US2786422A - Vane pump with improved discharge port - Google Patents

Description

March 26, 1957 N. o. RosAL-:N ET AL Sheets-Sheetl 1 Filed Deo. l5, 1952 Fiel March 26, 1957 y N. o. RosAr-:N ETAL 2,786,422

VANS PUMP WITH IMPROVE@ DISCHARGE PORT Filed Dec. l5, 1952 3 Shets-Sheet 2 42 Fie. 3 41 INVENToRs Nils ORosaen and OscarERosaen ATTORNEYS March 26, 1957 N. o. RosAEN ETAL 2,786,422

VANE PUMP WITH IMPROVED DISCHARGE PORT Filed Dec. l5, 1952 5 Sheets-Sheet 3 INVENTORS Nils O.Rosaen al OscarEfRos'aen i @JLA ATTORNEYS VANE PUM'P WTH IMPROVED DISCHARGE PORT Nils 0. Rosaen and Oscar E. Rosaen, Detroit, Mich., as-

signors to The New York Air Brake Company, a con'l porahon of New Jersey Application December 15, 1952, Serial No. 326,071

8 Claims. (Cl. 10S- 136) This invention relates to vane pumps and particularly to the porting of the cheek plates in the discharge zone. The invention has been embodied with success in the well known balanced type of vane pump in which there are two diametrically opposed Working spaces, the cam ring having a form resembling an ellipse. The principles, however, have general applicability in the vane pump field, regardless of the number of Working spaces.

In a vane motor in which the vanes are projected radially by hydraulic pressure the vanes seat with considerable force in the cam ring and so are held against tilting in their slots. This is not the case in Vane pumps, for the vanes are not heavily pressure loaded, and some force not clearly identified, but quite possibly the drag of liquid flowing to the discharge port from the intervane Spaces causes the vanes to tilt and score the cheek plates over extended arcs in the general vicinity of the discharge ports. This has long posed a problem.

In an effort to subject the vanes to balanced fluid pressures balancing recesses which in outline are mirror images of the discharge ports in one cheek plate are commonly formed on the other cheek plate, the port'and recess being precisely opposed each to the other and connected by passages drilled through the interposed cam ring. Similar treatment, except that there was no interconnection except through the Vane slots, has been adopted for arcuate ports through which liquid ows out ofthe vane slots, as the vanes move radially inward while passing a discharge port. Despite the supposedly balanced flow, scoring still occurred. n

The present invention starts with cheek platesvand interposed cam ring formed as above described but rearranges the flow paths from the ports in the plates.

Two special arrangements are adopted:

l. The discharge port (which is an arcuate channel in the face of one cheek plate of considerable length and partly overlaid by the cam ring) has its discharge outow passage localized at that end'of said arcuate channel over which the vanes first pass (called the approach end), so that the motion of the vanes is opposite to the direction of ow within the arcuate channel toward the outflow passage. It is even desirable to locate the passage as an undercut partly beyond the end of the arcuate port, so that at the point Where flow from between the vanes tends to be directly toward the passage the latter is atleast partially masked.

This is a sharp departure from prior practice which was to use a series of outflow openings from ports, spaced along the length of the port channel. In addition, the cross connecting passages through the cam ring are locatedat the leaving end of the outlet port, i. e. the end remote from the outlet passage.

2. Discharge of liquid from the vane slots is into the arcuate groove in the inlet cheek plate and at that end thereof last overtraveled by the vane slot (the leaving end), and from the groove to the balancing recess opposite to the discharge port so that at least some of this liquid discharges through the intervane spaces to the latentp.-

2,786,422 e Patented Mar. 26, 1957 2 discharge port, where it is added to the main discharge ow.

The probable effect is to ensure a greater slot backpressure in the discharge cheek-plate ends of the vane slots, but Whatever be the explanation the result is beneficial.

Proportions for the two elects can be such that the vanes entirely lose their cooking and scoring tendencies.

