US2255787A - Fluid pressure device and system - Google Patents

Description

Sept 16, 1941- c. MpK'ENDRlcK 2,255,787

`FLUID PRESSURE DEVICE AND SYSTEM Filed March 6, 1941 5 Sheets-Sheet 'l Z (575 72 7/ 45 j? 43 .ggg 64 M d On /Vea/fs far 6/ 53 /1/@0/29 far Vary/)2Q r/Wce TE INVENTOR Sept 16, 1941 c. M. KENDRICK 2,255,787

'FLUID PRESSURE DEVICE AND SYSTEM Filed March 6, 1941 3 Sheets-Sheet 2 ATTORNEYl Sept 16, 1941- c. M. KENDRICK l 2,255,787

. FLUID PRESSURE DEVICE AND SYSTEM Filed March 6, 1941 5 Sheets-Sheet 3 X4 5*.' ,f if/19.5.

/a w 4f V/mllllll ?atented Sept. 16, 1941- PRESSURE DEVICE AND SYSTEM Charles M. Kendrick, New York, N. Y., assignor to I Manly Corporation, Washlngto ration of Delaware n, D. 0., a corpo- Application March 6, 1941, Serial No. 381,956

7 Claims. (Cl. 121-92) This invention relates to fluid pressure devices h and systems which are adapted to transmit power by means of fluid under pressure and more particularly to devices and systems of this character which include`a vane type fluid motor.

in which the vanes are urged into contact with the vane track by fluid pressure means. The

present application is a continuation in part of my co-pending application led February 17,

1940, Serial No. 319,399.

The widest present use for devices and syste of this general class is-as hydraulic devices and systems, that is to say, devices andsystems for 1 handling, or whose motive uidis a liquid, such for example, as oil. The present invention will accordingly be described in connection with such use although it will be understood that the invention is also applicable to devices and systems operating with elastic iluids.

Vane type motors of the character mentioned above include a vane track that surrounds the rotor and vane assembly. For quiet andsatisfactory operation of the motor it is practically essential that the outer ends of the vanes be urged into contact with the vane track when operation of the motor is started and that such contact be maintained continuously during its operation. In order to provide this track-contacting and track-following action of the vanes it is necessary to supplement the' action of centrifugal force With an auxiliary force acting to urge the vanes outward, at least during the portion of their rotary travel in which they are passing through the intake area or areas of the motor, so that the outer ends of the vanes will be held rmly in contact with the surrounding vane track and thus provide a movable resistance to the pressure uid admitted to the outer ends of the vanes of the fluid motor, wherebyrrotary motion is imparted to the rotor and driven shaft "1 of the vane motor. In the vane motor forming part of the fluid pressure device and system of the present invention, fluid pressure means are utilized to provide this auxiliary force and this is accomplished by introducing or admitting, behind the inner ends of the vanes, pressure fluid having a pressure greater than but related to the pressure of the fluid admitted to the pressure areas at the outer ends of said vanes, as

fully explained in my co-pending application filed March 28, 1938, Serial Number 198,449. Thus fluid under tWo different but related operating pressures is used; the uid having the higher of these two pressures, which for convenience is termed the differential high pressure fluid, is admitted to the radially inner ends of the vanes, while iluid under the lesser of these two pressures (for convenience termed the working pressure uid or operating pressure fluid) is admitted to the pressure areas at the outer ends of the vanes of the vane motor. In the fluid pressure device and systemv of the present invention these two different but related pressures are obtained by passing the supply of fluid going to the motor through differential pressure or resistance mechanism positioned in of the motor will then vary substantially in versely with the speed of rotation so that in all events the Volume of operating pressure fluid, at any given pressure thereof, supplied to the outer ends of the vanesv determines the power that is transmitted by the vane motor.

As indicated above, certain parts of the disclosure are common to the present application and the above-mentioned application Serial No. 319,399, such, for example, as the provision of unitary means "for 4performing the dual functions of regulating the speed of the vane type motor and providing diierential high pressure vfluid for urging the vanes of the motor into contact with the vane track. The arrangement of the present invention differs from that of the above-mentioned co-pending application Serial No. 319,399, however, in several important respects. For example, the present invention provides novel and improved means whereby either a single vane type motor or a plurality of vane type motors may be operated bypressure fluid supplied by. a single source, with the speed of the co-pending application Serial No. 319,399

the speed of the motor is varied and controlled by varying and controlling either the volume of pressure iluid supplied Iby a variable delivery pump or by by-passing the unused portion of the uid volume delivered by a constant capacity pump, whereas according to thewpresent inven tion the speed of each vane type motor is varied and controlled solely by regulating and controlling the volume-of fluid whichl is permitted to pass to or through each motor, without respect to the quantity of pressure fluid available from the source or the disposition of any surplus of the fluid pressure supply. Other diierencesfwill appear from comparison of the accompanying.-

tion Serial No. 319,399 and from the description which follows.

An object of the present invention is to pro-V vide an improved fluid pressure device and system of the character above indicated.

Another Objectis to provide an improved, simple and economical fluid pressure device and system including one or more vane type uid motors and employing for each motor unitary means for performing the dual functions of regulating the speed of the corresponding motor and of providing fluid at a pressure sutlicient to urge the vanes of said motor into contact with its vane track.

