CA1192811A - Flow divider-combiner valve - Google Patents
Flow divider-combiner valveInfo
- Publication number
- CA1192811A CA1192811A CA000429712A CA429712A CA1192811A CA 1192811 A CA1192811 A CA 1192811A CA 000429712 A CA000429712 A CA 000429712A CA 429712 A CA429712 A CA 429712A CA 1192811 A CA1192811 A CA 1192811A
- Authority
- CA
- Canada
- Prior art keywords
- cavity
- elements
- passageways
- pressure
- divider
- 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
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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
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/022—Flow-dividers; Priority valves
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluid-Pressure Circuits (AREA)
- Vehicle Body Suspensions (AREA)
- Servomotors (AREA)
Abstract
Abstract of the Disclosure A novel flow divider-combiner valve unit is disclosed.
A valve body includes fluid passageway means for con-trolling fluid flow through the divider-combiner valve unit. The fluid passageway means comprises: a cavity, first, second and third passageways; first and second pressure-responsive elements; and biasing elements for retaining the pressure-responsive elements substantially in open positions until a predetermined substantial pressure differential exists in the divider-combiner valve unit. The biasing elements also enable the pressure-responsive elements to move substantially independently of each other toward closed positions when a first pressure differential in the divider-combiner valve unit exceeds the predetermined pressure differen-tial. The biasing elements additionally cause the pressure-responsive elements to move substantially in unison when a second pressure differential in the divider-combiner valve unit exceeds the predetermined pressure differential. The first and second passage-ways communicate with first and second spaced portions of the cavity. The third passageway communicates with an intermediate portion of the cavity. The first and the second pressure-responsive elements are movable in the cavity respectively between first open positions and progressively closed positions. The fluid passage-way means controls fluid flow through the divider-combiner valve unit by controlling fluid flow between the first and the second cavity portions and the first and the second passageways.
A valve body includes fluid passageway means for con-trolling fluid flow through the divider-combiner valve unit. The fluid passageway means comprises: a cavity, first, second and third passageways; first and second pressure-responsive elements; and biasing elements for retaining the pressure-responsive elements substantially in open positions until a predetermined substantial pressure differential exists in the divider-combiner valve unit. The biasing elements also enable the pressure-responsive elements to move substantially independently of each other toward closed positions when a first pressure differential in the divider-combiner valve unit exceeds the predetermined pressure differen-tial. The biasing elements additionally cause the pressure-responsive elements to move substantially in unison when a second pressure differential in the divider-combiner valve unit exceeds the predetermined pressure differential. The first and second passage-ways communicate with first and second spaced portions of the cavity. The third passageway communicates with an intermediate portion of the cavity. The first and the second pressure-responsive elements are movable in the cavity respectively between first open positions and progressively closed positions. The fluid passage-way means controls fluid flow through the divider-combiner valve unit by controlling fluid flow between the first and the second cavity portions and the first and the second passageways.
Description
FLOW DIVIDER-COMBINER VALVE
Background of ~he Invention This invention i5 directed t~ a novel flow control valve, alld more particularly, is directed to a novel flow divider-combiner valve.
A flow divider-combiner valve is generally designed for use with a system which uses a pressurized hydraulic fluid to drive at least -two hydraulic cylinders, motors, or the like, one such being driven independently of the other. Such a valve functions as a flow divider when a single stream of hydraulic fluid, from a hy-draulic fluid source, flows through the valve and there-by is divided into at least two hydraulic fluid streams.
When flow of hydraulic fluid through such a valve is reversed, the valve functions as a flow combiner to combine several such hydraulic fluid streams.
For example, such a flow divider-combiner valve is often used in combination with a wheeled vehicle having at least two independently driven wheels. Each wheel of the vehicle is generally driven by a respective hy-draulic motor. Each hydraulic motor is generally ~..
connected to the combiner side oE such a valve as wellas to the divider side. Independent connections be-tween the flow-divider side of the valve and the respec-tive hydraulic motors are made in a manner such that the flow divider-combiner valve supplies each hydraulic motor, independently, with hydraulic Eluid. In addi-tion, independent connections between the flow-cornbiner side of the valve and the re!spect;ve motors are made in a manner such that the divider-combiner valve re-ceives at least two independent streams or flows ofhydraulic ~luid from the separate hydraulic motors.
Thus t the flow divider~combi~er valve e;ther indepen-dently supplies hydraulic fluid to or independently receives hydraulic fluid from each such hydraulic motor.
For such a wheeled vehicle, flow of hydraulic fluid through the valve causes each of the driven wheel~s to rotate at about the same speed and in the same direc-tion. When flow of fluid is reversed through the valve, rotation of the wheels is similarly reversed.
Thus, when equipped with a flow-combiner valve, the wheeled vehicle does not require a conventional trans-mission.
It is desirable that the divider-combiner valve cause the wheels to rotate at about the same speed so that the wheeled vehicle moves in a linear and predictable fashion.
Commercially available divider-combiner valves genera~-ly independently control flow of hydraulic fluid to each hydraulic motor by being responsive to pressures within and thereby accordingly ad~justing or regulating the flows within the connections, lines or conduits supplying hydraulic fluid to or receiving hydraulic fluid from the hydraulic motorsO A problem is encoun-tered when using such commercially available divider-com~iner valves, however, when one motor is subjected to a no load condition (such as when its respective wheel is on ice) or when the vehicle is turning. ~ost of the commercially available divider-combiner valves react to such situations in two ways. E'irst, as to the no~load condition, conventional divider-combiner valves generally re~porld to ~uch a con~ition by reduc-ing flow of hydrau~lc fluid through the no-load motor and by reducing flow through the other motor as well, resulting in the slowing down or stopping of the vehicle.
Second, when the vehicle is directed around a corner, the wheel traversing the greater arc causes its r~espec-tive motor to act as a pump7 in contrast to the motor guiding the vehicle through the turn. The motor which acts as a pump causes a low resistance to flow to be sensed at the conventional divider-combiner valve con-nected thereto. The divider-combiner valve responds by reducing the flow of hydraulic fluid to the motor guiding the vehicle through the turn. In addition, when the wheeled vehicle is directed around a corner, the wheel traversing the greater arc sometimes locks up, and upon being dragged across the ground by the wheel traversing the lesser arc, generally gene,rates skid marks upon the ground, rug or such support sur-face.
Objects and Summary of the Invention Accordingly, it is a general object of this inventionto provide a novel divider-combiner valve.
A more speclfic objec-t is to provide such a valve which, when used with an apparatus such as a wheel.ed vehic]e, does not react to cause such a vehicle -to stop when one wheel oE the veh.icl.e is subjected to a no-load condition.
A related object: is to p:rovic1e such a valve which, when used with such a vehicle, is adapted to substantially avoi.d a whee1 lock-up condition whiGh otherwise might occur when such a vehicle is directed around a corner.
~riefly, and in accordance with the foregoing objects, a Elow divid.er-combiner valve unit will now be summarized.
According to one aspect of the invention a flow divi-der-combiner valve unit comprises a cavity having first and sec-ond spaced portions and a cavity portion intermediate the first and second cavity portions. First and second passageways com-municate with the first and second cavity portions, and a third passageway communicates with the intermediate cavity portion.
First and second pressure-responsive elements are individually movable in the cavity respectively between open positions and progressively closed positions thereby for controlling fluid flow between the first and second cavity portions and the first and second passagewaysO The first and second elements respect--ively include fourth and fifth passageways providing communica-tion between the first and second passageways and the cavity.
