WO1982004293A1 - Hydraulic linear actuator - Google Patents
Hydraulic linear actuator Download PDFInfo
- Publication number
- WO1982004293A1 WO1982004293A1 PCT/GB1982/000157 GB8200157W WO8204293A1 WO 1982004293 A1 WO1982004293 A1 WO 1982004293A1 GB 8200157 W GB8200157 W GB 8200157W WO 8204293 A1 WO8204293 A1 WO 8204293A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- actuator
- piston
- hydraulic
- rotation
- rod
- Prior art date
Links
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
- F15B15/28—Means for indicating the position, e.g. end of stroke
- F15B15/2815—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
- F15B15/2823—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT by a screw mechanism attached to the piston
Definitions
- This invention relates to an hydraulic linear actuator.
- Conventional hydraulic linear actuators when used in closed loop positional servo control systems, require the use of a positional transducer which is incorporated as a separate device in the mechanism being controlled.
- the positional transducer provides a feedback which is measured to enable adjustment of the actuator, more especially to adjust the stroke of the piston.
- a positional transducer In general, therefore, a positional transducer, must be specifically matched to the particular stroke of the actuator, which is in turn a function of its specific application. Disadvantageously, therefore, even for similar applications differing combinations of transducer and actuator are required. A further disadvantage arises because positional transducers are generally not robust in comparison with the actuator, and are thereby liable to damage.
- an hydraulic linear actuator having a linearly driven piston, wherein a mechanism is incorporated within the actuator and coupled to the piston to produce rotation of a member proportional to incorporated within the actuator to sense the rotation of said member.
- the rotary transducer which may be of a variety of types such as an opti cal sens or , electr ic ( potentio etr ic ) sen s or or electromagnetic ( inductive) sensor, is provided within the actuator.
- the transducer is inherently matched to the piston stroke, thus f aci litating the use of the identical transducer for differing actuator strokes .
- the actuator- piston is held against rotation and carr ies a nut formation within which engages a screwthreaded rod which constitutes the said member .
- a tens ioned rod may pass through the piston to hold it against rotation.
- a non-circular piston may move in a matching non-circular bore.
- the rotary transducer may be located at one end of the actuator in an enclosure sealed from the hydraulic chambers of the actuator and into which the rotationally driven rod extends from the ad jacent chamber.
- Figure 2 is a longitudinal cross-section on the line 2-
- Figure 3 is a part longi tudinal cross-section on the line 3-3 of Figure 1.
- the hydraulic linear actuator has 10 a hous ing 10 sealed by end closures 12 and 14. W ithin the hous ing 10 is a piston 16 connected to a pi ston rod 18 which emerges th rough the end c lo su re 12.
- the pi ston 16 i s linearly displaceable along the housing 10 by the passage of oil to or from hydraulic chambers 20 , 22 on oppos ite s ides 1 5 of the piston 16.
- Port 24 ( Figure 2) connects to the chamber 20
- port 26 (F igure 3 ) connects through a pas sage 28 in the wall of the hous ing to the chamber 22.
- the piston 16 i held against rotation by a tens ioned rod 30 f ixed between the end closures 12 and 14 and passing through said piston.
- a mechanism is incorporated within the actuator to produce a rotation proportional to piston di splacement, thereby to enable a rotational position sensor also to be incorporated
- the mechan i sm compr ises a nut assembly 32 located in a bore in the piston rod 18. This
- 25 bore extends over a part of the length of the piston rod 18 to enable a screwthreaded rod 34, which is in screwthreaded engagement with the nut assembly 32, to extend therefrom out
- an end cap 38 On the exterior of the end closure 14 an end cap 38 dif ines an enclosure into which extends the end of the rotationally driven rod 34.
- An 0-ring 40 ( Figure 3 ) seals the rod 34 in the bore in the end closure 14 between the bearings 36, thus isolating the end cap enclosure from the adjacent hydraulic chamber 20.
- a rotational positional sensor 42 Within the end cap enclosure is located a rotational positional sensor 42, which may be a transducer of any of a variety of convenient types such as those previously mentioned.
