US2006880A - High pressure radial piston hydraulic pump or motor - Google Patents

Description

y 1935. E. K. BENEDEK 2,006,880

HIGH PRESSURE RADIAL PIS TON HYDRAULIC PUMP OR MOTOR Filed Oct. 1, 1951 3 Sheets-Sheet 1 4! 55 INVENTOR [if/f A. BEA/05K A TTORN July 2, 1935. E. K. BENEDEK 6,880

HIGH PRESSURE RADIAL PISTON HYDRAULIC PUMP OR MOTOR Filed Oct. 1, 1931 s Sheets-Sheet 2 9L AMORNZ? y 1935- E. K. BENEDEK 2,006,880 0 HIGH PRESSURE RADIAL PISTON HYDRAULIC PUMP OR MOTOR Filed Oct. 1, 1931 s Sheets-Shet s Hllflllllllllllm.

V ummw //Mm|m|mw// 1201* /r. Bnvmnr Patented July 2, 1935 UNITED STATES PATENT OFFICE HIGH PRESSURE RADIAL PISTON HY- DRAULIC PUMP OR MOTOR Elek K. Benedek, Mount Gilead, Ohio, assignor to The Hydraulic Press Manufacturing Company, Mount Gilead, Ohio Application October 1, 1931, Serial No. 566,381 6 Claims. (o1. 103-161 and compact in construction and yet is capable of producing a higher pressure and more uniform, variable output when operating as .a pump, or when operating as a motor,-is capable of producing materially greater starting torque due to the many points at which propelling force is applied during a single revolution and is thus better adapted for starting at creeping speeds, than is possible in pumps or motors of like types of which I am at present aware Pumps of conventional forms of this type usually are limited to the use of five or seven pistons or plungers because the crossheads which are found necessary in connecting the pistons with the eccentric or impeller are-more or less large and complicated in construction and require the employment of cylinder barrels of greater length than are desirable or would otherwise be necessary. These types of pumps are'capable only of non-uniform fluctuating delivery and cannot be used efficiently for many purposes, say for example in grinding, drilling and threading machines in which it is absolutely essential that the rate of feed be kept at a predetermined constant value.

Furthermore, conventional forms of pumps of the types stated usually employ rotating cylinder barrels in the bores of which pistons are. caused to reciprocate because of their connection, through the medium of crossheads, with an eccentric or impeller adapted to rotate with the barrel about an axis disposed eccentrically with relation to the axisof' rotation of the barrel, and, thus serving as rotation imparting elements, the pistons are necessarily subjected to lateral strains or torque which results in much unnecessary friction and wear and materially reduces the life of the pump structure.

Having in mind remedying the defects above enumerated, I have designed the improved structure herein disclosed with the object of providing a pump or motor in which novel means other than pistons and crossheads are employed to cause the cylinder barrel and the eccentric or impeller to rotate together, thus entirely relieving the pistons of the objectional strains to which they are subjected in the pumps and motors above referred to. I

Another object of the invention is to provide in a pump or motor novel piston "construction and arrangement enabling efiicient employment of an unusually large number of pistons in an unusual- 'driven shaft, being shown in elevation.

ly small space and in a manner assuring, high pressure output at a uniform rate when used as a pump, and enabling easy starting at creeping speeds when used as a motor, due to the large number and small separation of points where 5 power is applied during a single revolution.

Other objects will in part be obvious and in be pointed out hereinafter. Y

To the attainment of the aforesaid objects and ends the invention still further resides in the novel details of construction, the combination and arrangement of .parts, all of whichwill be first fully described in the following detailed description and "then particularly pointed out in the appended claims; reference being had to the accompanying drawings in whichz- Figure 1 is a horizontal section taken through the axis of a pump or motor. embodying my invention, the pintle and a portion of a driving or part Figure 2 is a vertical cross section taken on the line 2-2 on Figure 1.

Figure 3 is a detail vertical cross section taken on the line 3-3 of Figure 1.

Figure 4 is a detail vertical cross section taken on the line 4-4 on Figure 1.

Figure 5 is a detail vertical cross section taken on the line 5-5 on Figure 1 Figure 6 is a central longitudinal sectional view of the cylinder barrel.

Figure 7 is a right-hand end elevation of the cylinder barrel shown in Figure 6.

Figure 8 is aninner face view of one of the supplemental coupling rings. I

Figure 9 is anouter face view of the coupling ring shown in Figure 8.

Figure 10 is a vertical cross section'of the coupling ring shown in Figures 8 and 9 V Figure 11 is an end elevation of the eccentric or impeller ring. 40

Figure 12 is a longitudinal section of the eccentric or impeller ring.