The fourth passageways are alignable with one of the firs-t and second ,~ -4a-passageways and the fi:L-th passageway is alignable w:i-th the other of the firs-t and second passageways for thereby providi.ng the open positions for enabling substantially unrestricted flow individually through -the one and through the other of the Eirst and second passageways. Means are disposed within the cavity and are cooperatively engagable with the :Eirst and second ele-men-ts in a :Eirst predetermined inrler position fixed against fur-ther movemen-t inwardly of -the cavity for individually retaining the first ~nd second elements substantially in the open positions untll there is at least a predetermined substantial pressure difference between fluid pressures in the first and second cav-ity portions and the intermediate cavity portion~ Means are disposed within the caivty and are coactable with the retaining means, permitting movement of the retaining means from the inner position outwardly of the ca~ity under influence oE the adjacent press~e--responsive element for enabling the first and second elements to move substantially independently oE each other toward the respective closed positions when a predetermined pressure differential between the intermediate cavity portion and one of the first and second cavity portions exceeds the predetermined pressure difference, and for causing the first and second ele~
ments to move substantially in unison when the pressure diEfer-ential between the intermediate cavity portion and both of the first and second cavity portions exceeds the predetermined pressure difference.
-4b-According to another aspect of the invention there is providedl in combination with a fluid source, a flow divlder combiner valve unit comprising a cavity having first and second spaced end por-~ions and an intermecliate por-tion disposed between the first and second cavity end por-tions. First and second passageways provide fluid communication between the source and respective ones of the first and second spaced cavi.ty end portions. A third passageway provides fluid communication betwe~en the source and the in-termedi.ate cavi-ty portion. First and second pressure-responsive elements are individually movable in the cavity respectively between open positions and progress-ively closed positions thereby for controlling fluid flow be-tween the first and second cavity end portions and the first and second passageways. The first and second elements res-pectively include Eourth and fifth passageways providing com--munication between the first and second elements respectively, inlcuding fourth and fifth passageways providing communication between the first and second passageways and the cavity. The fourth passageway is alignable with one of the first and second passageways and the fifth passageway is alignabl.e with the other of the first and second passageways for thereby providing the open positions for enabling substantially unrestricted flow individually through the one and through the other of the first and second passageways. Means are disposed within the cavity and are cooperatively engageable with the first and second elements for individually retaining the first and second ele-ments in a first predetermined inner position fi~ed against r'~
fur-ther movement inwardly of the cavlty substantially in the open positions unti:l there is at least a predetermined substan-tial pressure dif:Eerence between fluid pressures in the first and second cavity portions and the intermediate cavity portion.
Means are disposed within the cavity and are coactable with the retaining means for permittlng rnovement of the retaining means :Erom the inner posit:ion ou-twardly oE the cavity under in-:EI.uence o:E the adjacent pressure-responsive element fo:r enabling the first and second elements to move substantially independen-tly of each other toward the respectlvely closed positions when a predetermined pressure differential between the intermediate cavity portion and one of the first and second cavity portions exceeds the predetermined pressure diference between the inter-mediate cavity portion and both of the first and second cavity portions exceeds the predetermined pressure difference.
Br;ief Description of the Drawings The foregoing, as well as other objects, features and advantages of the invention will become more readily understood upon reading the following detailed description of the. illus-trated embodimen-t, together with reference to the drawings, wherein:
~9 ~
FIG. 1 is a schematic of a hydraulic circuit incorporat-ing the divider-combiner valve of the invention;
FIG. 2 is a side view, partially in section, of a pre-ferred embodiment of the flow divider-combiner valve in accordance with the invention, respectively present-ing open positions between ~irst and second spaced por-tions of the cavity and :Eirst and second passageways through the valve body;
FIG. 3 is a partial view, in section, presenting upward-ly directed axial ~ovement of the upper pressure-respon-sive Elow control e-ement within the cavity and subse quent partial closure of one of the passageways;
FIG. 4 is also a partial view, in section, but present-ing downwardly directed axial movement of the flow con-trol element presented in FIG. 3 (within the cavity) and subsequent partial closure of the passageway;
FIG. 5 is a side view, partially in section, presenting one fluid-flow situation where the two pressure-respon-sive flow control elements axially move in unison within the cavity; and, FIG. 6 is a side view, partially in section, presenting another such fluid-flow situation where the two pres-sure-responsive flow control elements axially move in unison within the cavity.
B~L~
Detai3ed Description of the Illustrated Embodiment Referring to the drawings and initially to FIG. 1, the novel divider~combiner valve wi]l now be discussed as it is used in combination with a typical hydraulic cir-cuit. The hydraulic circuit ;ncludes a fluid source 217 and a pump 23 for drawirlg the hydraulic Eluid from the source 21 ~via a conduit 25) and for pumping the fluid forward through a system or hydraulic circuit ~6. Flow of hydraulic fluid through the circuit 26 can be accomplished in any one of at least three dif-ferent ways.
A well-known schematic representation for a convention-al, bîased, threc-position solenoid valve, referred to generally by the reference numeral 27, presents a Eirst position 29 which permits or causes the hydraulic fluid to bypass much of the hydraulic circuit 26 and to be directed back to the fluid source 21 via a con-duit 31.
A second position 33 of the solenoid valve 27 permitsor causes hydraulic fluid to be directed forward in the hydraulic circuit 26 via a conduit 35 and into the flow divider-combiner valve, referred to generally by the reference numeral 37. With the solenoid valve ~7 in the second position 33, the flow divider-combiner valve 37 functions as a flow divider, hydraulic fluid being directed through individual conduits 39, 41 to individual, respective hydraulic motors 43, 45. Eac~
hydraulic motor 43, 45 is directly coupled to and is used to drive a respective wheel (wheels not shown).
$
Hydraulic fluid individually exLts each hydraulic motor 43, 45 via a respective conduit 47,49. The hydraulic Eluid exiting the motors 43, 45 ls combined in a mani-fold 51 and conveyed orwardwlthin the manifold 51, through the conduit 31 and ultimately, is conveyed throu~h the conduit 31 bacl~ into ~he source 21. to com-plete the flow of h~draulic fluid throu~h the circuit 26.
~en the solenoid valve ~7 i.s set at a third position 53, flow of hydraulic ~luid through much of the divider-combincr valve 37 and hydra~llic motor 43, 45 portions of the hydraulic clrcui-t ~6 is reversed and the flow divider-combiner valve 37 functions as a flow combiner:
whereby hydraulic fluid, which is flowing out of the divider-combiner valve 37,is directed via the conduit 35, through the conduit 31, and ~ack into the fluid source 21.
~eferring to FIGo 2, i~ will be seen that khe preferred embodiment of ~he flow divider-combiner valve 37 of the present invention is generally cylindrical in shape and adapted ~o be disposed within a cavity (referred to generally by the reerence numeral 55) o~ a valve body 57. The cavity 55.comprises a series of individual steps 58A, 58B, 58C, and.58D, all of which are concen-tric with each other. The diameters of the steps 58A, 58B, 58C and 58D progressively decrease moving inwardly into the cavity 55. ., The divider-co~biner valve 37 structure presented in FIGS. ~-6 includes ex~ernal circum~erential threads 59 near the opening or mouth of the cavity 55 so that the divider-combiner valve 37 can be screwed into mated threads which have been cut or otherwise formed in the valve body 57.
A first O-ring 61, located near the outer or ex~erior surface of the valve body 57 and circumferentially mounted at ~he opening or mouth o:E the cavity 55, is urged against ~he threads 59 (at the junction of the divider-combiner valve 37 and the -valve body 57) by,a portion of a valve ca~ or retainer 63 in a manner such that the flrst O~ring 61 seats and thereby seals the divider-combiner valve 37 into the cavity 55.
A second ~-ring 65, circumferentially carried by the divider-combiner valve 37, seats against a circum-ferential portion of ~he inner periphery of the cavity55, is urged outwardly against such circumferential portion by the divider-combiner valve 37 and ther,eby seals the first step 58A o the cavity S5 from the second step 58B. A third O-ring 67 similarly carried by the divider-combiner'valve 37 and similarly circum-ferentially urged against different portions of the inner periphery of the cavity 55 similarly seals off or isolates the second step 58B from the third step 58C. A fourth O-ring 69 similarly isolates the third step 58C from the fourth step 58D.
The valve body 57 presented in FIGS. 2-6 includes a first or upper passageway 71 which permits co~unica-tion of hydraulic,fluid between the hydraulic fluid source 21 and the first step 58A of the cavity 55. The valve body 57 also includes a second or intermediate passageway 73 which permits similar hydraulic fluid ~ 10 -communication between the hydraulic fluid source 21 and the second step 58B of the cavity 55. The valve body 57 further includes a third or lower passageway 75 (presented in FIGS. 2, 5 and 6) which permits com munication between the hydraulic fluid source 21 and the third and fourth steps 58C and 58D.