- the transducer 42 is wholly enclosed and thereby protected within the body of the actuator, whi ch includes the end cap 38 rigidly fixed to the end closure 14. If desired, moreover, the rotational position transducer 42 can a lterna t ively be i ncorpor ated w i th in one of the
- alternative or additional transducers can be employed for measurement of velocity or acceleration.
Abstract
An hydraulic linear actuator having a linearly driven piston (16) in which a mechanism (32) is incorporated within the actuator and coupled to the piston (16) to produce rotation of a member (34) proportional to piston displacement, and a rotational position sensor (42) is incorporated within the actuator to sense the rotation of said member (34).
Description
HYDRAϋLIC LINEAR ACTUATOR
This invention relates to an hydraulic linear actuator.
Conventional hydraulic linear actuators, when used in closed loop positional servo control systems, require the use of a positional transducer which is incorporated as a separate device in the mechanism being controlled. The positional transducer provides a feedback which is measured to enable adjustment of the actuator, more especially to adjust the stroke of the piston.
In general, therefore, a positional transducer, must be specifically matched to the particular stroke of the actuator, which is in turn a function of its specific application. Disadvantageously, therefore, even for similar applications differing combinations of transducer and actuator are required. A further disadvantage arises because positional transducers are generally not robust in comparison with the actuator, and are thereby liable to damage.
It is an object of this invention to provide an hydraulic linear actuator capable of minimising or overcoming the above-described disadvantages.
According to the invention, there is provided an hydraulic linear actuator having a linearly driven piston, wherein a mechanism is incorporated within the actuator and coupled to the piston to produce rotation of a member proportional to
incorporated within the actuator to sense the rotation of said member.
Thus , in acc ordance wi th the invent io n , the rotary transducer, which may be of a variety of types such as an opti cal sens or , electr ic ( potentio etr ic ) sen s or or electromagnetic ( inductive) sensor, is provided within the actuator. In addition, the transducer is inherently matched to the piston stroke, thus f aci litating the use of the identical transducer for differing actuator strokes .
In a practical arrangement, the actuator- piston is held against rotation and carr ies a nut formation within which engages a screwthreaded rod which constitutes the said member .
A tens ioned rod may pass through the piston to hold it against rotation. Alternatively, a non-circular piston may move in a matching non-circular bore.
The rotary transducer ( rotational position sensor) may be located at one end of the actuator in an enclosure sealed from the hydraulic chambers of the actuator and into which the rotationally driven rod extends from the ad jacent chamber. However, it is alternatively possible to locate the rotary transducer (if of an appropriate type) in one of the hydraulic fluid chambers. This simplifies sealing require¬ ments, since the rotationally driven rod is not required to pass through a sealed bore into a separate enclosure.
The invention will now be described further, by way of example, with reference to the accompanying drawings, in
•• which:- Figure 1 is an end view"of the actuator;
5 Figure 2 is a longitudinal cross-section on the line 2-
2 of Figure 1; and
Figure 3 is a part longi tudinal cross-section on the line 3-3 of Figure 1.
Referring to the drawings, the hydraulic linear actuator has 10 a hous ing 10 sealed by end closures 12 and 14. W ithin the hous ing 10 is a piston 16 connected to a pi ston rod 18 which emerges th rough the end c lo su re 12. The pi ston 16 i s linearly displaceable along the housing 10 by the passage of oil to or from hydraulic chambers 20 , 22 on oppos ite s ides 1 5 of the piston 16. Port 24 (Figure 2) connects to the chamber 20 , and port 26 (F igure 3 ) connects through a pas sage 28 in the wall of the hous ing to the chamber 22. The piston 16 i s held against rotation by a tens ioned rod 30 f ixed between the end closures 12 and 14 and passing through said piston.
