US3667496A - Pressure-modulated hydraulic control valve - Google Patents

Pressure-modulated hydraulic control valve Download PDF

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Publication number
US3667496A
US3667496A US3667496DA US3667496A US 3667496 A US3667496 A US 3667496A US 3667496D A US3667496D A US 3667496DA US 3667496 A US3667496 A US 3667496A
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United States
Prior art keywords
valve
control
pressure
bore
plunger
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 - Lifetime
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English (en)
Inventor
John Wayne Schletzbaum
Reno Antonio Rodeghiero
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.)
Deere and Co
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Deere and Co
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 Deere and Co filed Critical Deere and Co
Application granted granted Critical
Publication of US3667496A publication Critical patent/US3667496A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D25/00—Fluid-actuated clutches
    • F16D25/12—Details not specific to one of the before-mentioned types
    • F16D25/14—Fluid pressure control
    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • F16D2048/0209—Control by fluid pressure characterised by fluid valves having control pistons, e.g. spools
    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • F16D2048/0212—Details of pistons for master or slave cylinders especially adapted for fluid control
    • 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
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • F16D2048/0221—Valves for clutch control systems; Details thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/2496—Self-proportioning or correlating systems
    • Y10T137/2559—Self-controlled branched flow systems
    • Y10T137/2574—Bypass or relief controlled by main line fluid condition
    • Y10T137/2605—Pressure responsive
    • Y10T137/2607—With pressure reducing inlet valve
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86574—Supply and exhaust
    • Y10T137/8667—Reciprocating valve
    • Y10T137/86694—Piston valve
    • Y10T137/8671—With annular passage [e.g., spool]