It can be appreciated that t:he valve hody 57 can in-clude a plurality of individual passage.ways at any of the above-discussed first (or upper), second (or in-termediate) or third (or lower~ passageways 71, 73 or 75~ which respective~y perm~t fluid co~munication between the hydraulic fl.uid source 21 and the first, second and third (and fourth) steps 58A,.58B and 58C
(and 58D) of the cavity 55.
When the divider-combiner valve 37 functions as ~ flow divider, the second passageway 73 functions as a fluid input or inlet port for the valve 37,.and the first and ~hird passageways.71, 75 function as fluid output or outlet port~. When the valve 37 functions as a flow . combiner~ inlet and outle~ functions of the passage-ways 71, 73 and 75 are reversed.
The illustrated.embodiment of the valve 37 is disposed within the cavity 55 along an axis 77; and a valve housing 79 (static in relation to the valye body 57) separates the inner working parts of ~he valve,37 .
from the cavity 55. The valve hcusing 79 includes threads 80 externally circumferentially cut or Dther-wise formed along a portion of the outer periphery of the valve housing 79 proximate to the opening or mouth of the cavity 55. A circumferentlal inner portion of the retainer 63 includes mated threads 80, the retainer 63 being screwed onto the valve housing 79 at the threads 80, the valve housing 79 thereby being held or otherwise S urged into the cavity 55 by the retainer 63.
The ~alve housing 79 provides a generally cylindrical shell, on line with and oriented about the axis 77, enclos:ing a cylindrical chalmel 81 through which hy-draulic fluid flows alld.wi~hin w'hich two pressure-responsive flow con-tro'l elernents 83, 85 snugly fit.
Movement of the flrst and seeond flow control elements 83 r 85 is permitted generally along the axis 77.
Each flow con.trol elemen~ 83, 85 has ~n inner core portion 87, a plurality of orifices 89, and a plura].ity of respective ports 91A, 91B. Each respective inner core por~ion 87 provides each respective flow control element 83, 85 with a eylindrically-shaped inner void oriented substantially about the axis,77. Each o'rifice . 89 forms a cylindrically-shaped void through a portion of the respective flow control elements 83, 85, each - orifice 89 being oriented substantially transverse to ~he axis 77 and permitting fluid communication between a portion of t.he channel 81 and the inner core 87.
Each orifice 89 has a relatively small diameter, as contrasted agains~ the relatively large diamete.r of the core portion 87. Each flow control elemen~ 83, 85 has a respective p'lurality of ports 91A, 91B which pro-vide fluid communication between portions of the channel81 and respective inner portions 87 of the flow control elements 83, 85. Like ~he orifices89, each port 91A, 91B forms a cylindrically-shaped void through a por~ion of the respective flow control element 83, 85, each respective port 91A, 91B being oriented substantially transverse to t'he axis 77. An individual port 91A, 91B has a greater diameter than an individual orifice 89~ In addition, as -to the upper or the lower flow con-~rol element 83 or 85, the c~ulati.ve cross-sectional area of all of the ports 91A or 91B is substan-tially greater than the cumulative cro~ss-sectional area of all of the orifices 89.
As an initially empty valve 37, functioning as a flow divider, is fille~ with hydraulic fluid; hydrau].ic fluid enters`the cavity 55 via the second or inter-mediate passageway 73 and flows ~rom the second step 58B (of the cavity 55), through the valve housing 79 via a.first opening 93, and into an intermediate por-tion 95 of the channel 81. Once in the intermediate portion 95, fluid flows through the orifices 89 and into the core portion 87 of each respective flow con-trol-element 83,-85. Hyd~aulic fluid eventually fills 'each inner core portion 87 and the remainder portions 97, 98 ~of,~he channel 81) and thereafter is caused to flow out of the channel 81 via the ports 91A, 91B, and into the first (or upper) and third (or lower) passageways.71, 75. The first and third passageways 71, 75 are appropriately connected individually to hydraulic ~otors 43, 45 (FIG. 1), as discussed above.
First and second end caps 99, 101 seal respective ends of the channel 81 thereby isolating the channel 81 frorn the cavity 55. The upwardly oriented or outwardly extending end cap 99 is not integral with the end portion of the valve housing 79, but, rather, is urged against such end portion of the valve housing 79 by a spacer 103, which itself is biasly engaged and inwardly urged in~o the cavity 55 by ~he above~discussed cap or re~ainer 63.
Nor is khe downwardly orlent:ed or inwardly extending end cap 101, located at the other end portion oE the ~ralve housing 79, integral with ~he valve housing 79.
Rather, the lower end cap 101 i5 urged against the opposite end portion of the valve housing 79 by the base 102 of the ca-~:Lty 55.
A first or upper spring 105, preloaded to a pressure corresponding to about 50 psi and partially restrained by a first or upper spri.ng guide 107 which is secured by a bolt 109 to the upper end cap 99, is oriented along the axis 77 between the end cap 99 and the first flow control element 83 such that the upper spring 105 urges the upper flow control element 83 away from the end cap 99. Biasing action of the upper spring 105 upon the upper flow control element 83 is restrained, however, when the upper spring guide 107 is restrained, by the head of the upper bolt 109 (FIGS. 2, 4 and 6).
Such a restraint; by the upper spring guide 107 is of a one-way nature and the spring guide 107 is generally free to mo~e axially along the axis 77 compressing the upper spri.ng 105 (FIGS. 3, 5). However, it is.the action of the first or upper flow control element 83, acting upon the upper spring guide 107, which compresses the upper spring 105 (FIGS. 3 and 5).
In a similar fashion, a second or lower spring 111, also preloaded to a pressure corresponding to abou-t 50 psi, is partially restrained by a second or lower spring guLde 113 which is secured to the lower end cap lOl by a second bolt 115. ]:n a manner somewhat similar to ~.he above discussion, the lower spring 1].l. generally urges the lower flow control element 85 and the lower end cap lOl apart but is restrai.ned by the lower spring guide 113 engaging the head o the lower bolt 115.
Restraint of the lower spring 111 is similar to the one-way klnd of restraint discussed above in that as the lower flow control element 85 move.s upwardly away from the lower spring guide 113,.the lower flow control element 85 eventually becomes fr~e from in:Eluence of the lower spring 111 (FIG~ 6). However, the compressive action of the lower flow control element 85 upon the lower spring guide 113 comp~esses the lower spring 111.
Whenever the first spring 105 or the second spring 111 is in such a restrained 5 tate (FIG. 2) and while the upper and lower flow-control elements 83~ 85 respectively touch the upper and lower spring guides 107, 113, the ports 91A and 91B of the first .(or upper) and second (or lower) flow control elements 83 and 85 substantially line up respectively.with a second and third opening 117 and 119 through the valve housing 79 thereby permit-. ting flow of hydraulic fluid therethrough and fluidcommunication between respective first and thi~d pas-sageways 71 and 75 and a core portion 87 of respective first and second flow control elements 83, 85.
Prior to the present invention, the first and second springs 105 and lll had been moderately weak springs.
It was not uncommon, in a commercially available divider-combiner flow valve, to preload end springs to a presswre corresponding to about 5 psi. Hydraulic fluid pressures generally encowntered in passagewa~s 71 and 75 can easily cause the flow con-trol elements 83 or 85 to compress such a sprirlg and to restrict, sometLmes adversely, flow through such passageways 71 or 75.
In addition, the present invention incorporates spring guides 107 and 113 -to restrain the end springs 105 and 111 and, more importantly, to maintain a substantially unrestricted flow conditio~ permit~ing hydraul.ic fluid to generally freely flow ~hrough the passageways 71 and 75. Thus, it is the cooperation between the springs 105, 111 and respective spring guides 107, 113 wh.i.ch permits fluid flow thrcugh passageways 71, 75 to be relatively insensitive to operating upsets which other-wi~e result in fluid pressu~e changes and resultantchanges in flows of hydraulic fluid occurring within the passageways 71, 75.
