EP0089652B1 - Power transmission - Google Patents

Power transmission Download PDF

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Publication number
EP0089652B1
EP0089652B1 EP83102729A EP83102729A EP0089652B1 EP 0089652 B1 EP0089652 B1 EP 0089652B1 EP 83102729 A EP83102729 A EP 83102729A EP 83102729 A EP83102729 A EP 83102729A EP 0089652 B1 EP0089652 B1 EP 0089652B1
Authority
EP
European Patent Office
Prior art keywords
meter
actuator
valve
pressure
valve means
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
Application number
EP83102729A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0089652A3 (en
EP0089652A2 (en
Inventor
Henry Delano Taylor
Vinod Kumar Nanda
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.)
Vickers Inc
Original Assignee
Vickers Inc
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 Vickers Inc filed Critical Vickers Inc
Publication of EP0089652A2 publication Critical patent/EP0089652A2/en
Publication of EP0089652A3 publication Critical patent/EP0089652A3/en
Application granted granted Critical
Publication of EP0089652B1 publication Critical patent/EP0089652B1/en
Expired 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors

Definitions

  • This invention relates to power transmission in hydraulic systems that are found, for example, on mobile equipment such as excavators and cranes.
  • the valve system disclosed in the aforementioned patent comprises an independent pilot operated meter-in element; a pair of load drop check valves; a pair of independently operated normally closed meter-out elements; a pair of load pressure responsive valves; and a pair of anti-cavitation valves.
  • the meter-in element functions to direct fluid flow to one or the other of the actuator ports.
  • the normally closed meter-out elements are associated with each of the actuator ports for controlling fluid flow from the port opposite to the actuator port to which the meter-in element is directing fluid.
  • the meter-out elements function as variable orifices metering fluid between the appropriate actuator port and a low pressure zone such as a reservoir tank.
  • Each of the meter-out elements has associated therewith the load pressure responsive valves which act on the meter-out elements in response to load pressure to enable the meter-out elements to also provide pressure relief protection.
  • the anti-cavitation valves are associated with each of the actuator ports and are adapted to open the appropriate port to tank.
  • the valve system is directly mounted on the actuator port manifold and is supplied by one full flow high pressure line, a pair of pilot pressure lines, and a load sensing line.
  • the operation of the valve system is controlled through the pilot lines from a manually operated hydraulic remote control valve.
  • the meter-in element assumes a centered or neutral position with the check valves, the meter-out elements, the pressure responsive valves, and the anti-cavitation valves, all in closed position.
  • the valve system hydraulically locks the load in position. Fluid flow from the actuator is blocked thereby preventing uncontrolled lowering of an overhauling load in the event of a rupture of any of the connecting hydraulic lines.
  • the pump output is made to match that which is required by the load. In contrast, in a non-load sensing system, the pump output may exceed that required by the load with the excess power being dissipated as heat.
  • valve system Under certain conditions, it may not be possible or desirable to mount the valve system directly on the actuator. Such conditions may exist due to space limitations on the actuator or wherein it is desirable to limit the number of supply and pilot lines, such as to the topmost section of a telescoping boom or when a brake, such as in a winch- type application, is used for counterbalancing the load. Under these conditions, the valve system is mounted on the equipment remote from the actuator with a pair of lines running to the actuator port manifold.
  • valve system of the aforementioned type which is operable in a counterbalance mode or with the use of external counterbalance valves or brakes with improved stability.
  • the meter-in element of the above described valve system is provided with a small feedback or load piston to establish a steady-state relationship between the metered flow and the outlet pressure of the valve system.
  • the controlled pressure established by this steady-state relationship is used to control external counterbalance valves or to provide for the controlled release of a brake if it is desired to control an overhauling load by braking rather than hydraulic metering.
  • the present invention also provides for operating one of the meter-out elements of the valve system as a counterbalance valve when it is desirable to mount the valve system directly to the actuator port manifold.
  • the hydraulic system embodying the .invention comprises an actuator 20, herein shown as a linear hydraulic cylinder, a rod end 20a, a piston end 20b and output shaft 21 extending from the rod end that is moved in opposite directions by hydraulic fluid supplied from a variable displacement pump system 22 which has load sensing control in accordance with conventional construction.
