US3596569A - Valve for a closed-loop hydraulic torque amplifier - Google Patents

Valve for a closed-loop hydraulic torque amplifier Download PDF

Info

Publication number
US3596569A
US3596569A US830076A US3596569DA US3596569A US 3596569 A US3596569 A US 3596569A US 830076 A US830076 A US 830076A US 3596569D A US3596569D A US 3596569DA US 3596569 A US3596569 A US 3596569A
Authority
US
United States
Prior art keywords
spool
valve
fluid
screw
hydraulic motor
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
Application number
US830076A
Other languages
English (en)
Inventor
Jerry D Wisbey
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.)
Milacron Inc
Original Assignee
Cincinnati Milling Machine Co
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 Cincinnati Milling Machine Co filed Critical Cincinnati Milling Machine Co
Application granted granted Critical
Publication of US3596569A publication Critical patent/US3596569A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
    • F03C1/00—Reciprocating-piston liquid engines
    • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/0678—Control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
    • F03C1/00—Reciprocating-piston liquid engines
    • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/061—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders
    • F03C1/0615—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders distributing members
    • F03C1/0618—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders distributing members cylindrical distribution members
    • 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/08—Servomotor systems incorporating electrically operated control means
    • 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
    • F15B9/00—Servomotors with follow-up action, e.g. obtained by feed-back control, i.e. in which the position of the actuated member conforms with that of the controlling member
    • F15B9/14—Servomotors with follow-up action, e.g. obtained by feed-back control, i.e. in which the position of the actuated member conforms with that of the controlling member with rotary servomotors