Another object is to provide a fluid pressure device and system ofd the character above set forth, and in which the speed of each vanertype motor and the difference between the pressures of the operating pressure iluid and the fluid supplied for urging its vanesnto contact with its vane track are held substantially constant irrespective of the load that is imposed on the vane motor and independent of the speed of any other motor employed in the fluid pressure system.

A further object is to provide such a fluid pressure device and system in which the speed of each'vane type motor is held substantially 7 constant independent of change in viscosity of the circulated fluid.

yOther and more specific objects will appear from the description which follows.

'I'he invention will be understood from a consideration of the accompanying drawings which illustrate, by way of example, several embodi ments of the present invention.

In the accompanying drawings:

Fig. 1 is a 'diagrammatic view, partly in section, showing an illustrative embodiment of the present invention in a uid pressure system that includes a plurality of vane type motors;

Fig. 2 is a fragmentary diagrammatic view, partly in section; showing a modification in which lmeans are provided to compensate for change in viscosity of the circulated fluid;

radial direction; this illustrative motor forms ii part per se, however, of the present invention but a part of said co-pending lapplication Serial Number 198,449 and certain features of its construction are similar to those shown in co-pending application iiled December 6, 1939, Serial Number 307,755. For convenience the same vane motor will be presumed to beemployed throughout all" embodiments illustrated in the accompanying drawings and will accordingly be first described.

Referring now to Figs. 4 to 8 inclusive, each motor B includes a casing I0 formed with an open-ended rotor cavity for the rotor I5 and associated parts as shown in Figs. 4 and 5. The rotor cavity is closed (Fig. 4) by an end head or cover member I I which is attached to the casing I0 as by cap screws I2. The rotor I5 is provided with a plurality of vanes I1 which are movable in a substantially radial direction inward and outward in the vane slots I6: A vane track ring 25 surrounds the rotor and vane assembly and its`v inner'circumferential surface 2liA forms fa track adapted to contact the radially outer ends of the vanes I1 as the rotor revolves and to guide and control the vanes in their inward and outward movement; the surface 26 will hereinafter be referred to as the vane track.

The rotor I5 and driven shaft 20 may be mounted and thetwo parts may be operatively .connected with each other in any appropriate manner. In the present instance the rotor I5, shaft 20, their mountings and the operative connection there-between are the same as disclosed in said co-pending application Serial Number 307,755. As shown in Fig. 4, the shaft 20 is revi olubly supported by a pair of bearing elements 23 and 24 carried 4by the casing I0 and the rotor I5 is supportedly mounted on the end of the shaft 20 which projects into the rotor cavity. For this i purpose the end of the shaft 20 is.formed with Fig. 3 is also afragmentary diagrammatic view,

partly in section, showing another modification;

Fig. 4 is a longitudinal sectional view, taken along the line 4-4 of Fig. 5, of an illustrative embodiment of the vane type motor forming part of the pressure device and system of the present invention;

Fig. 51s a view in vertical section transverse the axis of rotation of the vane type motor and is taken `along the line 5--5 of Fig. 4;

Fig. 6 is also a vertical transverse sectional .I

view taken -along the line 6-6 of Fig. 4, looking in a direction opposite to that of Fig. 5; n

Fig. 7 shows an inner elevation of one of the members of the vane motor, for convenience termed an end plate or cheek plate; and

Fig. 8 is a sectional view of the cheek plate Y taken along the line 8`8 of Fig'. 7.

, The embodiment of the invention illustrated in Fig. 1 includes a plurality of vane type motors B, here shown as two in number although a smaller or greater number may be employed if desired. The vane type motors B may be of the same or of dierent constructions. For example, each motor vB may be of either constant'or variable displacex ment per revolution of its rotor, or one may be` constant displacement and the other of variable displacement. For purposes of illustration,I however, I have chosen a constant capacity vane type motor in ,which the vanes move inward and i. outward with respect to the rotor in a generally axially extending splines 2I (Figs. 4 and 5) and the rotor I5 is formed in its central opening with mating splines I8. The arrangement is such that the rotor I5 is freely' movable in an axial direction on the shaft splines 2| while also permitting a limited angular or rocking motion of the rotor I 5 relative to the shaft 20 in such manner that thev cheek plates 34 and 35, to be presently described, deterinine the axial and angular position of the rotor on the shaft and the plane of rotation of the rotor as fully explained in c6- pending application Serial Number 307,755 above mentioned.

'Ihe rotor I5 is hydraulically balanced with respect to all forces 'imposed thereon by iiuid presusre. Hydraulic balance of forces acting on the rotor in awradial direction is obtained by dividing the space intermediate the periphery of the rotor II5 and the vane track '26 into two equal and oppositely positioned fluid sections, each yfluid section comprising a working chamber anked by an inlet area and an outlet area. As shown in Fig. 5, the division betweenthe two fluid sections is effected by cofoperation of the rotor I5 and the outer endsf the vanes I1 with 'the vane track 26 at the regions of the vane tracks-,least diameter which in thepresent embodiment is adjacent the horizontal centerline. The vane track 26 is preferably provided at each of ,these points of division with an arc 21, for convenience termed the sealing arc, substantially concentric with the rotorA I5 and extending in a circumferential direction for a distance equal astma# to ai; least the angular distance between a pair of adjacent vanes I1.