Figures 13 and 14 are inner and outer face. views, and

Figure 15 a vertical cross section of one of the main coupling rings.

Figures 16 and 17 are side elevation and invertedplan views of' one of the piston elements.

Figure 18 is'a side elevation and part section of a modified form of piston.element, and

Figure 19 is atop plan view of the piston'element shown in Figure 18. g t

In the practical development of the invention I provide a pump casing in the nature ofan annular ring 5 having an integral supporting 55 base portion 6, horizontally and diametrically oppositely disposed bosses provided with guide bores 1 and upper and lower slide guide pads 8. One end of the casing is closed by a wall 9 and the other end thereof is formed open but is normally closed by an end cover plate l which is secured as at H to the casing ring 5.

The cover plate is provided with an annular film bearing wall ring l2 opposing a similar like designated ring formed on the casing wall 9 and is bored as at l3 to receive the enlarged head 14 of a pintle I5, said head being secured in the bore by a key IS.

The pintle I5 is provided with an upper pairl1 and a lower pair l8 of longitudinal passages. The upper pasages l1 communicate through a common port l9 in the pintle head M with a combined inlet and outlet port formed in the hub of the cover plate I0 and with three upper cutouts 2| disposed in spaced relation along the pintle IS. The lower passages l8 similarly communicate through a common port 22 in the pintle head with a combined inlet and outlet port 23 in the cover plate hub and with three lower cutouts 24 disposed in spaced relation along the pintle and each in the same plane with an associated upper cutout 2|.

The passages l1 and I8 terminate in the free end of the pintle beyond the cutouts 2| and 24 and attheir other ends, where they pass through the pintle heads l4, they are plugged as at 26. It will be observed by reference to Figure 2 of the drawings that the formation of the cutouts provides for solid bridge portions 21 which separate the upper and lower cutouts and provide cylinder bore cutoffs.

The end wall 9 of the casing is provided with an axial hub extension which is bored axially from its respective ends to form a shoulder 28 and annular-recesses at its respective ends and separated by said shoulder, the recess at the inner end serving to accommodate a shaft receiving film-bearing member 29, andthe recess at the outer end serving to accommodate a gland packed as at 30 and the gland head 3| of which is secured as at 32 to said hub extension.

A driving or driven shaft 33 is rotatably mounted in the bearings provided therefor in the hub extending from the casing wall 9 and is equipped with a head 34 which is rotatable in the pump casing and is secured as at 35 to a cylinder barrel 38 equipped with an axial bore to fit and have rotative bearing on the pintle l5. The cylinder barrel 38 is provided with a plurality, of sets of radial cylinder bores 31. In this particular disclosure I have shown three such sets of bores and each set comprises five radial bores all of which are disposed in a common plane intersecting one upper and lower pair or set of pintle cutouts 2| and 24. The sets of bores are arranged in individual phase relation so that each bore will lie in a distinct radius, thus providing fifteen distinct bore radii disposed equidistantly about the common axis of the cyl inder barrel and pintle.

-An eccentric and impeller ring 38 surrounds the "cylinder barrel in spaced relation, and surrounding this ring 383s a shifter ring 39 in which the impeller or eccentric ring 38 is afforded rotative bearing in a high pressure oil film as indicated at 40. This film bearing may be 'of any suitable structure, but is preferably .constructed in accordance with the disclosure in co-pending application Serial No. 557,888, filed August 18, 193i. .Shifter rods' 4| are slide guided in the casing bores 1 and are secured as at 42 to the shifter ring 39 so that when they are moved longitudinally by any suitable control means (not shown) the shifter ring will be shifted in a straight line coincident with an imaginary line drawn through the axis of the pintle and centrally through the bridge portions 21 thereof because of the guiding function of the casing pads 8 and the coacting pads 43 with which the shifter ring 39 is provided.

The eccentric or impeller ring 38 is provided with a plurality of tongue receiving grooves 44 in each end edge thereof and the cylinder barrel 36 is equipped with similar tongue receiving grooves 45 which, however, are disposed normally with relation to the grooves formed in the ring 38. A coupling ring is disposed at each side of the casing and each such ring is formed compositely of a main ring 46 and a supplemental ring 41 secured to the main ring as indicated at 48. Each main ring 46 is equipped with a plurality of tongues or keys 49 which project into and slide freely in the grooves 44 in the ring 38, and each supplemental ring 41 is equipped with a plurality of tongues or keys 50 which are suitably positioned for projecting into and sliding freely in the grooves 45 formed in the cylinder barrel.

