EP0092315A2 - Hydraulische Pumpensteuerung - Google Patents

Hydraulische Pumpensteuerung Download PDF

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Publication number
EP0092315A2
EP0092315A2 EP83301402A EP83301402A EP0092315A2 EP 0092315 A2 EP0092315 A2 EP 0092315A2 EP 83301402 A EP83301402 A EP 83301402A EP 83301402 A EP83301402 A EP 83301402A EP 0092315 A2 EP0092315 A2 EP 0092315A2
Authority
EP
European Patent Office
Prior art keywords
load
pressure
valve
connection
port
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Withdrawn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
EP83301402A
Other languages
English (en)
French (fr)
Other versions
EP0092315A3 (de
Inventor
Alastair John Young
Adrian John Chettle
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.)
Automotive Products PLC
Original Assignee
Automotive Products 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 Automotive Products PLC filed Critical Automotive Products PLC
Publication of EP0092315A2 publication Critical patent/EP0092315A2/de
Publication of EP0092315A3 publication Critical patent/EP0092315A3/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Withdrawn legal-status Critical Current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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F15B2211/20584—Combinations of pumps with high and low capacity
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/25—Pressure control functions
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow control characterised by the type of actuation actuated by fluid pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/455—Control of flow in the feed line, i.e. meter-in control
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/76—Control of force or torque of the output member

