US2737895A

US2737895A - Axial type pump

Info

Publication number: US2737895A
Application number: US321476A
Authority: US
Inventors: Ferris Walter
Original assignee: Oilgear Co
Current assignee: Oilgear Co
Priority date: 1952-11-19
Filing date: 1952-11-19
Publication date: 1956-03-13
Anticipated expiration: 1973-03-13

Description

March 13, 1956 w. FERRIS AXIAL TYPE PUMP Filed Nov. 19, 1952 m 17 Sheets-Sheet 1 INVENTOR WALTER FERRIS ATTORNEY March 13, 1956 Filed Nov, 19, 1952 FIG. 2

W. FERRIS AXIAL TYPE PUMP 17 Sheets-Sheet 2 INVENTOR WALTER FERRIS BYWkM ATTORNEY March 13, 1956 w. FERRIS AXIAL TYPE PUMP 1'7 Sheets-Sheet 3 Filed Nov. 19, 1952 INVENTOR WALTER FERRIS BY v ATTORNEY March 1956 w. FERRIS 2,737,895

AXIAL TYPE PUMP Filed Nov. 19, 1952 17 Sheets-Sheet 4 INVENTOR WALTER FERRIS ATTORNEY March 13, 1956 w. FERRIS AXIAL TYPE PUMP l7 Sheets-Sheet 5 Filed NOV. 19, 1952 INVENTOR WALTER FERRIS ATTORNEY March 13, 1956 w. FERRIS 2,737,895

AXIAL TYPE PUMP Filed Nov. 19, 1952 17 Sheets-Sheet 6 INVENTOR ATTORNEY WALTER FERRIS' w. FERRIS 2,73 7,895

AXIAL TYPE PUMP March 13, 1956 Filed Nov. 19, 1952 17 Sheets-Sheet 8 WALTER FERRIS ATTORNEY March 13, 1956 w. FERRIS AXIAL TYPE PUMP 17 Sheets-Sheet 9 Filed NOV. 19, 1952 INVENTOR WALTER FERRIS ATTORNEY March 13, 1956 Filed Nov. 19, 1952 FIG. I4

.53 I56 I55 I56 FIG. l3

w. FERRIS 2,737,895

AXIAL TYPE PUMP 17 Sheets-Sheet 1O INVENTOR WALTER FERRIS WVVM'A ATTORNEY March 1956 w. FERRIS 2,737,895

AXIAL TYPE PUMP Filed Nov. 19, 1952 17 Sheets-Sheet 12 FIG. I?

/ 238 35 a V 4 MM (44 23s I Fl GI '9 \V 229 7" zspflg 23| ATTORNEY March 13, 1956 w. FERRIS AXIAL TYPE PUMP l7 Sheets-Sheet 14 Filed NOV. 19, 1952 INVENTOR WALTER FER RIS BY WW ATTORNEY March 13, 1956 w. FERRIS AXIAL TYPE PUMP 17 Sheets-Sheet 15 Filed Nov. 19, 1952 www INVENTOR WALTER FERRIS WEM ATTORNEY W. FERRIS AXIAL TYPE PUMP March 13, 1956 17 Sheets-Sheet 17 Filed NOV; 19, 1952 INVENT WALTER FER MW ATTORNEY United States Patent AXIAL TYPE PUMP Walter Ferris, Milwaukee, Wis, assignor to The Oii'gear Company, Milwaukee, Wis, a corporation of Wiscousin Application November 19, 1952, Serial No. 321,476 2s Claims. (Cl. 103-38) This invention relates to multiple piston axial type pumps for pumping liquid at high pressures, the liquid usually being employed to energize hydraulic motors. The pump includes a cylinder barrel or block in which the pistons and cylinders are arranged in one or more circular rows about a central axis and are usually parallel to each other and to the axis. In a pump embodying the invention, the cylinder block is non-rotatable, such as by being fixed to or forming part of the main frame, and the pistons are reciprocated at adjustable stroke by a driving plate or cam which is inclinable to and is fixed for rotation with adrive shaft the axis of which coincides with the axis of the cylinder block.

The present invention has as an object to provide a pump capable of discharging a larger volume of liquid at high pressures than the pumps whichwere heretofore commercially available.

Another object is to provide a machine of the above type with novel means for varying its displacement.

Another object is to provide a pump of the above type with improved means for transmitting motion between the shaft and the pistons.

Another object is to provide for such a stationary cylinder pump a rotating driving mechanism having an inclina'ole driving plate to actuate the pistons at variable strokes, with novel counter-balancing means to maintain the driving mechanism in dynamic balance.