  • the hydraulic system further includes a manually operated controller, not shown, that directs a pilot pressure to a valve system 24 for controlling the direction of movement of the actuator, as presently described.
  • Fluid from the pump 22 is directed to the line 25 and line 26 to a meter-in valve 27 that functions to direct and control the flow of hydraulic fluid to one or the other end 20a or 20b of the actuator 20.
  • the meter-in valve 27 is pilot pressure controlled through pilot lines 28, 29 and lines 30, 31 which lead to the opposed ends of valve 27.
  • hydraulicfluid passes through a motor line 32, connected with the rod end 20a, or a motor line 33 connected with the piston end 20b of the actuator 20.
  • motor lines 32 and 33 are connected to low pressure through restrictors, not shown.
  • the hydraulic system further includes a meter-out valve 34 associated with the rod end 20a of the actuator and connecting line 32 to a tank line 36 for controlling the flow offluid from the rod end 20a of the actuator.
  • the meter-out valve 34 has two pistons 34a, 34b and spring means 34c, the former tending to open the valve 34 when there is pilot pressure in line 28, the latter tending to close the valve 34.
  • the hydraulic system further includes spring-loaded poppet valves 37, 38 in the lines 32, 33 and spring-loaded anti-cavitation valves 39, 40 shown in Fig. 2-5, which are adapted to open the lines 32, 33 to the tank passage 36.
  • the system also includes a back pressure valve 41 to keep the return ortank line 36 filled.
  • Acharge pump relief valve 42 is provided to take excess flow above the inlet requirements of the pump 22 and apply it to the back pressure valve 41 to augment the fluid in the tank line 36 available to the actuator, when an overrunning or a lower load tends to drive the actuator down. Therefore, back pressure valve 41 functionsto minimize cavitation.
  • Meter-in valve 27 comprises a bore in which a spool is positioned and in the absence of pilot pressure maintained in a neutral position by springs.
  • the spool normally blocks the flow from the presure passage 26 to the motor lines or passages 32, 33.
  • pilot pressure is applied to either passage 30 or 31, the meter-in spool is moved in the direction of the pressure until a force balance exists among the pilot pressure, the spring load and the flow forces.
  • the direction of movement determines which of the passages or motor lines 32, 33 is provided with fluid under pressure from passage 26.
  • Each valve system 24 includes a line 43 extending to a shuttle valve 44 that receives load pressure from an adjacent actuator through line 45.
  • Shuttle valve 44 senses which of the pressures is greater and shifts to apply the higher pressure to pump 22.
  • each valve system in succession incorporates a shuttle valve46which compares the load pressure in lines 32 and 33 and signals the higher of the two pressures to shuttle valve 46 which is then compared with the load pressure of an adjacent valve system. The higher pressure is transmitted to the adjacent valve system in succession and finally the highest load pressure is applied to pump 22.
  • the above described circuit is similar to that shown and described in the aforementioned United States Patent No. 4,201,052 which is incorporated herein by reference.
  • the single meter-in valve 27 may be replaced by two meter-in valves.
  • a single side (here the left side) of meter-in valve 27 is provided with a load piston 47 which is connected by line 48 so that it senses the motor line or outlet pressure which may drive an overhauling load, f.i. is directed to the rod end 20a of the actuator and provides a pressure on the meter-in valve 27 opposing the pilot pressure (here at 31) which is tending to open the meter-in valve 27 in a direction to supply fluid to the rod end 20a of the actuator.
  • a conventional counterbalance valve 49 is connected in a line 50 between piston end 20b (line 33) and tank line 36. Pressure from line 32 is applied to the counterbalance valve 49 through a line 51 to tend to open the counterbalance valve.
  • the counterbalance valve 49 has pistons 49a, 49b and a spring means 49c, the latter acting to close the valve 49.
  • the movable element of the counterbalance valve 49 takes a position to throttle the flow in line 50 to a greater or lesser extent.
  • line 33 supplies fluid to piston end 20b through a check valve 38a, which can be constructed similar to spring-loaded poppet valve 37.
  • the counterbalance valve 49 is interposed between line 33 and piston end 20b and a second meter-out valve 52 is provided between line 33 and tank line 36 in series with the counter-balance valve 49.
  • Meter-out valve 52 has a piston 52a, which is connected to pilot pressure line 28 through a line 53, a further piston 52b connected to line 33 and spring means 52c acting against the pistons 52a, 52b.
  • Meter-out valve 52 is normally open.
  • pilot pressure is provided in line 28 to open the meter-in valve 27 to direct fluid to the piston end 20b of actuator through line 33
  • the same pilot pressure closes meter-out valve 52 through line 53 and opens meter-out valve 34 to direct the fluid to the tank line 36.