The invention as here described is embodied in that type of pump in which the inlet ports are formed in one cheek plate and the discharge ports in the other cheek plate, each such port in one plate being opposed by a mirror-image balancing recess in the other plate. This is done to simplify description, and because that arrangement is customarily used by applicants assignee and so is the one in which the invention has been used extensively enough to demonstrate its utility. The invention has to do solely with the exhaust port zone, and the illustration of a particular scheme of inlet porting is simply in the interests of an adequate disclosure, and does not imply necessary limitation to any particular inlet porting.

In the drawings which show a preferred commercial embodiment:

Fig. 1 is a section transverse to the axis of the pump on the plane of the cheek plate in which the inlet ports are formed (called the inlet cheek plate).

Fig. 2 is a fragmentary View of one of the discharge port regions of Fig. l, but with the rotor removed.

Fig. 3 is a fragmentary axial section the plane of section being indicated by line 3 3 on Fig. l.

Fig, 4 is a face View of the cheek plate in which the discharge ports are formed (called the discharge cheek plate).

Fig. 5 is a face view of the inlet cheek plate.

Fig. 6 is a fragmentary perspective showing a portion of the cam ring adjacent the lower discharge port in Fig. l.

Fig. 7 is a fragmentary perspective which is somewhat simplified and is intended merely to facilitate tracing of the discharge paths.

Pumps of the vane type are usually enclosed in a multi-part housing lwhich carries bearings for the shaft and the inlet and outlet connections', and which clamps the cam ring and cheek plates in fixed functional relationship.

Because the housing is conventional, involves nothing related to the presentinvention, and can take various forms only a fragment of it, indicated at l1, is illustrated. This ring-like portion of the housing engages the peripheries of the cam ring 12, the discharge cheek plate 13 and the inlet cheek plate 14 and holds the three in coaxial relation. As is usual the cheek plates 13 and 14 are clamped upon the cam ring. The rotor 15 keyed on shaft 16 turns between the cheek plates 13 and 14 and makes a running t therewith.

The heads of the housing which clamp the cheek plates upon the cam ring, support the shaft-bearings and carry the inlet and outlet connections which respectively supply liquid to ports in the inlet cheek plate and receive liquid from ports in the discharge cheek plate are not shown. It should be understood that they engage peripheral portions of the backs of the plates, as usual, and that the plates have through passages for inlet and discharge.

The cam ring 12 surrounds the rotor 15 and has an internal face which is a noncircular cylinder made up of two opposed longer-radius circular cylindrical portions which define working chambers, two shorter radius circular cylindrical portions which Iare closely spaced from the periphery of the rotor and define idle chambers of negligible volume, and four transition portions which are curved surfaces smoothly connecting successive portions of the two different radii. The four transition portions are approximately coextensive with respective ports leading to and from the working chambers, i. e. one inlet port and one discharge port for, and at opposite ends of, each of the two working chambers.

The periphery of the rotor has a plurality of radial slots 17 which r ceive the vanes. The walls of the slots are ilat and parallel and each slot terminates in a cylindrical enlargement 18. These facilitate the operations for nishing the slot walls and they also atord extra space for flow of liquid to and from the bottoms of the slots. Sixteen slots are shown.

Each slot receives a rectangular vane made up of a pair of identical at plates 19 assembled face to face. Each plate of a pair has three beveled edges on that face which contacts the other plate, and the pairs are so mounted in the slots that each vane has an edge-groove (formed by two bevels conjointly) along the middle of the vane edge which contacts the cam ring. rlf'his groove is connected with the bottom of the corresponding slot 17 alonelr each radial edge of the vane by grooves also zlriorded by conjunction of the beveled edges ofthe plates The vanes thus are essentially the same .in form and operative characteristics as those described in the patent to Rosaen 2,393,223, issued January l5, 1946. These are preferred but other vanes could be substituted.

rThe cheek plates 13 and 14 have plane faces presented to the rotor 15, but each is relieved at the center as indicated at 21, and each carries a bearing bushing 22 for the shaft 16 (see Fig. 3). The relative positions of the ring 1.2 and plates 13, 14 are xed by a stake 23s which extends through a hole in ring 12, and engages at its ends in positioning recesses 23p in respective plates 13 and 14. The holes designated 23 in the ring 12 and cheek plates 13 and 14 register to form a drain port.