Definitions

  • ABSTRACT A torque amplifier for translating a number of digital input pulses into a proportional angular displacement of a rotary piston and cylinder hydraulic motor.
  • the input pulses drive an electric stepping motor which imparts a linear displacement to a valve.
  • the valve displacement functions to meter fluid into the valve and consequently to the hydraulic motor.
  • the hydraulic motor through a coupling means, transmits its rotation back to the valve.
  • the valve rotation first, operates to sequentially distribute the fluid from said valve to the hydraulic motor cylinders, and second, provides a mechanical feedback to displace the valve back to its neutral position.
  • a valve must meter a volume of fluid into the device that is proportional to a number of pulse inputs to the stepping motor. Second, this volume of fluid must be distributed to individual cylinders of a hydraulic motor. This requires two separate and independent valve devices.
  • the first valving device consists of a spool and sleeve arrangement.
  • SUMMARY Applicants device has an input means, a hydraulic valve and an output drive all on a common axis of rotation.
  • An electric stepping motor upon receiving a number of input pulses rotates its armature shaft through a precise angular displacement.
  • the armature shaft is coupled to a positioning nut axially fixed but free to rotate about the axis of rotation.
  • a positioning screw is contained in the nut and linearly displaces a distance proportional to the angular displacement of the armature shaft and positioning nut.
  • a valve spool coaxially connected to the positioning screw is contained within a stationary valve sleeve. The spool follows the displacement of the screw and meters a volume of fluid from a source through a first porting means into an annular spool groove.
  • pintle porting refers to a valving action generated by a rotating member or pintle inside a mating sleeve.
  • the rotation of the pintle controls the flow of fluid between the pintle and the sleeve.
  • the hydraulic action in the motor causes rotation of an output drive shaft which has one end coupled to the valve spool. As the drive shaft turns, the spool and screw rotate to simultaneously perform two operations. First, the valve spool operating as a pintle continues to distribute fluid to the cylinders of the motor.
  • the screw is rotating with respect to the positioning nut and operates to return the spool to its original axial position.
  • rotation of the motor provides timing for the sequential distribution of fluid to and from the motor cylinders.
  • Fluid is exhausted from the motor by the pintle porting arrangement and is returned through the spool and sleeve to exhaust lines of the source.
  • fluid is simultaneously ported into the valve and motor by a single hydraulic valving device displacing the motor an amount proportional to the number of input pulses.
  • FIG. 2 is a vertical sectional view taken along the line 2-2 of FIG. I.
  • FIG. 4 is a partial cross-sectional view of a valve spool.
  • FIG. 5 through 8 are vertical sectional views taken along lines 5-5, 6-6, 7-7 and 8-8 of FIG. 4.
  • FIg. 9 is a fragmentary view looking in the direction of arrow 9 in FIG. 4.
  • FIG. 1 is a longitudinal sectional view illustrating a preferred embodiment of the torque amplifier.
  • the input is provided by a stepping motor 20 which is a commercially available unit. Step increments and torque speed characteristics may be chosen as required by different applications.
  • the input shaft 22 on the output of the motor 20 is coupled to the positioning nut assembly 26 by a coupling 24. Coupling to the nut assembly 26 as opposed to a valve spool reflects the lowest possible inertia back to the input motor.
  • the coupling 24 is a flex-type coupling that allows a small radial misalignment between the coupled axes but maintains a true angular relation between the shaft 22 and the nut assembly 26.
  • the nut assembly 26 is free to rotate about an axis of rotation on thrust bearings 28 but is-restrained from any axial movement by the thrust plate 30 attached to the stationary sleeve 32.
  • a bowed snap ring 34 is used to absorb any end play in the bearing stack 28.
  • a positioning screw 36 is mounted coaxially in the nut assembly 26 and is free to rotate about the rotational axis common to the nut assembly 26 and the shaft 22.
  • the nut assembly 26 and the screw 36 combine to form a motion transformer. A rotation of the nut 26 or first member generating a relative angular displacement between the nut 26 and screw 36 will cause the screw 36 to axially translate.
  • valve spool 50 coaxially mounted about the axis of rotation.
  • Hg. 4 is a partial cross-sectional view of the valve spool 50.
  • Positioned at various axial points on the spool are small annular balancing grooves 52. These grooves 52 help maintain an equal radial pressure distribution along the length of the spool 50.
  • a larger annular groove 54 is placed in fluidic communication with a first pintle porting section by a first axial blind hole 56.
  • FIG. 5 is a cross section at this point.
  • an axial drain hole 58 passing through the spool. The drain hole 58 operates to relieve any hydraulic pressure differentials that may exist on the spool end faces.
