US20060222519A1 - Pump device - Google Patents

Pump device Download PDF

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Publication number
US20060222519A1
US20060222519A1 US11/297,430 US29743005A US2006222519A1 US 20060222519 A1 US20060222519 A1 US 20060222519A1 US 29743005 A US29743005 A US 29743005A US 2006222519 A1 US2006222519 A1 US 2006222519A1
Authority
US
United States
Prior art keywords
working oil
choke
pump
passage
flow rate
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.)
Abandoned
Application number
US11/297,430
Other languages
English (en)
Inventor
Tomoyuki Fujita
Masamichi Sugihara
Yoshinobu Yasue
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.)
KYB Corp
Original Assignee
Kayaba Industry Co Ltd
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 Kayaba Industry Co Ltd filed Critical Kayaba Industry Co Ltd
Assigned to KAYABA INDUSTRY CO., LTD. reassignment KAYABA INDUSTRY CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FUJITA, TOMOYUKI, SUGIHARA, MASAMICHI, YASUE, YOSHINOBU
Publication of US20060222519A1 publication Critical patent/US20060222519A1/en
Abandoned legal-status Critical Current

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Classifications

    • 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
    • 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
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/50—Conditions before a throttle
    • 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
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/52—Conditions after a throttle
    • 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
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/70—Safety, emergency conditions or requirements
    • F04C2270/701—Cold start