The tongue and groove equipments 44, 45, 49 and 50 of the rings 38, 46 and 41 and the cylinder barrel 36 provide universal coupling for the eccentric or impeller ring 38 and the cylinder barrel 36, causing them to rotate together regardless of the degree of eccentricity to which the ring 38 has been shifted. It is to be understood, of course, that during active operation of the device as a pump or motor the cylinder barrel rotates about the axis of the pintle and the eccentric or impeller rotates about an axis spaced from or bearing eccentric relation to said pintle axis.

A piston 5| is reciprocable in each cylinder bore 31 and includes a cylindrical portion to fit the respective bore and a small flat head extension which projects beyond the bore and serves as a retaining means limiting inward movement of the piston and yet is so small that the degree of its projection beyond its respective bore, and which might be said to limit the number of sets of piston and bore equipments which could be arranged along a given cylinder barrel length, is negligible and in no wise hinders the degree of compactness possible in my improved pump or motor.

The fiat heads of the pistons frictionally engage the inner wall of the eccentric or impeller ring 38 so that during half a rotation of the cylinder barrel said wall will serve to limit the outward travel of the pistons and during the remainder of the rotation said wall will engage said piston heads and force them radially inward. If desired the piston heads may be provided with ball seats 53 and anti-friction balls 54 disposed in the seats for engagement with the eccentric or impeller wall.

The structure hereinbefore described, is designed for use as a pump or motor, and when used as a pump is capable of delivering fluid at hgh pressure and at a uniform rate. When so used the pump is preferably supercharged from an ordinary low pressure pump (not shown) and will build up the desired high pressure and deliver the fluid in a smooth non-fluctuating manner.

This construction of pump will be found particularly desirable for use in feeding machine tools such as grinding machines, drilling'machines or threading machines in which it is very important to keep the rate of the feed at a predetermined constant value.

In the conventional "forms of pump now in use and in which five plungers usually are provided, there are a maximum of two or three pis-' tons on the pressure'side at any given time delivering two or three harmonic impulses at one time to the feed cylinder. It is obvious that in case of two pistons, the impulses are too great and also the slip variation is, even under normal conditions, not permissible. Such difficulties can be overcome only in high pressure application by multiple plunger type pumps such as I have disclosed 1 herein. When the number of plungers delivering atlzt given instant to a feed cylinder is about six or seven, it is obvious that the fluc- 'tuation in the volume of delivery, as well as the fluctuation of the resulting flow, is less in the proportion of the greater number of plungers.

In Figure 2 of the drawings I have shown the eccentric or impeller ring shifted to the neutral position in which no outputof fluid will be effected. When the ring 38 is shifted to the right it will rotate about an axis disposed eccentrically with reference to and at the right of the pintle axis and the pistons in the upper half of the cylinder barrel will be moved outwardly and therefore will suck fluid through the upper ports and passages 20, I9 and I1 and the pistons in the lower half of the cylinder barrel will be moved inwardly and will expel fluid smoothly at high pressure and uniform rate through lower ports and passages I8, 22 and 23. By shifting the eccentric or impeller ring and thus varying the eccentricity thereof the output of the pump may be varied, and by shifting the axis of said ring to the opposite side of the pintle axis the pump may be reversed in a manner well known in this art.

As hereinbefore stated the structure which I have dsclosed herein operates very efliciently as a motor and enables starting of the motor easily at creeping speeds, for reasons previously disclosed. The present designs of hydraulic motors of which I am aware have the following limitations:

1. Limited number of pistons. The maximum number of plungers possible practically in presentccnstructions is five to seven, which means that in the working chamber of the motor three or four at most, and posthe driving torque required from the motor at any given time. It is evident that the resultant torque of two pistons is non-uniform and fluctuating, especially if one of the pistons has some unusual leakage. torque is left entirely to the effort of a single plunger which fact shows that in such a phase the motor would be inadequate to furnish sufficient starting torque for its requirement.

2. The locking tendency of the pistons in the dead center position.

Let us assume that the above mentioned two or three working pistons are on the expansion side of the motor and that one plunger is in its dead center at the beginning of the fluid expan In that case, the resultantnumber of pistons in'present conventional constructions is impossible due to the fact that in these constructions the piston units having special crossheads which limit the number of pis-.=

tons which can be accommodated. A multi-row arrangement of the pistons in such constructions is almost impossible due to the fact that the crosshead masses which they employ would cause undesirable unbaflanced forces in the unit and also would make the construction too expensive. 3. The impossibility of exerting high starting torque in above mentioned constructions by using a piston unit as a coupling element between the impeler or eccentric unit and the driven unit or cylinder barrel of the motor. No matter what is the contructive solution for transmitting the driving torque to the rotor of the motor by pressure of the fluid on the'pistons thus coupled, it will be evident that the fluctuationof the load on the motor shaft would cause tangential forces on the piston units and therefore it would be subjected to wear and strain which would materially affect the life of the tures of my device employed as a motor can be summarized as follows:

' (a) Elimination of complicated, space consuming crossheads.