Definitions

  • This invention relates to fluid pressure supply systems for supplying hydraulic fluid under pressure to loads such as for example power steering or automatic transmission systems for motor vehicles.
  • Dual output pumps or twin pumps have been proposed in which the first pump operates continuously and the second is brought on load as required by flow sensitive control means.
  • Such.control means include a flow restrictor upstream of the load to sense the higher flow rate and thus the requirement for the second pump.
  • a disadvantage with this arrangement is that the restrictor inevitably has a pressure drop across it, which places an additional energy consuming load on the pump.
  • An object of the invention is to provide a fluid pressure supply system which provides a high output when required but has a low overall energy consumption.
  • a fluid pressure supply system comprising main and auxiliary positive displacement fluid pressure sources, a connection to a load from the main source, a pressure relief valve arranged to limit pressure at the load connection to a normal working pressure and a drain connection from the auxiliary source whereby it can pump to drain at low pressure, wherein flow cut off means in the drain connection is controlled by the pressure at the load connection to close the drain connection when this pressure falls below normal working pressure and there is a controlled connection from the auxiliary source to the load connection to permit flow from the auxiliary source to the load connection when the drain connection is closed.
  • the system incorporates a non-return valve in the controlled connection from the auxiliary source to the load connection whereby fluid flows from the auxiliary source to the load connection when the auxiliary source pressure exceeds the load connection pressure but reverse flow is prevented.
  • the flow cut off means and the controlled connection from the auxiliary source to the load connection are incorporated in a common valve which closes the flow cut off means and opens the controlled connection from the auxiliary source to the load connection in a single action.
  • the pressure relief valve is a spool valve with inlet and drain connections and a spool controlled by spring loading and by pressure in the load connection to open the drain connection when normal working pressure is reached, the spool valve also having an inlet from the auxiliary source connected to drain through the spool valve when load pressure is below normal working pressure but disconnected from drain by movement of the spool as normal working pressure is reached.
  • the valve spool may also incorporate the controlled connection from the auxiliary source to the load connection, control being by movement of the spool in response to load pressure.
  • control valve means of a dual output pump for supplying fluid under pressure to a load and including relief valve means to limit the maximum supply pressure of fluid to said load, a first pump outlet for direct connection to said load and a second pump outlet for connection to said load through load valve means, said relief valve means comprising a spool valve having an inlet port for connection to the load supply, a drain pore and a valve spool movable against return spring means in response to increasing pressure at said inlet port to interconnect the inlet and drain ports above a predetermined supply pressure, said load valve means having an inlet port for connection to the second pump outlet, an outlet port for connection to the load and a drain port, the load valve means being responsive to the position of the relief valve spool to interconnect its inlet and outlet ports below a predetermined supply pressure and to interconnect its inlet and reservoir ports above that pressure.
  • said spool valve includes a signal port and a second drain port, the valve spool being movable to interconnect the inlet port and signal port below the predetermined supply pressure and to interconnect the signal and second drain ports above that pressure, the load valve means being responsive to fluid pressure at said signal port.
  • said relief valve means and said load valve means comprise a spool valve having a common valve spool, said supply port and outlet port being common and the valve spool having an internal passage from the inlet to the outlet ports, a non-return valve in the passage preventing fluid flow from the outlet to the inlet ports only.
  • FIG. 1 With reference to figure 1 there is shown a fluid reservoir 11 from which a pump assembly 12 supplies fluid under pressure to a fluid load 13.
  • the pump assembly 12 comprises a main positive displacement pump or pressure source P1 and auxiliary positive displacement pump or pressure source P2 intended to be brought on-load as required.
  • the pump assembly may be a single pump with two separate working chambers or may comprise two independent pumps driven together from a common drive. A wide variety of conventional types of pump are suitable.
  • the output from main pump P1 is supplied through load connection 10 to a load 13.
  • the load may be an automatic transmission which has a high demand for fluid while starting up or shifting gear but a low demand at most other times.
  • Another load which can be supplied is a power steering pump which has high fluid pressure demand for manoeuvring but lower demand at other times.
  • a pressure relief valve 14 limits maximum system pressure and a load valve 15 diverts the output of auxiliary pump P2 between drain and the load as will be described.
  • the relief valve 14 comprises a spool 16 returned to one end of its bore 17 by a spring 18.
  • An inlet port 19 is connected to the load connection 10 and a drain port 21 is provided to the reservoir 11.
  • inlet 19 is connected through bore 9 to the end of the spool remote from the spring so that inlet pressure acts on the spool in opposition to the spring load.
  • Increasing fluid pressure in the relief valve urges the spool 16 to move against the force of spring 18 and thus causes the inlet and drain ports to become interconnected as a land 8 clears drain port 21. This drain port opens when normal working pressure is reached.
  • a signal port 22 of the relief valve is connected to the inlet port 19. Up to a predetermined pressure somewhat less than relief pressure this signal port is connected to inlet port 19 through the valve, but land 7 closes off this port 22 at this predetermined pressure. As working pressure is reached, land 22 again clears signal port 22 but then connects it to a further drain port 23.
  • the load valve 15 comprises a spool 25 urged to one end of its bore 26 by a return spring 27.
  • a signal port 28 connected to the port 22 opens onto the end of the spool 25 remote from spring 27.
  • an inlet port 29 from auxiliary pump P2 is connected to a drain port 31 through a space between valve lands 5 and 6.
  • a passage through the spool 26 from land 5 includes a non-return valve 32 and provides communication between the inlet port 29 and an outlet port 33 connected to the load 13 in the rest position and in the position shown.
  • Pump P2 is off-load in that it is pumping fluid against very little resistance through inlet port 29 and drain port 31. Direct communication from inlet port 29 to outlet port 33 is closed by the land 5 and reverse flow through the passage in the spool 25 is prevented by the non-return valve 32.
  • Pump P1 supplies fluid direct to the load, and on starting up the system pressure rises in the load, the load connection and the relief valve.
  • Spool 16 of relief valve begins to move against its return spring as pressure builds up. This pressure also acts on the load valve spool 25 via inlet port 19 and signal ports 22 and 28.
  • the spool 25 moves against the force of spring 27 so that land 5 closes the drain port 31 from inlet port 29.
  • the inlet port 29 and outlet port 33 are interconnected through the non-return valve 32 so that fluid from the auxiliary pump is supplied through this valve to the load connection 10. Further movement of the spool 25 connects the ports 29 and 33 directly bringing the pump P2 fully on-load to supplement the output of pump P1 to fill the load at relatively low pressure.
  • the non-return valve connection ensures that during the transition between connection of pump P2 to drain and bringing it on-load, a flow path is always available for fluid from the pump P2.
  • the load valve spool 25 then returns under the influence of spring 27 to its rest position to reconnect the inlet port 29 to drain port 31 so that the pump P2 comes off-load. Flow from port 33 to port 29 is prevented, as before, by the non-return valve 32 and the land 5 of the spool 25. This off-loading of pump P2 occurs at a pressure very slightly below normal working pressure. When normal working pressure is reached in the load connection 11 by means of further fluid from pump P1, land 8 opens port 21 to prevent normal working pressure from being exceeded.
  • a main pump of low capacity can be used so that a relatively small volume of fluid is pumped up to working pressure and discharged through the relief valve.
  • the auxiliary pump is available to come on load for periods of high demand but is normally pumping at very low pressure and so consuming very little energy. In this way considerable energy savings are effected.
  • the pressure at which the auxiliary pump is brought on-load and the capacities of the two pumps can be determined by the particular duty required. Equal pump capacities has the advantage of simplifying pump design.
  • Figure 2 shows an alternative embodiment, using the same relief valve as in figure 1, but a modified load valve.
  • the load valve 35 has an inlet port 36, outlet port 37, signal port 38 and drain port 39 connected as previously described.
  • a light spring 41 biases a spool 42 to one end of its bore 43 (as shown) in which position the inlet port 36 and outlet port 37 are interconnected, the drain port 39 being closed by a land 47 of the spool.
  • a further land 48 controls communication with the outlet port 37.
  • a non-return valve 44 is again provided in a passage within the spool.
  • Fluid pressure at the outlet port 37 acts through a damping restriction 45 on one end of the spool 35 in opposition to the light spring 41 and the signal port 38 is connected to the other end of the spool.
  • the auxiliary pump P2 is consequently brought off-load and idles. Further pressure increase from main pump P1 is then limited by the relief valve 14.
  • the passage in the spool is provided for the same reason as the corresponding passage in figure 1.
  • spool 42 is moving there is a transitional stage at which land 48 is just closing off connection from inlet 36 to outlet 37 and the drain connection to port 39 is only just opening.
  • the passage in the spool allows an alternative path for fluid from pump P2.
  • the non-return valve 44 prevents reverse flow through the spool to drain.
  • the auxiliary pump P2 is thus brought on-load until the load demand is satisfied, at which stage the pump is again connected to drain as described above.
  • FIG. 3 shows a simplified system with a spool valve 51 in which the functions of relief valve and load valve are combined.
  • the valve 47 is similar in many respects to the load valve of figure 2.
  • a spool 52 slides within the bore of a valve body and is urged to one end of the bore by a control spring 53.
  • the common pressure at inlet 56 and outlet 57 is connected through a non-return valve 58 and a passage 59 in the spool to the end of the spool opposite relief valve spring 53 to provide a pressure force in opposition to the spring force.
  • the valve also incorporates drain ports 61 and 62 which in the rest position of the valve are closed off by lands 54 and 63.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Power Steering Mechanism (AREA)
  • Control Of Transmission Device (AREA)
EP83301402A 1982-04-15 1983-03-15 Hydraulische Pumpensteuerung Withdrawn EP0092315A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB08210999A GB2120418A (en) 1982-04-15 1982-04-15 Hydraulic pump control
GB8210999 1982-04-15