A third or intermediate spring 121, preloaded to a pressure corresponding to about 25 psi, is oriented ~long the axis 77 such that the first flow control element 83 is bi~sed against the second flow control element 85.
When the valve 37 functions as a flow divider, it can be appreciated that the orifices 89 effect a pressure drop for the hydraulic fluid flowing from the inter-media~e portlon 95 (of tlle channel 81) into the hollow inner cores 87 of the respective flow control elements ~3, 85. Referring to -the :Eirst or upper pressure~
responsive flow control element 83 (FIG. 2), it wi.ll be appreciated that such a press~.re drop e~ists becau~e the orifices 89 offer much m~re resistance to flow than do the ports 91~. ~ecause ~.he orifi.ces 89 o~e.r such a resistance to flow, a fi.rst pressure di~ferential exists between a firs~ pressure-responsive swrface 123 and a second pressure-r~sponsi~e surface 125 of the first flow control element 83.
The orifices 89B (of the second flow control element 85) are similarly responsible for a second pressure differential acting upon the second flow control ele-ment 85.
When the valve 37 functions as a flow divider, it will be appreciated that as fluid pressure in the inter-mediate portion 95 of the channel 81 causes the sum of the first and the second pressure differentials to exceed 25 psi, the upper and the lower springs 105, 111 become compressed by the respective.flow control ele-ments 83, 85. As the first flow control element 83 compresses the first spring 105, the ports 91A of the first flow control element 83 move in relation to the (corresponding) second opening 117 (FIG. 3) and flow therethrough becomes restricted (to a slight degree).
Likewise, compression of the second or lower spring 111 by the second or lower flow control element 85 similarly moves the ports 91B (of the second flow control element 85) in relation to the (corresponding) third opening 119 similarly resulting in slight restriction of hy-~ 17-draulic fluid therethrough.
The first and the second flow control elements 83, 85 each incLude an L-shaped ~all 127, 129 structurally integral therewith and ext:endi}lg outwardly therefrom in the direction of the ot.her flow control element 83, 85. The L-shaped end ~r. tail 127 of the upper flow control element 83 and the I..-shaped tail 129 of the lower flow control element 85 are axially inserted in-to opposite ends of the intel~medlate spring 121, are adapted to inter~it therein, and are fur~her adapted to engage at end portions 131 of the L-shaped tails 127, 129 so that the first and second flow control elements 83, 85 move in un.ison (FIG. 5) when fluid pressure in the intermediate portion 95 (of the cavity 55) is sufficient to compress the end springs 105, 111 and cause the end portions 131 of opposing tails .127, 129 to touch. And when fluid pressure within the upper passageway 71 or the lower passageway 75 or both such passageways 71, 75 ~FIG. 6) is sufficiently greater than the pressure exer~ed by the intermediate spring 121, the intermediate spring 121 becomes compressed and the L-shaped tail 127, 129 of one flow control element 83, 85 butts agains~ the other flow control element at ends 133; and both flow.control elements-83, 85 move in unison ~FIG. 6) within the channel 81.
When the divider-combiner valve 37 is functioning as a flow divider and the first or upper passageway 71 is supplying a hydraulic.motor 43 or 45 which is under little or no load (as would be the case when such a hydraulic motor 43 or 45 drives a wheel on ice), the -1.7A-no-load hydraulic mo~or ~3 or 45 offers very little resistclnce to flo~ o.E hydraulic fluid and hydxaulic fluid pressure resul~ingly drops in the first passage-way 71. ~Iydraulic fluid pressure in the inner core 87 of the first or upper flow control elemen-t 83 accor-dingly drops, which results in an increase in the (first) pressure ~lferen-till (between the first and t'he second pressure-responsive sur~aces 123 and 125) of the first or upper flow control element 83. Whereupon, the first flow control element 83 moves upwardly ln the cavlty 81, usually compressi~g the upper spring 1~5 (FIG. 3).
However, because the upper spring 105 is relatively insensitive to most pressures no~mally experienced within the upper passageway 71, the upper spring 105 is not substantially compressed and flow through the first or upper passageway 71 is not entirely cut off (FIG. 3); and if the flow control elements 83, 85.are acting in unison (FIG. 5), fluid ~low through the lower fluid passageway 75 is not greatly affected.
When flow of hydraulic fluid i9 reversed through the divider-combiner valve 37, the present invention pre-sents substantially the same advantages as to flow of hydraulic fluid through the passageways 71 and 75.
The flow control elements 83, 85 of the valve 37 are generally responsive to fluid pressure in the first (or upper) and third (or lower~.fluid passageways 71, 75, and are adapted to generally adjust flow of hy-draulic fluid accordingly. ~owever, the various ele-ments of the novel divider-combiner valve 37 of the inven~ion act or operate co-operatively to prevent total cut-off or restriction of hydraulic fluid through the passageways 71, 75 when the valve 37 is responding to operating upsets.
8~
Accordingly, -the present in-vention is relativel~ insen-sitive to system upsets such as would normally be ex-perlenced when the wheeled vehicle (discussed above) is on ice or is rotmding a corner. Incorporation of the valve 37 of ~he present invention within such a whee]ed vehicle has substantially eliminated the wheel ]ock-up problem discussed above and has significantly reduced the wheel-dragging problem (addressed above) experienced when the wheeled vehicle negotiates a curve.
The flow control elements 83, 85 of ~he divider-combiner valve 37 of the pr~sent invention normally act indepen-dently at the start o~ operation? eventually act in unison (FIGS. 5, 6), normally initially act independently when a system upset arises and eventually again act in unison sometime thereafter.
What has been illustrated and described herein is a novel flow divider-combîner valve unit. While the divider-combiner valve unit of the present invention has beenillustrated and described wi~h reference to a preferred embodiment, the invention is not limited thereto. On the contrary, al~ernatives, changes or modifications may become apparent to those skilled in the art upon reading the foregoing description. Accordingly, such alterna-tives, changes or modifications are to be considered as forming a part of the invention insofar as they f~l within the spirit and scope of the appended cl~ims.
Background of ~he Invention This invention i5 directed t~ a novel flow control valve, alld more particularly, is directed to a novel flow divider-combiner valve.
A flow divider-combiner valve is generally designed for use with a system which uses a pressurized hydraulic fluid to drive at least -two hydraulic cylinders, motors, or the like, one such being driven independently of the other. Such a valve functions as a flow divider when a single stream of hydraulic fluid, from a hy-draulic fluid source, flows through the valve and there-by is divided into at least two hydraulic fluid streams.
When flow of hydraulic fluid through such a valve is reversed, the valve functions as a flow combiner to combine several such hydraulic fluid streams.
For example, such a flow divider-combiner valve is often used in combination with a wheeled vehicle having at least two independently driven wheels. Each wheel of the vehicle is generally driven by a respective hy-draulic motor. Each hydraulic motor is generally ~..
connected to the combiner side oE such a valve as wellas to the divider side. Independent connections be-tween the flow-divider side of the valve and the respec-tive hydraulic motors are made in a manner such that the flow divider-combiner valve supplies each hydraulic motor, independently, with hydraulic Eluid. In addi-tion, independent connections between the flow-cornbiner side of the valve and the re!spect;ve motors are made in a manner such that the divider-combiner valve re-ceives at least two independent streams or flows ofhydraulic ~luid from the separate hydraulic motors.
Thus t the flow divider~combi~er valve e;ther indepen-dently supplies hydraulic fluid to or independently receives hydraulic fluid from each such hydraulic motor.
For such a wheeled vehicle, flow of hydraulic fluid through the valve causes each of the driven wheel~s to rotate at about the same speed and in the same direc-tion. When flow of fluid is reversed through the valve, rotation of the wheels is similarly reversed.
Thus, when equipped with a flow-combiner valve, the wheeled vehicle does not require a conventional trans-mission.
It is desirable that the divider-combiner valve cause the wheels to rotate at about the same speed so that the wheeled vehicle moves in a linear and predictable fashion.
