US3561214A - Flushing apparatus for reversible hydrostatic drives - Google Patents

Flushing apparatus for reversible hydrostatic drives Download PDF

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Publication number
US3561214A
US3561214A US724498A US3561214DA US3561214A US 3561214 A US3561214 A US 3561214A US 724498 A US724498 A US 724498A US 3561214D A US3561214D A US 3561214DA US 3561214 A US3561214 A US 3561214A
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United States
Prior art keywords
flushing
pressure
valve means
valve
piston
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Expired - Lifetime
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US724498A
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English (en)
Inventor
Gerhard Bobst
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Von Roll AG
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Von Roll AG
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F16H61/4078—Fluid exchange between hydrostatic circuits and external sources or consumers
    • F16H61/4139—Replenishing or scavenging pumps, e.g. auxiliary charge 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/04—Special measures taken in connection with the properties of the fluid
    • F15B21/044—Removal or measurement of undissolved gas, e.g. de-aeration, venting or bleeding
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H39/00—Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution
    • F16H39/02—Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution with liquid motors at a distance from liquid pumps

Definitions

  • a flushing valve means which is controlled by the momentary prevailing high pressure.
  • a pressure limiting valve means which is connected after the flushing valve means incorporates a piston member Which is impacted via a direct connection by the flushing pump means.
  • This piston member is provided with two control edge portions, one of which is effective when the slide member of the flushing valve means is in its null or neutral position and the other of which is effective when such slide member has assumed an operating position.
  • the present invention relates to an improved flushing or scavaging device for reversible hydrostatic drives and is of the type comprising a flushing or scavaging pump, a respective feed valve means for each pressure side of the drive, a fiushing valve means controlled by the momentarily prevailing high pressure and a pressure limiting valve means.
  • This valve opens the momentary low pressure side and feeds the quantity of flushing fluid delivered by the pump minus the leakage losses via a low pressure valve back to the reservoir of the flushing or scavaging pump. At this location the fluid is again sucked up by the flushing pump and delivered through the pressure conduit and, if desired, via filter means and heat exchange means through the corresponding check valve which is designated as a feed valve to the low pressure side of the drive.
  • the mentioned flushing valve is operatively connected with a respective connection to both pressure sides of the drive. It is generally constructed in the form of a slide valve, which in both terminal positions closes the momentary pressure side and communicates the low pressure side with the drain or discharge controlled by a pressure limiting valve. In its neutral or central position, that is to say, when the drive does not transmit any power or work, in other words the primary portion of the drive has a zero or null stroke volume, the
  • flushing valve closes both connections to ⁇ the discharge or considerably throttles them. In both cases this results in a corresponding pressure increase which is limited by the provision of a pressure limiting valve arranged at the flushing or scavaging pump.
  • two pressure limiting valves are provided at the flushing circuit, of which, however, the one pressure limiting valve at the flushing pump must be adjusted to a higher pressure in order to fulfill the purpose of the flushing circuit than the pressure limiting valve which is arranged after the ushing Valve.
  • a flushing fluid circuit in which a single pressure limiting valve is arranged after the flushing valve.
  • the slide member of the flushing valve is constructed, in this case, as a hollow slide and therefore can be employed as the flow path for the quantity of uid delivered by the flushing pump when the flushing valve is in its central position. In the terminal positions of the slide member this path is blocked or closed, the flushing oil arriving via the relevant feed valve at the low pressure side and ows via the flushing valve and the low pressure valve back to the reservoir.
  • Another object of the present invention is to provide an improved flushing device for reversible hydrostatic drives which effectively overcomes the aforementioned drawbacks of the prior art structures.
  • the invention is manifested by the features that the piston of the pressure limiting valve which is connected after the flushing valve is impacted via a direct connection by the flushing pump and this piston possesses two control-edge portions, one of which is effective when the slide member of the flushing valve is in its null or neutral position, and the other of which is effective when such slide member has assumed an operating position.
  • FIG. 1 illustrates a preferred embodiment of the inventive flushing device, partially shown in section and partially schematically represented in order to improve clarity in illustration;
  • FIG. 2 is a fragmentary view, partially in section, of details of the flushing slide member and the pressure limiting valve, with the flushing slide member in its null or neutral position;
  • FIG. 3 is a cross-sectional view taken through the flushing slide piston depicted in FIG. 2.
  • reference numeral 1 represents an adjustable primary unit which is driven by a non-illustrated prime mover and reference numeral 2 designates the fixed secondary unit of a hydrostatic drive which drives a non-illustrated working machine.
  • the flushing fluid circuit comprises the constant delivery pump 3 which can be driven from the same prime mover as the primary unit 1 or can be separately driven. Further, it comprises both of the feed Valves 4 and 4" which are constructed as nonreturn or check valves. Additionally, the illustrated flushing circuit incorporates the flushing valve means 6 which is connected via the conduits 5 and 5 to the pressure sides and further includes the pressure limiting valve means 8 which is connected after the flushing valve means 6 via the connection means 7.
