US3043233A - Hydraulic pump face type valve plate auto balancing - Google Patents

Description

y 1962 R. D. RUMSEY 3,043,233

HYDRAULIC PUMP FACE TYPE VALVE PLATE AUTO BALANCING Filed March 20, 1958 v 2 Sheets-Sheet l F LZ be :lZ'Uf v I Fo/h fi Doug/a5 Ramsey b H 'fiff L375 R. D. RUMSEY July 10, 1962 HYDRAULIC PUMP FACE TYPE VALVE PLATE AUTO BALANCING 2 Sheets-Sheet 2 Filed March 20, 1958 j m T LL52 ILZUT Fol/4 Day/as Pumas; [:7 L77 M fi [[95 3,043,233 HYDRAULIC PUMP FACE TYPE VALVE PLATE AUTO BALANCING Rollin Douglas Rumsey, Bulialo, N.Y., assiguor to Houdaille Industries, Inc., Buffalo, N.Y., a corporation of Michigan Filed Mar. 20, 1958, Ser. No. 722,683 4 Claims. (Cl. 103-161) This invention relates to means of maintaining uniform light pressure between a pump rotor and valve plate by means of a servo mechanism type pressure balance control.

It is the general object of the invention to provide an improved pump comprising a stable servo mechanism embodying two small anti-rock pistons combined with a high pressure radial piston pump having a rotor embodying a plurality of pistons, in radial cylinders, and a piston drive system, the rotor and the piston drive system riding on suitable bearings within a suitable housing.

Another object of the invention is to provide an improved pump of the class stated capable of operating at high speeds, featuring a stable servo means affording a uniformly light contact pressure between the rotor and the valve plate by means of a servo mechanism type pressure balance control embodying a plurality of small anti-rock pistons, and yet of simpler and cheaper construction than heretofore known.

Another object of this invention is to provide structure permitting a minute amount of leakage across the valve plate face and confined ring of a radial piston pump at all times which will serve as a lubricating film and thereby prevent severe scoring, galing, as well as rocking, and, at the same time, the leakage not being of large enough magnitude to destroy the efliciency of the pump.

Another object of this invention is to provide servo means to stabilize the movement of the valve plate with reference to the rotor at a fixed position and wherein only a slight amount of leakage fluid flow is maintained continuously. a

A further object of this invention is to provide a minute fluid flow passage from the passage at the rear of the valve plate to the inlet port in order to allow the pressure behind the valve plate to bereduced in the event it gets too high. a

A still further object of this invention is .to provide suificient leakage of fluid across and to the rear of the face of an underbalanced valve to build up pressure .approximately A of the outlet pressure in a fluid zone which acts against the substantially entire rear orback face of the inner member of the valve plate causing it t nearly reseal and become balanced. Y

Various other objects, features and advantages-of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrated presently by the preferred embodiments thereof and wherein: V

FIGURE 1 is a vertical cross sectional view through a fragmentary portion of a housing and valve assembly unit constructed according to this invention, the valve plate of said valve assembly being mounted in conjunction with an annular thrust member and a pump rotor shown in side elevation; I

FIGURE 2 is an end elevational view of the pump rotor showing the five ports which rotate in contact with the face of the valve plate of the valve assembly; FIGURE 3 is an end elevational view showing the face of the valve plate, the outer ,COnfined ring, a d the associated parts of the valve assembly; and FIGURE 4 is a fragmentary cross-section through the valve assembly taken on line IVIV of FIGURE 3.

The invention may be embodied with any high pressure radial piston-type pump or the axial type, but for purpose of illustration, it has been shown with a five cylinder radial piston hydraulic pump.

Referring now first to FIGURES l and 2, a high pressure pump rotor and valve assembly constructed according to this invention generally comprises a housing 20, an adaptor 21, a rotor 22, and a face type valve assembly 23 including an inner valve member 24 and an outer confined ring, or poppet 25, and an endcap 26 provided with a threaded fluid inlet opening 27 and a threaded fluid outlet opening 28.

A drive shaft 37 and the rotor 22 are journalled by bearings in the housing 20 to rotate about a centerwithin an annular radial thrust member 29, and it may be seen from FIGURE 2 that the rotor is provided with a series of circumferentially spaced arcuate grooves 30 in its periphery. The rear hub portion or adaptor 21 is constructed in a suitable manner to have assembled therein a driving shaft extension on the end of the drive shaft 37. The rotor has embodied therewtih, for example, five passageways 32, 33, 34, 35 and 36 communicating with the five cylinders of the pump.

