US3439623A - Rotary pump for power steering systems - Google Patents

Rotary pump for power steering systems Download PDF

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Publication number
US3439623A
US3439623A US676426A US3439623DA US3439623A US 3439623 A US3439623 A US 3439623A US 676426 A US676426 A US 676426A US 3439623D A US3439623D A US 3439623DA US 3439623 A US3439623 A US 3439623A
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United States
Prior art keywords
flow
pump
cam ring
bypass
valve
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Expired - Lifetime
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US676426A
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English (en)
Inventor
Georg Dietrich
Georg Kehrer
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ZF Friedrichshafen AG
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ZF Friedrichshafen AG
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Publication date
Application filed by ZF Friedrichshafen AG filed Critical ZF Friedrichshafen AG
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Publication of US3439623A publication Critical patent/US3439623A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
    • F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F04C14/26—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels

Definitions

  • the disclosure relates to rotary vane pumps, particularly high pressure and high speed pumps for operating hydraulic motors of power booster systems.
  • the invention features a pump having special passages and flow guidance means for auxiliary flow to the inlet chambers so that as the speed increases there will be an increased pressure at the inlet chambers which is proportional to the speed to effect an increase in intake flow to the pump rotor. Accordingly, cavitation due to high pump speeds which causes incomplete filling of the inlet chambers and the rotor cells is avoided.
  • Full filling of the intake chambers is insured at extremely high speeds by an arrangement which increases intake to the pump chambers in proportion to the difference between the statics pressures actuated on the left and right side of a control valve piston, a function of pump speed within operating limits.
  • cavitation is the result of operating a pump above a critical speed such that insuflicient fluid flows into the intake chambers and the rotor is only partially filled. Such phenomenon also causes increased noise and is, of course, highly undesirable.
  • the present invention overcomes the drawbacks of the prior art without increasing the conduits or channels of the pump housing in size, an important aspect of the invention because of the compactness required for the components of modern automobile engines and vehicles.
  • the invention comprises the provision of a valve housing having a vane type rotor and a cam ring, i.e., a stator, together with check plates or sealing plates therein and a bypass valve whereby outlet pressure actuates the valve in order to provide a regulated amount of fluid to bypass from the outlet chambers to the inlet chambers to increase flow to the suction chambers, with increased pump speed,
  • a valve housing having a vane type rotor and a cam ring, i.e., a stator, together with check plates or sealing plates therein and a bypass valve whereby outlet pressure actuates the valve in order to provide a regulated amount of fluid to bypass from the outlet chambers to the inlet chambers to increase flow to the suction chambers, with increased pump speed
  • the arrangement just described is generally conventional, and heretofore known, as disclosed in prior art.
  • the instant invention provides pumping etiiciency by improving the conventional construction to the extent of furnishing a specially shaped bypass channel for the bypass of fluid from
  • bypass channel is a noncircular channel having flow characteristics of a channel having a cross flow contour, i.e., the cross section, of an equilateral triangle which contour would be the ideal channel but which would be very difficult to machine into the housing of the pump.
  • a cross flow contour i.e., the cross section
  • the bypass channel By arranging such an approximately triangular bypass channel as the outlet port of the bypass valve so as to direct flow from an apex, or an approximate apex, of the channel towards a flow director, there is a split or divided flow around the cam ring and into the intake chambers. Such flow going in both directions uniformly fills the chambers from a point at which the flow divider is located.
  • a channel shaped as described is superior to a conventional circular channel since a circular channel serving as a valve port cannot control flow as a constant in proportion to the differential pressure which actuates the valve, as later explained.
  • a particular constructional feature of the invention resides in the fact that the flow divider is a support for the cam ring and by utilizing two additional formations identical to or similar to such flow divider, a three point suspension or support for the cam ring is afforded within the housing of the pump.
  • Such a construction permits the elimination of dowel pins which are normally used to support the cam ring, except for a single dowel pin utilized in the invention to prevent rotation of the cam ring.
  • the elimination of the dowel pins improves the performance of the pump by substitution of the three support segments, one of which serves as a flow divider.
  • FIGURE 1 is a cross sectional elevation of a pump incorporating the features of the invention
  • FIGURE 2 is a section through II-II of FIGURE 1;
  • FIGURE 3 is a section through IIIIII of FIGURE 1;
  • FIGURE 4 is a section through IVIV of FIGURE 1;
  • FIGURE 5 is a section through VV of FIGURE 3.
  • FIGURE 6 is a graph showing the improved performance of the invention in comparison with a conventional pump.
  • a pump housing 2 which supports a rotary shaft 1 on which is mounted the pump rotor 4 having radially slidable vanes 7 and which rotor rotates within a stator or cam ring 5, all in the usual manner.
  • the sealing plates or check plates 6 and 6' maintained in sealing engagement with the rotor and stator by a spring backed by the cover plate 3 as well as by outlet pressure to which their outer faces are exposed. Sealing rings 18 are utilized in the usual manner for sealing the plates 6 and 6' Within the housing.