The working chambers of the two uid sections are formed by means of two diametrically positioned arcs 3 I, preferably concentric .with the 'rotor I5 and termed working arcs, which are located in the regions of greatest diameter of the vane track 26. 'I'he working chambers extend in a circumferential direction for an arcuate distance substantially equal to the distance between the outer ends of two adjacent vanes I1 which at any given instant are moving in contact with the working arcs 3|. Operating pressure fluid is admitted between the vanes as they move through the inlet areas toward the working chambers and fluid is discharged as the vanes recede therefrom through the outlet areas of the two fluid sections. The inlet area of each fluid section is thus at all times separated from the outlet area of the same fluid section by at least one of the vanes I1 and the difference in pressures on the opposite sides or faces of such vane causes rotation of the rotor I5, which in the present instance is in a clockwise direction as viewed in Fig. 5. Thev portions of the vane track 26 intermediate the sealing arcs 21 and working arcs 3I may be given any suitable curvature producing satisfactory rates of inward and outward movement of the vanes I1 as the rotor I5 revolves.

The sides or axial ends of the working chambers are closed by a pair of mating disc-shaped members 34 and 35 (Figs. 4, 5, 7 and 8), for convenience termed end plates or cheek plates, which are provided with holes at their centers for the shaft 20. The outer surfaces of the cheek plates 34 and 36 fit snugly against the wall surfaces of the casing I and end head I.I respectively and form substantially fluidtight ts with the several ports and passages to be presently described. The inner or opposing faces of the cheek plates 34 and 35 form iluidtight fits with the sides of the vane track ring 25 by which they are axially positioned with respect to the rotor I in such manner that the rotor is permitted to turn freely while its sides and the sides of the vanes I1 form substantially iluidtight running flts with the adjacent faces of the cheek plates 34 and 35. The cheek plate 34 will hereinafter be termed the casing cheek plate and the cheek plate 35 will be termed the end head cheek plate. Y

The cheek plates 34 and 35 are each provided with co-extensive mating ports (Figs. 4, 5 and 7) the ports of one cheek plate being axially opposite the ports of the other cheek plate when the parts are in position in the casing I8 so that all forces exerted upon the rotor I5 'and vanes I1 in an axial direction by fluid pressure are thus completely balanced. V The ports in thek cheek plates 34 and 35 will be best understood from Figs. 7 and 8, in which Fig. 7 shows an inner'elevation or the rotor face of the end head cheek plate 35. Referring to Fig. 7, each cheek plate is provided with apair of diametrlcally opposed arcuate inlet slots orports 36 and a similar pair of diametrically opposed outlet slots or ports 31;' these ports are also partially shown in Fig.f 5|' and the inlet ports 36 are showninthesectional y view of Fig.'4 and theoutl t1ports'31a're shown"v ports 38 of the casing cheek plate 34 are not.` l

in Section in Fis. 8-

ope ating pressure am@ isf admittedto the "outer ends-of jthejwariesy I I through the inlet ports 36 of thecasng cheek plate 34, and, similarly, fluid-discharged or=ex` hausted by said vanes passes out through the on the sides or axial ends of the vanes I1 and rotating parts, as already stated.

' and 7) that registers with the inner end of one i `of the two vpassages I3 formed. in the end head outlet ports 31 of the same cheek plate. The ports 36 and 31 of the end head cheek plate 35 Y function principally as balance ports to contain fluid under the same pressure as that in the corresponding ports of the casing cheek plate 34 in order to produce hydraulic balance of the Each of the cheek plates 34 and 35 is also provided with two pairs'of arcuate recesses or vane slot ports 38 and 39 in the faces thereof adjacent the rotor I5 as best shown in Fig. 7; the vane slot ports 38 are, however, also shown in the sectional view of Fig. 4 and the vane slot ports 39 are likewise shown in the sectional view of Fig. 8. These vane slot ports 38 and 39 are positioned to register successively with the inner ends of the vane slots I'6 as the'rotor revolves and the vane slot ports` of each pair are positioned diametrically `opposite each other. The arrangement is such that the inner end of each vane slot I6 connects with one of the vane slot ports 38 while the vane I1 therein is passing through the inlet area of each uid section and also while traversing the sealing arcs 21 and working arcs 3l. The arrangement is also such that the'inner end of each vane slot I6 connects with one of the vane slot ports 39 while the vane in said slot is passing through the outlet area of each uid section; the vane slot ports 33, preferably of both- cheek plates 34 and 35, are connected with the corresponding outlet ports 31 by radial grooves 32 formed on the outer faces of said cheek plates, as indicated by dotted lines in Fig. 7 and shown in the sectional view of Fig. 8. In this manner fluid discharged by the inner ends of the vanes passes out through the outlet ports of the casing cheek plate 34.