Commercially available divider-combiner valves genera~-ly independently control flow of hydraulic fluid to each hydraulic motor by being responsive to pressures within and thereby accordingly ad~justing or regulating the flows within the connections, lines or conduits supplying hydraulic fluid to or receiving hydraulic fluid from the hydraulic motorsO A problem is encoun-tered when using such commercially available divider-com~iner valves, however, when one motor is subjected to a no load condition (such as when its respective wheel is on ice) or when the vehicle is turning. ~ost of the commercially available divider-combiner valves react to such situations in two ways. E'irst, as to the no~load condition, conventional divider-combiner valves generally re~porld to ~uch a con~ition by reduc-ing flow of hydrau~lc fluid through the no-load motor and by reducing flow through the other motor as well, resulting in the slowing down or stopping of the vehicle.
Second, when the vehicle is directed around a corner, the wheel traversing the greater arc causes its r~espec-tive motor to act as a pump7 in contrast to the motor guiding the vehicle through the turn. The motor which acts as a pump causes a low resistance to flow to be sensed at the conventional divider-combiner valve con-nected thereto. The divider-combiner valve responds by reducing the flow of hydraulic fluid to the motor guiding the vehicle through the turn. In addition, when the wheeled vehicle is directed around a corner, the wheel traversing the greater arc sometimes locks up, and upon being dragged across the ground by the wheel traversing the lesser arc, generally gene,rates skid marks upon the ground, rug or such support sur-face.
Objects and Summary of the Invention Accordingly, it is a general object of this inventionto provide a novel divider-combiner valve.
A more speclfic objec-t is to provide such a valve which, when used with an apparatus such as a wheel.ed vehic]e, does not react to cause such a vehicle -to stop when one wheel oE the veh.icl.e is subjected to a no-load condition.
A related object: is to p:rovic1e such a valve which, when used with such a vehicle, is adapted to substantially avoi.d a whee1 lock-up condition whiGh otherwise might occur when such a vehicle is directed around a corner.
~riefly, and in accordance with the foregoing objects, a Elow divid.er-combiner valve unit will now be summarized.
According to one aspect of the invention a flow divi-der-combiner valve unit comprises a cavity having first and sec-ond spaced portions and a cavity portion intermediate the first and second cavity portions. First and second passageways com-municate with the first and second cavity portions, and a third passageway communicates with the intermediate cavity portion.
First and second pressure-responsive elements are individually movable in the cavity respectively between open positions and progressively closed positions thereby for controlling fluid flow between the first and second cavity portions and the first and second passagewaysO The first and second elements respect--ively include fourth and fifth passageways providing communica-tion between the first and second passageways and the cavity.
The fourth passageways are alignable with one of the firs-t and second ,~ -4a-passageways and the fi:L-th passageway is alignable w:i-th the other of the firs-t and second passageways for thereby providi.ng the open positions for enabling substantially unrestricted flow individually through -the one and through the other of the Eirst and second passageways. Means are disposed within the cavity and are cooperatively engagable with the :Eirst and second ele-men-ts in a :Eirst predetermined inrler position fixed against fur-ther movemen-t inwardly of -the cavity for individually retaining the first ~nd second elements substantially in the open positions untll there is at least a predetermined substantial pressure difference between fluid pressures in the first and second cav-ity portions and the intermediate cavity portion~ Means are disposed within the caivty and are coactable with the retaining means, permitting movement of the retaining means from the inner position outwardly of the ca~ity under influence oE the adjacent press~e--responsive element for enabling the first and second elements to move substantially independently oE each other toward the respective closed positions when a predetermined pressure differential between the intermediate cavity portion and one of the first and second cavity portions exceeds the predetermined pressure difference, and for causing the first and second ele~
ments to move substantially in unison when the pressure diEfer-ential between the intermediate cavity portion and both of the first and second cavity portions exceeds the predetermined pressure difference.
-4b-According to another aspect of the invention there is providedl in combination with a fluid source, a flow divlder combiner valve unit comprising a cavity having first and second spaced end por-~ions and an intermecliate por-tion disposed between the first and second cavity end por-tions. First and second passageways provide fluid communication between the source and respective ones of the first and second spaced cavi.ty end portions. A third passageway provides fluid communication betwe~en the source and the in-termedi.ate cavi-ty portion. First and second pressure-responsive elements are individually movable in the cavity respectively between open positions and progress-ively closed positions thereby for controlling fluid flow be-tween the first and second cavity end portions and the first and second passageways. The first and second elements res-pectively include Eourth and fifth passageways providing com--munication between the first and second elements respectively, inlcuding fourth and fifth passageways providing communication between the first and second passageways and the cavity. The fourth passageway is alignable with one of the first and second passageways and the fifth passageway is alignabl.e with the other of the first and second passageways for thereby providing the open positions for enabling substantially unrestricted flow individually through the one and through the other of the first and second passageways. Means are disposed within the cavity and are cooperatively engageable with the first and second elements for individually retaining the first and second ele-ments in a first predetermined inner position fi~ed against r'~
fur-ther movement inwardly of the cavlty substantially in the open positions unti:l there is at least a predetermined substan-tial pressure dif:Eerence between fluid pressures in the first and second cavity portions and the intermediate cavity portion.
Means are disposed within the cavity and are coactable with the retaining means for permittlng rnovement of the retaining means :Erom the inner posit:ion ou-twardly oE the cavity under in-:EI.uence o:E the adjacent pressure-responsive element fo:r enabling the first and second elements to move substantially independen-tly of each other toward the respectlvely closed positions when a predetermined pressure differential between the intermediate cavity portion and one of the first and second cavity portions exceeds the predetermined pressure diference between the inter-mediate cavity portion and both of the first and second cavity portions exceeds the predetermined pressure difference.
Br;ief Description of the Drawings The foregoing, as well as other objects, features and advantages of the invention will become more readily understood upon reading the following detailed description of the. illus-trated embodimen-t, together with reference to the drawings, wherein:
~9 ~
FIG. 1 is a schematic of a hydraulic circuit incorporat-ing the divider-combiner valve of the invention;
FIG. 2 is a side view, partially in section, of a pre-ferred embodiment of the flow divider-combiner valve in accordance with the invention, respectively present-ing open positions between ~irst and second spaced por-tions of the cavity and :Eirst and second passageways through the valve body;
FIG. 3 is a partial view, in section, presenting upward-ly directed axial ~ovement of the upper pressure-respon-sive Elow control e-ement within the cavity and subse quent partial closure of one of the passageways;
FIG. 4 is also a partial view, in section, but present-ing downwardly directed axial movement of the flow con-trol element presented in FIG. 3 (within the cavity) and subsequent partial closure of the passageway;
FIG. 5 is a side view, partially in section, presenting one fluid-flow situation where the two pressure-respon-sive flow control elements axially move in unison within the cavity; and, FIG. 6 is a side view, partially in section, presenting another such fluid-flow situation where the two pres-sure-responsive flow control elements axially move in unison within the cavity.
B~L~
Detai3ed Description of the Illustrated Embodiment Referring to the drawings and initially to FIG. 1, the novel divider~combiner valve wi]l now be discussed as it is used in combination with a typical hydraulic cir-cuit. The hydraulic circuit ;ncludes a fluid source 217 and a pump 23 for drawirlg the hydraulic Eluid from the source 21 ~via a conduit 25) and for pumping the fluid forward through a system or hydraulic circuit ~6. Flow of hydraulic fluid through the circuit 26 can be accomplished in any one of at least three dif-ferent ways.
A well-known schematic representation for a convention-al, bîased, threc-position solenoid valve, referred to generally by the reference numeral 27, presents a Eirst position 29 which permits or causes the hydraulic fluid to bypass much of the hydraulic circuit 26 and to be directed back to the fluid source 21 via a con-duit 31.
A second position 33 of the solenoid valve 27 permitsor causes hydraulic fluid to be directed forward in the hydraulic circuit 26 via a conduit 35 and into the flow divider-combiner valve, referred to generally by the reference numeral 37. With the solenoid valve ~7 in the second position 33, the flow divider-combiner valve 37 functions as a flow divider, hydraulic fluid being directed through individual conduits 39, 41 to individual, respective hydraulic motors 43, 45. Eac~
hydraulic motor 43, 45 is directly coupled to and is used to drive a respective wheel (wheels not shown).