  • the oil can flow from the pressure limiting valve means 8 via the discharge conduit 9 back into the reservoir 10 which is identical with the reservoir which is located beneath the flushing pump 3. Additionally, there will be recognized a separate conduit 11 by means of which the flushing pump 3 can impact the pressure limiting valve means 8.
  • the flushing valve means 6 embodies a piston slide member or spool 12 having a longitudinal bore dening a canal 12". Additionally the piston slide member 12 iS provided at its middle region with cut-away or recessed portions 12' (FIG. 3) and at both ends is equipped with a substantially cylindrical projection 13 having a smaller diameter than the middle region of the aforementioned piston slide member 12. Further, it will be seen that in the compartments or chambers 14 and 14l there is located a respective spring member 15 which serves to press the associated throughbored spring plate 16 against the shoulders or projections 17.
  • the fiushing slide operates in the following manner: In the null or neutral position, as shown in FIG. 2, the pressure in both pressure conduits, and therefore in the conduits 5 and 5" is the same. If the pressure in the upper conduit increases, then, the piston member 12 is displaced into its lower terminal position and opens the lower pressure conduit via the conduit 5 into the connection means or connecting chamber 7.
  • the flushing pump 3 continues to convey fluid medium via the conduit 11 to the underside of the piston 18 provided with a weak spring member 18.
  • the pressure is transmitted through this hollow bored piston 18 via the throttling orifice 19 to the cone valve means 20 which is loaded by a spring 21. If the pressure opens the cone valve means 20 and allows the oil to flow through the channel 20', then owing to the throttle orifice 19 the pressure beneath the cone valve means 20 drops and the piston 18 opens the control edge portion 22 thereof (as shown in FIG. 2) and the flushing oil from conduit 11 can flow back into the reservoir 10.
  • the control edge portion 22" of the piston 18 likewise opens the discharge from connection means 7 to conduit 9, but because of the central or neutral position of the piston member 12 no discharge occurs. This is the position of the apparatus depicted in FIG. 2. On the other hand, if the piston member 12 is located in the terminal position, as shown in FIG. 1, then the discharge takes place at the control edge portion 22.
  • valve opening at the control edge portion 22" is greater than what would correspond to the quantity of fluid delivered by the pump 3, then the pressure in the closed ushing circuit drops.
  • the valve 8 closes to such extent until the discharge from the flushing valve means 6 is throttled by the control edge portion 22. However, in the throttle position of the control edge portion 22 the control edge portion 22 is closed.
  • the delivered quantity of fluid medium of the pump 3 is greater than the valve opening at the control edge portion 22, then a part of the fluid medium must flow away via such control edge portion 22', since the pressure cannot be greater than that corresponding to the adjustment of the valve means 20.
  • flushing fluid medium ows either past the control edge portion 22", control edge portion 22 being closed, or else flushing fiuid medium flows away past the control edge portion 22 when the quantity of flushing fluid medium can not completely pass through the opening at the control edge portion 22".
  • the total quantity of Hushing medium flows away via the control edge portion 22.
  • the small quantity of medium flowing away via the precontrol valve 20, in both positions of the flushing valve means 6, need not be taken into account since it is very small.
  • the combination of throttling and pressure dampening which is possible by virtue of the longitudinal bore 12 provided at the piston member 12, has still the further advantage that, independently of the pressure side of the main fluid circuit, the high pressure can always be removed at the same location, as such is represented in FIG. 1 by the reference numerals HD.
  • This pressure can be, for instance, used to control further hydraulic or hydrodevices.
  • a flushing device comprising ushing pump means, a respective feed valve means communicating each pressure side of the hydrostatic drive with said flushing pump, a flushing valve means controlled by the momentary prevailing high pressure of the high pressure side, said ilushing valve means including a flushing slide member, pressure limiting valve means operably connected with said ilushing valve means, said pressure limiting valve means including a piston member and a discharge, means providing a direct connection from said flushing pump means to said pressure limiting valve means so that fluid medium delivered by said ilushing pump means impacts said piston member, said piston member being provided with two control edge portions, one of said control edge portions being eective to establish communication between said ilushing pump means and said discharge of said pressure limiting valve means when said flushing slide member is in its neutral position, and the other of said control edge portions being effective to establish communication between said ushing valve means and said discharge of said pressure limiting valve means when said ll
  • said ilushing slide member incorporates a piston provided with a substantially cylindrical projection of smaller diameter than the diameter of said piston, said ilushing Valve means incorporating shoulder means, said cylindrical projection cooperating with said shoulder means and an end face of said piston at the end of its stroke in order to provide a throttle dampening means.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Control Of Transmission Device (AREA)
  • Safety Valves (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
  • Fluid-Pressure Circuits (AREA)
US724498A 1967-05-02 1968-04-26 Flushing apparatus for reversible hydrostatic drives Expired - Lifetime US3561214A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH626367A CH454562A (de) 1967-05-02 1967-05-02 Spüleinrichtung für reversierbare hydrostatische Getriebe