Another object is to provide a machine of the above type with hydraulic thrust hearings to counterbalance, at least in. part, the pumping forces and with novel means for supplying pressure liquid to the thrust bearings.

Other objects and advantages will appear from the description hereinafter given of a pump in which the invention is embodied.

The invention is exemplified by the pump shown in part schematically in the accompanying drawings in which the views are as follows:

Fig. l is in part an elevation of and in part a longitudinal vertical central section through a pump in which the invention is embodied, the plane of the View being indicated by the line 1-1 of Fig. 2.

Fig. 2 is a transverse vertical section taken on the line 2-2 of Fig. 1 but drawn to a larger scale.

Fig. 3 is a transverse vertical sectional view illustrating the trunnions for a counterbalance and also for a wobble plate which effects reciprocation of the pumping pistons in response to rotation of a drive shaft, the view being taken on the line 3-3 of Fig. 1 but drawn to approximately the same scale as Fig. 2'.

Fig. 4 is a sectional plan view taken through the pumping portion of the pump on the irregular line 4-4 of Fig. 2.

Fig. 5 is a sectional plan view taken through the other end portion of the pump on the line 5-5 of Fig. 3.

Fig. 6 is an end view of the pump with a cover plate removed and illustrates the mechanism for shifting the valves which control the main flow of liquid to and from,

thepump cylinders, the view being taken on the line 6-6 of Fig. l but drawn to approximately the same scale as Fig. 2.

Fig. 7 he view showing two check values through which liquid may flow to and from a cylinder when the valve which controls the main flow of liquid to and from that cylinder is closed, the view being taken in the same plane as Fig. 1 but drawn to a considerably larger scale.-

Fig. 8 is a view illustrating how each piston is connected to the wobble plate which prevents torque from being transmitted to the pistons, the view beingtaken in the same plane as Fig. 1 but drawn to approximately the same scale as Fig. 7.

Fig. 9' is a diagram of the hydraulic circuit in the pumping portion of the pump, only four of the pistons and the valves associated therewith being shown.

Fig. 10 is a View of the front face of the wobble plate, the view being taken on the line 10-10 of Fig. 1 but drawn to a larger scale.

Fig. 11 is a rear face view of an' element which engages the front face of the wobble plate and functions both as a hydraulic thrust bearing and as a valve, the View being taken on the line 11-11 of Fig. 1 but drawn to approximately the same scale as Fig. 10. I

Fig. 12 is a section taken through a part of the element shown in Fig. 11 and through a rocker which supports the element and is tiltable to vary the displacement of the pump, the view being drawn to approximately the same scale as Fig; 11 and taken in the plane indicated by the line 12-12 of Fig; 5 and also indicated by the line 12 12 of Fig. 11. I v

Fig. 13 is a developed" face View of a liner through which forces are transmitted between the arcuate face of the rocker and a driving head through which rotation is transmitted from the drive shaft to" the rocker and the wobble plate, the view being indicated by the arcuate line 13-13 of Fig. 12.

Fig. 14 is asection taken on the line 14-14 of Fig. 13.

Fig. 15 isa transversesectional view showing a partof the mechanism for tilting the rocker and for also tilt-' ing in the opposite direction a counterbalance which is provided to neutralize" the unbalahced centrifugal forces in therocker and thewobble plate; the view being taken on the irregular line 15-15 of Fig. 1 but drawn" to ap-' proximately the same scale as Figs. 26.

Fig. 16 is a longitudinal vertical sectionalview showing the rocker and apart of the tiltingmechanism, the

plane of the view being indicated by thehne 16-16 of Fig. 5 and by the line 16-16 of Fig. 15.

Fig. 17 is a' section through a mechanism for'applying' spring. force to the counterbalance, the view being taken on the line 17-17 of Fig.- 5-.

Fig. 18 is a sectiontaken on the line 18-18 of Fig. 17. Fig. 19 is a section through the driving head and'certa'ir'i adjacent parts taken on the irregular line'19-19' of Fig. 15 and showingthe hydraulic motors for tilting the locker and the counterbalance.

Fig. 20is a longitudinal vertical section through the portion ofthe pump which is shown in-elevation in Fig. l, the view being taken on the irregular line 20-20 of Fig.

5 andshowinga-part of the mechanism for controlling the '3 view of a modified form of the pump shown in Figs. 1-25, certain parts being shown in full and certain parts being broken away or omitted. Fig. 26A is taken on the line 26A-26A of Fig. 28. Fig. 263 is taken on the irregular line 26B26B of Fig. 30.