Definitions

  • This invention relates to flow control of a fixed capacity pump used for example in the power steering of a vehicle.
  • JPH09-170569A published by the Japan Patent Office in 1997 discloses a flow control valve for a fixed capacity pump that can be used in the power steering of a vehicle.
  • the flow control valve supplies working oil discharged from the fixed capacity pump to an actuator via a variable orifice.
  • the flow control valve is provided with a spool that displaces in response to a pressure loss in the orifice and, according to its displaced position, causes a part of the discharged working oil to flow into a recirculation passage.
  • Working oil that is sucked by the pump is supplied from a reservoir via a suction passage.
  • the recirculation passage recirculates working oil into the suction passage.
  • the orifice has a feature whereby the flow characteristic is constant irrespective of the temperature of the working oil that passes therethrough. For example, when the viscosity of the working oil is high due to low temperature, the pressure loss in the working oil passing through the orifice does not become very large with respect to the flow rate. On the other hand, when the viscosity of the working oil increases, frictional resistance in the suction passage inevitably increases, and the suction resistance of the pump increases.
  • the working oil recirculated from the recirculation passage is under a pushing force originating in the discharge pressure of the pump, and therefore the suction resistance of the pump when it sucks the recirculated working oil is small.
  • the pump suctions working oil from the reservoir via the suction passage it suffers a large suction resistance.
  • the entire suction resistance of the pump therefore depends on the ratio of the flow rate of the recirculated working oil to the flow rate of the working oil supplied from the reservoir.
  • this invention provides a pump device for supplying working oil to an actuator, comprising a fixed capacity pump, a choke through which working oil discharged by the pump flows, and a flow control valve which recirculates a part of the working oil discharged by the pump to a suction side of the pump, according to a pressure loss generated by the choke.
  • FIG. 1 is a hydraulic circuit diagram of a pump device according to this invention.
  • FIG. 2 is a longitudinal sectional view of a vane pump as a component of the pump device.
  • FIG. 3 is a longitudinal sectional view of a flow control valve according to this invention.
  • FIG. 4 is a diagram showing a result of an experiment performed by the inventors to test the effect of the working oil temperature on the flow characteristics of an orifice and a choke.
  • a pump device comprises a fixed capacity pump P and a flow control valve F enclosed in a casing C shown by a single dotted line.
  • the fixed capacity pump P is connected to a motive power source such as an internal combustion engine and, when driven by the motive power source, sucks work oil through a suction passage 1 formed in the casing C.
  • the suction passage 1 is connected, via an external conduit Rp, to a reservoir R disposed outside the casing C.
  • the fixed capacity pump P discharges pressurized work oil to a discharge passage 2 that is also formed in the casing C.
  • the discharge passage 2 is connected to an actuator A located outside the casing C.
  • a choke 21 is disposed in the discharge passage 2 .
  • a branch passage 2 b branches off from the discharge passage 2 at a position upstream of the choke 21 .
  • the branch passage 2 b is connected to an inlet port 4 of the flow control valve F.
  • the discharge passage 2 downstream of the choke 21 communicates with the actuator A and the discharge passage 2 upstream of the choke 21 communicates with the inlet port 4 of the flow control valve F via the branch passage 2 b.
  • the flow control valve F comprises a spool 5 , a control pressure chamber 6 and a spring chamber 7 .
  • the control pressure chamber 6 and the spiring chamber 7 are separated by the spool 5 .
  • the control pressure chamber 6 communicates with the branch passage 2 b via the inlet port 4 .
  • the spring chamber 7 communicates with the discharge passage 2 downstream of the choke 21 via a pilot passage 9 .
  • a spring 8 is enclosed in the spring chamber 7 .
  • the flow control valve F comprises a recirculation port 10 .
  • the recirculation port 10 communicates with the control pressure chamber 6 according to displacement of the spool 5 toward the right hand side of the figure.
  • the recirculation port 10 communicates with the suction passage 1 via a recirculation passage 11 formed within the casing C.
  • the recirculation port 10 communicates with the control pressure chamber 6 as a result of the displacement of the spool 5 , the working oil that has flown into the control pressure chamber 6 from the inlet port 4 recirculates to the suction passage 1 via the recirculation port 10 and recirculation passage 11 , and is sucked again by the fixed capacity pump P. It can be said that the oil that has flown into the recirculation port 10 recirculates in the casing C.
  • the working oil pressure in the control pressure chamber 6 acts on the spool 5 as a thrust force from the left hand side of the figure.
  • the working oil pressure in the spring chamber 7 and the pressure of the spring 8 act on the spool 5 as a thrust force from the right hand side of the figure. Accordingly, the spool 5 displaces to a position where these two forces balance.
  • the opening of the recirculation port 10 depends on the balanced position of the spool 5 .
  • the spool 5 displaces towards an opening increase direction of the recirculation port 10 , i.e., towards the right hand side in the figure.
  • the spool 5 displaces towards an opening decrease direction of the recirculation port 10 , i.e., towards the left hand side in the figure.
  • the recirculation passage 11 As the opening of the recirculation port 10 increases, the recirculation flow rate increases, and as the opening of the recirculation port 10 decreases, the recirculation flow rate decreases.
  • the flow rate Q 4 of the oil that is sucked by the pump P from the reservoir R outside the casing C is represented by the following relation (3).
  • Q 4 Q 1 ⁇ Q 3
  • the casing C comprises a body 12 and a cover 14 that closes a bore 13 formed in the body 12 .
  • a side plate 15 and a cam ring 16 are enclosed in this order from the bottom.
  • the cam ring 16 accommodates a rotor 17 which is fixed to a rotation shaft 20 .
  • the rotor 17 comprises plural vane grooves 18 formed in radial directions at equal angular intervals. In each vane groove 18 , a vane 19 is accommodated so as to be free to protrude radially therefrom.
  • vanes 19 protrude from the vane grooves 18 as a result of centrifugal force and their protruding tips contact the inner circumference of the cam ring 16 .
  • oil chambers are formed between adjacent vanes 19 .