$
Hydraulic fluid individually exLts each hydraulic motor 43, 45 via a respective conduit 47,49. The hydraulic Eluid exiting the motors 43, 45 ls combined in a mani-fold 51 and conveyed orwardwlthin the manifold 51, through the conduit 31 and ultimately, is conveyed throu~h the conduit 31 bacl~ into ~he source 21. to com-plete the flow of h~draulic fluid throu~h the circuit 26.
~en the solenoid valve ~7 i.s set at a third position 53, flow of hydraulic ~luid through much of the divider-combincr valve 37 and hydra~llic motor 43, 45 portions of the hydraulic clrcui-t ~6 is reversed and the flow divider-combiner valve 37 functions as a flow combiner:
whereby hydraulic fluid, which is flowing out of the divider-combiner valve 37,is directed via the conduit 35, through the conduit 31, and ~ack into the fluid source 21.
~eferring to FIGo 2, i~ will be seen that khe preferred embodiment of ~he flow divider-combiner valve 37 of the present invention is generally cylindrical in shape and adapted ~o be disposed within a cavity (referred to generally by the reerence numeral 55) o~ a valve body 57. The cavity 55.comprises a series of individual steps 58A, 58B, 58C, and.58D, all of which are concen-tric with each other. The diameters of the steps 58A, 58B, 58C and 58D progressively decrease moving inwardly into the cavity 55. ., The divider-co~biner valve 37 structure presented in FIGS. ~-6 includes ex~ernal circum~erential threads 59 near the opening or mouth of the cavity 55 so that the divider-combiner valve 37 can be screwed into mated threads which have been cut or otherwise formed in the valve body 57.
A first O-ring 61, located near the outer or ex~erior surface of the valve body 57 and circumferentially mounted at ~he opening or mouth o:E the cavity 55, is urged against ~he threads 59 (at the junction of the divider-combiner valve 37 and the -valve body 57) by,a portion of a valve ca~ or retainer 63 in a manner such that the flrst O~ring 61 seats and thereby seals the divider-combiner valve 37 into the cavity 55.
A second ~-ring 65, circumferentially carried by the divider-combiner valve 37, seats against a circum-ferential portion of ~he inner periphery of the cavity55, is urged outwardly against such circumferential portion by the divider-combiner valve 37 and ther,eby seals the first step 58A o the cavity S5 from the second step 58B. A third O-ring 67 similarly carried by the divider-combiner'valve 37 and similarly circum-ferentially urged against different portions of the inner periphery of the cavity 55 similarly seals off or isolates the second step 58B from the third step 58C. A fourth O-ring 69 similarly isolates the third step 58C from the fourth step 58D.
The valve body 57 presented in FIGS. 2-6 includes a first or upper passageway 71 which permits co~unica-tion of hydraulic,fluid between the hydraulic fluid source 21 and the first step 58A of the cavity 55. The valve body 57 also includes a second or intermediate passageway 73 which permits similar hydraulic fluid ~ 10 -communication between the hydraulic fluid source 21 and the second step 58B of the cavity 55. The valve body 57 further includes a third or lower passageway 75 (presented in FIGS. 2, 5 and 6) which permits com munication between the hydraulic fluid source 21 and the third and fourth steps 58C and 58D.
It can be appreciated that t:he valve hody 57 can in-clude a plurality of individual passage.ways at any of the above-discussed first (or upper), second (or in-termediate) or third (or lower~ passageways 71, 73 or 75~ which respective~y perm~t fluid co~munication between the hydraulic fl.uid source 21 and the first, second and third (and fourth) steps 58A,.58B and 58C
(and 58D) of the cavity 55.
When the divider-combiner valve 37 functions as ~ flow divider, the second passageway 73 functions as a fluid input or inlet port for the valve 37,.and the first and ~hird passageways.71, 75 function as fluid output or outlet port~. When the valve 37 functions as a flow . combiner~ inlet and outle~ functions of the passage-ways 71, 73 and 75 are reversed.
The illustrated.embodiment of the valve 37 is disposed within the cavity 55 along an axis 77; and a valve housing 79 (static in relation to the valye body 57) separates the inner working parts of ~he valve,37 .
from the cavity 55. The valve hcusing 79 includes threads 80 externally circumferentially cut or Dther-wise formed along a portion of the outer periphery of the valve housing 79 proximate to the opening or mouth of the cavity 55. A circumferentlal inner portion of the retainer 63 includes mated threads 80, the retainer 63 being screwed onto the valve housing 79 at the threads 80, the valve housing 79 thereby being held or otherwise S urged into the cavity 55 by the retainer 63.
The ~alve housing 79 provides a generally cylindrical shell, on line with and oriented about the axis 77, enclos:ing a cylindrical chalmel 81 through which hy-draulic fluid flows alld.wi~hin w'hich two pressure-responsive flow con-tro'l elernents 83, 85 snugly fit.
Movement of the flrst and seeond flow control elements 83 r 85 is permitted generally along the axis 77.
Each flow con.trol elemen~ 83, 85 has ~n inner core portion 87, a plurality of orifices 89, and a plura].ity of respective ports 91A, 91B. Each respective inner core por~ion 87 provides each respective flow control element 83, 85 with a eylindrically-shaped inner void oriented substantially about the axis,77. Each o'rifice . 89 forms a cylindrically-shaped void through a portion of the respective flow control elements 83, 85, each - orifice 89 being oriented substantially transverse to ~he axis 77 and permitting fluid communication between a portion of t.he channel 81 and the inner core 87.
Each orifice 89 has a relatively small diameter, as contrasted agains~ the relatively large diamete.r of the core portion 87. Each flow control elemen~ 83, 85 has a respective p'lurality of ports 91A, 91B which pro-vide fluid communication between portions of the channel81 and respective inner portions 87 of the flow control elements 83, 85. Like ~he orifices89, each port 91A, 91B forms a cylindrically-shaped void through a por~ion of the respective flow control element 83, 85, each respective port 91A, 91B being oriented substantially transverse to t'he axis 77. An individual port 91A, 91B has a greater diameter than an individual orifice 89~ In addition, as -to the upper or the lower flow con-~rol element 83 or 85, the c~ulati.ve cross-sectional area of all of the ports 91A or 91B is substan-tially greater than the cumulative cro~ss-sectional area of all of the orifices 89.
As an initially empty valve 37, functioning as a flow divider, is fille~ with hydraulic fluid; hydrau].ic fluid enters`the cavity 55 via the second or inter-mediate passageway 73 and flows ~rom the second step 58B (of the cavity 55), through the valve housing 79 via a.first opening 93, and into an intermediate por-tion 95 of the channel 81. Once in the intermediate portion 95, fluid flows through the orifices 89 and into the core portion 87 of each respective flow con-trol-element 83,-85. Hyd~aulic fluid eventually fills 'each inner core portion 87 and the remainder portions 97, 98 ~of,~he channel 81) and thereafter is caused to flow out of the channel 81 via the ports 91A, 91B, and into the first (or upper) and third (or lower) passageways.71, 75. The first and third passageways 71, 75 are appropriately connected individually to hydraulic ~otors 43, 45 (FIG. 1), as discussed above.
First and second end caps 99, 101 seal respective ends of the channel 81 thereby isolating the channel 81 frorn the cavity 55. The upwardly oriented or outwardly extending end cap 99 is not integral with the end portion of the valve housing 79, but, rather, is urged against such end portion of the valve housing 79 by a spacer 103, which itself is biasly engaged and inwardly urged in~o the cavity 55 by ~he above~discussed cap or re~ainer 63.
Nor is khe downwardly orlent:ed or inwardly extending end cap 101, located at the other end portion oE the ~ralve housing 79, integral with ~he valve housing 79.
Rather, the lower end cap 101 i5 urged against the opposite end portion of the valve housing 79 by the base 102 of the ca-~:Lty 55.