Inlet cheek plate 14 has two diametrically opposed arcuate inlet channels 24- formed as best shown in Fig. and each fed by inlet passages 25 which extend through the plate. The balancing recesses 26 in plate 13 are basically mirror-images of channels 24 and are connected thereto by holes 30 drilled through ring 12 (see Fig. l). The recesses 25 have tail grooves 27.

In plate 14 are diametrically opposed arcuate inlet grooves 28 which register with the trace of the slot enlargements 18, and are fed by inlet passages 29 which extend through the plate. In plate 13 are mirror-image grooves 31 each fed by a drilled passage 32 leading from a corresponding port 33. Port 33 registers with two drilled ports ,34 in ring 12 which are fed by a registering recess to which lead ports 35 drilled through plate 14 (see Fig. 5). Thus liquid is fed to the bottoms of the vane slots at both ends by separate paths.

The inlet tiow to ports 25, 29 and 35 is not described as suction flow. It could be flow under suction or the inlet could be charged at a pressure higher than atmospheric.

The discharge ports are arcuate channels 36 in the face of plate 13. Considering Fig. l the vanes move counterclockwise. The discharge passages 37 leave each from the approach end of its channel 36, i. e. the end first overtraveled by the vanes. Moreover the outlet passages 37 which are drilled from the back of the plate, are partially oiset beyond the approach end of the channel 36, and thus are masked over about h-alf their area.

In the plate 14 are balancing recesses 38 which in contour are mirror images of channels 36, and are connected with channels 36 by ports 39 drilled through ring 12. As best shown in Fig. 2 these ports 39 are at the leaving end, and hence remote from outlet 37.

in plate 13 are long blind arcuate grooves 41 which correspond to the trace of the vane groove enlargements 1S as the vanes pass over the discharge ports. In plate 14 are mirror image grooves 42 which are connected by drilled ports 43 with the balancing recesses 38.

The ports in plates 13 and 14 having been identified, it can now be explained that 24S, 26, 36 and 3S are partially overlaid by ring 12 but that each has a corresponding shouldered extension 24a, 25a, 36u or 33a which extends toward the center of the rotor and is exposed within the inner contour of ring 12. See Figs. l and 2. While these are effective as ports each is undesirably constricted at one end. Accordingly there `are cut in the edges of the inner surface of ring 12, four supplemental inlet ports 44 and four supplemental discharge ports 45 which supplement the flow section at the constricted end or each port. They are cylindrical notches. So far as the basic inventive concept is concerned the presence or the ports 44 and 45 is not strictly necessary, but they cooperate to improve the action.

The operative characteristics can best be explained by reference to Fig. 7. The ring 11 is broken away and the contour of port 36 has been simplified because the actual contour when drawn in perspective was confusing. The rotor 15 turns in the direction of arrow A. Thus the vanes are moving inward as they pass arcuate port 36 und the space between the rotor and ring is diminishing. Port 41 is blind so liquid forced by the retreating vanes 19 out of slots 17 flows across the enlargement at 18 into the port 42. From the exit end of 42 it ows via port 43 to the balancing cavity 38 and thence between vanes or through the holes 39 in ring 12 to discharge port 36 which it leaves through passage 37.

No `one can state with conviction Why the particular arrangement of ports 36, 37, 38, and 39 offers the desired vane stabilizing effect. Neither of the balancing recesses 3S is blind. Each communicates through ports 39 in ring 12 with the corresponding discharge port 36, and so must function to some extent as a discharge port. Presumptvely each would receive some liquid from intervane spaces, and of course each :receives liquid from the slot bottoms 18.