Because my hydraulic motor does not require any crosshead to exert sucking effort, therefore the omission of crossheads enables me to build a multiple row piston motor in a very limited space.

expensive,

The reason for this is that my motor pistons do not require any crosshead. The pressure fluid expands duringthe inlet period, thereby pushing the pistons outward toward the eccentrically located rotor, and during the exhaust period the rotor pushes the pistons inwardly thereby forcing the fluid into the exhaust line. It should be easy to understand that during the whole cycle of expansion and exhaust the force on the bottom of the piston always tends to push'the pistorrtoward the rotor, thus the piston always will be kept in contact with the rotor without any need for crosshead.

(b) The locking tendency of the pistons is eliminated by the great number of pistons active at a given interval.

In my present invention the motor is shown as having pistons or plungers arranged in three series of five each, in place of the five plungers, whereby the fluctuation of the resultant torque isthree times less, and generally speaking ntimes as low as inabovementioned construction. Experimental results of present conventional forms of motors show that due tothis locking tendency the'starting torque ,of the motor is practically zero and even at creeping speed the torque is below 50% of the theoretical torque of '1 ]able number of plungers for attaining the'desired smoothness in starting.

By considering the fact that only one plunger can-be in locking dead center position at any given time whereas the rest of the plungers, say six, in a' fifteen plunger motor, are exerting starting torque, it is evident that excluding the frictional resistance of the motor, only oneseventh of the total theoretical torque is lost by the fact that one piston is in the dead center, and besides the exerting thereof of positive braking effort. By braking effort I mean the fact that the plunger in the dead center, under fluid pressure, positively acts as a brake. Six of the cylinders which are working at a certain torque -radius easily overcome the locking effort of the brake piston and thus carry the load on the motor shaft with a fluctuation characteristic, say onesixth, or in terms of efficiency it can be seen easily that approximately only 16% of the theoretical torque causes fluctuation even if we assume that the pistons exert equal torques in every position of the expansion stroke. Actually, however, the torque radius of each piston changes according to a sine curve, therefore the loss around the dead center is not so great in the theoretical torque, but the loss is caused by the fact that the piston exerts braking of its maximum torque capacity, and this in unavoidable. To summarize the facts, it is evident that the greater the number of pistons, the greater starting torque can be obtained and a more uniform running torque can be maintained in a hydraulic motor.

(d) The application of a coupling (mechanical) between motor cylinder and motor eccentric.

An eflicient form of universal coupling has been applied at both ends of the cylinder and eccentric unit in order to exert the driving torque between the two elements. Therefore, any participation of the pistons in transmitting the torque is entirely eliminated. The hydraulic fluid pressure 'on the bottom of the pistons exerts an eccentric force around the center of rotation of the eccentric and therefore it causes the eccentric to rotate. The resultant of all the piston forces exerts a torque around the center line of the eccentric and ,will rotate the eccentric around that center line. This rotating force from the eccentric will be carried over to the cylinder unit by the universal coupling, which cylinder unit is secured to and imparts rotation to the motor shaft and thus gives off the work of the motor.

' Should the eccentric have been coupled to the cylinder by the pistons, naturally the torque of the eccentric would be transmitted to the rotor shaft by the pistons and this would cause more or less rapid wear on the pistons and cylinder walls.- By the elimination of friction losses by above mentioned mechanical coupling I claim that the efliciency of the motor has been improved considerably.

In present commercial motor practice, the main demands upon the motor are high starting torque, high running torque and high static or potential torque. All these requirements are demanded almost simultaneously but none of them has been satisfied up to the present time. I claim that my hydraulic motor can meet all above mentioned demands.

- The stroke of the pistons of my motor can be fixed or can be made. adjustable by providing means for varying the separation of the primary and secondary rotors, as is well known in the art. However, the employment-of a variable stroke pump to operate the motor usually obviates the need for a variable stroke motor. The number of plungers will determine the starting characteristics of the motor, and because in my construction the number of plungers is not limited; therefore I claim that I have a motor adapted for any requirement for uniform running torque and smooth starting.