20 A mechanism is incorporated within the actuator to produce a rotation proportional to piston di splacement, thereby to enable a rotational position sensor also to be incorporated
^ within the actuator body. The mechan i sm compr ises a nut assembly 32 located in a bore in the piston rod 18. This
It
25 bore extends over a part of the length of the piston rod 18 to enable a screwthreaded rod 34, which is in screwthreaded engagement with the nut assembly 32, to extend therefrom out
■• fREX OMPI
of the piston rod bore, through the hydraulic chamber 20 and thence through bearings 36 in the end closure 14 to the exterior of the latter. Two bearings 36 support the rod 34 for rotation under the drive of the nut assembly 32 when the piston 16 is linearly displaced, but hold such rod agains t longitudinal movement.
On the exterior of the end closure 14 an end cap 38 dif ines an enclosure into which extends the end of the rotationally driven rod 34. An 0-ring 40 (Figure 3 ) seals the rod 34 in the bore in the end closure 14 between the bearings 36, thus isolating the end cap enclosure from the adjacent hydraulic chamber 20. Within the end cap enclosure is located a rotational positional sensor 42, which may be a transducer of any of a variety of convenient types such as those previously mentioned.
I n use , the li near di sp lacement of the p i s ton 16 i s proportionately converted into rotational di splacement of the screwthreaded rod 34 , the rotation of which is detected and measured by the transducer 42. Clearly, the rotation sensed is inherently matched to the stroke of the actuator, however the latter changes as a function of the specific application to which the actuator is put.
In addition , the transducer 42 is wholly enclosed and thereby protected within the body of the actuator, whi ch includes the end cap 38 rigidly fixed to the end closure 14. If desired, moreover, the rotational position transducer 42 can a lterna t ively be i ncorpor ated w i th in one of the
OMP P
hydraulic chambers 20, 22, thus dispensing with the requirements for the end cap and also for seal 40, since the rod 34 is no longer required to extend beyond its bearings to the exterior of the end closure 14.
In a modified version of the above embodiment, alternative or additional transducers can be employed for measurement of velocity or acceleration.
Claims
1. An hydraulic linear actuator having a linearly driven piston, characterised in that a mechanism ( 32 ) is incorpo¬ rated within the actuator and coupled to the piston (16 ) to produce rotation of a member ( 34) proportional to piston displacement, and a rotational position sensor ( 42 ) is incorporated within the actuator to sense the rotation of said member (34).
2. An hydraulic actuator as claimed in claim 1, characte- rised in that the piston ( 16) is held against rotation, and carries a nut formation (32) within which engages a screw¬ threaded rod ( 34) which constitutes the said member.
3. An hydraulic actuator as claimed in claim 2, characte¬ rised in that a tensioned rod ( 30) passes through the piston (16) to prevent rotation of the latter.
4. An hydraulic actuator as claimed in any preceding claim, characterised in that the rotational position sensor ( 42 ) is located at one end of the actuator in an enclosure sealed from the hydraulic chambers ( 20 , 22 ) of the actuator and into which the said member ( 34) extends from the adjacent chamber.
