts. The other end ofspring 32 reacts against ashoulder 33 provided onpiston 13 to ensure that the piston always returns to the fully extended position shown in figures 1 and 2 when the associated pedal is released. - As can be seen from figure 2, when the piston is in the fully extended position, the
main seal 21 is in contact with theinternal diameter 34 ofsleeve 21 and theopenings 30 in the sleeve are no longer sealed allowing communication between theinlet 18 and theworking chamber 16 viapassage 20 and grooves 28 (see arrows X). Thus in the fully extended position of the piston the reservoir connected withinlet 18 is in communication with workingchamber 16 allowing recouperation of fluid into the workingchamber 16 to take account any increase in working stroke of the piston necessary due to the wear of the associated clutch or any leakage of fluid from the working chamber. - When
pedal 14 is pushed,piston 13 is moved to the left from its fully extended position shown in figure 2 so thatmain piston seal 21 moves to the left ofopenings 30 to cut-off flow throughgrooves 28 and allow pressurisation ofworking chamber 16 in the normal manner. - In accordance with the present invention the master cylinder is transported from its place of manufacture to the vehicle manufacturers assembly line in its fully retracted condition shown in figure 1. An
elastomeric sealing bellows 40 has anouter bead 41 which engages in agroove 42 inhousing 11 and also has aninner bead 43 which engages in agroove 44 formed in a larger diameter d2 ofpush rod 15 when the master cylinder is in the retracted position. Thus thebead 43 onbellows 40 serves to hold thepiston 13 in its fully retracted condition and also holds thepush rod 15 in axial alignment within thehousing 11 thus facilitating the attachment of the push rod to the associatedoperating pedal 14 via a snap-in ball joint or other suitable attachment. - When the master cylinder has been installed in its operating position the
push rod 15 is moved outwardly of thebody 11 in the direction of arrow A of figure 1 thus disengaging thebead 43 fromgroove 44 so that the bellows now assumes its natural condition (see Figure 2) and thebead 43 slides up and down the smaller diameter d1 ofpush rod 15 for the remainder of its operating life. The diameter d1 and d2 are connected via a taper 15b which facilitates the initial engagement ofbead 43 ingroove 44. - Although the present invention has been described above in relation to a particular master cylinder design the basic concept of using the protective bellows to hold the pushrod and piston in their retracted condition can be used on any type of pushrod master cylinder. Also, although described above in relation to a construction in which the pushrod/piston is held in its retracted (figure 1) condition the bellows arrangement of the invention can also be used to hold the pushrod/piston in its extended (figure 2) condition by appropriately axially
positioning groove 44 inpushrod 15.
Claims (5)
- An hydraulic actuator (10) comprising a housing (11) with a piston (13) slideable in the housing and a push rod (15) extending from one end of the housing, a bellows (40) encircles the push rod and is secured at one perimeter (41) to the housing and at a second perimeter (43) engages a formation (44) on the push rod, the actuator being characterised in that the second perimeter (43) of the bellows engages the formation (44) on the push rod (15) such that the bellows (40) retains the push rod in a predetermined extension position relative to the housing (11) during delivery of the actuator from the manufacturer to the end user, and that actuation of the actuator after connection to an associated hydraulic circuit disengages the second periphery (43) of the bellows from the formation (44) on the push rod to allow free movement of the push rod relative to the housing thereafter.
- An actuator according to claim 1 characterised in that the bellows (40) retains the push rod (15) in a concentric arrangement with the piston bore (12).
- An actuator according to claim 1 or 2 characterised in that the push rod (15) is provided with a ball end or other fastener which snaps into a ball socket or other cooperating fastener associated with an associated operating pedal (14).
- An actuator according to any one of claims 1 to 3 characterised in that bellows (40) is arranged to hold the push rod (15) either in an extended or in a retracted position.
- A master cylinder of a clutch actuating system comprising an actuator according to any one of claims 1 to 4.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0125692A GB0125692D0 (en) | 2001-10-26 | 2001-10-26 | Hydraulic dampers |
GB0125692 | 2001-10-26 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1306562A1 EP1306562A1 (en) | 2003-05-02 |
EP1306562B1 true EP1306562B1 (en) | 2004-11-17 |
Family
ID=9924554
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20020022504 Expired - Lifetime EP1306562B1 (en) | 2001-10-26 | 2002-10-07 | Hydraulic actuator with retainer |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1306562B1 (en) |
DE (1) | DE60201957D1 (en) |
GB (1) | GB0125692D0 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102009019586B4 (en) | 2008-05-23 | 2023-12-07 | Schaeffler Technologies AG & Co. KG | Master cylinder arrangement |
DE102010061948A1 (en) * | 2010-11-25 | 2012-05-31 | Mahle International Gmbh | Assembly procedure, assembly aid and actuator |
DE102014212678B4 (en) * | 2014-07-01 | 2023-05-25 | Schaeffler Technologies AG & Co. KG | Transport lock for a concentric slave cylinder |
ES2746249B2 (en) * | 2018-09-05 | 2020-07-06 | Rpk S Coop | Moving rod centering elastic unit piece |
CN113775669B (en) * | 2021-09-19 | 2022-05-10 | 安徽江淮汽车集团股份有限公司 | Clutch master cylinder with clutch semi-linkage point force adjusting structure and clutch system |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3066506D1 (en) * | 1979-10-11 | 1984-03-15 | Knorr Bremse Gmbh | Pneumatic positioning device for sustaining at least one element, for example an aeration or deaeration screen |
US4557361A (en) * | 1982-02-01 | 1985-12-10 | Automotive Products Plc | Shipping and installation strap for linear actuator |
JP4107788B2 (en) * | 2000-01-31 | 2008-06-25 | 日信工業株式会社 | Holding structure for vehicle actuator |
-
2001
- 2001-10-26 GB GB0125692A patent/GB0125692D0/en not_active Ceased
-
2002
- 2002-10-07 DE DE60201957T patent/DE60201957D1/en not_active Expired - Lifetime
- 2002-10-07 EP EP20020022504 patent/EP1306562B1/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
GB0125692D0 (en) | 2001-12-19 |
DE60201957D1 (en) | 2004-12-23 |
EP1306562A1 (en) | 2003-05-02 |
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