The valve plate assembly 23, clearly shown by FIG- URES l and 4, is arranged in a substantially fixed position, although as will now be described, the valve plate 24 and confined ring, or poppet 25, are permitted limited axial movement in theend cap 26. Therefore, the valve plate 24 can be defined as a balanced valve plate. Said valve plate 24 is maintained in fluid-sealing contact with the end face 38 of the rotor, but without unnecessarily high contact pressure. A helical spring 40 is positioned in a cylindrical bore 41 with one end 42 thereof in contact with a shoulder 43 at the base of the bore 41 and adjacent the outlet 28. The opposite end 44 of said spring 40 is in contact with the extended end portion 45 of the valve plate tubular piston extension 46 to bias the valve plate 24 towards the rotor 22. As any one of the five pistons in the rotor moves radially outwardly and recedes, from the bottom of one of the cylinders, as, for example, in cylinder 47, shown dotted in FIG- URE 2, fluid will flow through inlet 27, through port passage 49 in the valve plate-24, through an opening such as 36 and into one of the associated cylinders such as 47. As the piston is driven downwardly into its cylinder, it forces the fluid out through one of the passageways such as 36 to port passage 50 in the valve plate 24. As best shown by FIGURES land 4, the valve plate 24 is integrally fitted with a tubular piston 46 fitted in the bore 41. The internal passageway 52 of the tubular piston 46 is adapted to connect at one end with bore 41 which connects with outlet 28, while the opposite end of said passageway 52 is in communication with port passage 50 in the valve plate 24. The valve plate 24 is normally urged towards the end of the rotor 22 by the helical spring 40, as described above.

The high pressure fluid is forced through port 50, passageway 52, bore 41 and outlet 28. The valve plate 24 is acted upon by the high pressure fluid, such as oil, and as the fluid is discharged from passageway 36 of the rotor 22, the plate would be driven away from sealing engagement with the face of 'the "rotor were it not for the action of the spring 40 and the tubular piston 46 formed integral with the valve plate 24. The valve plate 24 is surrounded about its peripheral edge portion by the outer confined ring, or poppet 25, the space between said valve plate and said outer ring providing an annulus 55 to conduct fluid leakage to a fluid collecting zone 68 at the rear of said valve plate. The poppet, or outer ring 25, has a central bore 55 extending therethrough of an internal diameter approximately .00 larger than the outer diameter of the valve plate 24, thereby forming the annulus 55', and said poppet further is formed with a flange portion 56 having a face 57 which must be optically flat and square with said bore-55. The flange porend of said pin 60 is pressed into a bor'e in the inner tion 56 is provided with an outwardly extending boss 58 7 vertical wall of said end cap 26. The inner end of said end cap 26 is provided with a central bore 62 of a diameter greater than the outer diameter of the rear end of ',said poppet 25. A hub portion 64 of a diameter equal or slightly larger than that of said valve plate 24 is formed on the inner end of the cap 26 and extends into central bore 55 of poppet 25. The inner end of said end cap 26 is also recessed for a short distance with an enlarged bore 62 to provide clearance for the horizontal travel of the flange 56 of poppet 25. A helical spring 63 is arranged about the base portion 65 of the outer ring or poppet 25 and within the bore 62. One end of spring 63 engages the bottom portionof said bore 62, and'its opposite end is in contact with the underside of said flange 56 to bias said poppet 25 toward said rotor 22 of the pump. The cylindrical base portion 65 of said poppet 25 is of suflicient length to confinethe outer cylindrical walls of said valve plate 24 and said hub 64. The inner wall of said poppet 25 is provided with an annular groove 66 adjacent its inner end providing means to retain an O ring 67 providing a fluid seal between said surface intermediate the fluid passageways 84 and 85.

r The upper port 90 having circular side portions connects through the valve plate 24 to the fluid zone 68 at the rear poppet 25 and said hub 64. A fluid zone 68 is formed between the forward end surface of said hub 64 and the rear surface of said valve plate 24. A cylindrical bore 70 is provided in the rear surface of said valve plate 24 adjacent to and communicating with the port passage 49. A cylindrical bore 71, of the same diameter as bore 70, is provided in said end cap 26 communicating with said fluid passage 72 which is in communication with fluid flow inlet 27, said bore 71 being in horizontal alignment with saidbore 70. A sleeve 73 is horizontally arranged within said bores 70 and 71, said sleeve being provided with two annular grooves with O'ring's. therein to form a sealed passageway between said valve plate 24 and said fluid flow passage 72; the sleeve .73 ismovable rear- Wardly into said bore 71 when the valve plate 24 is biased rearwardly by high pressure fluid.