  • FIG. 4 shows an annular drain groove 60 approximately centrally located along the axis of the spool 50 and connected with the hole 58 by a radial passage 61.
  • the purpose of the groove 60 is to help relieve any radial pressure differentials.
  • a second larger annular groove 62 is placed in fluidic communication'with a second pintle porting section by a second axial blind hole 64.
  • FIG. 6 is a cross section further clarifying the valve construction at this point.
  • the axial holes 56 and 64 are connected to first and second arcuate grooves 66 and 68 by first and second passages 70 and 72 as shown in FIG. 9.
  • FIG. 8 is a crosssection centrally taken in the pintle porting area and clarifies the pintle porting configuration.
  • FIG. 9 shows a first and second pair of arcual balancing grooves 74 and 76. These are necessary to balance the radial forces caused by the pressure differential across the two pintle porting section. For example, if the first groove 66 is used to supply fluid under pressure and the second groove 68 is used as an exhaust line, the pressure differential across the spool will generate a substantial radial force. This will tend to deflect or cock the spool 50 in its mating sleeve 32. To overcome this problem, the two pairs of arcual balancing grooves 74 and 76 are used.
  • FIG. 7 is a cross section taken through one of the grooves in each of the pair of grooves 74 and 76.
  • groove 74 is connected to A hole 56 by a first passage 78; and groove 76 is connected to hole 64 by a second passage 80.
  • the other of the grooves of the pairs of grooves 74 and 76 are connected to the holes 56 and 64 respectively.
  • any radial force produced by pressure in groove 66 will have an equal but opposite force generated in the first pair of grooves 74.
  • any radial force produced in groove 68 is offset by radial forces produced in the second pair of grooves 76.
  • the spool 50 is totally contained within a coaxially mounted stationary sleeve 32.
  • the sleeve contains several pairs of opposed internal ports defined by the radial openings 82. Each pair of ports is adjacent to a corresponding annular body groove 84 in the valve body 86.
  • the pairs of ports 82 and the lands 83 on the valve spool 50 provide the first valving action upon axial translation of said spool 50.
  • radial holes 88 also shown in FIG. 2, and circumferentially spaced to complete the pintle porting.
  • Each radial hole 88 is positioned to match a corresponding motor cylinder and is connected by a straight radial passage through the body 86.
  • a rotary piston and cylinder hydraulic motor 90 is coaxially positioned about one end of the spool and sleeve assembly.
  • An output shaft 92 of the motor 90 is coupled to one end of the spool 50 through a feed back coupling 94.
  • the coupling 94 allows an axial translation of the spool 50 with respect to the motor shaft 92, but it maintains an accurate angular relation between the two members. Any rotation of the output shaft 92 is imparted to the valve spool 50 and provides a driving force for the pintle porting.
  • FIG. 2 best illustrates this action. Assume, for example, that the hole 56 supplies fluid under pressure. This will cause a counterclockwise rotation of the motor shaft 92 and the spool 50.
  • FIG. 2 shows a hydraulic motor with an even number of pistons and cylinders. It is well known to those skilled in the art that such a device is operable but undesirable. An even number was chosen for ease of illustration.
  • the apparatus disclosed can be adapted to any number of pistons and cylinders as required by a particular hydraulic motor.
  • the stepping motor receives electrical input pulses from an external source. Each pulse represents a discrete linear displacement of a movable element coupled to the hydraulic motor output. For each input pulse received, the stepping motor 20 drives its output shaft 22 through a precise angular displacement. This results in an identical displacement of the positioning nut assembly 26 and a proportional axial translation of the screw 36 and the valve spool 50. Assume the stepping motor 20 is rotated in a counterclockwise direction as viewed from the left end of said motor. This results in an axial translation of the positioning screw 36 and the valve spool 50 towards the right.
  • the axial translation of the spool 50 generates a first and second pair of orifices at points 96 and 98 between the internal ports 82 of the valve sleeve 32 and the corresponding lands 83 on'the valve spool 50.
  • Fluid enters the motor through input port 100 passes through an annular body groove 84, and is metered through a first pair of orifices at point 96 into the annular groove 54.
  • the axial hole 56 ports the fluid to the pintle porting area 66, shown in FIG. 2, which distributes the fluid through the radial holes of the valve sleeve 32 and the body 86 into the corresponding motor cylinders.
  • the fluid pressure forces a piston identical to the piston 102 shown in FIG.
  • One end of the hydraulic motor shaft 92 is coupled to the valve spool 50.
  • the positioning screw 36 rotates.
  • the stepping motor 20 is still providing a constant angular velocity to the nut assembly 26.