It has been suggested that liquid from each recess 38 flows through intervane spaces to reach port 36 and outlet 37. Assuming that some liquid takes this path, a considerable portion must pass through the holes 3%. This portion enters port 36 at the leaving end and so tlows the length of port 36, in a direction opposed to vane motion, on its way to `outlet 37 Undoubtedly, therefore, the novel porting arrangement stimulates active iiow of liquid in port 36 in opposition to vane motion. This flow sweeps over the radial edges of the oppositely moving vanes as the latter pass over the discharge port. There must be an active eddying effect. This may be what neutralizes the canting tendency of vanes passing the discharge port. The one fact known beyond question is that Something does so, when the described porting is used.

As stated the invention is not concerned with nor limited to any particular inlet porting, nor to a pump having two working spaces, nor to a pump in which inlet tlow and outlet ow occurs through opposite cheek plates. lt is well adapted to the specific construction illustrated and there offers its fullest benets. The problem which it solves is not usually presented by vane motors.

Vane motors are customarily reversible but like most rotary pumps this pun-rp is designed to turn in one direction, a circumstance which makes it convenient to differentiate the opposite ends of the ports in terms of the direction of rotation of the vaned rotor. The vane approaches one Iend of a port, sweeps the arcuate length of the port and then leaves the port from the opposite end. ln the claims, the term approach extremity will be used to define that extremity of any port which is rst approached by the vanes, and the term leaving extremity will be used to dene the opposite extremity of the port, i. e., the end at which the vane leaves the port.

What is claimed is:

l. In a vane pump comprising a pair of cheek plates having inlet and discharge ports, a cam ring between said s cheek plates, a rotor making a running lit between said cheek plates and defining with the cam ring and check plates alternating working and idle spaces, said rotor turning in one direction and having slots in its periphery, vanes movable in said slots to maintain engagement with said plates and said cam ring, and means serving to bias said vanes outward, the improvement which consists in forming the discharge port as an arcuate groove in the -face of a cheek plate subtending the arc through which the working space contracts, providing an outlet passage leading from the approach extremity of said arcuate groove, Said passage being lformed beneath the rotorcontacting surface of the plate with its point of communication with the groove offset contra to the direction of rotation of the rotor, so as to be at least partially ahead of the approach extremity of the ldischarge port groove and not directly exposed to liquid flowing from intervane spaces, whereby the discharge ilows within said discharge groove in the direction opopsite to the travel of the vane over said groove.

2. In a vane pump comprising a pair of cheek plates having inlet and discharge port grooves, a cam ring between said cheek plates, a rotor making a running t between said cheek plates and dening with the cam ring and cheek plates alternating working and idle spaces, said rotor turning in one direction and having slots in its periphery, vanes movable in said slots to maintain engagement with said plates and said cam ring, and means serving to bias said vanes outward, the improvement which consists in forming the discharge port groove in one plate and a substantially identical balancing groove in the other plate yand opposite said discharge port groove, there being means affording a How-passage interconnecting the leaving extremities of said `discharge port groove and balancing groove, and means aifording an outlet passage leading from the approach extremity of the discharge port, whereby an active tiow is caused to occur in the, -discharge port groove in the di-rection opposite to the travel of the varies over said port groove.

3. The combination deiined in claim 2 in which the output passage is formed in a cheek plate beneath the rotor-contacting surface thereof, and its junction with the port groove is offset relatively to the discharge port groove contra to the direction of rotation of the rotor so that said junction is not directly exposed to liquid flowing from intervane spaces.