. The valve plate 24 as shown by FIGURES 3 and 4 has embodied in the rear facethereof two bores 80 and 81, radially spaced from each other, and extending for a suitable depth, and said bores having bottoms 82 and 83 spaced a short distance from the face of said valve plate '24. Central passageways 84'and 85, or apertures, are

provided betweenthe face of the valve plate 24 and said bores 80 and 81. Balancing pistons 86 and 87 are assembled within said bores 80 and 81, each piston being chamfered at its ends. and provided with a central annular groove intermediate the ends thereof whereby 0 rings I may be inserted to liquid seal the pistons with the walls of the bores and prevent fluidflow from the fa ce of said valve plate, through passageways 84 and 85 to said bores 80 and Stand the fluid zone 68. A minute fluid flow passageway 89 (FIGURE 1) is provided in the end cap 26 extending from the fluid zone 68 to the fluid flow passage 72 communicating with the inlet 27 The passageway 89 connects the area behind the valve plate 24 to the inlet port 27 in order to allow fluid pressure behind the valve plate to be reduced in the event it gets too high, the

7 desired pressure being approximately'% that of the outlet 7 pressure.

The pump rotor 22 has been described above as having five arcuate shaped openings 32, 33, 34, 35 and 36 to provide passageways for the fluid being pumped thereby. The valve plate 24 and the poppet 25 are urged towards the end of the rotor, the poppet being urged by the helical spring 63 and the valve plate being urged by the helical spring40 arranged and cooperating therewith. The valve plate 24has two oval ports9t} and 91 arranged in its face of said face plate. FIGURE 3 shows the position of the pump rotor port positions as dotted for discussion. Therefore, it may be seen that the rotor ports communicate the pressurized hole from the balancing pistons to the high pressure discharge port of the valve, only when these ports are in certain positions as shown in FIGURE 3. It is only while in these positions that the additional balancing force provided by the anti-rock pistons 86 and 87 is required. Therefore, the pressure applied to the balancing pistons 86 and 87 depends upon the position of the rotor. This combination of circumstances results in the'selective balancing produced by said pistons 86 and 87. For example, when port 32 is in registry with passageway 84 as shown dotted in- FIGURE 3, the high pressure fluid flows through said passageway 84 coming into contact with the top of the piston.86. .The uppersurface of saidpiston 86'being greater than the lateral area of the passageway 84, the high pressure is exerted upon the bottom 82 of bore 8%) urging the face plate towards the rotor 22 tending to assist in balancing the face plate.

. To summarize the operation of the present device, fluid enters the inlet27 in the end cap'26 passing generally axially therethrough and into the passages 72 and 49 to one of the openings 32-36 in the rotor 22. The latter openings communicate with the five. cylinders, and pressurized fluid enters one of said openings during clockwise rotation of the rotor to drive the piston in the cylinder. Essentially simultaneously, fluid is ported from another cylinder through one of said openings to the valve plate passage 50 to the passageway 52 and through thebore 41 to the outlet 28 .in the end cap 26.

The valve plate 24 and guide ring or poppet 25 are urged against the rotor 22,by the springs 40 and 63, respectively, and the'valve plate is in fluid cushioned relation with the hub 64 of the end cap by means ofja fluid zone 68 therebetween. As appears in FIGURE 3, the valve plate 24 has ports 90 and 91 therein which selectivelycommunicate a pair of passages 32--36 with the passages 84 and 85 to the balance pistons 86 and 87 and with the outlet 28. Accordingly, during clockwise rotor rotation, as in FIGURE 3, fluid from the passages 32 and 35 in the rotor 22 acts against the pistons 86 and 87 simultaneously to perform the balancing function, and by provision of the communicating passage or port 90, the

V pressurized fluid is discharged through the outlet 28.

It will be observed that a novel high pressure displacement pump has been described, the pump embodying a rotor 22 with a plurality of radial pistons, a novel valve plate 24 with inlet and outlet ports in contact with the end of said rotor, and servo mechanism type pressure balance control for maintaining uniform light fluid pressure-between the rotor and valve plate assembled therewith. This invention provides novel means of aflording a uniform light contact pressure between the valve plate 24 and the rotor 22, being necessary since under normal conditions the only area in thervalve .plate 24 experiencing full discharge pressure is thearea of the discharge port and any area extended therefrom that is pressurized by interconnecting action of the rotor ports. This normal condition will occur all the while the valve plate 24 and rotor 22 are in intimate metal to metal contac'tjwhich occurs only if both faces are absolutely flat,

