US2074203A - Pump - Google Patents

Description

March 16, 1937. 5.. BENEDEK PUMP Filed Nov. 28, 1932 3 Sheets-Sheet 1 m Qt mama ar. 16, 1937 UNITED STATES PATENT OFFICE PUMP Elek Benedek, Mount Gilead. Ohio Application November 28, 1932, Serial No. 644,675 r This invention relates to improvements in pumps and motors of the variable delivery, rotary, multi-piston type and has for primary object the provision of a novel simplified structure which is able to carry substantially greater specific loads than pumps of conventional design and which is more efficient in operation.

Pumps of the conventional type include ordinarily an adjustable reaction member which cooperates with the pistons and which supports the hydraulic piston load on its supported ends through bearings which are disposed on either side of the pistons at a substantial axial span so that saidreaction member is loaded as a bothend supported beam is loaded at its center by a concentrated load? In such pumps the enormous hydraulic load deflects the reaction member, which is ordinarily a drum, during each revolution in the direction of the resultant piston load and causes periodic vibrations with a frequency proportional to the number of deflections per minute in the drum. This phenomena is further amplified by the harmonic swinging character of the resultant piston load, the plane of vibration of which is normal to the main deflection vibration or the drum. Such elastic deflections.

may be very minute in their magnitude; however, owing to the high speed of such pumps and the plurality of working pistons, their vibration may reach the frequency of sound vibrations which results in considerable noise and the destruction of the liquid-tight fits between pistons and cylinders and cylinder-barrel and pintle respectively. Such vibrations of the reaction member are similar in character to the vibration of an elastic stressed wire which is kept in elastic vibration by periodic external forces.

Further characteristics of pumps of. the conventional type are in the construction of their piston assemblies, wherein the load transmitting means betweenpiston and. crosshead is a small elastic gudgeon pin, supported at its ends similarly to the drum support. Under the enormous piston load, the small gudgeon pins will deflect and vibrate with the periodic piston load between suction and pressure periods and will cause a high frequency roaring noise in the pump and the connected pressure system, accompanied by considerable pressure fluctuation. The elastic vibrations of the cooperative active and passive load transmitting bearing members causes cavitation and overcompression in the pressure fluid and the pump willoperate with fluctuating pressure due to gases and non-homogeneous pressure medium in the system, causing trouble in the connected hydraulic working circuit.

The main purpose of this invention is to provide a. high pressure fluid pressure machine which operates with solid, non-fluctuating pressure fluid for novel industrial purposes such as required in steering gears of ships, in the catapults of airplane carriers,.in the hangars of airships, and which has a useful life which makes the application commercial for novel industrial purposes at greater eificiency than heretofore and with the required factor of safety. The above aims and purposes are accomplished by a novel simplified pump construction in combination with the application of a new machine element, capillary needle bearing equipment, which is fully described in my co-pending application, Serial No. 641,186, flied Nov. 4, 1932.

In order to describe more specifically the substance of this invention and make it more readily understood by those versed in this art, reference is made to the accompanying drawings forming a part of my claims and specifications, wherein: Fig. 1 is alongitudinal sectional view of a pump constructed in accordance with the present invention, taken through the central valve of the pump.

Fig. 2 is an enlarged detail portion or the reaction member in Fig. 1. 1

Fig. 3 is the partial sectional elevation of a piston and its novel crosshead.

Fig. 4 is an enlarged detail section of a new bearing provided to transmit the combined radial and axial load of the cylinder barrel.

Fig. 5 is a partial sectional side elevation of a crosshead structure provided to engage the piston with the reaction member.

Fig. 6 is a normal section of the crosshead in Fig. 5, taken through one of the coupling elemerits of the structure.

Fig. 6-A is a slight modification of Fig. 6 showing the novel U-shaped structure of the crosshead unit taken through coupling bar It! in Fig. 11.

Fig. 6--B.is a normal sectional view of the crosshead structure taken-through the centerline of the piston in Fig. 11.

Fig. 'Iis a transverse sectional view of the pump constructed in accordance with the present invention taken through the centerline of all pistons.