Publications (2)

Publication Number Publication Date
EP0092315A2 true EP0092315A2 (de) 1983-10-26
EP0092315A3 EP0092315A3 (de) 1984-07-18

Family

ID=10529718

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83301402A Withdrawn EP0092315A3 (de) 1982-04-15 1983-03-15 Hydraulische Pumpensteuerung

Country Status (3)

Country Link
EP (1) EP0092315A3 (de)
JP (1) JPS58193908A (de)
GB (1) GB2120418A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2245659A (en) * 1988-07-16 1992-01-08 Hiroshi Sato Fluid pressure supplying apparatus
FR2705657A1 (fr) * 1993-05-25 1994-12-02 Linde Ag Chariot de manutention avec un moyen pour recueillir la charge et deux vérins de levage montés en parallèle.

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8400698D0 (en) * 1984-01-11 1984-02-15 Automotive Prod Plc Motor vehicle transmission

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2549897A (en) * 1945-10-18 1951-04-24 Bolinder Munktell Pressure operated valve means for hydrostatic power transmitting systems
DE1209431B (de) * 1961-05-04 1966-01-20 Garbe Lahmeyer & Co Ag Druckmittelkreislauf mit zwei Druckmittelerzeugern
US3250411A (en) * 1964-12-23 1966-05-10 Hough Co Frank Hydraulic control system for tractor loader
GB1263118A (en) * 1968-11-13 1972-02-09 Deere & Co A hydraulic control system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2549897A (en) * 1945-10-18 1951-04-24 Bolinder Munktell Pressure operated valve means for hydrostatic power transmitting systems
DE1209431B (de) * 1961-05-04 1966-01-20 Garbe Lahmeyer & Co Ag Druckmittelkreislauf mit zwei Druckmittelerzeugern
US3250411A (en) * 1964-12-23 1966-05-10 Hough Co Frank Hydraulic control system for tractor loader
GB1263118A (en) * 1968-11-13 1972-02-09 Deere & Co A hydraulic control system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2245659A (en) * 1988-07-16 1992-01-08 Hiroshi Sato Fluid pressure supplying apparatus
FR2705657A1 (fr) * 1993-05-25 1994-12-02 Linde Ag Chariot de manutention avec un moyen pour recueillir la charge et deux vérins de levage montés en parallèle.
GB2279061A (en) * 1993-05-25 1994-12-21 Linde Ag Hydraulic lifting arrangement

Also Published As

Publication number Publication date
EP0092315A3 (de) 1984-07-18
JPS58193908A (ja) 1983-11-11
GB2120418A (en) 1983-11-30

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Effective date: 19850319

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Inventor name: YOUNG, ALASTAIR JOHN

Inventor name: CHETTLE, ADRIAN JOHN