A first or upper spring 105, preloaded to a pressure corresponding to about 50 psi and partially restrained by a first or upper spri.ng guide 107 which is secured by a bolt 109 to the upper end cap 99, is oriented along the axis 77 between the end cap 99 and the first flow control element 83 such that the upper spring 105 urges the upper flow control element 83 away from the end cap 99. Biasing action of the upper spring 105 upon the upper flow control element 83 is restrained, however, when the upper spring guide 107 is restrained, by the head of the upper bolt 109 (FIGS. 2, 4 and 6).
Such a restraint; by the upper spring guide 107 is of a one-way nature and the spring guide 107 is generally free to mo~e axially along the axis 77 compressing the upper spri.ng 105 (FIGS. 3, 5). However, it is.the action of the first or upper flow control element 83, acting upon the upper spring guide 107, which compresses the upper spring 105 (FIGS. 3 and 5).
In a similar fashion, a second or lower spring 111, also preloaded to a pressure corresponding to abou-t 50 psi, is partially restrained by a second or lower spring guLde 113 which is secured to the lower end cap lOl by a second bolt 115. ]:n a manner somewhat similar to ~.he above discussion, the lower spring 1].l. generally urges the lower flow control element 85 and the lower end cap lOl apart but is restrai.ned by the lower spring guide 113 engaging the head o the lower bolt 115.
Restraint of the lower spring 111 is similar to the one-way klnd of restraint discussed above in that as the lower flow control element 85 move.s upwardly away from the lower spring guide 113,.the lower flow control element 85 eventually becomes fr~e from in:Eluence of the lower spring 111 (FIG~ 6). However, the compressive action of the lower flow control element 85 upon the lower spring guide 113 comp~esses the lower spring 111.
Whenever the first spring 105 or the second spring 111 is in such a restrained 5 tate (FIG. 2) and while the upper and lower flow-control elements 83~ 85 respectively touch the upper and lower spring guides 107, 113, the ports 91A and 91B of the first .(or upper) and second (or lower) flow control elements 83 and 85 substantially line up respectively.with a second and third opening 117 and 119 through the valve housing 79 thereby permit-. ting flow of hydraulic fluid therethrough and fluidcommunication between respective first and thi~d pas-sageways 71 and 75 and a core portion 87 of respective first and second flow control elements 83, 85.
Prior to the present invention, the first and second springs 105 and lll had been moderately weak springs.
It was not uncommon, in a commercially available divider-combiner flow valve, to preload end springs to a presswre corresponding to about 5 psi. Hydraulic fluid pressures generally encowntered in passagewa~s 71 and 75 can easily cause the flow con-trol elements 83 or 85 to compress such a sprirlg and to restrict, sometLmes adversely, flow through such passageways 71 or 75.
In addition, the present invention incorporates spring guides 107 and 113 -to restrain the end springs 105 and 111 and, more importantly, to maintain a substantially unrestricted flow conditio~ permit~ing hydraul.ic fluid to generally freely flow ~hrough the passageways 71 and 75. Thus, it is the cooperation between the springs 105, 111 and respective spring guides 107, 113 wh.i.ch permits fluid flow thrcugh passageways 71, 75 to be relatively insensitive to operating upsets which other-wi~e result in fluid pressu~e changes and resultantchanges in flows of hydraulic fluid occurring within the passageways 71, 75.
A third or intermediate spring 121, preloaded to a pressure corresponding to about 25 psi, is oriented ~long the axis 77 such that the first flow control element 83 is bi~sed against the second flow control element 85.
When the valve 37 functions as a flow divider, it can be appreciated that the orifices 89 effect a pressure drop for the hydraulic fluid flowing from the inter-media~e portlon 95 (of tlle channel 81) into the hollow inner cores 87 of the respective flow control elements ~3, 85. Referring to -the :Eirst or upper pressure~
responsive flow control element 83 (FIG. 2), it wi.ll be appreciated that such a press~.re drop e~ists becau~e the orifices 89 offer much m~re resistance to flow than do the ports 91~. ~ecause ~.he orifi.ces 89 o~e.r such a resistance to flow, a fi.rst pressure di~ferential exists between a firs~ pressure-responsive swrface 123 and a second pressure-r~sponsi~e surface 125 of the first flow control element 83.
The orifices 89B (of the second flow control element 85) are similarly responsible for a second pressure differential acting upon the second flow control ele-ment 85.
When the valve 37 functions as a flow divider, it will be appreciated that as fluid pressure in the inter-mediate portion 95 of the channel 81 causes the sum of the first and the second pressure differentials to exceed 25 psi, the upper and the lower springs 105, 111 become compressed by the respective.flow control ele-ments 83, 85. As the first flow control element 83 compresses the first spring 105, the ports 91A of the first flow control element 83 move in relation to the (corresponding) second opening 117 (FIG. 3) and flow therethrough becomes restricted (to a slight degree).
Likewise, compression of the second or lower spring 111 by the second or lower flow control element 85 similarly moves the ports 91B (of the second flow control element 85) in relation to the (corresponding) third opening 119 similarly resulting in slight restriction of hy-~ 17-draulic fluid therethrough.
The first and the second flow control elements 83, 85 each incLude an L-shaped ~all 127, 129 structurally integral therewith and ext:endi}lg outwardly therefrom in the direction of the ot.her flow control element 83, 85. The L-shaped end ~r. tail 127 of the upper flow control element 83 and the I..-shaped tail 129 of the lower flow control element 85 are axially inserted in-to opposite ends of the intel~medlate spring 121, are adapted to inter~it therein, and are fur~her adapted to engage at end portions 131 of the L-shaped tails 127, 129 so that the first and second flow control elements 83, 85 move in un.ison (FIG. 5) when fluid pressure in the intermediate portion 95 (of the cavity 55) is sufficient to compress the end springs 105, 111 and cause the end portions 131 of opposing tails .127, 129 to touch. And when fluid pressure within the upper passageway 71 or the lower passageway 75 or both such passageways 71, 75 ~FIG. 6) is sufficiently greater than the pressure exer~ed by the intermediate spring 121, the intermediate spring 121 becomes compressed and the L-shaped tail 127, 129 of one flow control element 83, 85 butts agains~ the other flow control element at ends 133; and both flow.control elements-83, 85 move in unison ~FIG. 6) within the channel 81.
When the divider-combiner valve 37 is functioning as a flow divider and the first or upper passageway 71 is supplying a hydraulic.motor 43 or 45 which is under little or no load (as would be the case when such a hydraulic motor 43 or 45 drives a wheel on ice), the -1.7A-no-load hydraulic mo~or ~3 or 45 offers very little resistclnce to flo~ o.E hydraulic fluid and hydxaulic fluid pressure resul~ingly drops in the first passage-way 71. ~Iydraulic fluid pressure in the inner core 87 of the first or upper flow control elemen-t 83 accor-dingly drops, which results in an increase in the (first) pressure ~lferen-till (between the first and t'he second pressure-responsive sur~aces 123 and 125) of the first or upper flow control element 83. Whereupon, the first flow control element 83 moves upwardly ln the cavlty 81, usually compressi~g the upper spring 1~5 (FIG. 3).
However, because the upper spring 105 is relatively insensitive to most pressures no~mally experienced within the upper passageway 71, the upper spring 105 is not substantially compressed and flow through the first or upper passageway 71 is not entirely cut off (FIG. 3); and if the flow control elements 83, 85.are acting in unison (FIG. 5), fluid ~low through the lower fluid passageway 75 is not greatly affected.
When flow of hydraulic fluid i9 reversed through the divider-combiner valve 37, the present invention pre-sents substantially the same advantages as to flow of hydraulic fluid through the passageways 71 and 75.
The flow control elements 83, 85 of the valve 37 are generally responsive to fluid pressure in the first (or upper) and third (or lower~.fluid passageways 71, 75, and are adapted to generally adjust flow of hy-draulic fluid accordingly. ~owever, the various ele-ments of the novel divider-combiner valve 37 of the inven~ion act or operate co-operatively to prevent total cut-off or restriction of hydraulic fluid through the passageways 71, 75 when the valve 37 is responding to operating upsets.