Fig. 27 is a face view of a hydraulic hold-up element which functions both as a valve and as a hydraulic thrust bearing, the view being taken on the line 2727 of Fig. 26A.

Fig. 28 is a face view of a valve seat for the hold-up element shown in Fig. 27, the view being taken on the line 2828 of Fig. 26A.

Fig. 29 is a transverse section taken on the line 2929 of Fig. 26A.

Fig. 30 is a transverse section through the cylinder block taken in the plane indicated by the arrows 30-30 on Fig. 2613.

Figs. 31 and 32 are detail sectional views taken through the hold-up element and fragments of adjacent parts but drawn to a larger scale than the other views, the planes of the views being indicated, respectively, by the lines 31-31 and 32-32 of Fig. 27.

The pump illustrated is so large and the scale of the drawings is necessarily so small that some clearances and the sizes of some parts had to be exaggerated and some features, such as sealing means and bearings for rotating parts, had to be omitted.

FIGS. 1-25.

The pump shown in these figures is identical to the pump shown in application Serial No. 304,477 filed August 15, 1952 of which this application is a continuation in part.

General arrangement The pump has the greater part of its mechanism arranged within a casing 1 which has an end head 2 rigidly attached to and closing its front end and a cylinder block 3 closely fitted in and rigidly attached to its rear end portion. In order to simplify the drawings, casing 1 has been shown as a unitary structure but actually it is made of separate parts which are rigidly secured to each other. Also, it is provided with one or more ports which provide access to the interior and which are closed by removable cover plates. Casing 1 is adapted to be mounted upon a reservoir 4 which has not been shown in connection with casing 1 but has been shown schematically in Fig. 9.

A drive shaft 5 extends through casing 1 upon approximately the horizontal centerline thereof and is rotatably supported by a bearing 6 carried by end head 2, by a bearing 7 carried by cylinder block 3 at the front end thereof and by a bearing 8 carried by cylinder block 3 at the rear end thereof, bearings 7 and 8 being spaced apart by a spacer tube 9 arranged upon shaft 5.

Cylinder block 3 has a plurality of cylinders 10 formed therein in a circular row concentric with shaft 5. A piston 11 is fitted in each cylinder 10 and is connected by a connecting rod 12 to a non-rotating thrust member or wobble plate 13 which is rockably supported at its center upon a stationary spherical hearing or hollow ball 14 the center of which is on the axis of shaft 5 and through which shaft 5 extends with sufficient clearance to prevent the shaft from contacting the ball. As shown, ball 14 is provided with an annular flange 14 which is rigidly secured to the front end of cylinder block 3. Wobble plate 13 is provided with an annular split bearing 13 which is closely fitted therein and has an internal spherical surface complementary to and closely fitted upon ball 14 to rock thereon. The means for lubricating ball 14 has not been shown as it forms no part of the present invention.

Rotation of wobble plate 13 is prevented by a universal oint the ring 15 of which has wobble plate 13 pivotally connected thereto at diametrically opposite points by two pins 16 as shown in Figs. 1 and 3. Ring 15 is pivoted. at points spaced 90 from pins 16 upon two pins 17 3 and 5 arranged in the bifurcated ends of two arms 18 each of which is slidably supported in a bracket 19 carried by easing 1. The extended axes of

pins

16 and 17 pass through the center of ball 14. In order to simplify the drawings and to provide space for reference numerals, brackets 19 have been shown as being radial and fixed to the inner periphery of the casing but actually they are arranged axially and are attached to the inner end face of that portion of the casing in which cylinder block 3 is fitted.

Wobble plate 13 is restrained from axial movement against the thrust of pistons 11 by a thrust member or rocker 2t) which is arranged within a driving head 21. As will presently be more fully explained, rocker 20 and driving head 21 are fixed for rotation with shaft 5 and are restrained from axial movement. The forces which prevent axial movement of wobble plate 13 are transmitted through a hold-up element 22, which has been shown as engaging the fiat front face of wobble plate 13 and which is arranged in a recess 23 extending into rocker 20 from the fiat rear face thereof, and through a plurality of piston shoes 24 each of which is associated with a connecting rod 12 and bears against the fiat rear face of rocker 20 radially outward from element 22. The front face of rocker 20 and the rear face of driving head 21 are cylin-- drical and are accurately machined to radii struck from the center of ball 14. Concavo-convex liners (not appearing in Fig. 1) are closely fitted between the cylindrical surfaces to transmit axial forces from one to the other and to permit relative radial movement therebetween.