Definitions

  • a pressure-modulated hydraulic control valve is provided for controlling fluid flow to engage and disengage a differential lock.
  • a manual actuator acts through a modulating spring to shift a spool valve to selectively establish conditions in the control valve for engaging and disengaging the differential lock and the manual actuator includes a length adjustable link which may be adjusted without disassembly to change the modulating force to desired values.
  • a check valve in the pressure port normally prevents flow to the spool valve when the lock is disengaged and a pin extends from the check valve into the valve bore and is engaged and moved by a ramp on the spool valve to unseat the check valve when the spool valve is shifted to establish the condition for engaging the lock.
  • This invention relates to a pressure-modulating hydraulic control valve and more particularly relates to a control valve for a hydraulic differential lock.
  • Hydraulic differential locks are known in the art and the control valve of the present invention is particularly suited for use with a differential lock of the type disclosed in the commonly assigned U.S. Pat. No. 3,292,720 granted-to Harvey, Dec. 20; 1966.
  • the control valve presently used with the Harvey differential lock requires that the valve be disassembled for adjusting the modulating pressure and includes a poppet valve element, which is affected by changes-in the inlet pressure.
  • a pressure-modulating control valve which has means for adjusting the modulating pressure without disassembling the valve.
  • Another object is to provide a control valve, which includes a spool valve element that remains unaffected by changes in inlet pressure.
  • a further object is to provide a check valve in the inlet, for blocking flow to the spool valve to substantially eliminate parasitic losses when the spool valve is in the position corresponding to disengagement of the differential lock, and a mechanical actuator for lifting the check valve from its seat when the spool valve element is shifted to the position corresponding to engagement of the differential lock.
  • Still a further object is to provide a control valve of simple and inexpensive construction.
  • FIG. -1 is a fragmentary view, partly in elevation, partly schematic, and partly in section as respects the tractor differential and control valve, the parts illustrated in a condition in which the differential is locked.
  • FIG. 2 is a partialschematic and sectional view of the prior art control valve.
  • FIG. 1 there is shown a fragmentary section of a tractor differential of the type with which the control valve of the present invention is particularly adapted for use.
  • the differential has an input shaft 12 which lies along the fore-and-aft axis A A of the tractor and carries a bevel pinion 14 that is meshed with a ring gear 16 of the differential 10.
  • the ring gear is connected, in a conventional manner, to a differential carrier 17 which includes a plurality of differential pinions 18 in constant mesh with right and left-hand side gears 20 and 22 which are keyed respectively to rightand left-hand axles 24 and 26 having an axis B B perpendicular to the axis A A.
  • a multiple disk clutch28 is selectively engageable and disengageable between the left-hand side gear 22 and the carrier 17 by actuating a clutch piston 29.
  • the differential When the clutch is disengaged or released, the differential performs its normal function. When the clutch is engaged, the differential is locked up and the axles 24 and 26 are driven as one.
  • the clutch piston 29 is hydraulically controlled by fluid pressure from a pump 30 through a differential control valve 32, having a pressure line 34 leading to the clutch via drilled passages that will be obvious without further description.
  • the differential control valve 32 includes a generally upright valve body 38 having a valve bore 40 formed therethrough.
  • the lower end of the valve bore serves as a control port 42 and is connected to the pressure line 34 by means of a fitting44.
  • Return and pressure ports 46 and 48 respectively intersect the bore at axially spaced locations intermediate the ends of the bore.
  • the return port is connected to a fluid reservoir 49, and the pressure port is connected to the pump 30.
  • valve spool 52 Arranged serially in the valve bore 40 from the bottom 'to the top thereof (FIG. 1) are a return spring 50, a valve spool 52, a pressure-modulating spring 54 and a valve plunger 56.
  • the valve spool 52 includes an upper land 58 and a lower land 60 respectively separated from an intermediate land 62 by a pair of annular grooves. Extending in the valve. spool 52 between and fluidly interconnecting the bottom of the valve spool 52 with the annular groove located between the upper land 58 and the intermediate land 62 is a passage 64'.
  • the valve spool 52 isshifted axially in the bore 40 among an upper position wherein the control port 44 is fluid-connected to the return port 46 to establish a released condition in the clutch 28, a lower position (that shown) wherein the control port 44 is fluid-connected to the pressure port 48 to establish an engaged condition in the clutch 28 and an intermediate position wherein the control and pressure ports 44 and 48 are blocked from each other and the return port to establish a hold condition in the clutch 28 wherein the latter is held engaged at a selected pressure.
  • the position of the valve spool 52 and hence the condition of operation of the clutch 28 is dictated by the plunger 56, which is selectively shiftable axially in the bore between extreme upperand lower positions in the bore 40 in a manner to be described below.
  • the valve spool 52 is held in its upper position by the action of the return spring 50.
  • the action of the modulating spring 54 quickly overcomes the return spring 50 must be overcome in order to move the valve spool 52 from its lower to its intermediate position, increases as the modulating spring 54 ascends in the bore 40 and that the condition for establishing a maximum clutch'engaging pressure is effected by moving the plunger 56 to its lowermost position in the bore 40.
  • a check valve 68 is provided in the pressure port 48 and includes a check ball 70 biased against a seat 72 by a spring 74 to prevent flow into the valve bore 40.
  • a pin 76 extends from the check ball 70 slightly into the bore 40 where it is engaged and shifted by an annular ramp 78 at the lower side of the intermediate land 62 to unseat the ball as the spool 52 is shifted downwardly.
  • a prior art control valve 1 10 is illustrated in FIG. 2 in order that applicants contribution to the art may be readily perceived.
  • the control valve is generally similar to the control valve 32, described above, and includes a valve bore 112 in which a valve plunger 1 13 is manually shifted to act through a modulating spring 1 l4 and shift a flow control valve element 1 16.
  • the modulating force of the spring 114 may be adjusted by disassembling the valve and adding or removing in trial and error fashion shims, such as 118, between the spring and the flow control valve element 1 16.
  • a poppet-type check valve is normally biased against a seat 122 by a spring 124 to prevent pressurized fluid from the In order to prevent parasitic losses or leakage across the pump 30 from flowing through a fluid passage 126 to the schematically shown differential clutch 28.
  • the valve plunger 112 When it is desired to engage the clutch 28, the valve plunger 112 is shifted toward the check valve to the position illustrated and the check valve is unseated by a pin 128 which is between the flow control valve element and the check valve. It is important to note that the check valve opens against the inlet pressure and its action is thus affected by changes in the line pressure, and therefore, the check valve is somewhat unstable in operation. Movement of the plunger to the left from the illustrated position disengages the clutch by connecting the clutch to the fluid resevoir via the bore.
  • a manual control 130 is provided for shifting the valve plunger 112'and includes a bell crank 132 connected by means of an overcenter shiftable link 134 to the valve plunger.
  • control valve 32 The operation of the control valve 32 is briefly reiterated as follows:
  • a manual control linkage 80 is provided for selectively shifting the valve plunger 56 axially in the bore 40 between the aforementioned extreme upper and lower positions.
  • the control 80 includes an on-off" pedal 82 pivotally mounted on a transverse horizontal pin 84 carried in a bracket 86, which is integral with and extends above the valve body 38.
  • the pedal 82 is in the form of a bell crank having an upper arm or pad portion 88 and a lower arm 90, the latter being pivotally connected by means of a pin 92 to the upper end of a link 94.
  • the lower end of the link 94 is pivotally connected to the top of the plunger 56 via a pin 96.
  • the pivot pin 92 moves overcenter relative to the pivot pins 84 and 96 when the pedal 82 is pivoted between an on position, as shown, wherein it is prevented from further clockwise pivoting by a stop surface 98 on the bracket 86, and an off position wherein it is prevented from further counterclockwise pivoting by a stop pin 99 projecting from the bracket 86 into the path of movement of the pedal 82.
  • the return spring 50 acts through the spool 52 and modulating spring 54 to maintain a constant upward bias on the plunger 56 and thus biases the pedal 82 against the surface 98 when the pin 92 is left of center as shown and biases the pedal 82 against the pin 99 when the pin 92 is to the right of center.
  • the arrangement of the pedal 82 and link 94 is such that the valve plunger 56, and hence the modulating spring 54 are progressively shifted farther downwardly in the bore 40 as the pedal 82 is rotated from its "off" to its on position.
  • the pin 92 is only slightly to the left of center when the pedal 82 is in the on" position.
  • the overcenter characteristic of the linkage defined by the pedal 82, link 94 and plunger 56 acts in conjunction with the stop surface 98 to effectively releasably hold the plunger 56 in its lowermost position once the pin 92 is moved to the left of center. It can then be appreciated that the maximum modulated pressure for engaging the clutch 28 can be obtained and maintained by moving the pedal 82 to and keeping the pedal 82 in its on" position.
  • the link 94 is constructed so as to be length-adjustable.
  • the link 94 includes an upper portion 100 and a lower portion 102, the lower portion including a stem 104 threaded into the upper portion. Adjustment is made by moving the link 94 into axial alignment with the bore 40 and then by turning the valve plunger 56 one way or the other for lengthening or shortening the link 94 as desired, respectively resulting in the plunger 56 being disposed a greater or lesser distance downwardly in the bore 40, which, of course, in turn results in the modulating spring 54 being respectively disposed at greater or lesser distance downwardly in the bore 40.
  • a pressure-modulated control valve comprising: a valve body defining a valve bore having pressure, return and control ports opening thereinto; a valve plunger, a compressible modulating spring, a valve member and a compressible return spring being serially arranged in said bore respectively from one end thereof, the valve plunger projecting from said one end; a manual control linkage means connected to said valve plunger and being movable between ofF and on" positions for respectively moving said plunger between first and second positions respectively of minimum and maximum extent into the bore; said return spring holding said valve member in a first position establishing fluid communication between said control and return ports when said control linkage means is in said off" position; the control port being so located relative to the valve member that pressure at the control port acts against the valve member and causes the latter to shift in the direction of the modulating spring; the valve plunger and modulating spring acting to shift the valve member from its first position to a second position establishing fluid communication between said control and pressure ports when the control linkage means is moved from said ofi to said on
  • length-adjustable link includes two portions, one being threadedly received in the other.
  • control linkage includes pivotable means pivotally connected to the end of the link opposite from the end connected to the valve plunger and movable to dispose the link in axial alignment with said bore; whereby the length of the link may be adjusted by rotating the valve plunger.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
US3667496D 1969-10-22 1969-10-22 Pressure-modulated hydraulic control valve Expired - Lifetime US3667496A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US86849869A 1969-10-22 1969-10-22