probably better than two light bands, that is, .000006". In actual practice, the flatness of two light bands does not generally persist for any period of time. Therefore, when high pressure displacement pumps of the said type are used, wear or hot spots often occur and great leakage extends across these surfaces which extends the area of high pressure to an'area larger than the valve port itself. When the balancing pistons in a valve plate are set up to exactly balance the discharge port area only, then as soon as wear and leakage start to occur the valve plate will immediately be blown away from the rotor by the increased force developed by the pressure acting over a large area. In order to prevent the valve plate from blowing off, current pump practice has been to supply excessive balancing pressure or force such that under ideal conditions very high contact pressure exists between the rotor and valve. This situation is conducive to high dry friction and wear, thereby initiating the vicious cycle mentioned above, which-must be eliminated. The object of this invention is to provide a minute amount of leakage across the valve plate face at all times which will serve as a lubricating film and prevent hot spots and wear and, at the same time, not be of large enough magnitude to destroy the pump efliciency. This is accomplished by virtue of the fact that as high pressure fluid flows across the valve face into the annulus 68 between the valve plate 24 and the outer ring, or poppet 25, pressure is built up behind the whole valve plate except for the area of the discharge port which is subjected to inlet pressure. The port sizes have been chosen such that this pressure buildup will act as nearly as possible behind the high pressure outlet port; in common practice this is not perfectly realized. If the pressure behind the valve'plate builds up as a consequence of this leakage, it exerts a greater pressure,

hence the force on the rear of the valve plate 24 thereby drives it toward the rotor 22 in order to reduce this leakage. With any friction whatsoever in the system this action will stabilize at a fixed position wherein only a slight amount of flow is maintained continuously. This flow is further retained because a minute passageway 89 is provided from the zone 68 behind the valve plate 24 into the passage 72 communicating with the inlet port 27 in order to allow this pressure to reduce in the event it gets too high.

It is believed that this invention provides a new and novel stable servo mechanism capable of performing the function and objects as stated.

I have, in the drawings 'and specification, presented a detailed disclosure of the preferred embodiments of my invention, but it is to be understood that I do not intend to limit the invention to the specific form disclosed but intend to cover all modifications, changes and alternative constructions falling within the scope of the principles taught by my invention.

I claim as my invention:

1; A high pressure piston pump or motor comprising:

(a) a rotor having a plurality of piston-receiving cylinders therein, and a plurality of passages communicating said cylinders with openings in an end face of said rotor;

(12) a valve housing having inlet and outlet passages;

(c) an annular guide ring slidably carried .by said housing, said guide ring having an annular sealing face disposed against the outer periphery of the rotor end face;

(d) first spring means continually urging said guide ring against said rotor;

(e) a valve plate disposed within said guide ring and slidably carried by said housing, said valve plate having a sealing face adapted to be disposed against the rotor end face, said plate being ported through said sealing face for successively communicating the inlet and outlet passages of said valve housing with said openings of the rotor;

t5 (1) second spring means continually urging said valve plate toward said rotor;

(g) a fluid collection zone defined jointly by said guide ring, said housing, and that side of said valve plate which is opposite to its sealing face, said zone excluding and being substantially sealed from valve plate portions on said side communicating with the inlet and outlet passages; and (h) an annular passage defined jointly by said guide ring and said valve plate, and freelycornmunicating said sealing face of said valve plate with said collection zone; whereby, during operation, slight continued leakage at said sealing face, tending to move said valve plate with respect to said housing, in a direction away from said rotor end face, will be continually conducted by said annular passage to said collection zone for acting on and thereby assisting said second spring means in moving the valve plate toward said rotor end face to an equilibrium position of slight spacing with respect to said rotor end face for minimizing the quantity of continual leakage and for lubricating said faces with a continuous flow.

2. A high pressure piston pump or motor comprising:

(a) a rotor having a plurality of piston-receiving cylinders therein, and a plurality of passages communicating said cylinders with openings in an end face of said rotor;

(b) a valve housing having inlet and outlet pass-ages;

(c) an annular guide ring slidably carried by said housing, said guide ring having an annular sealing face disposed against the outer periphery of the rotor end face;

(d) first spring means continually urging said guide ring against said rotor;

, (e) a valve plate disposed within said guide ring and slidably carried by said housing, said valve plate having a sealing face adapted to be disposed against the rotor end face, said plate being ported through said sealing face for successively communicating the inlet and outlet passages of said 'valve housing with said openings of the rotor;

(f) second spring means continually urging said valve plate toward said rotor;

(g) a fluid collection zone defined jointly by said guide ring, said housing, and that side of said valve plate which is opposite to its sealing face, said zone excluding and being substantially sealed from valve plate portions on said side communicating with the inlet and outlet passages;