As already stated, in order for the motor B to operate quietly and smoothly it is necessary to supplement the action of centrifugal force with an auxiliary forceurging the vanes I1 into contact with the vane track 26 during at least the portion of their rotary travel in which the outer ends of said vanes are passing through the inletareas of the motor. This is accomplished by introducing behind the inner ends of the vanes, through the vane slot ports 38. pressure fluid (hereinafter termed the differential high pressure uid) having a pressure greater than but correlated with ther pressure of the operating pressure fluid supplied to the inlet areas of the motor B where it acts upon the exposed outer ends ofthe vanes, as fully explained in co-pending application Serial Number 198,449to which reference has already been made. Each of the vane slot ports 38 of the end head cheek vplate 35 n is accordingly provided with a hole 33 (Figs. 4

Il. The outer ends of the passages I3 connect with a passage I4 which in turn is appropriately connected with a conduit 45" through whichdifferential high pressure uid is supplied, said dif-4 ,l ferential high pressure fluid being obtained in ar y i, manner to be presently explained. .The vane slot l substantially'` balance, the hydraulic forces vactingf-m rotor I5 and thus prevent binding of the parts.

1 predetermined pressure drop thereacross. i means by which this is accomplished will now be i described,

other.

"KIhe uid circuit of the motor B also includes a branched uid inlet channel 40 (Figs. 4 and 6) the fluid supply conduit 42 and is also connected with the uid inlet ports 36 of the casing cheek plate 34 as by the slanted passages 44 shown in Fig. 4. The fluid outlet channel 4| is similarly connected. with the outlet or exhaust conduit 43 and with the outlet ports 31 in the casing cheek plate 34 byslanted passages, not shown, similar to the slanted passages 44.

In the embodiment of the invention illustrated in Fig. 1 the two vane type motors B are operated by pressure fluid supplied thereto through a branched fluid supply conduit or line 42 which in vturn is supplied with pressure fluid by any suitable source, not shown, such, for example, as an accumulator, a 'reservoir or a pump with suitable output control or iiuid escape means therefor. Fluid exhausted by the two motors passes out through the Abranched discharge conduit 43 with which each motor is appropriately connected.

The differential high pressure fluid for urging the vanes I1 of each motor B into contact with its vane track 26 is obtained by providing a variable orifice in the branch of the conduit 42 leading to each motor B and the resistance to flow through each of said orifices creates the difference in pressures between the differential high pressure fiuid going 'to the inner ends of the vanes I1 and the operating pressure fluid going to the outer ends of the vanes of the corresponding motor B. The conduit 45 of each motor B is accordingly connected with its corresponding branch of the conduit 42 at a point on the inlet side of the corresponding orifice l0. The volume of pressure fluid permitted to pass through each i variable orifice 10 is regulated to provide the proper volume to produce a predetermined pressure drop thereacross, for any extent of opening l Y of the corresponding orifice l0, so that the difference in pressures between the differential high pressure fluid and the operating pressure fluid is held substantially constant and Vchange'in the volume of fluid passing through said orifice 'l0 is effected responsive to the pressure dropactually existing across said orice 116 relative to the The germs? f this control of connection being effected by the extent to which the head 62 closes or covers the outlet port 56 and hence the extent to which said outlet port 56 is connected with the inlet port 55 through the portion of the valve bore 52 intermediate the ports 55 and 56. It will be understood that partial covering or closing of the outlet port 56 by the head .62 presents a resistance to the flow of iiuid therethrough, which resistance `increases as the head 62 approaches its position o in which it completely closes the outlet port 56 and prevents the passagel of any fluid therethrough. The movement of the valve piston 60 in the valve bore 52 is preferably limited by pro-v portioning of the parts to permit the head 62 to completelyclose the outlet port 56 in its extreme downward position of movement and to completely open or uncover the outlet port 56 in its extreme upward. position. tions are preferably made such that the inlet port 55 is at all times connected with the reduced neck 63 or tapered portion 64 of the valve piston 60.

The valve piston 66 is moved and its position is controlled responsive to the pressure drop actually existing across the orifice 'l0 relative to a predetermined pressure drop thereacross. The upper end o'f the valve bore 52 is accordingly connected with the inlet side of the orice 10, as by a passage 12 here shown as branching from the passage leading to the inner ends of the vanes I1. Similarly, the lower end of the valve bore 52 is connected, as by a passage 13, with the outlet side of the orifice 16 and the lower end of said valve bore 52 is also provided with a spring 65 whichexerts a force supplementing the upward force exerted on the valve piston 60 by action of pressure fluid from the outlet side of said orice 10. It is thus seen that pressure fluid from the inlet side of the orifice 10 exerts a force on the valve piston 66 in a direction tending to move it downward to thereby cause the head 64 to close the outlet port 56, thus decreasing the volume of fluidL permitted to pass into the "inlet port 55 and A fluid flow or control valve means, broadly vided for each vane motor B and,- while only one port \ designated by the reference numeral 50, is proof them is shown in section in Fig. 1, it will be understood that they are of identical structure through said outlet port 56; this force is opposed and balanced by the combined forces of the spring 65- and the action of the pressure fluid from the outlet side of the orifice 10 which exert a force tending to move the valve piston .upward and to increase the volume of fluid permitted to pass through the outlet port 56.