  • the housing provides support for the stator, with a three point support, comprising integrally cast radially protruding segments 12, 12' and 12", seen in radial view on FIGURE 1.
  • Such segments are an integral part of the housing and have smoothly finished surfaces 19, 19 and 19", respectively, which abut the periphery of the stator.
  • the dowel pin 11 does not effect a support for the stator, the stator being supported by the generally triangular and streamlined segments 12, 12' and 12" which extend longitudinally across the periphery of the stator approximately one-third the way as indicated in FIGURE 5.
  • the housing is provided with an inlet 15 (FIGURES 1 and 2) which conducts fluid to a suction bore 13, the bore 13 terminating perpendicularly in inlet channel 14 which leads to inlet chambers 8 and 8' peripherally surrounding the major portion of the stator ring and fashioned to permit flow lngitudinally into the cells between adjacent vanes 7.
  • Outlet chambers 9 and 9 are provided which connect to pressure chamber 9" to the housing outlet 16 and a bypass 16'.
  • a pressure responsive bypass control valve actuatable by outlet pressure is indicated at 10 in FIGURES 1, 3 and 4.
  • a pressure channel 10' transmits a reduced pressure on the valve.
  • the construction of this valve and the passageways leading to it (FIGS. 3 and 4) at both ends have been heretofore known, except for the coactio-n with the novel passageway comprising channels 14 and 17 which effect an outlet bypass port for the valve, bypassing flow from pump outlet to pump inlet when the valve opens.
  • the outer face of the valve piston is exposed to outlet pressure as will be evident from FIG. 3, while the reduced central portion of the valve communicates with bore 13 and channel 14.
  • Channel 14 is not completely circular but has a side channel 17 (FIG. of approximately half the diameter of channel 14 to form a prebypass channel in relation to the bore 14 which forms a bypass channel.
  • channels 14 and 17 can be readily provided by boring.
  • FIGURE 5 the configuration of the channels 14 and 17 is roughly that of an equilateral triangle wherein the apex formed by the pre-bypass channel 17 is generally directed toward the apex of the streamlined shape of the support segment 12 in its position with respect to the stator 5.
  • flow coming upwardly through channels 14 and 17, after valve opens will be divided by the segment 12 so as to flow clockwise and counterclockwise around the stator and in the intake chambers 8' and 8, respectively.
  • This dividing of the fiow produces a uniformity of filling of the intake chambers and in conjunction with the particular effect and coaction of the channels 14 and 17, substantially reduces or eliminates cavitation at high speeds.
  • the performance of the pump is illustrated in the graph of FIGURE 6 wherein the performance of a conventional pump is indicated by the line I, the inlet pressure being the ordinate in terms of atmospheres and the pump speed being in terms of revolutions per minute.
  • the test conditions provide for an average outlet pressure of 50 atmospheres.
  • Curve II illustrates the improved performance in terms of higher intake pressures where the pre-bypass channel 17 has been provided in a pump which utilizes dowel pins to support the stator but does not have the support segments, particularly the flow dividing segment 12.
  • Curve III illustrates the further improvement where the flow divider segment 12 is utilized in conjunction with the pro-bypass channel 17.
  • the axial length of the bypass channel means comprising channels 14 and 17 might be 20% to 70% of the axial width of the cam ring.
  • a 10% to 50% axial length of the flow divider segment 12 may be used.
  • an even greater range of axial width for the channel means or flow divider may be utilized; e.g., 20% for the channel means and 60% for the flow divider.
  • a rotary vane pump having a housing and a cam ring and rotor therein, said housing having an inlet passage and an outlet passage, a pressure responsive bypass valve connected so as to be actuated by a pressure differential in response to pump speed for bypassing flow to said inlet passage from said outlet passage, a bypass channel means effecting an outlet port for said valve and connecting said valve to said inlet passage; said bypass channel means having a cross section transversely of fiow in a contour affording an apex of open area as said valve opens wherein said apex diverges in the direction of opening of said valve.
  • bypass channel means comprising a merging of two circular bores to effect the approximate contour of an equilateral triangle, one bore being approximately half the diameter of the other bore and being joined thereto generally on a diameter of said one bore and effecting said apex.
  • said bypass channel means comprising a merging of two circular bores to effect the approximate contour of an equilateral triangle, one bore being approximately half the diameter of the other bore and being joined thereto generally on a diameter of said one bore and effecting said apex, said rotary pump having inlet chambers enveloping a portion of respective radial faces of said cam ring and extending around respective portions of the periphery of said cam ring; a flow dividing element disposed to protrude axially of said cam ring exteriorly thereof and intermediate the peripheral portions of said inlet chambers; said bypass channel means terminating intermediate the peripheral portions of said inlet chambers, the apex of said bypass channel means diverging in the direction of said flow divider element so as to direct flow therefrom toward said flow divider element for dividing flow peripherally around said cam ring in opposite directions into said inlet chambers.
  • a rotary vane pump as set forth in claim 6, including at least two additional spacer and support members intermediate said housing and cam ring, whereby said cam ring is supported wholly by said spacers including said flow divider element, and means connecting said housing and cam ring to prevent rotation of said cam ring.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rotary Pumps (AREA)
  • Details And Applications Of Rotary Liquid Pumps (AREA)
US676426A 1966-10-22 1967-10-19 Rotary pump for power steering systems Expired - Lifetime US3439623A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1966Z0012488 DE1553290B2 (de) 1966-10-22 1966-10-22 Fluegelzellenpumpe mit stromregelventil

Publications (1)

Publication Number Publication Date
US3439623A true US3439623A (en) 1969-04-22

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ID=7622558

Family Applications (1)

Application Number Title Priority Date Filing Date
US676426A Expired - Lifetime US3439623A (en) 1966-10-22 1967-10-19 Rotary pump for power steering systems

Country Status (7)

Country Link
US (1) US3439623A (de)
AT (1) AT272844B (de)
CH (1) CH471325A (de)
DE (1) DE1553290B2 (de)
GB (1) GB1182476A (de)
NL (1) NL6714190A (de)
SE (1) SE376274B (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3528757A (en) * 1967-07-08 1970-09-15 Dunlop Co Ltd Rotary machines
US3632238A (en) * 1969-09-05 1972-01-04 Eaton Yale & Towne Pump assembly
US4199304A (en) * 1978-03-13 1980-04-22 Ford Motor Company Positive displacement compact slipper pump
US4373871A (en) * 1981-05-04 1983-02-15 General Motors Corporation Compact power steering pump
US4505655A (en) * 1980-12-27 1985-03-19 Toyoda Koki Kabushiki Kaisha Vane pump with positioning pins for cam ring and side plates
US5664941A (en) * 1995-12-22 1997-09-09 Zexel Usa Corporation Bearings for a rotary vane compressor
US20030202888A1 (en) * 2002-04-26 2003-10-30 Toyoda Koki Kabushiki Kaisha Pump apparatus
WO2012158490A1 (en) * 2011-05-13 2012-11-22 Siemens Healthcare Diagnostics Inc. Rotary shear valve with tree-point stator seating
US10316840B2 (en) 2016-08-29 2019-06-11 Windtrans Systems Ltd Rotary device having a circular guide ring
US20250012266A1 (en) * 2023-07-07 2025-01-09 Fas Medic S.A. Fluid Delivery Apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2403007C2 (de) * 1974-01-23 1983-01-05 Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen Vorgesteuertes Druckbegrenzungsventil

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2544988A (en) * 1949-03-12 1951-03-13 Vickers Inc Power transmission
US2853023A (en) * 1955-08-12 1958-09-23 American Brake Shoe Co Fluid energy translating apparatuses
US3059580A (en) * 1959-12-29 1962-10-23 Chrsler Corp Power steering pump
US3236566A (en) * 1963-03-20 1966-02-22 Chrysler Corp Hydraulic pump
US3253548A (en) * 1958-09-19 1966-05-31 Gen Motors Corp Pump
US3311064A (en) * 1963-07-05 1967-03-28 Zahnradfabrik Friedrichshafen Vane-type rotary pumps

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2544988A (en) * 1949-03-12 1951-03-13 Vickers Inc Power transmission
US2853023A (en) * 1955-08-12 1958-09-23 American Brake Shoe Co Fluid energy translating apparatuses
US3253548A (en) * 1958-09-19 1966-05-31 Gen Motors Corp Pump
US3059580A (en) * 1959-12-29 1962-10-23 Chrsler Corp Power steering pump
US3236566A (en) * 1963-03-20 1966-02-22 Chrysler Corp Hydraulic pump
US3311064A (en) * 1963-07-05 1967-03-28 Zahnradfabrik Friedrichshafen Vane-type rotary pumps

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3528757A (en) * 1967-07-08 1970-09-15 Dunlop Co Ltd Rotary machines
US3632238A (en) * 1969-09-05 1972-01-04 Eaton Yale & Towne Pump assembly
US4199304A (en) * 1978-03-13 1980-04-22 Ford Motor Company Positive displacement compact slipper pump
US4505655A (en) * 1980-12-27 1985-03-19 Toyoda Koki Kabushiki Kaisha Vane pump with positioning pins for cam ring and side plates
US4373871A (en) * 1981-05-04 1983-02-15 General Motors Corporation Compact power steering pump
US5664941A (en) * 1995-12-22 1997-09-09 Zexel Usa Corporation Bearings for a rotary vane compressor
US6877961B2 (en) 2002-04-26 2005-04-12 Toyoda Koki Kabushiki Kaisha Vane pump with a bypass valve and passage arrangement for equalizing excess fluid flow through dual suction passages
EP1357290A3 (de) * 2002-04-26 2003-11-12 Toyoda Koki Kabushiki Kaisha Pumpe mit Umleitungsventil
US20030202888A1 (en) * 2002-04-26 2003-10-30 Toyoda Koki Kabushiki Kaisha Pump apparatus
CN100374728C (zh) * 2002-04-26 2008-03-12 株式会社捷太格特 液压泵装置
WO2012158490A1 (en) * 2011-05-13 2012-11-22 Siemens Healthcare Diagnostics Inc. Rotary shear valve with tree-point stator seating
EP2659172A4 (de) * 2011-05-13 2014-11-19 Siemens Healthcare Diagnostics Drehscherschieber mit dreipunkt-statorsitz
US9140376B2 (en) 2011-05-13 2015-09-22 Siemens Healthcare Diagnostics Inc. Rotary shear valve with three-point stator seating
US10316840B2 (en) 2016-08-29 2019-06-11 Windtrans Systems Ltd Rotary device having a circular guide ring
US10851777B2 (en) 2016-08-29 2020-12-01 Windtrans Systems Ltd Rotary device having a circular guide ring
US20250012266A1 (en) * 2023-07-07 2025-01-09 Fas Medic S.A. Fluid Delivery Apparatus

Also Published As

Publication number Publication date
SE376274B (de) 1975-05-12
CH471325A (de) 1969-04-15
DE1553290A1 (de) 1970-04-09
AT272844B (de) 1969-07-25
DE1553290B2 (de) 1976-12-02
GB1182476A (en) 1970-02-25
NL6714190A (de) 1968-04-23

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