When my device is operating as a motor, the high pressure fluid enters and passes through a selected group of the ports and passages 20, I9 and IT, or 23, 22 and I8, and through the associated pintle cutouts 2| or 24 into the registered cylinder barrel bores 31. This high pressure fluid exerts hydraulic pressure on the bottom of the associated pistons and this pressure is distributed through the pistons to the wall of the eccentric or impeller 38 causing it to rotate together with the cylinder barrel and the driven shaft attached to the end thereof. The moment the piston reaches the horizontal or dead center position it will be passing one of the bridge portions of the pintle and approaching the exhaust side of the motor chamber where it will be forced radially inward by the engaging impeller wall causing the theretofore working fluid to be expelled from the motor through the associated group of cutouts discharges and ports.

Thus it will be seen that the pressure fluid enters the motor, engages the pistons therein and delivers work to the rotor shaft giving up its power through the period of expansion. The pistons having finished their; working stroke then act to expel fluid from the motor.

There is an expansion period for the fluid down to about atmospheric pressure if there is no resistance in the exhaust line, then an exhaust period during which the fluid is forced out of the pump. It will be seen that the fluid in the motor always is under pressure. There is no suction period which would cause partial filling of the individual cylinders. The motor preferably functions as a 100 per cent supercharged metering pump which discharges a uniform amount of fluid per revolution. The amount of fluid is determined by thefsize of the cylinders and the piston stroke theoretically, and practically by the cavitation caused by the restricted passages of the pressurefluid which tends. to fill out the individual cylinders while they are in communication with the pressure chamber of the motor. While there is limited time for this purpose. ample passages are provided in the pump so that the individual cylinders will be completely filled out with pressure fluid without the considerable loss of pressure or velocity head.

From the foregoing description taken in connection with the accompanying drawings, it is thought that the novel details of construction, the manner of use and the advantages of my improved pump or motor will be readily apparent tothose skilled in the art to which it relates.

I claim:

1. A hydraulic pump or motor comprising a primary rotor, a secondary ;rotor in spaced relation thereto, a plurality of radially disposed cylinders in said primary rotor, pistons reciprocable in said cylinders and operatively connected to said secondary rotor, and-universal coupling and driving meansconnecting the corresponding opposite ends of said rotors and having multiple inter-engaging portions adapted simultaneously to transmit power therebetwcen and to brace said rotors relative to one another whereby to provide supporton the opposite sides of said cylinders against the unequal stressesset up in the radial tion thereto, universal coupling and driving means connecting the corresponding opposite ends of said rotors and having multiple inter-- engaging portions adapted simultaneously to transmit power therebetween and to brace said rotors relative to one another, and a plurality of pistons reciprocably mounted in said primary rotor and having circumferential sliding engagement with s'aid'secondary rotor, said pistons be- .ing disposed in a plurality of spaced banks along the axis of said primary rotor.

3. A hydraulic pump or motor comprising a primary rotor, a secondary rotor in spaced relation thereto, universal coupling and driving means connecting the corresponding opposite ends of said rotors and having multiple interengaging portions adapted simultaneously to transmit power therebetween and, to brace said rotors relative to one another, and a plurality of rocable in said cylinders and operatively connected to said secondary rotor, and universal coupling and driving means connecting the corresponding opposite ends of said rotors and having multiple inter-engaging portions adapted simultaneously to transmit power therebetween and to brace said rotors relative to one another, said coupling and driving means comprising a coupling ring and co-operating sets-of multiple tongues and grooves respectively disposed among the primary rotor, the secondary rotor and the coupling ring, whereby to provide support on the opposite sides of said cylindersagainst the unequal stresses set up in the radial reciprocation of said pistons.

5. In a hydraulic pump or motor,-the combination of a rotatable primary rotor, a plurality of cylinder and piston units therein, a rotatable secondary rotor, and universal coupling devices interconnecting the primary and secondary rotors to cause them to rotate in unison about separated axes, said coupling devices comprising a coupling ring disposed on each side of the secondary rotor with rotative bearing on the walls of the housing, and cooperating sets of tongues and grooves disposed normally relative to one another and distributed among thecoupling ,connected by universal coupling devices; said coupling devices comprising a coupling ring disposed on' each side of the secondary rotor with rotative bearing on the walls of the housing and cooperating sets of tongues and grooves disposed normally relative to one another and distributed among the coupling rings and the primaryand' secondary rotors, and a shifter ring having provision for forming a high pressure film bearing in which the secondary rotor has rotative hearing, said film bearing and said universal coupling devices being fed with lubricant from the lubricant bath in the housing.

ELEK K.'BENEDEK.

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