  • the feedback from the motor shaft rotation will drive the screw 36 at the same angular velocity, and the screw 36 will maintain a constant axial position with respect to the nut assembly 26.
  • the input from the stepping motor 20 ceases.
  • the hydraulic motor will continue to rotate providing a feedback to the spool 50in the screw 36.
  • the rotation of the screw 36 in the stationary nut assembly 26 axially translates the screw 36 and the spool 50 back to their original positions closing the orifices at points 96 and 98.
  • An improved torque amplifier of the type comprised in part of a hydraulic motor being powered by fluid from a source and driven through an increment of motion in accordance with an angular displacement of an input shaft, wherein the improvement comprises:
  • a hydraulic valve comprised of a rotatable spool adapted inside a stationary member, said spool being coupled l. at one end to the input shaft and responding to the angular displacement by axially translating a distance proportional to a relative angular displacement between the input shaft and the spool, and
  • c. means fluidally connected to the metering means for providing a timely and direct distribution of fluid between the valve and the hydraulic motor in response to the spool rotation.
  • An improved torque amplifier of the type comprised in part of a rotary piston and cylinder hydraulic motor being powered by fluid from an external source and having a drive shaft rotated about an axis through an increment of motion in accordance with an angular displacement of an output shaft of an electric stepping motor responding to a number of electrical input pulses, wherein the improvement comprises:
  • a hydraulic valve comprised of a rotatable spool inside a stationary sleeve and coaxially mounted about the axis, said valve including 1. a first porting means operating upon an axial translation of the spool relative to the sleeve for metering fluid between the external source and the valve, and
  • a second porting means in fluidic communication with the first porting means and operating upon a spool rotation
  • a motion transformer comprising a first member connected to the output shaft and in mechanical communication with a second member connected to one end of the spool, said transformer producing an axial translation of the spool in response to a rotation of the output shaft generating a relative angular displacement between the members;
  • a threaded nut defining the first member and rotatably mounted about the axis, said nut rotating with the output shaft with no angular error but being restrained from having any axial movement
  • An improved torque amplifier of the type comprised in part of a rotary piston and cylinder hydraulic motor being powered by fluid from a source and having a drive shaft rotated about an axis through an increment of motion in accordance with an angular displacement of an output shaft of an electric stepping motor responding to a number of electrical input pulses, wherein the improvement comprises:
  • a threaded nut coupled to said output shaft and axially fixed about the axis to rotate through the angular displacement
  • a threaded screw rotatably mounted within the nut about the axis, said screw axially translating a distance proportional to a relative angular displacement between the screw and nut;
  • a cylindrical stationary sleeve coaxially mounted on the axis and including 1. a plurality of sets of radial openings, and 2. a plurality of holes;
  • a cylindrical spool rotatably mounted in the stationary sleeve and rigidly connected at one end to the threaded screw and including 1. a pair of annular grooves, upon the spool axially translating, one of the annular grooves receives fluid under pressure from the source through one of the sets of radial openings in the sleeve and the other of the annu-' lar grooves exhausts fluid to the source through another of the sets of radial openings,
  • one of the arcuate grooves supplies fluid under pressure to the hydraulic motor cylinders through a number of the radial holes in the sleeve, and the other of the arcuate grooves receives fluid from the hydraulic motor c.
  • means adapted between the nut and screw for removing cylinders through other of the radial holes, and
  • said hydraulic valve passages connecting one of the annular grooves with further comprises: one of the arcuate grooves, and the other of the passages connecting the other of the annular grooves with the other of the arcuate grooves; and means for coupling the other end of the spool to the output drive shaft of the hydraulic motor and transmitting the rotation of the motor to the spool and screw, said screw rotation being operative to decrease the relative angular displacement between the screw and nut and reverse the axial translation of the screw thereby interrupting the supply of fluid between the source and the annular grooves in the spool.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Analytical Chemistry (AREA)
  • Hydraulic Motors (AREA)
  • Reciprocating Pumps (AREA)
US830076A 1969-06-03 1969-06-03 Valve for a closed-loop hydraulic torque amplifier Expired - Lifetime US3596569A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US83007669A 1969-06-03 1969-06-03