Figure 8 is a slight modification of Figure 3, showing the application of the new needle bearing element in the piston crossheads in case of larger pump units.

Figure 9 is a normal section of Figure 8 showing the novel combination ofthe piston and its associated circular crosshead structure.

' Figure is a slight modification of Figure '7,

5 showing the reaction memberin its extreme eccentric position and the piston gudgeon pins packed with the new bearing needle elements.

Figure 11 is a normal section ofa piston as'- sembly taken through its plane of longitudinal,

- ates with the tapered cylindrical valve 2 and adjacent to that it has a smaller cylindrical bore as at 3 ,in which the enlarged portion i of shaft I is pressed in against cooperative shoulders I and 3" of the shaft and barrel respectively. The shaft and drum are keyed together by key .38 and are secured rigidly against tangential and axial displacements by lock nut 31.

A plurality of radial pistons 4 is arranged to operate in radial bores 3 Each piston 4 is provided with a load-transmitting shoulder and a suction operating threaded portion l 'which both cooperate with a gudgeon pin 5 with the particular purpose in view, that the enormous pressure will be transmitted through and by the shoulder 4 whereas the much smaller suction work will be taken up by the threaded reduced portion 4 of the piston-4, see Figure 3.

Each gudgeon pin 5 is-rockably mounted in the crosshead and is supported throughout its entire length in a structure comprising a circular prismatic segment which in the transverse section has a rigid U or H shape respectively. See Figures 5, 6, 6-A and 6B. Within the U or H channel sections 6 and 1 is an integral element 6 or 6 respectively which is'bored to receive and engage gudgeon pin 5. It willbe noticed that the U or H shaped part of the'circular structure is not bored through transversely as would be necessaryif the segment were made from one piece, but they are only rigidly secured to the gudgeon pin actuating members 5 and 6 respectively by coupling bolts l8 so that they have a certain required section modulus in the direction of the load transmission which is a very es,- sential requirement for the efiicient load transmission. This prevents fatigue and warpage of the U or H structure, and assures the free reciprocation of the segmental crosshead structure peripherally in its circular cooperating channel formed by reaction members 8 and 9.

I have discovered that if the circular crosshead structures in which the gudgeon pins are engaged are bored throughout their entire widths, they deform, losing their circular shape and consequently are unable to operate freely in their circular pathways, this being due to a weakened section resulting from the bore which pro-- duces the undesirable effects in operation referred to, even though the crossheads be other- 7 wise of strong construction. To eliminate the friction and the accompanying seizure of the crossheads in their circular pathways, formed by members 9 and 9 respectively, I provided the above described rigid circular structures of Fig- 75 ures 5, 6, 6A, 6-LB and Fig. 11 respectively.

The structure of the pathways for the several piston cross-head structures is also formed in a novel'manner resulting in a rigid permanent U- shaped construction, the arrangement of the parts being such as to permit assembly of the pump in a novel and improved way.

Notably in present invention the reaction member proper 9, which encircles the'cylinder and piston assemblies, is not split in the plane of the pistons as is customary in present routine designs of pumps but it is integral and has ground inner and outer plain cylindrical bearing. surfaces in accordance with the substance of the in the respectively associated cylinders, the whole cylinder, piston and cross-head assembly may be moved relativelyinside of the reaction member 9.

After the cylinder and piston assembly has been moved in member 9, the crossheads can be radially pulled out so that cheek plates 8 and their circular rims 8 will coordinate the crossheads with reaction member 9. Right after that is done powerful headless set screws engage.

members 8 and 9 in one assembly forming a rigid centrally positioned-circular path for the shoes or crossheads. It is evident that a radial shoulder not shown in the drawings may be provided for advantage between 8 and 9 so that they may line up flush in the assembly.

The-members 8 and 9, when thus secured together, provide a rigid reaction device formed" with spaced outer and inner annular tracks, there being an outer track portion provided by the member 9 and an inner track provided by the rim 8' of the cheek plate 9 on each side of a plane containing the axes of the cylinders.