The valve pistonp is thus moved responsive to the pressure drop across the orifice 'I0 and takes a position to permit the passage through the outlet port 5 6 of just the proper uid volume to produce a' pressure drop across said orifice 'l0 equal in amount. to the value determined by the spring 65. Upon any departure of the actual pressure drop from the predetermined "amount thereof, the

56 which are axially spaced from one another in the valve bore so that the portions of the supply conduit 42 connected with these ports have a somewhat off-set positional relation to each Suitably fitted in each valve bore 52 is a valve 62.. The head 62 controls the extent o f connection between the inlet port 55 and outlet port 56,

valve piston 60 is immediately moved in a direction .tocorrectively alter the volume of fluid passing through the outlet port 56 so that the predetermined pressure drop across the orifice 10 is thus restored and maintained substantially constantat all times. IInese corrective changes and restoring movements of the valve piston 60 take place almost instantaneously and the adjust'- ments are such as to set the corrective mechanism into operation upon slight departures in the'pressure/'drop to be maintained across the orifice. 10.

It .will thus be seen that lthespring 65 determines the amount of pressure drop to be main-v tained across the orifice 'lllfand hence the differ- The compression of the spring 465 is accordingly Similarly, the propormade such as to provide a pressure drop across the orifice 'I0 of an amount or value such that the differential high pressure fluid from the inlet i side of the orifice 'I0 exceeds the pressure of the operating'pressure fluid from-the outlet side of the orifice by an amount suilicient to provide satisfactory action of the motor vanes I1. Position and movement of the valve piston 60 are determined and effected entirely by relative pressures existing on the inlet and outlet sides respectively of'the orifice 10 and are substantially independent of absolute pressures; that is to say,

the valve pistons 'movement and position result vanes of the motor.

'ually varied and controlled and with desired differential provided between the pressures of the 'differential high pressure fluid and the opfrom the dilerence between these pressures regardless of their actual amounts so that the differential high pressure fluid is kept at a pressure or pressures exceeding by a substantially constant amount the pressure or pressures of the operating pressure, uid, regardless of the amount of or change in the pressure ofsaid operating pressure fluid, and the inner ends of the motor vanes I1 are Vthus supplied with fluid at a pressure greater than but correlated with the pressure of the fluid admitted to the outer ends thereof. It will also be seen that this correlated or differential pressure relation is maintained between the pressures existing on the inlet and outlet sides respectively of the orifice and is without any valve bore 52, as the difference in pressures insaid inlet port 55 and outlet port 56 can and frequently will vary over a relatively wide range, the amount of such difference in pressures in said inlet and outlet ports being determined by the amount of resistance to flow through the valve means 50 required to provide flow of fluid from the outlet port 56 in the proper volume to pro-v duce the predetermined pressure drop across the orifice 10. Y

The speed of the motor. B is thus held substantially constant (viscosity change neglected) for any extent of opening of the orifice 10. The speed of each motor B'is regulated and varied by varying the size or extent 'of opening of the corresponding variable orifice 10, as for exam? ple. by the means 'H schematically illustrated which may be adjusted manually or in any other suitable manner. As the size or extent of opening of each orifice I may be infinitely varied, the speed of each motor B may likewise r be infinitely varied from zero to maximum and the motor may thus be operated at any desrecla speed which will be held substantially cons an As already stated and as illustrated in Fig. l. a separatecontrol valve means 50 and a separate variable orifice 10 is provided for each motor B and these elements cooperate to regu-I late the speed of the corresponding motor B and to provide the predetermined difference in pressures between the differential high pressure fluid and the operating pressure fluid, irrespective of the speed at which the other motor or motors may be operating. Thejspeed of each individual motor B may thus be regulated and controlledindependent of the -speed of any other motor or motors and will be held substantially constant at the speed corresponding t0 the extent of opening of its corresponding variable orifice 10 and irrespective of the load imposed thereon.-

The invention has numerous advantages. For example, it provides simple and economical means for performing the dual function of regerating pressure uid for each individual motor. It is thus possible, for example, to operate two or more vane type motors, with each motor operating at a diiferent but controlled speed, as is frequently desirable, and with the speed of each motor capable of easy and prompt variation. Or all of the motors in the system may be operated at'the same speed, with assurance that the speed of each and all of them will be held substantially constant irrespective of variation of load or loads imposed thereon and with almost instantaneous correction of variation' constant for any. extent of Aopening of its cor' responding variable orifice 10 provided the viscosity of the circulated fluid remains constant. Lubricating oil is usually employed as the ycirculated. fluid in systems of this character and is subject to relatively large changes in viscosity as its temperature changes. Such viscosity changes alter the resistance to flow through the orifice 10 and therefore noticeably aiect the volume of fiuid that is permitted to pass therethrough (for any given opening of said orifice 10) which in turn causes corresponding change in the speed of the motor ,B unless means are provided to compensate for such viscosity changes.l Such viscdsity compensating means are provided in the 'embodiment illustrated in Fig. 2 and `will now be described. 4For convenience in illustration, only one branch of the supply conduit 42 and the motor B, etc. therefor has been shown in Fig. 2 but it will be un-. derstood that said conduit 42 may have either one or a plurality of branches, each ofy whichv is provided with a motor Band associated mechanism therefor. A-