Publications (1)

Publication Number Publication Date
US3596569A true US3596569A (en) 1971-08-03

Family

ID=25256256

Family Applications (1)

Application Number Title Priority Date Filing Date
US830076A Expired - Lifetime US3596569A (en) 1969-06-03 1969-06-03 Valve for a closed-loop hydraulic torque amplifier

Country Status (7)

Country Link
US (1) US3596569A (enrdf_load_stackoverflow)
JP (1) JPS4936885B1 (enrdf_load_stackoverflow)
DE (1) DE2026424C3 (enrdf_load_stackoverflow)
FR (1) FR2048993A5 (enrdf_load_stackoverflow)
GB (1) GB1303188A (enrdf_load_stackoverflow)
NL (1) NL7007795A (enrdf_load_stackoverflow)
SE (1) SE361918B (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4009643A (en) * 1975-02-26 1977-03-01 Heinz Thumm Hydraulic motor for rotating the bucket of an excavating machine
US4253380A (en) * 1978-09-05 1981-03-03 David P. McConnell Rotary manifold valve mechanism
US4286927A (en) * 1978-08-14 1981-09-01 Mcdonnell Douglas Corporation Hydraulic power transfer unit
US4429707A (en) 1978-08-14 1984-02-07 Mcdonnell Douglas Corporation Hydraulic power transfer unit
US4491057A (en) * 1982-08-03 1985-01-01 Anthony D. Morris Axial piston machine having double acting pistons and a rotary control valve
US4605359A (en) * 1984-02-28 1986-08-12 Nippondenso Co., Ltd. Radial plunger pump
US4805516A (en) * 1986-09-12 1989-02-21 Ckd Corporation Axial air motor
US20090294709A1 (en) * 2008-06-02 2009-12-03 Stretch Dale A Two step valve actuator
US20090293976A1 (en) * 2008-06-02 2009-12-03 Stretch Dale A Two position three way valve
US20090294710A1 (en) * 2008-06-02 2009-12-03 Stretch Dale A Hydraulic system
US20160169401A1 (en) * 2010-07-14 2016-06-16 Mac Valves, Inc. Stepper motor operated balanced flow control valve

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2229877A1 (en) * 1973-05-17 1974-12-13 Agiman Jacques Electro-hydraulic rotating servo-jack - controls high torque rotating movement through a small servo motor
DE4015101A1 (de) * 1990-05-11 1991-11-14 Eckehart Schulze Hydraulische antriebsvorrichtung

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US786652A (en) * 1902-03-13 1905-04-04 Standard Plunger Elevator Company Pilot-valve for hydraulic elevators.
US3131602A (en) * 1961-11-16 1964-05-05 Kingston Products Corp Steering torque amplifier
US3310284A (en) * 1964-08-20 1967-03-21 Fujitsu Ltd Hydraulic system rotary pilot valve
US3457836A (en) * 1967-05-29 1969-07-29 Superior Electric Co Digitally operated electrohydraulic power system
US3516333A (en) * 1967-04-07 1970-06-23 Pratt Precision Hydraulics Ltd Hydraulic torque amplifiers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US786652A (en) * 1902-03-13 1905-04-04 Standard Plunger Elevator Company Pilot-valve for hydraulic elevators.
US3131602A (en) * 1961-11-16 1964-05-05 Kingston Products Corp Steering torque amplifier
US3310284A (en) * 1964-08-20 1967-03-21 Fujitsu Ltd Hydraulic system rotary pilot valve
US3516333A (en) * 1967-04-07 1970-06-23 Pratt Precision Hydraulics Ltd Hydraulic torque amplifiers
US3457836A (en) * 1967-05-29 1969-07-29 Superior Electric Co Digitally operated electrohydraulic power system