The hydraulic piston load of the pistons is supported by a relatively fixed or stationary adjustable bearing shell II, which surrounds the cylinders and pistons. Between the relatively rotating and relatively stationary reaction members 9 and II is a noveltype of capillary needle bearing described in my co-pending application above re ferred to which comprises a plurality of slightly contacting cylindrical needle-rollers I! of about inch in diameter in the present instance and about 1 inch in length, separated in axial direction by a circular ring i3. The needle bearing elements l2, together with the intervening capillary oil bodies, transmit the thrust load between the relatively rotatable reactance element 9 and the relatively fixed reactance element ll and distribute the load so as to provide for power transmission with low friction loss and also to provide for rapid conduction of heat from the inner reactance element 9 to the outer reactance element Ii, thus promoting cooling of the entire machine. I

Similar needles ll are provided to transmit the load of the crossheads 6 or 9 and 6 to the rotary reaction bearing member 9. Each piston thrust load is distributed over a substantially continuous area constituted conjointlyby the-needle bearing elements it and a plurality of intervening capillary oil bodies. This arrangement provides for power transmission with low frictional loss, and moreover provides for rapid transfer of heat from the piston and crosshead outwardly to the rotatable reactance element 9.

According to the substance of 'my present and above referred to inventions, the contacting roll er-needles form a capillary oil-field between the bearing member races which, owing to the large line contact needle bearing area and the capillary oil film between them permits individual rolling of the working needles, and floating for the idle needles at a specific bearing load as high as 10,000 pounds per square inch, which is ten times as great as is permissible in plain or anti-friction bearings of conventional design. It is notnecessary to further amplify the significance of such bearings in high pressure pumps before those who are familiar with the problems of high pressure and high speed pump designs in view of the fact that the bearing is the main limiting factor today in variable delivery pumps in regard to higher pressure and higher efficiency. Today 3000 pounds is the maximum specific pressure which can be applied continuously and without overheating in pumps of conventional design. Fortunately in most of the hydraulic applications the maximum pressure is required only at peak pressure and for a few seconds, thus for a fractional part of the minute. In pumps of sub-normal capacity with small size pistons, a higher specific pressure may be carried, however those cases are only exceptions and built on the intensifier principle. The normal capacity pump is the one in which the piston diameter has a well established commercial ratio to the maxi mum stroke of the piston. In such pumps today it is difiicult to secure the proper anti-friction bearings which would fit into the desired and available space and within commercial price.

The stroke-piston diameter ratio above referred to is slightly greater than unity and it ranges between one and two in present high pressure variable delivery pumps.

Needles M are packed in an H shaped retainer l5 so as to keep the needles in rolling or sliding parallelism as described in my application above referred to,

Each crosshead is provided with a pair of end plates IE on its ends to control the position of the individual needle bearings for the crossheads. Each plate I6 is secured to the circular structure 6 and I or to 6 and 6 by a plurality of machine screws I! respectively.

55 Adjustable bearing ring II forms the relatively Y" stationary or passive race of my novel type of needle bearing, while reaction member 9 is the inner or active race of the bearing. The very small or capillary spaces between them taken up by the needles i2 occupy but a very little radial dimension and thus the bearing means is formed practically from pump parts or it may be said that the complete needle bearing is formed by inner race 9, needles l2 and outer race ll, thus the reaction member and the bearing for same make in assembly one complete needle bearing. One of them may be regarded as eliminated when compared with a present routine type of pump.

Figure 2 shows a double row needle bearing in which needles I2 are separated by separator I3. In outer race ll there is provision as at H to retain the needles against axial displacement in such a way that H forms circular shoulders H but still maintains an axial circular clear- 7 ance as at H so as to permit the capillary equipment.

interspaces of the needles and their races to draw in lubricant by capillary attraction from axial direction.

Similar provision is made for the crosshead needles .which are lubricated by the lubricant maintained in the drum structure 8 and 9 from the slip passing the pistons by centrifugal force in a'well-known manner. However, needles H which have a diameter between to inch provide for the pistons under pressure a rolling flexible bearing structure, which under the combined action of centrifugal and capillary-force lubrication, permit the needles to roll under the working crossheads around their individual axes with a theoretical friction coefllcient of 0.004 instead of sliding with a coefficient of 0.10 to 0.01 under the most favorable sliding conditions.