The arrangement is such that rocker 20 may be swung about the center of ball 14 either upward or downward in respect to Fig. 1 to accurately adjusted positions at one side or the other of the neutral position shown in Fig. 1. Swinging rocker 20 away from its neutral position causes its rear face to be inclined to the axis of shaft 5 and to gyrate about the shaft axis as the shaft and rocker 20 rotate. Since shoes 24 and hold-up element 22 bear against the rear face of rocker 20, gyration of that face causes wobble plate 13 to pivot upon pins 16, ring 15 to pivot upon pins 17 and wobble plate 13 to wobble upon ball 14, thereby effecting reciprocation of pistons 11.

The pumping mechanism Cylinder block 3 is circular in cross-section and is closely fitted in a bore 25 formed in the rear end portion of casing 1. Cylinder block 3 and bore 25 are tapered slightly so that block 3 can be inserted nearly to its final position in bore 25 and then rotated step by step during assembly of the pump and so that it can then be forced into bore 25 until a fluid tight seal is formed between it and the wall of bore 25.

As shown in Figs. 1, 2 and 4, each of cylinders 10 has a piston valve 26 associated therewith and the several valves are arranged in a circular row concentric with the row of cylinders 10. Each valve 26 is preferably fitted in a ported sleeve which is arranged in a bore formed in cylinder block 3 but in order to simplify the drawings each valve 26 has been shown fitted for reciprocation in a bore 27 which is formed in cylinder block 3 and has three annular grooves or

ports

28, 29 and 30 formed in its wall. Each port 28 communicates through a passage 31 (Fig. 2) with one of the cylinders 10. Each port 29 communicates through a passage 32 with an annular passage 33 which is formed in the wall of the bore 25 in casing 1 and communicates with a passage 34 (Fig. 4) by means of which the pump may be connected to one side of a hydraulic circuit. Each port 30 communicates through a passage 35 with an annular passage 36 which is formed in the wall of bore 25 and communicates with a passage 37 (Fig. 4) by means of which the pump may be connected to the other side of the hydraulic circuit.

Valves 26 may be made large enough to permit cylinders to be filled with liquid from an adjacent reservoir in response to retraction of pistons 11 but the size of valve 26 and the forces required to reciprocate them may be considerably reduced if the pump is supercharged at a pressure, such as p. s. i., which is relatively low but is high enough to obtain the necessary velocity of the liquid passing through the valves 26 on the intake side of the pump.

As shown schematically in Fig. 9, liquid for supercharging the pump may be supplied by an auxiliary pump which draws liquid from reservoir 4 and discharges it through a channel 41, a selector valve 42 and either a channel 43 into passage 33 or through a channel 44 into passage 36. Since the pump may be employed in a differential hydraulic circuit, a low pressure relief valve 45 is connected to channel 41 and discharges into reservoir 4 so that whenever liquid is returned to the main pump in excess of the liquid required to fill cylinders 19, the excess liquid may be exhausted through relief valve 45.

Since the pressure required to supercharge the main pump is low, supercharge pump 41) may be of a constant displacement type and the liquid dischar ed by it in excess of the liquid required to fill cylinders 1% may be exhausted through relief valve 453. But preferably the supercharge pump is a constant pressure pump. That is, a pump which will discharge liquid at a predetermined maximum rate until it creates a predetermined pressure and then it will automatically reduce its displacement until it is delivering just enough liquid to maintain that pressure substantially constant, such as the supercharge pump shown in Patent No. 2,484,337.

Selector valve 42 includes a body 46 which is fastened to casing 1 and has an axial bore 47 and three annular grooves or

ports

43, 49 and formed in the wall of bore 47. Port 48 is connected by channel 41 to pump 40, port 49 is connected by channel 43 to passage 33 and port 50 is connected by channel 44 to passage 36. Communication between port 43 and

ports

49 and 59 is controlled by a valve plunger 51 which is fitted in bore 47 and has two

ducts

52 and 53 extending into it from its opposite ends and then extending radially outward into communication with ports 49 and 5t? respectively.

The arrangement is such that, when high pressure is created in passage 33, liquid will flow therefrom tr rough channel 43, port 49 and duct 52 to one end of bore 4 7 and will shift plunger 51 into the position shown and plunger 51 will open port St to port 48 so that liquid can flow from pump 49 through channel 41, selector valve 42 and channel 44 into passage 36 and, when high pressure is created in passage 36, liquid will flow therefrom through channel 44, port 50 and duct 53 to the other end of bore :7 and will shift plunger 51 into its other position and plunger 51 will open port 49 to port 48 so that liquid can flow from pump 40 through channel 41, selector valve 42 and channel 43 into passage 33.