5. An hydraulic actuator as claimed in any of claims 1 to 3 , wherein the rotational position sensor ( 42) is located in one of the hydraulic fluid chambers (20, 22) of the actuator.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8116323 | 1981-05-28 | ||
GB8116323810528 | 1981-05-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1982004293A1 true WO1982004293A1 (en) | 1982-12-09 |
Family
ID=10522104
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1982/000157 WO1982004293A1 (en) | 1981-05-28 | 1982-05-28 | Hydraulic linear actuator |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0080466A1 (en) |
WO (1) | WO1982004293A1 (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0126796A1 (en) * | 1983-05-30 | 1984-12-05 | Kowa Shoji, Ltd. | Positioning control and locking device for a fluid powered actuator |
US4509408A (en) * | 1982-04-20 | 1985-04-09 | Kowa Shoji, Ltd. | Fluid pressure actuator |
FR2583117A1 (en) * | 1985-06-07 | 1986-12-12 | Hemscheidt Maschf Hermann | DEVICE FOR THE DIGITAL DETERMINATION OF THE RUNNING OF THE PISTON OF A WALKING HYDRAULIC SUPPORTING JACK |
WO1990013747A1 (en) * | 1989-05-07 | 1990-11-15 | Hans Hartmann | Hydraulic drive |
US5350390A (en) * | 1992-03-25 | 1994-09-27 | Arieh Sher | Device for removal of intraluminal occlusions |
US5467684A (en) * | 1992-03-25 | 1995-11-21 | Sher; Arieh | Rotary piston driving mechanism |
EP1054164A3 (en) * | 1999-05-19 | 2002-03-13 | Lucas Industries Limited | Actuator |
EP1384021A2 (en) * | 2001-03-27 | 2004-01-28 | Aprion Digital Ltd. | Vacuum distribution controller apparatus |
GB2405933A (en) * | 2003-09-12 | 2005-03-16 | Page Aerospace Ltd | Measuring movement of a hydraulic actuator |
DE102013220298A1 (en) * | 2013-10-08 | 2015-04-09 | Danfoss Power Solutions Gmbh & Co. Ohg | Device for detecting the servo piston position in a hydraulic machine |
US9526846B2 (en) | 2009-08-19 | 2016-12-27 | Safety Syringes, Inc. | Patient-contact activated needle stick safety device |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1181958B (en) * | 1960-10-22 | 1964-11-19 | Garbe Lahmeyer & Co Ag | Device for indicating the position of pistons in working and control cylinders |
DE1299432B (en) * | 1967-12-30 | 1969-07-17 | Maurer Ludwig | Method and device for travel measurement in a piston-cylinder unit acted upon by a pressure medium |
GB1224238A (en) * | 1967-09-15 | 1971-03-03 | Bergwerksverband Gmbh | Hydraulic jack arrangement in particular for use in mining operations |
FR2216467A1 (en) * | 1973-10-09 | 1974-08-30 | Poclain Sa | |
GB2076469A (en) * | 1980-04-29 | 1981-12-02 | Secretary Industry Brit | Fluid actuated ram with position measuring device |
WO1981003679A1 (en) * | 1980-06-16 | 1981-12-24 | W Foxwell | Power cylinder with internally mounted position indicator |
-
1982
- 1982-05-28 EP EP19820901526 patent/EP0080466A1/en not_active Withdrawn
- 1982-05-28 WO PCT/GB1982/000157 patent/WO1982004293A1/en unknown
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1181958B (en) * | 1960-10-22 | 1964-11-19 | Garbe Lahmeyer & Co Ag | Device for indicating the position of pistons in working and control cylinders |
GB1224238A (en) * | 1967-09-15 | 1971-03-03 | Bergwerksverband Gmbh | Hydraulic jack arrangement in particular for use in mining operations |
DE1299432B (en) * | 1967-12-30 | 1969-07-17 | Maurer Ludwig | Method and device for travel measurement in a piston-cylinder unit acted upon by a pressure medium |
FR2216467A1 (en) * | 1973-10-09 | 1974-08-30 | Poclain Sa | |
GB2076469A (en) * | 1980-04-29 | 1981-12-02 | Secretary Industry Brit | Fluid actuated ram with position measuring device |
WO1981003679A1 (en) * | 1980-06-16 | 1981-12-24 | W Foxwell | Power cylinder with internally mounted position indicator |
Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4509408A (en) * | 1982-04-20 | 1985-04-09 | Kowa Shoji, Ltd. | Fluid pressure actuator |