Under the sucking pistons above the dead centers of rods l9 and 20 in Fig. 10, the needles -l4 are naturally idle and they will float between two oil films with a floating sliding motion.

For larger units gudgeon pins 5 may also be packed with needles as shown in Figs. 8, 9' and 10 in such a way that on the pressure side of the pins full length needles 28 and for the suction side shoulder needles 28 are provided. To facilitatethe packing of needles into their capillary circular recesses, I usually fill the recess with heavy grease and then pack the needles therein.

Preferably the gudgeons are mounted in the cross heads between the outer and inner curved running surfaces of the latter which engage respectively with the outer and inner tracks on the reaction device 8-9.

.To provide for the axial thrust of the tapered cylinder and pintle assembly, I provided a novel type of capillary needle bearing to support the barrel 3 at its ends in-which the needle rollers 2| are slightly taper ground as in Fig. 4 and mounted in complete bearing form between inner and outer bearing races 22 and 23; said races are hardened to a Brinnell of not less than 650 and made of high grade nickel alloy steel.

As shown, the rollers 2| are tapered and have .their axes inclined with respect to the pintle axis, the smaller ends of the rollers 2| being closer to the pintle than the larger ends, and the smaller ends of each anti-friction bearing assembly facing towards the other anti-friction bearing assembly. By virtue of this arrangement, the bearings 2| effectively carry radial loads and axial loads in both directions and thus maintain the cylinder barrel inconcentric relation to the pintle.

The entire pump is enclosed in cylindrical casing 29 which is provided with load transmitting sliding bearing pads 30 and 3! respectively, and with bosses 29 for the mounting of pump control The control equipment ordinarily cooperates with passive bearing race II and its connecting means H with control rods l9 and 20 respectively.

Sliding bearing pads 30 and 3| cooperate with similar complementary pads ll provided in bearing ring ll. Pump body 29 is axially closed by end covers 34 and 35 respectively, in which tapered needle bearings 2| are mounted to support the cylinder barrel 3 and one of the pintle end covers 34 is provided for inlet and exhaust connections as at 21 and 21 respectively. 21 is diametrically opposite to 21 on the enlarged portion 2 of the pintle 2 and cooperates with coincident passages provided in hub 34 of end cover 34 in a well known manner. Inlet and exhaust passages 21 and 21 are in communication with pintle passages 24, 24 and 25, 28 in a well known manner which further communicate with main pump ports 26 and 26 which are reversible and at different times each one of them may be 5 pressure or suction port as well. Suction and pressure ports 28 and 28 further communicate with a sucking and delivery group of pistons respectively which are separated by a solid bridge portion 2". See Figure 10.

10 Pump body 29 is further provided with stop shoulders- 38 in order to limit the maximum stroke of the pump and with an eye bolt 33 for lifting purposes-drain connection 32 is quite an essential feature of the casing. The slippage l6 fluid will be drained through this connection so that the rotary pump assembly will rotate freely in the drained casing. End covers 34 and 35 are further provided with stiflening'flanges I4 and it" in order to make the pump supportrigid 20 and vibrationless.

Drive shaft I is rigidly secured to barrel 3 by key 38 and lock nut 31 and its projection through hub 35 is guarded against slip by packing ring 38.

L The pump will operate in a well known manner. 25 For example, let arrow 40 show the rotation of the pump, and the rotary needle bearing be shifted by control rods l8 and 20 from its center position as shown in Figure 7 toward its right oil-center position as shown in Figure 10. It is 30 evident then how during the upper half of each revolution the pistons are carried outward by the needle bearing which is forced to rotate with the driving cylinder barrel and will suck through port 26. The pistons during the lower half of 35 the revolution are forced inward by the needle bearing and consequently will compress the fluid through port 26 When the needle bearing is in its on-center position with the cylinder body, the relative position of the plungers in their cylinders remains unchanged during the revolution and, although the pump is running it will not deliver any fluid. Figure 7 shows the pistons and the needle bearing in their on-center positions.