  • pilot pressure is in line 29, fluid is applied to the rod end 20a of the actuator through line 32 and the system functions to stabilize an overhauling load condition in the same manner as the circuit in Fig. 1.
  • a circuit is shown wherein a hydraulic brake 55 is utilized to control a lowering or possible overhauling load and the actuator comprises a rotary hydraulic motor 56 having ports 56a and 56b.
  • the brake 55 has a piston 55a connected to the motor line 32 through line 51, and spring means 55b acting against the force of the piston 55a. Otherwise the circuit of Fig. 3 is the same as shown in Fig. 2.
  • meter-in and meter-out valves can be located at the actuator
  • the hydraulic system shown in Fig. 4 can be used. This is similar to that of Fig. 1 except that the counterbalance valve is omitted.
  • the system comprises the meter-in valve 27 and the normally closed meter-out valves 34 and 57 instead of a single meter-out valve pilot operated. Again the left hand end of meter-in valve 27 includes the piston 47 and line 48.
  • the spring chambers of the meter-out valves 34 and 57 are connected to the pilot pressure lines 29 and 28, resp.
  • the second meter-out valve 57 includes two pistons 57a, 57b and spring means 57c acting in opposed directions on the valve 57.
  • the piston 57a is connected to the motor line 32 through a line 58 which may include restrictors 59 and 60.
  • a line 61 including a further restrictor 62 branches off from the line 58 between the restrictors 59 and 60 and is connected to the pilot pressure line 28.
  • the second meter-out valve 57 is not opened by pilot pressure but by pressure of the main fluid in line 32 to the rod end 20a of the actuator applied through line 58.
  • the second meter-out valve 57 When meter-in valve 27 is operated to direct fluid to the rod end 20a of the actuator for lowering a load, the second meter-out valve 57 functions as a counter-balance valve. Initially it is opened, but if the load tends to overrun, the subsequent reduction in pressure in line 32 and line 58 tends to close meter-out valve 57.
  • anti-cavitation valves 39, 40 serve to supply additional fluid to the inlet of the actuator to prevent cavitation of the actuator.
  • pressure in line 32 decays through line 28.
  • the decay in presure is sensed at the second meter-out valve 57 through line 58 causing the second meter-out valve 57 to move in closing direction. Inertia of the load tends to force fluid out of the exhaust port of the actuator building up pressure in line 33.
  • the meter-out valve 57 moves in opening direction allowing the throttled exhaust fluid to join the fluid being pumped through line 36 to the anti- caviation valve 39 or 40 by the charge pump.
  • meter-in valve 27 When meter-in valve 27 is operated by pilot pressure in line 29 to direct fluid to the actuator 20, there will be a bleed flow through the restrictors 59 and 62 from the line 32 to line 28 which provides for an approximately four to one (4:1) build-up of pressure between the pressure in lines 32 and 58 (at 57a).
  • the second meter-out valve 57 has been set on a crack-open value at one-fourth the pressure in line 32.
  • the build-up of the pressure in line 32 will apply back pressure on anti-cavitation valve 39 preventing recirculation of fluid exhausting from the second meter-out valve 57 to the actuator. Such recirculation of fluid would result in undesirable overspeeding when the actuator is driven by an overhauling load.
  • Applying back pressure to the anti-cavitation valve 39 also prevents overheating of the actuator by allowing fresh fluid to be applied to the actuator by the pump.
  • Restrictors 59 and 62 in combination with restrictor 60 in line 58 also augment the load stability by providing additional damping to the system, i.e. slowing the speed of response of the second meter-out valve 57 when subjected to sudden pressure surges.
  • the valve system shown is similar to that shown in FIG. 4 wherein the meter-out valve 57 functions in a counterbalance mode as previously described.
  • the actuator comprises a rotary hydraulic motor 70 having ports 70a and 70b.
  • the second meter-out valve 57 is not opened by pilot pressure but by pressure of fluid applied to port 70a through line 32 and applied to the meter-out valve 57 through line 58.
  • restrictors 59, 62 placed in lines 58 and 61 prevent recirculation of fluid through the rotary motor which would result in an overspeeding condition of the motor or overheating of the motor.
  • the controlled outlet pressure out of the meter-in valve means is utilized to control either a counterbalance valve or a hydraulic brake for controlling the overhauling load.
  • the meter-out valve which normally controls the flow in the direction of the overhauling load can be omitted or operated as a normally open valve when an external counterbalance is used.
  • the meter-out valve must also be normally open when a brake is used and when a meter-out valve is used as a counterbalance valve is must be normally closed.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
EP83102729A 1982-03-22 1983-03-19 Power transmission Expired EP0089652B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US36060482A 1982-03-22 1982-03-22
US360604 1982-03-22