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4009643A (en) * 1975-02-26 1977-03-01 Heinz Thumm Hydraulic motor for rotating the bucket of an excavating machine
US4286927A (en) * 1978-08-14 1981-09-01 Mcdonnell Douglas Corporation Hydraulic power transfer unit
US4429707A (en) 1978-08-14 1984-02-07 Mcdonnell Douglas Corporation Hydraulic power transfer unit
US4253380A (en) * 1978-09-05 1981-03-03 David P. McConnell Rotary manifold valve mechanism
US4491057A (en) * 1982-08-03 1985-01-01 Anthony D. Morris Axial piston machine having double acting pistons and a rotary control valve
US4605359A (en) * 1984-02-28 1986-08-12 Nippondenso Co., Ltd. Radial plunger pump
US4805516A (en) * 1986-09-12 1989-02-21 Ckd Corporation Axial air motor
US20090293971A1 (en) * 2008-06-02 2009-12-03 Stretch Dale A Valve having integrated pressure assist mechanism
US8235070B2 (en) 2008-06-02 2012-08-07 Eaton Corporation Two position three way valve
US20090294710A1 (en) * 2008-06-02 2009-12-03 Stretch Dale A Hydraulic system
US20090294709A1 (en) * 2008-06-02 2009-12-03 Stretch Dale A Two step valve actuator
US20100012204A1 (en) * 2008-06-02 2010-01-21 Stretch Dale A Valve manifold
US20100236651A1 (en) * 2008-06-02 2010-09-23 Stretch Dale A Valve damping system
WO2009149092A3 (en) * 2008-06-02 2010-10-07 Eaton Corporation Valve manifold
US20090293976A1 (en) * 2008-06-02 2009-12-03 Stretch Dale A Two position three way valve
US8302627B2 (en) 2008-06-02 2012-11-06 Eaton Corporation Hydraulic system
US8356630B2 (en) 2008-06-02 2013-01-22 Eaton Corporation Valve damping system
US8464754B2 (en) 2008-06-02 2013-06-18 Eaton Corporation Valve manifold
US8590570B2 (en) 2008-06-02 2013-11-26 Eaton Corporation Two step valve actuator
US8646481B2 (en) 2008-06-02 2014-02-11 Eaton Corporation Valve having integrated pressure assist mechanism
US9435438B2 (en) 2008-06-02 2016-09-06 Eaton Corporation Valve manifold
US20160169401A1 (en) * 2010-07-14 2016-06-16 Mac Valves, Inc. Stepper motor operated balanced flow control valve

Also Published As

Publication number Publication date
DE2026424C3 (de) 1973-10-25
DE2026424B2 (de) 1973-04-05
NL7007795A (enrdf_load_stackoverflow) 1970-12-07
FR2048993A5 (enrdf_load_stackoverflow) 1971-03-19
SE361918B (enrdf_load_stackoverflow) 1973-11-19
GB1303188A (enrdf_load_stackoverflow) 1973-01-17
JPS4936885B1 (enrdf_load_stackoverflow) 1974-10-04
DE2026424A1 (de) 1970-12-10

Similar Documents

Publication Publication Date Title
US3596569A (en) Valve for a closed-loop hydraulic torque amplifier
US6283721B1 (en) Production of hydrostatic axial piston machines by means of stepper motors
US4867000A (en) Linear motion power cylinder
US4639202A (en) Gerotor device with dual valving plates
US3457836A (en) Digitally operated electrohydraulic power system
US6470913B1 (en) Balanced rotary servovalve
US4759186A (en) Self-powered rotary actuator utilizing rotation-generated centrifugal head
US3185439A (en) Hydraulic motor control system
JPH02296001A (ja) 液圧制御装置
US3112902A (en) Rotary actuator
US3211182A (en) Servo valve with rotary first stage
US4308892A (en) Rotary valve
US4173303A (en) Hydraulic push drive for pusher centrifuges
US5390495A (en) Assembly of a hydraulic motor and of a brake and compactor applying same
US3892503A (en) Apparatus and method for multiple mode motor
US3131605A (en) Flat valve for hydraulic machine
EP0326581A1 (de) Durchflussmessgerät zum messen eines volumenstromes.
US3079899A (en) Feedback-type oil-hydraulic drive
GB2132948A (en) A hydraulic controller, especially for vehicle power, steering
US3662551A (en) Fluid pressure controlling
US3722371A (en) High ratio linkage mechanism
US4136602A (en) Hydraulic motor
US4700747A (en) Proportional hydraulic distributor
US4359866A (en) Rotatable controller system
US3502110A (en) Hydraulic encoder