The modified fluid flow or control valve means 50' of Fig. 2 is generally similar to the control valve means 50 of Fig. 1 except forl the provision '60 .of Fig. 1.

cludes, however, a pair of extension rods 'l1 and of the viscosity compensating means. It includes a valve housing 5I having a valve bore 52' provided with axially spaced annular inlet and outlet ports 55 and 56 respectively which vare connected with'the portions of the supply 18, of equal diameter, which extend from the heads 6i" through suitable openings in the closures for the ends of the valve bore .52' in such manner and 62 respectively and project that theyform substantially fluidtight fits ltherewith.v The upper and lower ends of the Q valve bore 52' are connected with the inlet and outlet sides respectively of the orice 10 by the sure fluid from the outlet side of the orice 10.

It will thus be seen that this portion of the modified control valve means 58' of Fig. 2 is subi stantially identical with that of the control valve means 50 ofFig. 1 from which it differs, as described up to this point, principally with respect tothe provision of the extension rods 11 vand I18. This portion of the control valve means 50 is therefore capable of functioning in the same manner as described in connection with Fig. 1 and may, if desired, be so employed without'regard to the viscosity compensating means l which will now be described.

The viscosity compensating means includes a 3 pair of cylinders or bores 18 and 80 respectively,

for convenience termedy compensating cylinders, which in the present instance are formed #in the members 15 and 16 which close the ends of the valve bore 52'. The compensating cylinders are provided with slidably tted pistons, termed compensating pistons, operatively connected with the valve piston 60 and the ends of the rods 11 and `18 are utilized as the compensating pistons in the present embodiment.

j Each compensating piston is of such size that its cross-sectional area equals the cross-sectional area of one of the end portions of the valve piston 60 which are exposed to the pres- 1 sure uid in the ends of the valve bore 52', that is to say, the cross-sectional area of each compensating piston equals the cross-sectional area of the head 6I', or 62', minus the cross sectional j area of the corresponding rod 11-or 18; this lrelation ishere obtained by making the rods 11 and 18 of such size that the cross-sectional i area of each of them is one-half the area of a section through the heads 6l' or 62' of the valve piston 60'. l

The viscosity compensating mechanism also `includes an auxiliary fluid circuit, which may be termed the compensating circuit, which in y turn includes a small constant capacity pump -83 adapted to be continuously driven at a constant speed. 'Ihe pump 83 .receives its supply 1 of oil or other iiuid through an inlet conduit 84 1 which is adapted to be connected in any suitable manner with a supply of iiuid having the same 1 viscosity as the fluid simultaneously passing l through the orifice 18;.as here shown theinlet conduit 84 is connected with the discharge con- I duit 43, preferably at av point in said conduit 43 where little or no pressure exists. The pump 83 isv also provided with a discharge conduit combines with the force exerted by the spring 65' conformably with any change taking place in the viscosity of said fluid. As the iiuid passing through the orifice 86 is of substantially the same viscosity as the iluidl passing through the oriiice 10, it will be seen that change in viscosity of the circulated fluid will produce identical changes in the amounts of the pressure drop across both orifices for constant rates of flow through them. The rate of fluid flow through the orifice 86 is constant for the reason that the pump 83'is of constant capacity and is driven at constant speed. Hence the change in the pressure drop across the orifice 86'is an exact measure of the corresponding change, due to change in viscosity, which takes place during thesame interval in the amount of pressure drop across the oriiice 10 for any particular rate of uid iiow therevconduit 84 at a point on the outlet side of said orifice 86. 'I'he compensating cylinders 1 8 and 80 are thus supplied with ud having the same pressures as the pressures existing'on the inlet and outlet sides respectively of the orifice 86.

Two additional opposing forces are thus brought to bear upon the valve piston by the compensating pistons. These two opposing forces have a net difference tending to move the valve piston 60' upward, this net difference corresponding to'and varying with the amount of the pressure drop existing across the orice 86. The effect, therefore, is that of a force tending to move .the valve piston 60' upward and which varies conformably with the amount of the pressure drop across the orifice 86; hence likewise varies with the viscosity of the iiuid.

The net diterence of forces thus exerted upon the valve piston 66' by the compensating pistons to determine the amount of pressure drop to be maintained across the oriiice 18 which is, there- 'fore, modified by change in the amount of said net difference. The amount of the pressure drop to be maintained across the oriiice 10 is thus modiiied conformably with the change in viscosity of the fluid and in exact accordance with the change occurring in the amount of the pressure drop across the orice 10, with a con- 85 leading to a suitable reservoir, not shown, i and having an orifice 86 which is here shown -during operation.

f as a variable orifice although a fixed orice may be employed since the size thereof is not adjusted *With this arrangement, the amount of. the pressure-drop across the orice 86 will be consta-nt size of opening thereof and a constant rate of uid ow therethrough, resulting from viscosity change. In other words, decrease in viscosity, of the fluid reduces the amount of pressure drop across the orifice 16 produced by a constant flow of iiuid therethrough and therefore reduces the net difference of the forces exerted upon the' valve piston 60' by uid fromthe inlet and .outlet sides of the orice 10, which net difference or resultant tends to move the increases thelforces tendingto move thegvalve A piston downward and those tending to move it upward. The relative balance of forces acting upon the 'valve piston 60 is therefore undis` turbed by change in viscosity of the fluid.