4. In `a vane pump comprising a pair of cheek plates having inlet and discharge port grooves, a cam ring between said cheek plates, a rotor making a running t between said cheek plates and defining with the cam ring and cheek plates `alternating working and idle spaces, 'said rotor turning in one direction and having slots in its periphery, vanes movable in said slots to maintain engagement with said plates and said cam ring, and means serving to bias said vanes outward, the improvement which consists in forming the discharge port groove in one plate and a substantially identical balancing groove in the other plate and opposite said discharge port groove, there being means affording a flow-passage interconnecting the leaving extremities of said discharge port groove and balancing groove and means aiording lan outlet passage from the approach extremity of the discharge port groove, and forming in said other plate an arcuate port groove of greater arcuate extent than said balancing groove and with which the bottoms of the vane slots communicate as the Vanes pass over said balancing groove and from which a passage leads to the balancing groove, whereby an active ow of substantially all liquid discharged by the pump occurs in the discharge port groove in a direction opposite to the travel of the vanes over said port groove.

5. The structune dened in claim 4 in which the passage leading to the balancing groove leads from the leaving extremity of the arcuate port groove.

6. In a vane pump comprising 'a pair of cheek plates having inlet and discharge port grooves, a cam ring between said cheek plates, a rotor making Ia running tit 'between said cheek plates and delining with the cam ring and cheek plates alternating working and idle spaces, said rotor turning in one direction and having slots in its periphery, vanes movable in said slots to maintain engagement with said plates and said cam ring, and means serving to bias said vanes outward, the improvement which consists in forming a discharge port groove in one plate subtending the arc through which the working space contracts, providing outlet passage means leading from a point substantially at the approach extremity of said port groove and serving to direct the outlet ow from the approach end of said port groove, forming in the other plate an arcuate port groove with which the bottoms ot the vane slots communicate as the vanes pass over said outlet port groove, and providing a flow path through the body ot said plate and thence through said ring from the last named arcuate port groove to the leaving extremity of said discharge port groove.

7. T he combination defined in claim 6 in which said liow path connects the leaving extremity of said arcuate port groove with the leaving extremity of said discharge port groove.

8. in a vane pump comprising a pair of cheek plates having inlet and discharge lport grooves, a cam ring interposed between said cheek plates and seating against the peripheral portions of the cheek plates throughout substantial annular areas of contact, a rotor making a running iit between said cheek plates and deining with the cam ring and cheek plates alternating working and idle spices, said rotor turning in one direction and having slots in its peripheral portions, vanes movable in said slots to maintain engagement with said plates and said cam ring, and means serving to 'bias said varies outward; the improvement which consists in forming a discharge port groove in one plate and la substantially identical bal ancing groove in the other plate opposite sai-d discharge port groove so that a part of the port groove and of the balancing groove extend, each into `one of said areas of contact, there being means affording a flow passage through the cam ring interconnecting the leaving extremities ot' said discharge port groove and balancing groove, and there being means affording an outlet passage leading from the approach extremity of the discharge port groove, the edges of the cam ring being beveled opposite the leaving extremity of the outlet port groove and opposite the leaving extremity of the balancing groove to enlarge the flow passages from t-he working spa-ce to said port groove and 'balancing groove.

References Cited in the le of this patent UNITED STATES PATENTS 160,974 Upham Mar. 16, 1875 1,436,863 Crouse Nov. 28, 1922 1,558,696 Marion Oct. 27, 1925 1,692,473 Smith NOV. 20, 1928 1,989,900 Vickers Feb. 5, 1935 2,033,218 irava Mar. 10, 1936 2,037,894 Grisell Apr. 21, 1936 2,124,539 Brelsford et al July 26, 1938 2,335,284 Kendrick Nov'. 30, 1943 2,417,568 Reilich Mar. 18, 1947 2,460,047 Von Wangenheim Jan. 25, 1949 2,635,551 De Lancey Apr. 21, 1953 2,641,193 Klessig June 9, 1953 2,669,189 De Lancey et al Feb. 16, 1954 2,677,330 Rosaen May 4, 1954 2,742,861 OConnor et al. Apr. 24, 1956 FOREIGN PATENTS 149,107 Australia Nov. 19, 1952 687,998 Great Britain Feb. 25, 1953

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