EP0126796A1 (en) * | 1983-05-30 | 1984-12-05 | Kowa Shoji, Ltd. | Positioning control and locking device for a fluid powered actuator |
FR2583117A1 (en) * | 1985-06-07 | 1986-12-12 | Hemscheidt Maschf Hermann | DEVICE FOR THE DIGITAL DETERMINATION OF THE RUNNING OF THE PISTON OF A WALKING HYDRAULIC SUPPORTING JACK |
WO1990013747A1 (en) * | 1989-05-07 | 1990-11-15 | Hans Hartmann | Hydraulic drive |
US5350390A (en) * | 1992-03-25 | 1994-09-27 | Arieh Sher | Device for removal of intraluminal occlusions |
US5467684A (en) * | 1992-03-25 | 1995-11-21 | Sher; Arieh | Rotary piston driving mechanism |
US5592866A (en) * | 1992-03-25 | 1997-01-14 | Sher; Arieh | Rotary piston driving mechanism |
US5806404A (en) * | 1992-03-25 | 1998-09-15 | Sher; Arieh | Rotary piston driving mechanism |
EP1054164A3 (en) * | 1999-05-19 | 2002-03-13 | Lucas Industries Limited | Actuator |
EP1384021A2 (en) * | 2001-03-27 | 2004-01-28 | Aprion Digital Ltd. | Vacuum distribution controller apparatus |
EP1384021A4 (en) * | 2001-03-27 | 2010-01-20 | Hewlett Packard Ind Printing | Vacuum distribution controller apparatus |
GB2405933A (en) * | 2003-09-12 | 2005-03-16 | Page Aerospace Ltd | Measuring movement of a hydraulic actuator |
US9526846B2 (en) | 2009-08-19 | 2016-12-27 | Safety Syringes, Inc. | Patient-contact activated needle stick safety device |
US10314985B2 (en) | 2009-08-19 | 2019-06-11 | Safety Syringes, Inc. | Patient-contact activated needle stick safety device |
US11400234B2 (en) | 2009-08-19 | 2022-08-02 | Safety Syringes, Inc. | Patient-contact activated needle stick safety device |
DE102013220298A1 (en) * | 2013-10-08 | 2015-04-09 | Danfoss Power Solutions Gmbh & Co. Ohg | Device for detecting the servo piston position in a hydraulic machine |
DE102013220298B4 (en) * | 2013-10-08 | 2019-01-17 | Danfoss Power Solutions Gmbh & Co. Ohg | Device for detecting the servo piston position in a hydraulic machine by means of a rotary sensor |
Also Published As
Publication number | Publication date |
---|---|
EP0080466A1 (en) | 1983-06-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO1982004293A1 (en) | Hydraulic linear actuator | |
US4736674A (en) | Abutment arrangement and position detector for a piston and cylinder actuator | |
AU1446900A (en) | Precision sensor for a hydraulic cylinder | |
US4669365A (en) | Slide-like drive means | |
EP2182222B1 (en) | Adjustable cylinder position sensor | |
CN1821587B (en) | Air pressure cylinder for positioning control | |
CA2201610A1 (en) | Metering gauge trumpet valve | |
JP2690886B2 (en) | Continuous valve stroke monitoring device | |
SE9203037D0 (en) | TORSION DEVICE | |
SE8306980D0 (en) | PRESSURE DRIVE WORKING CYLINDER | |
US5002441A (en) | Drilling unit | |
BR0215188A (en) | Pressure compensation / control for fail-safe gate valve | |
US3550631A (en) | Valve plunger drive mechanism | |
CA2068962C (en) | Missile control fin actuator system | |
ATE153419T1 (en) | FLUID ACTUATED DRIVE | |
US4394787A (en) | Hydraulic door closer construction | |
ES525787A0 (en) | DOUBLE ACTING WORKING CYLINDER, ACTUATED BY A PRESSURE MEDIA | |
GB2282641A (en) | Volume-compensated low-wear reciprocating seal assemblies | |
GB2076469A (en) | Fluid actuated ram with position measuring device | |
EP0267656B1 (en) | Device for recording the cylinder capacity of hydraulic motors having radial variable cylinder-piston unit | |
AU5110590A (en) | A method and arrangement for positioning accurately the pistons of load-carrying pressure-fluid cylinder devices | |
US5488278A (en) | Load limit system for mechanical linear actuator | |
US5022499A (en) | Axially slit pressure cylinder with brake means | |
US4204553A (en) | Valves | |
SE9400270D0 (en) | Hydraulic torque impulse generator |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Designated state(s): JP US |
|
AL | Designated countries for regional patents |
Designated state(s): AT BE CH DE FR GB LU NL SE |