It can readilybe seen that the distance the needle bearing is eccentric with regard to the cylinder body determines the amount of the stroke and hence, the volume of the discharge, and that the finest variation from zero to a maximum can be obtained without stopping the p mp.

Novel detail operative features of the pump are as follows:

Central valve 2 is rigidly supported in hub 34 of end cover 34 through a heavy press fit so that the position of the valve is entirely independent and concentric in regard to the position of the barrel and when, after careful assembly and lap flt one in the other the slight selective 60 clearance between them acts as a continuous capillary interspace and will draw in fluid to provide capillary lubrication which is not the case when the cylinder is supported directly or semi-directly in the valve as in pumps of the 65 prior art.

Side flanges 8 of the inner race of the needle bearing are reaching beyond the outer diameter of the cylinder disc inwardly to retain fluid during the operation of the pump by the centrifugal 7 force and seals the end of the cylinders to prevent air suction at all times. This is an essential feature for the successful operation of a pump.

Various changes may be made in the embodiment of the invention hereinabove specifically 7 described, without departing from or sacrificing any of the advantages of the invention as defined in the appended claims.

I claim:

1. In a pump or motor the combination of a pintle, a plurality of radial piston and cylinder assemblies surrounding said pintle, a complete needle bearing surrounding said assemblies, a crosshead associated with each assembly, a reciprocating thrust needle bearing between each crosshead and the inner race of said complete bearing 'to sustain the hydraulic load of the pistons, said thrust needle bearing comprising a plurality of parallel, bodily reciprocating capillary elements and associated cage member for maintaining the needles in their bodily relation during reciprocation and means associated with said inner race to maintain said crossheads in working relation with said thrust needle bearings and to retain pressure lubricant to seal the outer end of each cylinder bore against suction of air.

2. A pump assembly including a pintle member, a cylinder barrel mounted for rotation about said pintle and having-a plurality of cylinders therein, valve means for said cylinders, a piston for each of said cylinders, a crosshead for each piston, each of said crossheadsbeing substantially U-shaped in cross-section and having an insert therein, means for attaching said inserts to said crossheads, each of said inserts having a bore for the reception of a gudgeon, a stem on each of said pistons, a gudseon on each stem, said gudgeons being received in the bores of the inserts, and reaction means surrounding said cross-heads and having thrust-transmitting driving connection therewith.

3. A pump assembly including a pintle member, a cylinder barrel mounted for rotation about said pintle and having a plurality of cylinders therein, valve means for said cylinders, a piston for each of said cylinders, a crosshead for each piston, each of said crossheads being substantially U-shaped in cross-section and having an insert therein, means for attaching said inserts to said crossheads, each of said inserts having a bore for the reception of a gudgeon, a stem on each of said pistons, a gudgeon on each of said stems, said gudgeons being received in the bores of the inserts, needle bearing anti-friction devices intermediate each of said gudgeons and walls of the associated bores, and reaction means surrounding said crossheads and having thrust-transmitting driving connection therewith.

4. In a pump assembly, the combination of a stationary pintle, a rotatable cylinder barrel mounted for rotation about said pintle and having a plurality of cylinders, a piston for each cylinder, duct means interconnecting said pintle with said cylinders and affording communication for the working fluid therebetween, a crosshead for each piston, piston actuating means disposed about said cylinder barrel and including reaction means having thrust-transmitting engagement with said crossheads for imparting a suction stroke and a pressure stroke to each piston during each revolution, saidcrossheads each comprising a body portion having depending walls, an insert lying between the walls of each crosshead and being joined thereto, each of said inserts having a bore therein, the wall of which forms one wall of a bearing chamber, a stem on each of said pistons, gudgeons each having an aperture for receiving said stems respectively, said gudgeons being adapted to lie in the bores in said inserts and forming the other walls of said bearing chambers, 1 and needle bearing members disposed in saidchambers.