Change in viscosity thus affects the amount of pressure drop to be maintained across the orifice 10, and alters the amount thereof in exact accordance with the effect of such change in viscosity upon the amount of .the pressure drop actually taking place across the orifice with a constant rate of uid ow therethrough. The compensating mechanism therefore cooperates with the other parts of the mechanism to hold substantially constant the volume of operating pressure uid passing through the orifice 10 to the outer ends of the motor vanes I1 and hence to hold the speed of the motor B substantially constant irrespective of change in viscosity of the circulated fluid. The difference in pressures between the operating pressure uid and the differential high pressure fluid will vary, however, with change in viscosity of the circulated fluid and the spring 65 is accordingly made such that the drop across the orifice 10, and hence the difference in pressures of the operating pressure fluid and differential high pressure fluid, is sufficient to provide satisfactory action of the motor vanes I1 when the pressure drop across the orice 86 is minimum for the particular fluid employed. This provides satisfactory operation of the motor at all times and with all viscosities of the fluid.

It may here be noted that only one compensating circuit is required for use in connection with a plurality of modified control valve means employed in a uid system, as the compensating cylinders 19 and 80 of each of said modied vcontrol valve means 50 may be connected with the inlet and outlet sides respectively of the same compensating orice 86.

In the embodiments illustrated in Figs. 1 and 2 the variable orifice 10 and control valve means for each motor B' are positioned in the` supply line in advance of the motor. It is essential that the variable orice 10 be positioned in advance of its corresponding motor B in order that it may provide the differentialpressure relation between the differential high pressure fluid yand the operating pressure fluid but the fluid flow or control valve means may be located at other points in the fluid system. For example, the control valve means may be positioned in the branch of the discharge conduit 43 leading fromathe corresponding motor B as illustrated in Fig. 3 and either the control valve means 50 of Fig. 1 or the modified control valve means 50 of Fig. 2 may be employed at this location in the fluid system. f

The/control valve means 50 illustrated in Fig. 3 is identical with the controlvalve Vmeans 50 of Fig. 1, the difference between the arrangements of these two figures being solely in the position in the fluid system at which said control valve means is located. 'I'he operation of the modified arrangement of Fig. 3 is generally similar to that described in connectionwith Fig. '1,

the valve piston SII moving responsive to the substantially constant at an amount producing a pressure drop across the orificeV 10 equal to the predetermined drop thereacross as determined by the spring 65. In the arrangements of both Figs. 1 and 3, therefore, the control valve means 50 functions to control the speed of the corresponding motor B and to maintain the required difference in pressures between the differential high pressure fluid and the operating pressure fluid. In the arrangement of Fig. 1 this control is effected by varying the resistance to flow from the source of pressure fluid to the motor B, whereas in the arrangement of Fig. 3 control is effected by varying the resistance to discharge of fluid by the motor B which in turn regulates the vol- Y ume of fluid permitted to pass into said motor B through the corresponding orice 10. 4

Each 4of the embodiments shown and described thus provides accurate and dependable means for regulating the speed of the motor B, or motors B, and one of them provides corrective action to compensate for all variations in the motors speed except the variation due to the leakage or slip of fluid past the rotor I5 and vanes I1 from the motors inlet areas to its outlet,areas, which is usually small. The 4same means employed for controlling the speed of the motor B is likewise utilized to provide a pressure drop in the supply line whereby the difference in pressures is obtained between the differential high pressure fluid supplied to the vinner ends of the motor vanes I1 to urge them into contact with the vane track `26 and the operating pressure fluid supplied to the outer ends of the vanes I1 pressure drop across the orifice 10 to regulate and control the volume of fluid that is permitted to pass out through the outlet port 56 and hence (in the arrangement of Fig. 3) regulating the volume of uid that is permitted to b'e discharged by the corresponding motor B. l In this mannerr the volum'e of fluid permitted to. pass through the variable orifice 10 is regulated and maintained 'to cause rotation of the rotor I5, which difference in pressures is essential for satisfactory operation of the motor as hereinbefore explained. A simple, economical arrangement is thus provided in which the several parts cooperate to provide satisfactory operation at the desired speed', with many attendant advantages, some of which have already been mentioned.

As previously stated, each embodiment of the invention described herein may be used in a fluid system including either one or a plurality of vane type fluid motors. DiiIerent embodiments of the invention may, however, be employed iny the same fluid system if desired; for example, the modified control valve means 50' of Fig. 2 may be employed in a uid system that also,employs the controlvalve means 50 according either to the arrangement shown in Fig. 1 or in Fig. 2 or both of them.

It will be understood that the several embodiments of my invention have been described for the purpose of illustrating the operation and construction of the apparatus of my present invention and that changes, some of which have been indicated, may be made without6 departing from the spirit of the invention.