Publications (1)

Publication Number Publication Date
US3561214A true US3561214A (en) 1971-02-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US724498A Expired - Lifetime US3561214A (en) 1967-05-02 1968-04-26 Flushing apparatus for reversible hydrostatic drives

Country Status (8)

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US (1) US3561214A (forum.php)
AT (1) AT282272B (forum.php)
BE (1) BE714410A (forum.php)
CH (1) CH454562A (forum.php)
FR (1) FR1565059A (forum.php)
GB (1) GB1206504A (forum.php)
NL (1) NL6806242A (forum.php)
SE (1) SE336259B (forum.php)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3730206A (en) * 1970-12-17 1973-05-01 Constantin Rauch Flushing valve arrangement for reversible hydrostatic gear mechanisms
US5687566A (en) * 1995-05-15 1997-11-18 Petty; Jon A. Arrangement and method for removal of air from a hydraulic system
WO1998019074A1 (en) * 1996-10-29 1998-05-07 Phoenix Systems, L.L.C. Removal of air from hydraulic system
US5813225A (en) * 1995-05-15 1998-09-29 Phoenix Systems, L.L.C. Arrangement and method for removal of air from a hydraulic system
US6189319B1 (en) 1995-05-15 2001-02-20 Phoenix Systems, L.L.C. Removal of air from hydraulic system
US6233933B1 (en) 1996-10-29 2001-05-22 Phoenix Systems, L.L.C. Arrangement and method for removal of air from a hydraulic system
FR2819023A1 (fr) * 2000-12-28 2002-07-05 Poclain Hydraulics Ind Circuit de prelevement comprenant une valve de prelevement pour echange et/ou balayage du carter d'un moteur hydraulique
US20040006981A1 (en) * 2002-07-12 2004-01-15 Xingen Dong Hydraulic devices for smooth operations of hydrostatic transmission
US20040211175A1 (en) * 2003-04-04 2004-10-28 Sauer-Danfoss (Neumunster) Gmbh & Co. Ogh Hydraulic spool valve for use in a hydraulic vehicle drive
US20060053784A1 (en) * 2002-10-28 2006-03-16 Poclain Hydraulics Industrie Exchange and/or scavenging device for a circuit comprising at least one hydraulic motor
CN105179348A (zh) * 2015-09-15 2015-12-23 宁波斯达弗液压传动有限公司 一种液压马达内置冲洗和冷却阀
CN111417802A (zh) * 2017-10-09 2020-07-14 波克兰液压工业设备公司 启动时液压流体的冲洗
CN111417803A (zh) * 2017-10-09 2020-07-14 波克兰液压工业设备公司 疏通入口过滤器