5.-In a pump assembly, the combination of a stationary pintle, a rotatable cylinder I barrel 5 mounted for rotation about said pintle and having a plurality of cylinders, a piston for each cylinder,

duct-means interconnecting said pintle with said cylinders and affording communication for the a working fluid therebetween,a crosshead for each piston, piston actuating means disposed about said-cylinder barrel and including reaction means having thrust-transmitting engagement with said crossheadsfor imparting a suction stroke and a pressurestroke toeach piston during each revolution,.said crossheads each comprising a body portion having depending walls, an insert lying between the walls of eachcrosshead body portion and being joined thereto, each of said inserts having a transverse bore the wall of which forms one wall of. a bearing chamber, a stem on each of said pistons, gudgeons each having an aperture for receiving one of said stems, each of said gudgeons'being adapted for rocking movement in said bore of the associated insert, each of said gudgeons. forming the other wall of the associated bearing chamber, and capillary needle members comprising elongated body portions lying in said bearing chambers thus formed to supply and maintain an effective double oil film in said chambers by capillary attraction.

6. In a pump assembly, the combination of a stationary pintle, a rotatable cylinder barrel having a plurality of cylinders, a piston for each cylinder, duct means interconnecting said pintle with said cylinders and affording communication for the Working fluid therebetween, a crosshead for each piston, piston actuating means disposed about said cylinder barrel and including reaction means having thrust-transmitting engagement with said crossheads for imparting a suction stroke and a pressure stroke to each piston during each revolution, said crossheads comprising a body portion having depending walls, an insert lying between said walls and being joined thereto at spaced points having a transverse bore therein,

the wall of said bore forming one wall of a bearing chamber, a stem on said piston, a gudgeon having an aperture for receiving said stem, said gudgeon being adapted for rocking movement in said bore of said insert in forming the other wall of said bearing chamber, and anti-friction devices disposed in said chamber, to supply and maintain an effective oil film in said chamber by capillary attraction, the depending walls of said crossheads preventing axial displacement in said gudgeon members and said anti-friction devices in a transverse direction.

7. In a pump assembly, the combination of a pintle, a rotatable cylinder barrel having a plurality of cylinders, a piston mounted for reciprocation in each cylinder, duct means interconnecting said pintle with said cylinders and affording communication for the working fluid therebetween, a reaction device surrounding said cylinder 65 barrel and being formed with spaced outer and inner annular tracks, there being an outer track portion and an inner track spaced therefrom on each side of a plane containing the axes of said cylinders, means for supporting said reaction de- 70 vice in a position eccentric with respect to said pintle, a rigid cross head for each piston having outer and inner running surfaces curved to conform to said tracks and engaging said outer track portions and said inner tracks on both sides of 75 said plane, a bore in each cross head extending parallel to the axis of said pintle and being located between the outer and inner running" surfaces on said cross head, and a gudgeon connected to each piston and extending into the borein the associated cross head whereby the 5 pistons are pivotally connected to their I'BSPCG? tively associated cross heads at points between the engagement of the cross heads with the outer and inner tracks on the reaction device.

8. In a pump assembly, the combination of a 10 pintle, a rotatable cylinder barrel having a plurality of cylinders, a piston mounted for reciprocation in each cylinder, duct means'interconnecting said pintle with said cylinders and afford- 7 ing communication for the working fluldthere- 15 between, a reaction device surrounding said cylinder barrel and being formed with spaced outer and inner annular tracks, there being an outer track portion and'an inner track spaced therefrom on each side of a plane containing the 20 axes of said cylinders, means for supporting said reaction device in a position eccentric with respect tosaid pintle, a rigid cross head for each piston having outer and inner running surfaces curved to conform to saidtracks and engaging said outer 25 track portions and said inner tracks on both sides of said plane, a bore in each cross head extending parallel to the axis of said pintle and being located between the outer and inner running surfaces on said cross head, and a gudgeon secured to each piston and being received in the bore of theassociated cross head, and anti-frictiondevices disposed between the gudgeon of each piston and the-associated cross head here to supply and vmaintain an oil film between the gudgeon and the bore wall by capillary attraction, whereby the pistons are pivotally connected to their respective-- ly associated cross head at points between the engagement of the cross heads with the outer and inner tracks on the reaction device. so