Publications (1)

Publication Number Publication Date
US3667496A true US3667496A (en) 1972-06-06

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ID=25351807

Family Applications (1)

Application Number Title Priority Date Filing Date
US3667496D Expired - Lifetime US3667496A (en) 1969-10-22 1969-10-22 Pressure-modulated hydraulic control valve

Country Status (3)

Country Link
US (1) US3667496A (enrdf_load_stackoverflow)
CA (1) CA927238A (enrdf_load_stackoverflow)
FR (1) FR2065448A5 (enrdf_load_stackoverflow)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1999964A (en) * 1932-10-12 1935-04-30 Clarence W Gustafson Air brake operating device
US2424331A (en) * 1943-09-20 1947-07-22 Alco Valve Co Brake valve
US2476054A (en) * 1948-04-14 1949-07-12 Goodrich Co B F Pressure-regulating valve assembly
US2698205A (en) * 1948-01-27 1954-12-28 Bendix Aviat Corp Control valve
US2844166A (en) * 1954-11-03 1958-07-22 Deere Mfg Co Hydraulic detent for valve
US2968316A (en) * 1956-03-05 1961-01-17 Bendix Corp Power steering valve
US3473566A (en) * 1968-04-19 1969-10-21 Clark Equipment Co Control valve

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1999964A (en) * 1932-10-12 1935-04-30 Clarence W Gustafson Air brake operating device
US2424331A (en) * 1943-09-20 1947-07-22 Alco Valve Co Brake valve
US2698205A (en) * 1948-01-27 1954-12-28 Bendix Aviat Corp Control valve
US2476054A (en) * 1948-04-14 1949-07-12 Goodrich Co B F Pressure-regulating valve assembly
US2844166A (en) * 1954-11-03 1958-07-22 Deere Mfg Co Hydraulic detent for valve
US2968316A (en) * 1956-03-05 1961-01-17 Bendix Corp Power steering valve
US3473566A (en) * 1968-04-19 1969-10-21 Clark Equipment Co Control valve

Also Published As

Publication number Publication date
FR2065448A5 (enrdf_load_stackoverflow) 1971-07-23
CA927238A (en) 1973-05-29

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