(h) an annular passage defined jointly by said guide ring and said valve plate, and freely communicating said sealing face of said valve plate with said'collection zone; and

(i) a bleed passage connecting said fluid collection zone with a lower pressure region within said housing;

whereby, during operation, slight continual leakage at said sealing face, tending to move said valve plate with respect to said housing, in a direction away from said rotor end face, will be continually conducted by said annular passage to said collection zone for acting on and thereby assisting said second spring means in moving the valve plate toward said rotor end face to an equilibrium position of slight spacing with respect to said rotor end face for minimizing the quantity of continual leakage and i for lubricating said faces with a continuous flow, said bleed passage being operative to preclude a pressure buildup in said collection zone of such magnitude as would stop said continual leakage.

3. A high pressure piston pump or motor comprising: (a) a rotor having a plurality of piston-receiving cylinders therein, and a plurality 'of passages communicating said cylinders with openings in an end face of said rotor; (b) a valve housing having inlet and outlet passages;

(c) an annular guide ring slidably carried by said housing, said guide ring having an annular sealing face disposed against the outer periphery ofthe ro tor end face; V (d) first spring means continually urging said guide ring against said rotor; i (e) a valve plate disposedwithin said guide ring and slidably carried by said housing, said valve plate having 'a sealing face adapted to be disposed against the rotor end face, said plate being p'orted through said sealing face for successively communicating the inlet and outlet passages of said valve' housing with said openings of the rotor; (f) second spring means continually urging said valve plate toward said rotor; 1 (g) a fluid collection zone defined jointly by said guide ring, said housing, and that side ofsaid valve plate which is'opposite to its sealing face, saidzone excluding and being substantially sealed from valve plate portions on said side communicating with the inlet and outlet passages; and

(h) a groove o'pening'into thesealingface of saidvalve plate'remotely from the porting thereof, said valve plate having a further passage interconnecting said groove and said fluid collection zone; whereby, during operation, slight continual leakage at said sealing face, tending to move said valve plate with respect to said housing, in a direction away from said rotor end face, will be continually conducted by said groove and further passage to said collection zone for acting on and thereby assisting said second spring means in moving the valve plate toward said rotor end face to an equilibrium'position of slight spacing with respect to.

said rotor end face for minimizing the quantity of continual' leakage and for lubricatingsaid faces with a continuous flow. 7 V V v '4. A high pressure piston pur'np or motor comprising: (a) a rotor having a plurality of piston-receiving cylinders therein, and a plurality of passages communicating said cylinders with openings in an end face ofs aid rotor; K (b) a valve housing having inlet and outlet passages; (c) an annular guide. ring slidably carried by said housing, said guide ring having an annular sealing face disposed against the outer periphery of the rotor end face; a 7

'(d) first spring means continually urging said guide ring against said rotor;

(e) a valve plate disposed Withinsaid guidering and slidably carriedby said; housing, said valve plate having a sealing face adapted to be disposed againstthe rotor end face, said plate being ported ,through said sealing face for successivelyv communicating themlet and outlet passages of said valve housing with said openings of the rotor; Y i

(7) second spring means continually urging said valve plate toward said rotor;

(g) a fluid collection zone defined jointly by said guide ring, said housing, and that side of said valve plate which is opposite to its sealing face, said zone excluding and being substantially sealed from valve plate portions on said side communicating with the inlet and outlet passages;

(h) an annular passage defined jointly by said guide ring and said valve plate, and freely communicating said sealing face of said valve plate with said collection zone; and V V (i) a groove opening into the sealing face of said valve plate remotely from the porting thereof, said valve plate having a further passage interconnectingsaid groove and said fluid collection zone; I

whereby, during operation, slight continual leakage at said sealing' face, tending to move said valve plate with respect to said housing, in a direction away from said rotor end face, will be continually conducted by said annular passage and by said groove and further passage to said collection zone for acting on and thereby assisting said second spring meansin moving the valve .plate toward said rotor end face to an equilibrium position of slight spacing with respect to said rotorend face for minimizing the quantity of continual leakage and for lubricating said faces with a continuous flow.

References Cited in'the file of this patent UNITED STATES PA EN S 2,430,764 Gabriel Nov. 11, 1947 2,484,337 Ferris Oct. 11, 1949 2,525,498 Naylor et a1. Oct. 10, 1950 2,608,934 Ferris Sept. 2,,1952

2,620,736 Overbeke Dec.9,1-1 952 ,j2,733,666 Poulos Feb. 7,' 1956 5, 1958

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