Publications (3)

Publication Number Publication Date
EP0089652A2 EP0089652A2 (en) 1983-09-28
EP0089652A3 EP0089652A3 (en) 1984-09-05
EP0089652B1 true EP0089652B1 (en) 1986-11-12

Family

ID=23418707

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83102729A Expired EP0089652B1 (en) 1982-03-22 1983-03-19 Power transmission

Country Status (6)

Country Link
EP (1) EP0089652B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS58174702A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
AU (1) AU566463B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CA (1) CA1202228A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE3367655D1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IN (1) IN159265B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4569272A (en) * 1982-03-22 1986-02-11 Vickers, Incorporated Power transmission
FR2586463B1 (fr) * 1985-08-26 1987-12-24 Leblon Hubert Valves cartouches a inserer multi-fonctions coaxiales et application a la commande d'un verin a double effet
JPS62171501A (ja) * 1986-01-25 1987-07-28 Tezuka Kosan Kk 復動シリンダ装置の流体圧回路
JP2746906B2 (ja) * 1988-04-01 1998-05-06 日立建機株式会社 油圧モータのブレーキ回路
US20060168955A1 (en) * 2005-02-03 2006-08-03 Schlumberger Technology Corporation Apparatus for hydraulically energizing down hole mechanical systems
JP7274887B2 (ja) * 2019-02-25 2023-05-17 ナブテスコ株式会社 制御装置及び建設機械

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4201052A (en) * 1979-03-26 1980-05-06 Sperry Rand Corporation Power transmission

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4407122A (en) * 1981-05-18 1983-10-04 Vickers, Incorporated Power transmission
FI72579C (fi) * 1981-11-12 1987-06-08 Vickers Inc Transmission.

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4201052A (en) * 1979-03-26 1980-05-06 Sperry Rand Corporation Power transmission

Also Published As

Publication number Publication date
EP0089652A3 (en) 1984-09-05
JPS58174702A (ja) 1983-10-13
DE3367655D1 (en) 1987-01-02
JPH0350125B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1991-07-31
AU566463B2 (en) 1987-10-22
EP0089652A2 (en) 1983-09-28
CA1202228A (en) 1986-03-25
IN159265B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1987-04-25
AU1240183A (en) 1983-09-29

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