8~
Accordingly, -the present in-vention is relativel~ insen-sitive to system upsets such as would normally be ex-perlenced when the wheeled vehicle (discussed above) is on ice or is rotmding a corner. Incorporation of the valve 37 of ~he present invention within such a whee]ed vehicle has substantially eliminated the wheel ]ock-up problem discussed above and has significantly reduced the wheel-dragging problem (addressed above) experienced when the wheeled vehicle negotiates a curve.
The flow control elements 83, 85 of ~he divider-combiner valve 37 of the pr~sent invention normally act indepen-dently at the start o~ operation? eventually act in unison (FIGS. 5, 6), normally initially act independently when a system upset arises and eventually again act in unison sometime thereafter.
What has been illustrated and described herein is a novel flow divider-combîner valve unit. While the divider-combiner valve unit of the present invention has beenillustrated and described wi~h reference to a preferred embodiment, the invention is not limited thereto. On the contrary, al~ernatives, changes or modifications may become apparent to those skilled in the art upon reading the foregoing description. Accordingly, such alterna-tives, changes or modifications are to be considered as forming a part of the invention insofar as they f~l within the spirit and scope of the appended cl~ims.
Claims (6)
1. A flow divider-combiner valve unit comprising: a cavity having first and second spaced portions and a cavity portion intermediate said first and second cavity portions; first and second passageways communicating with said first and second cavity portions and a third passageway communicating with said intermediate cavity portion; first and second pressure-responsive elements individually movable in said cavity respectively between open positions and progressively closed positions thereby for controlling fluid flow between said first and second cavity portions and said first and second passageways, said first and second elements respectively including fourth and fifth passageways providing communication between said first and second passageways and said cavity, said fourth passageways being alignable with one of said first and second passageways and said fifth passageway being alignable with the other of said first and second passageways for thereby providing said open positions for enabling substantially unrestricted flow individually through said one and through said other of said first and second passageways; means disposed within said cavity and cooperatively engagable with said first and second elements in a first predetermined inner position fixed against further movement inwardly of the cavity for individually retaining said first and second elements substantially in said open positions until there is at least a predetermined substantial pressure difference between fluid pressures in said first and said second cavity portions and said intermediate cavity portion and; means disposed within said cavity and coactable with said retaining means permitting movement of said retaining means from the said inner position outwardly of the cavity under influence of the adjacent pressure-responsive element for enabling said first and second elements to move substantially independently of each other toward said respective closed positions when a predetermined pressure differential between said intermediate cavity portion and one of said first and second cavity portions exceeds said predetermined pressure difference and for causing said first and second elements to move substantially in unison when the pressure differential between said intermediate cavity portion and both of said first and second cavity portions exceeds said predetermined pressure difference.
2. The valve unit of Claim 1 wherein said retaining means comprises: restraint means disposed within said cavity and limitedly movable between first and second positions for engaging with and thereby restraining movement of at least one of said first and second elements; and spring means disposed within said cavity for biasing said restraint means against said one of said first and second elements from said restraint means thereby affecting response of said one of said frist and second elements to fluid pressure in at least one of said first, second and intermediate cavity portions.
3. The valve unit of Claim 2 wherein said spring means include at least one helical spring preloaded to about 50 psi pressure.
4. The valve unit of Claim 1 wherein said enabling and causing means comprises: first hook means integral with one of said first and second elements and second hook means integral with said other of said first and second elements said second hook means being disposed toward said one of said one of said first and second elements and engageable with said first hook means and said one of said first and second elements, for enabling said first and second elements to engage and thereby move substantially in unison;
and spring means disposed intermediate and engaging said first and second elements for urging said first and second elements apart.
and spring means disposed intermediate and engaging said first and second elements for urging said first and second elements apart.
5. The valve unit of Claim 4 wherein said spring means includes a helical spring preloaded to about 25 psi pressure and disposed about said first and second hook means.
6. In combination with a fluid source, a flow divider combiner valve unit comprising: a cavity having first and second spaced end portions and an intermediate portion disposed between said first and second cavity end portions; first and second passageways providing fluid communication between said source and respective ones of said first and second spaced cavity end portions; a third passageway providing fluid communication between said source and said intermediate cavity portion; first and second pressure-responsive elements individually movable in said cavity respectively between open positions and progressively closed positions thereby for controlling fluid flow between said first and second cavity end portions and said first and second passageways, said first and second elements respectively including fourth and fifth passageways providing communication between said first and second elements respectively including fourth and fifth passageways providing communication between said first and second passageways and said cavity, said fourth passageway being alignable with one of said first and second passageways and said fifth passageway being alignable with the other of said first and second pasageways for thereby providing said open positions for enabling substantially unrestricted flow individually through said one and through said other of said first and second passageways; means disposed within said cavity and cooperatively engageable with said first and second elements for individually retaining said first and second elements in a first predetermined inner position fixed against further movement inwardly of the cavity substantially in said open positions until there is at least a predetermined substantial pressure difference between fluid pressures in said first and said second cavity portions and said intermediate cavity portion and; means disposed within said cavity and coactable with said retaining means permitting movement of said retaining means from the said inner position outwardly of the cavity under influence of the adjacent pressure-responsive element for enabling said first and second elements to move substantially independently of each other toward said respectively closed positions when a predetermined pressure differential between said intermediate cavity portion and one of said first and second cavity portions exceeds said predetermined pressure difference between said intermediate cavity portion and both of said first and second cavity portions exceeds said predetermined pressure difference.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US40413182A | 1982-08-02 | 1982-08-02 | |
| US404,131 | 1982-08-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1192811A true CA1192811A (en) | 1985-09-03 |
Family
ID=23598293
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000429712A Expired CA1192811A (en) | 1982-08-02 | 1983-06-03 | Flow divider-combiner valve |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0100589B1 (en) |
| JP (1) | JPS5929877A (en) |
| CA (1) | CA1192811A (en) |
| DE (1) | DE3370847D1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH676347A5 (en) * | 1988-11-18 | 1991-01-15 | Bucher Maschf Gmbh | |
| FR2640329A1 (en) * | 1988-12-13 | 1990-06-15 | Bennes Marrel | Hydraulic distribution device with flowrate regulation, and spreader vehicle including it |
| NL1024151C2 (en) | 2003-08-22 | 2005-02-23 | Actuant Corp | Vehicle, in particular camping vehicle, with hydraulically operated roof component. |
| CN102518837A (en) * | 2012-01-06 | 2012-06-27 | 徐州重型机械有限公司 | High-precision flow distributing and collecting valve and crane |
| CN104235101B (en) * | 2014-09-03 | 2016-05-04 | 西安交通大学 | A kind of Bidirectional end face cam continuous rotary hits at a high speed two position four-way hydraulic valves |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3481489A (en) * | 1967-12-05 | 1969-12-02 | Robert E Stauffer | Means for extending and retracting boom sections of a crane |
| DE2326857C2 (en) * | 1973-05-25 | 1974-10-03 | Hydromatik Gmbh, 7900 Ulm | Hydrostatic transmission with two or more hydraulic motors driven in parallel by a common setting pump |
| US3955473A (en) * | 1973-10-05 | 1976-05-11 | Trw Inc. | Power steering gear with proportional flow divider |
| US4121601A (en) * | 1976-08-18 | 1978-10-24 | Cross Manufacturing, Inc. | Flow compensated divider valve |
-
1983
- 1983-06-03 CA CA000429712A patent/CA1192811A/en not_active Expired
- 1983-06-07 EP EP19830303279 patent/EP0100589B1/en not_active Expired
- 1983-06-07 DE DE8383303279T patent/DE3370847D1/en not_active Expired
- 1983-07-13 JP JP12629383A patent/JPS5929877A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0100589B1 (en) | 1987-04-08 |
| DE3370847D1 (en) | 1987-05-14 |
| EP0100589A1 (en) | 1984-02-15 |
| JPS5929877A (en) | 1984-02-17 |
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| MKEC | Expiry (correction) | ||
| MKEX | Expiry |