I. claim:

1. In a uid pressure power transmission system, a fluid pressure supply line, resistance means in said supply line, a vane motor having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof, said vane motor also having a vane track to guide said vanes in their in and out movement, a discharge line for vthe exhaust of fluid from said motor, means for supplying pressure iiuid from the inlet side of said resistance means to one of the ends of said vanes to urge said vanes into contact with said vane track, means for simultaneously supplying pressure fluid from the outlet side of said resistance means .to the other ends of said vanes to i of fluid passing from said motor.

cause rotation of said rotor and motor speed control means responsive to the difference in pressures on the inlet and outlet sides of said resistance means, said motor speed control means including a valve bore having inlet and outlet ports connected in one of said lines and an element movable responsive to the difference in pressures on the inlet and outlet sides ofsaid resistance means and active to regulate the volume of fluid entering said inlet port.

2. In a fluid pressure system comprising a vane type uid motor and a supply line connected thereto, said vane motor having a vane track said vane motor also having a vane track to guide said vanes in their in and out movement, means for supplying pressure fluid from Vthe inlet side of said orifice to one of the ends of .said vanes to urge them into contact with said vane "track,

\ therethrough to hold substantially constantat a predetermined value the difference in pressures and a rotor provided with a plurality of vanes y movable inwardly and outwardly thereof, said vanes being urged into operating position in contact with said vane track at least in part by fluid pressure means, in combination, means for controlling the operation of said motor including resistance means in said supply line for producing a pressure drop whereby two pressures are obtained in the portions of said supply line atopposite ends of said resistance mechanism; means supplying uid having the higher of said pressures to one of theends of said vanes to urge them into operating position in contact'with said vane track and valve means in said. supply line '.having an element responsive to the pressure drop across said resistance means and active to regulate the volume of iiuid passing therethrough.

3. In a uid pressure system comprising a vane type fluid motor having a supply line' and a discharge line connected thereto, said vane motor having a vane track anda rotor provided with a plurality of vanes movable inwardly and on the inlet and outlet sides of said orifice and viscosity means cooperating with said last named means to modify the value of the pressure drop to be maintained across said orifice conformably with change in the viscosity of the circulated uid.

6. In a iiuid pressure power transmission system, a uid pressure supply line, resistance means in said supply line, a vane motor having a rotor provided with a plurality of vanes'movable inwardly and outwardly thereof, said vane motor also having a vane track to guide said vanes in their in and out movement, means for supplying pressure` iiuid from the inlet side of said resistance means to one of the ends of said vanes to outwardly thereof, said vanes being urged into operatingposition in contact with said vane track at least in part by uid pressure means, in combination, means for controlling the operation of said motor including resistance means in said supply line for producing a pressure drop whereby two pressures are obtained in the portions of said supply line at opposite ends of said resistance mechanism; means supplying fluid having the higher of said pressures to one ofthe ends of said vanes to urge them into operating position in contact with s'aid vane track and valve means in said discharge line having an element responsive-to the pressure drop across said'resistance means and active to regulate the volume 4. In a fluid pressure system, a fiuid pressure supplyv line, an orifice in saidline, alvane motor having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof, said vane motor also having a vanetrack to guide said vanes in their in and out movement. means for supplying pressure iiuid from the inlet side of said orifice to one of the ends ofsaid vanes .tol urge them into contact with said vane track, means for simultaneously supplying pressure iiuid from the outlet side of said orifice 'to the other ends of said vanes to 'cause yrotation of said rotor and means responsive to the difference in pressures on the inlet and outlet sides of said orifice active to regulate the volume kof ud passing therethrough to hold substantially constant at a predetermined value the difference in pressures on the inlet and outlet sideszof said orice.

- 5. In a fluid pressure system, a uid pressure supply line, an oriflce inzrsaid line, a vane mourge said vanes into contact with said vane track, a discharge line for the exhaust of uid from said motor, means for simultaneously supplying pressure uid from the outlet side of said resisting a valve bore having inlet and outlet ports' connected in onel of said lines and an element movable responsive to the di'erence in pressuresI on the inlet and outlet sides of said resistance means and active to regulate the volume of iiuid entering said inlet port, and viscosity compensating means cooperating with said .last named means to hold substantially constant the volume of fluid passing through said orice irrespective oi' changes in the viscosity of the circulated uid.

7. In a uid pressureV power transmission systema fluid pressure supply line, resistance means in said supply line, a vane motor having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof, said vane motor also having a vane track to guide vsaid vanes in their in and out movement, means for supplying pressure uid from the inlet`side of said resistance means to one of the ends of said vanes to urge said`vanes into contact with said vane track, a discharge line for the exhaust of fluid from said motor, means for simultaneously supplying pressure fluid from the outlet side of said resistance means to the other ends of said vanes to cause rotation of said rotor and motor speed control means responsive to ther difference in pressures on the inlet and outlet sides of Vsaid resistance means, said motor speed control means including a valve bore having inlet and outlet ports connected in one of said lines and an element movable responsive to the rdifference in pressures on the in let and outlet sides of said resistance means and active to restrict the 'exten of connection between said ports.

CHARLES M. KENDRICK.

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