9. In a pump or motor, the combination of a plurality of rotatable radial piston and cylinder assemblies, each including a relatively reciprocable member having a thrust-transmitting surface; rotatable annular reaction means sur- 45 rounding said assemblies and having thrusttransmitting surface portions associated respectively with the thrust-transmitting surfaces of said reciprocable members; and needle bearing equipment interposed between the thrust-trans- 50 mitting surfaces of said reciprocable members and the associated thrust-transmitting surfaces of said reaction means, said needle bearing equipment comprising a plurality of parallel, closely contiguous, individually rolling elements of very small diameter, said elements being of such size and so closely positioned relatively to each other as to provide, conjointly with said associated thrust-transmitting surfaces, a plurality of capillary oil spaces containing bodies of oil, whereby the load on each of said reciprocable members is distributed over a substantially continuous area constituted by the needle bearing elements and the capillary oil bodies, the continuous loadtransrnitting area providing also for rapid transfer of heat by conduction from said reciprocable elements to said reaction means.

10. In a pump or motor, the combination of a plurality of rotatable radial piston and cylinder assemblies, each including a relatively reciprocable member having an arcuate thrust-transmitting surface; rotatable annular reaction means surrounding said assemblies and having arcuate thrust-transmitting. surface portions associated respectively with the thrust-transmitting surfaces of said reciprocable members; and needle bearing equipment interposed between the thrusttransmitting surfaces or said reciprocable mem-'- bers and the associated thrust-transmitting survoil, whereby the load on each of said reciprocable members is distributed over a substantially continuous area constituted by the needle bearing elements and the capillary oil bodies, the continuous load-transmitting area providing also for rapid transfer or heat by conduction from said reciprocable elements to said reaction means;

11. In a pump or motor, the combination of a plurality of rotatable radial piston and cylinder assemblies, one member of each assembly being reciprocabie; a relatively iixed annular bearing element surrounding said assemblies; a relatively floating annular bearing element also surrounding said assemblies and disposed between the latter and said relatively fixed element; a needle bearing equipment interposed between said relatively fixed and said relatively floating elements, said equipment comprising a plurality of lubricated, closely contiguous cylindrical bearing elements of such size and being so closely positioned relatively to each other as to provide, conjointiy with said relatively floating element and said relatively flxed element, a plurality of capillary oil spaces containing bodies of oil, whereby the load transmitted between said relatively fixed element and said relatively floating element is distributed over a substantially continuous area constituted by the needle bearing elements and the capillary ao raaos oil bodies, the continuous load-transmitting area providing also for rapid transfer 0! heat by consaid relatively flxed element; and a similar needle bearing equipment interposed between said relatively floating element and the reciprocablemember of'each piston and cylinder assembly.

12. In a pump or motor, the combination of a plurality of rotatable pistona'nd cylinder assemblies, one element oi each assemblybeing reciprocable relatively to the other element thereof a relatively rotatable annular reactance element surrounding said 'assemblies;- a relatively fixed annular reactance element surrounding said relatively rotatable reactance element; thrust-loadtransmitting bearing means interposed between said relatively reciprocable elements and said relatively rotatable reactance element and being constructed to conduct heat ei'iiciently from said relatively reciprocable elements to said relatively rotatable reactance element; and thrust-loadtransmitting bearing means interposed between said two reactance elements and being constructed' to conduct heat emciently from said relatively rotatable reactance element to said relatively fixed reactance element, one of said bearing means comprising a plurality of lubricated. closely contiguous, elongated cylindrical needle bearing elements of such size and being so closely positioned relatively to each other as to provide, conjointly with the elements between which they are positioned, a plurality oi. capillary oil spaces containing bodies or oil, whereby the thrust load is distributed over a substantially continuous area constituted by the cylindrical needle bearing elements and the capillary ofl bodies. the continuous load-transmitting area providing also for rapid transfer of heat by conduction. I

ELEK BENEDEK.

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