  • the rotation shaft 20 penetrates through the body 12 and connects to the motive power source such as an internal combustion engine outside the casing C.
  • the vanes that are in contact with the inner circumference of the cam ring 16 move forward and backward, and accordingly the oil chambers formed by the vanes and the inner circumference of the cam ring 16 expand and shrink.
  • the expansion and shrinkage of oil chambers take place simultaneously. More precisely, some oil chambers expand while others shrink.
  • the suction passage 1 is formed in the cover 14 .
  • the suction passage 1 communicates with the expanding oil chambers and the discharge passage 2 communicates with the shrinking oil chambers through one or both of two side faces of the cam ring 16 .
  • Each of the oil chambers sucks working oil from the suction passage 1 when it expands, or in other words, when it is in a suction stroke.
  • the suction passage 1 shrinks, or in other words when it is in a discharge stroke, it pressurizes the sucked working oil and discharges it to the discharge passage 2 .
  • the branch passage 2 b branches off from the discharge passage 2 as the discharge passage 2 extends toward the choke 21 .
  • the branch passage 2 b communicates with the control pressure chamber 6 via the inlet port 4 .
  • this configuration in the circuit diagram has been drawn for the purpose of explanation. The real construction is somewhat different as shown in FIG. 3 .
  • the branch passage 2 b shown in FIG. 1 is imaginary and in reality the discharge passage 2 directly communicates with the control pressure chamber 6 as shown in FIG. 3 .
  • the working oil in the control pressure chamber 6 is separated into two oil streams by the spool 5 , i.e., a stream to the actuator A via the choke 21 , and a stream to the suction passage 1 via the recirculation port 10 .
  • the branch passage 2 b and the inlet port 4 are therefore not shown in FIG. 2 and FIG. 3 .
  • This invention provides the choke 21 instead of an orifice in the discharge passage 2 . Pressure loss caused by an orifice is not affected by the temperature of the working oil, or the viscosity thereof.
  • FIG. 4 shows an experimental result obtained by the inventors with respect to the effect of the temperature of working oil on the flow characteristics of an orifice and a choke.
  • the orifice and choke have a same diameter D and the flow path length L of the choke is set at 1.33 times of the diameter D.
  • the flow rate of the choke is highly affected by the temperature or the viscosity of the working oil and the differential pressure between the upstream and downstream sides of the choke significantly increases in a low temperature state at an identical flow rate.
  • a differential pressure between the upstream and downstream sides of an orifice is explained as a differential pressure of an orifice
  • a differential pressure between the upstream and downstream sides of a choke is explained as a differential pressure of a choke.
  • the discharge flow rate Q 1 of the fixed capacity pump P is obtained as a product of a unit discharge volume and a rotation speed of the pump P.
  • the rotation speed of the fixed capacity pump P depends on the rotation speed of the motive power source such as an internal combustion engine.
  • the discharge flow rate Q 1 of the fixed capacity pump P increases accordingly, even in a low temperature state. If the differential pressure of the orifice were large in this situation, the recirculation flow rate Q 3 via the recirculation port 10 would increase, so the suction flow rate of the fixed capacity pump P would not suffer a shortage.
  • the differential pressure of the orifice is small even in a low temperature state, and so the flow rate Q 2 of working oil supplied to the actuator A increases and the recirculation flow rate Q 3 decreases relatively.
  • the suction resistance by the pump P is small, because the recirculated working oil is under the influence of a pushing force originating from the discharge pressure of the fixed capacity pump P.
  • the suction resistance of the fresh working oil supplied from the reservoir R is larger than the suction resistance of the recirculated working oil.
  • the suction flow rate of the fixed capacity pump P may not match the discharge flow rate thereof due to an excessively large suction resistance. This situation generates a negative pressure in the pump P which causes cavitation and generates noise.
  • This invention focuses attention on the temperature characteristics of an orifice and choke as shown in FIG. 4 , and by the use of the choke 21 that generates a large differential pressure under low temperature, achieves a relative increase in the recirculation flow rate Q 3 with respect to the flow rate Q 4 of the working oil supplied from the reservoir R in a low temperature state.
  • the choke As follows. Both the choke and orifice generate pressure loss due to restriction of the flow area.
  • the choke denotes a narrow flow area with a long flow path length L
  • the orifice denotes a narrow flow area that has a short flow path length L.
  • the choke indicates a narrow flow path in which the pressure loss decreases as the working oil temperature increases and takes a constant value when the working oil temperature is above a predetermined temperature.
  • the fixed capacity pump P does not suffer from a shortage of work oil for suction, while the flow rate Q 4 of the working oil sucked through the conduit Rp remains small.
  • the flow rate Q 3 represents the flow rate of the working oil that recirculates through the recirculation passage 11 formed internally in the casing C, and so the pressure loss due to recirculation is small.
  • the flow characteristic of the choke is no longer affected by the viscosity of the oil.
  • the choke 21 functions in the same way as an orifice.
  • the suction resistance due to friction in the conduit Rp does not become very large.
  • the fixed capacity pump P can therefore suck an adequate amount of working oil without suffering a large suction resistance, and the working oil is supplied to the actuator A at a constant flow rate defined depending on the flow diameter D and flow path length L of the choke 21 .
  • the fixed capacity pump does not suffer from an insufficient suction flow rate, and therefore cavitation or generation of noise is prevented from occurring even when the rotation speed of the motive power source increases in a low temperature state.
  • this invention is applied to a pump device wherein the fixed capacity pump P is connected to the reservoir R via the conduit Rp, but this invention may also be applied to a pump device wherein the fixed capacity pump is directly connected to the reservoir, not via a conduit.
  • the opening of the choke 21 is not limited to a circular shape.
  • the shape of the opening is polygonal, the diameter D of a circular opening that has the same cross-sectional area should be used to determine the flow path length L of the choke 21 .