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3730206A (en) * 1970-12-17 1973-05-01 Constantin Rauch Flushing valve arrangement for reversible hydrostatic gear mechanisms
US5687566A (en) * 1995-05-15 1997-11-18 Petty; Jon A. Arrangement and method for removal of air from a hydraulic system
US5813225A (en) * 1995-05-15 1998-09-29 Phoenix Systems, L.L.C. Arrangement and method for removal of air from a hydraulic system
US6189319B1 (en) 1995-05-15 2001-02-20 Phoenix Systems, L.L.C. Removal of air from hydraulic system
WO1998019074A1 (en) * 1996-10-29 1998-05-07 Phoenix Systems, L.L.C. Removal of air from hydraulic system
US6233933B1 (en) 1996-10-29 2001-05-22 Phoenix Systems, L.L.C. Arrangement and method for removal of air from a hydraulic system
US6802182B2 (en) 2000-12-28 2004-10-12 Poclain Hydraulics Industrie Tapping circuit including a tapping valve for replenishing and/or flushing the casing of a hydraulic motor
FR2819023A1 (fr) * 2000-12-28 2002-07-05 Poclain Hydraulics Ind Circuit de prelevement comprenant une valve de prelevement pour echange et/ou balayage du carter d'un moteur hydraulique
US20040006981A1 (en) * 2002-07-12 2004-01-15 Xingen Dong Hydraulic devices for smooth operations of hydrostatic transmission
US6837047B2 (en) * 2002-07-12 2005-01-04 Parker-Hannifin Corporation Hydraulic devices for smooth operations of hydrostatic transmission
US20060053784A1 (en) * 2002-10-28 2006-03-16 Poclain Hydraulics Industrie Exchange and/or scavenging device for a circuit comprising at least one hydraulic motor
US7231764B2 (en) * 2002-10-28 2007-06-19 Poclain Hydraulics Industrie Exchange and/or scavenging device for a circuit comprising at least one hydraulic motor
US20040211175A1 (en) * 2003-04-04 2004-10-28 Sauer-Danfoss (Neumunster) Gmbh & Co. Ogh Hydraulic spool valve for use in a hydraulic vehicle drive
DE10315512A1 (de) * 2003-04-04 2004-11-04 Sauer-Danfoss (Neumünster) GmbH & Co OHG Hydraulischer Steuerschieber, Verwendung eines hydraulischen Steuerschiebers und hydraulischer Fahrzeugantrieb
US7000387B2 (en) 2003-04-04 2006-02-21 Sauer-Danfoss (Neumunster) Gmbh & Co. Ohg Hydraulic spool valve for use in a hydraulic vehicle drive
DE10315512B4 (de) * 2003-04-04 2006-04-13 Sauer-Danfoss (Neumünster) GmbH & Co OHG Hydraulischer Steuerschieber, Verwendung eines hydraulischen Steuerschiebers und hydraulischer Fahrzeugantrieb
CN105179348A (zh) * 2015-09-15 2015-12-23 宁波斯达弗液压传动有限公司 一种液压马达内置冲洗和冷却阀
CN111417802A (zh) * 2017-10-09 2020-07-14 波克兰液压工业设备公司 启动时液压流体的冲洗
CN111417803A (zh) * 2017-10-09 2020-07-14 波克兰液压工业设备公司 疏通入口过滤器

Also Published As

Publication number Publication date
FR1565059A (forum.php) 1969-04-25
DE1750171A1 (de) 1971-01-21
NL6806242A (forum.php) 1968-11-04
BE714410A (forum.php) 1968-09-16
AT282272B (de) 1970-06-25
DE1750171B2 (de) 1976-05-20
CH454562A (de) 1968-04-15
SE336259B (forum.php) 1971-06-28
GB1206504A (en) 1970-09-23

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