Port 43 in valve 42 is also connected by a passage 54 to an annular passage 55 which extends around cylinder block 3 and has been shown as being formed in part in casing l and in part in cylinder block 3. Passage 55 is thus continuousy supplied with supercharging liquid.

The mechanism for shifting valves 26 has been shown in Figs, 1, 4 and 6 as being arranged within a cylindrical housing 53 which is attached to the rear end of cylinder block 3 and is closed at its rear end by a cover plate 59. Each of valves 26 has a universal joint 69 fixed to its rear end and connected by linkage 61 to one of the several arms 62 of a valve actuator 63 which is journaled as by means of bearings 64 upon a tubular cam 65 which is fixed upon the rear end portion of shaft 5. The axis of the outer periphery of cam 65 is inclined to the axis of the inner periphery thereof so that actuator 63 is inclined to the axis of shaft 5.

Actuator 63 is pivoted at diametrically opposed points on its horizontal center line to a ring 66 by two pins 67. Ring 66 is pivoted at diametrically opposite points on its vertical center line upon two pins 68 carried by two arms 69 which are supported in two brackets 70 carried by housing 58. The arrangement is such that, 7

when shaft 5 is rotated, cam 65 will cause actuator 63 to pivot upon pins 67, ring 66 to pivot upon pins 68 and actuator 63 to wobble about the intersection of the axes of shaft 5 and pins 67.

Cam 65 is fixed upon shaft 5 in such a position that, when rocker 2G is adjusted to cause wobble plate 13 to be inclined to the axis of shaft 5 as previously explained, the plane of valve actuator 63 will be spaced from the plane of wobble plate 13. The arrangement is such that, when the pump is pumping liquid and any piston 11 is at either end of its stroke, the valve 26 associated with the cylinder containing that piston will be in its closed position and will be blocking the port 28 leading to that cylinder as shown in Fig. 1. after, both the piston and the valve start to move but the piston will be moving at its slowest speed while the valve will be moving at its highest speed so that the valve will quickly open port 23. The piston will accelerate and the valve will decelerate until the piston is at half stroke at which time the valve will be fully open as shown in Fig. 4. Then the piston will decelerate and the valve will accelerate until the piston reaches the other end of its stroke at which time the valve will have closed port 28 as shown in Fig. 1,

In Fig. 25 driving head 21 has been shown in the same position as in Fig. l but rocker 20 has been shown as having been swung downward in respect to Fig. 1 so that its rear face is inclined to the axis of shaft 5 and will gyrate about the shaft axis when shaft 5 and rocker 20 are rotated. The thrust of pistons 11 holds piston shoes 24 against the rear face of rocker 2t and thereby maintains wobble plate 13 parallel to the rear face of rocker 2d. Two diametrically opposite points at which piston shoes 24 contact the rear face of rocker 20 have been indicated at A and 3, point A being the contact point farthest from cylinder block 3 and point B being the contact point nearest to cylinder block 3.

With rocker 20 in the position shown in Fig. 25, the upper piston designated 11 is at the end of its outstroke and its shoe 1 4 is in contact with the rear face of rocker Ztl point A. Cylinder block 3 contains an odd number of cylinders so that no two pistons are diametrically opposite each other but, for the purpose of this explanation, a piston 11 has been shown diametrically opposite piston 11 in Fig. 25 with the shoe 24 of the lower piston lid in contact with the rear face of rocker Bil at point B, in which position piston 11 is at the end of its instrolce.

When shaft 5 is rotated in the direction indicated by the arrow on Fig. 25, driving head 21 and rocker 29 will rotate with it and the rear face of rocker 29 will slide across the faces of the several piston shoes 24. During the first half-revolution of rocker 20 from the position shown in Fig. 25, its rear face will move the shoe 24 of upper piston 31* rearward or inward harmonically until point B comes into alinement with that shoe at which time piston 11 will have been moved to the end of its in-stroke or into a position corresponding to the position of piston 11 shown in Fig. 25.

During the next half-revolution of rocker 25), its rear face will permit the shoe 24 of piston 11* to be moved forward harmonic-ally. if the pump is supercharged as shown, piston 11 will be moved forward or outward by the supercharge pressure. If the pump is not supercharged, piston lll will be drawn forward or outward by wobble plate 13. In either case, piston 11* will be moved forward or outward harmonically until point A comes into alinement with the shoe 24 of that piston at which time piston 11 will have made a complete reciprocation and will be in the position shown in Fig. 25. Continuous rotation of rocker 20 will cause continuous reciprocation of the piston.

Instantly there-