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Details And Applications Of Rotary Liquid Pumps (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Rotary Pumps (AREA)
  • Reciprocating Pumps (AREA)
US11/297,430 2004-12-22 2005-12-09 Pump device Abandoned US20060222519A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2004370463A JP2006177230A (ja) 2004-12-22 2004-12-22 ポンプ装置
JP2004-370463 2004-12-22

Publications (1)

Publication Number Publication Date
US20060222519A1 true US20060222519A1 (en) 2006-10-05

Family

ID=36096147

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/297,430 Abandoned US20060222519A1 (en) 2004-12-22 2005-12-09 Pump device

Country Status (4)

Country Link
US (1) US20060222519A1 (de)
EP (1) EP1674729A3 (de)
JP (1) JP2006177230A (de)
CN (1) CN1793651A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100307599A1 (en) * 2009-06-03 2010-12-09 Benjamin James Morris Fluid device with magnetic latching valves
CN106662103A (zh) * 2014-08-29 2017-05-10 Ｋｙｂ株式会社 泵装置
US10436081B2 (en) * 2015-06-18 2019-10-08 Hyundai Motor Company Method for reducing noise of electric oil pump for vehicle

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2042737B1 (de) * 2007-09-28 2016-01-13 Parker-Hannifin Corporation Druckwiederherstellungssystem
JP5544904B2 (ja) * 2010-01-29 2014-07-09 株式会社ジェイテクト 流量制御装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5860797A (en) * 1995-04-04 1999-01-19 Aisin Seiki Kabushiki Kaisha Flow rate control device for a pump
US5982162A (en) * 1996-04-22 1999-11-09 Mitsubishi Denki Kabushiki Kaisha Internal voltage generation circuit that down-converts external power supply voltage and semiconductor device generating internal power supply voltage on the basis of reference voltage
US6012907A (en) * 1996-12-09 2000-01-11 Luk Fahrzeug-Hydraulik Gmbh & Co. Kg Flow-regulating arrangement for a hydraulic transporting device
US6238976B1 (en) * 1997-07-08 2001-05-29 Micron Technology, Inc. Method for forming high density flash memory

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2887060A (en) * 1953-06-22 1959-05-19 American Brake Shoe Co Variable volume pumping mechanism
JPS5034250B1 (de) * 1969-04-01 1975-11-07
IN153744B (de) * 1980-08-11 1984-08-18 Sperry Corp
JPS58113892U (ja) * 1982-01-29 1983-08-03 三菱自動車工業株式会社 パワ−ステアリング用のオイルポンプ装置
JPH01178783A (ja) * 1987-12-29 1989-07-14 Nippon Denso Co Ltd 油圧アクチュエータ制御システム
US5161959A (en) * 1991-03-11 1992-11-10 Ford Motor Company Viscosity sensitive hydraulic pump flow control
JP3729525B2 (ja) * 1994-12-16 2005-12-21 ジヤトコ株式会社 可変容量型オイルポンプのライン圧制御装置
JP2000161246A (ja) * 1998-06-23 2000-06-13 Bosch Braking Systems Co Ltd オイルポンプ
JP2001073963A (ja) * 1999-08-31 2001-03-21 Kayaba Ind Co Ltd ベーンポンプの焼き付き防止構造

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5860797A (en) * 1995-04-04 1999-01-19 Aisin Seiki Kabushiki Kaisha Flow rate control device for a pump
US5982162A (en) * 1996-04-22 1999-11-09 Mitsubishi Denki Kabushiki Kaisha Internal voltage generation circuit that down-converts external power supply voltage and semiconductor device generating internal power supply voltage on the basis of reference voltage
US6012907A (en) * 1996-12-09 2000-01-11 Luk Fahrzeug-Hydraulik Gmbh & Co. Kg Flow-regulating arrangement for a hydraulic transporting device
US6238976B1 (en) * 1997-07-08 2001-05-29 Micron Technology, Inc. Method for forming high density flash memory

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100307599A1 (en) * 2009-06-03 2010-12-09 Benjamin James Morris Fluid device with magnetic latching valves
CN106662103A (zh) * 2014-08-29 2017-05-10 Ｋｙｂ株式会社 泵装置
US20170227007A1 (en) * 2014-08-29 2017-08-10 Kyb Corporation Pump device
US10436081B2 (en) * 2015-06-18 2019-10-08 Hyundai Motor Company Method for reducing noise of electric oil pump for vehicle

Also Published As

Publication number Publication date
EP1674729A2 (de) 2006-06-28
CN1793651A (zh) 2006-06-28
JP2006177230A (ja) 2006-07-06
EP1674729A3 (de) 2012-10-17

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Legal Events

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AS Assignment

Owner name: KAYABA INDUSTRY CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FUJITA, TOMOYUKI;SUGIHARA, MASAMICHI;YASUE, YOSHINOBU;REEL/FRAME:017339/0822

Effective date: 20051128

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION