US2991723A - Wobble plate diaphragm pump - Google Patents

Description

July 11, 1961 J, Z Y 2,991,723

WOBBLE PLATE DIAPHRAGM PUMP Filed Feb. 5, 1958 4 Sheets-Sheet 1 INVENTOR.

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WOBBLE PLATE DIAPHRAGM PUMP Filed Feb. 5, 1958 4 Sheets-Sheet 2 INVENTOR.

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WOBBLE PLATE DIAPHRAGM PUMP Filed Feb. 5, 1958 4 Sheets-Sheet 3 IN VENTOR.

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July 11, 1961 J, ZUBATY 2,991,723

WOBBLE PLATE DIAPHRAGM PUMP Filed Feb. 5, 1958 4 Sheets-Sheet 4 INVENTOR wry 7 5:10;;

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2,991,723 WOBBLE PLATE DIAPHRAGM PUB/[P Joseph Zubaty, Flint, Micln, assignor to General M- tors Corporation, Detroit, Mich, a corporation of Delaware Filed Feb. 5, 1958, Ser. No. 713,391 8 Claims. (Cl. 103-150) This invention relates to diaphragm pumps and more particularly to diaphragm pumps of the wobble plate type and which are capable of delivering fluid at pressures sufliciently high to serve in the field of fuel injection for internal combustion engines.

Pumps for pumping engine fuel at pressures higher than those achieved by the use of conventional diaphragm pumps as used in automobiles have recently been found desirable. Simplicity of structure, ruggedness, cost and compactness are essential factors which obviously must be given considerable weight in developing a pump if it is to constitute an advance in this field. It is clear that such a pump may have many other uses and is not necessarily limited to the handling of fuel.

An object of the present invention is to provide an improved diaphragm pump which is capable of developing a liquid discharge pressure higher than obtained in conventional diaphragm pumps and suitable for fuel injection use.

To this end, a feature of the present invention pertains to a unitary wobble plate comprising a plurality of plungers. Another feature comprises pumping diaphragm combined with a plurality of plungers arranged sequentially to act upon and displace portions of the diaphragm means with a minimum of relative motion taking place between the surfaces of the diaphragm means and the surfaces of the plungers contacting the diaphragm means. Another feature is a diaphragm pump including a wobble plate having a plurality of plungers in an arrangement subject to convenient adjustment for changing the pump displacement or discharge capacity.

These and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the drawings:

FIG. 1 shows a cross-sectional view of a pump in which the present invention is embodied;

FIG. 2 is a view similar to that of FIG. 1 but showing a modification;

FIG. 2a is a view looking in the direction of the arrows 2a2a in FIG. 2;

FIG. 3 is a sectional view looking in the direction of the arrows 33 in FIG. 1 and showing a wobble plate with its plungers;

FIG. 4 is a sectional view looking in the direction of the arrows 44 in FIG. 1 and omitting parts pertaining to the wobble plate and its plungers;

FIG. 5 is a sectional view looking in the direction of the arrows 55 in FIG. 1;

FIG. 6 is a sectional View looking in the direction of the arrows 66 in FIG. 1 and showing outlet passages;

FIG. 7 is a view looking in the direction of the arrows 77 in FIG. 1;

FIG. 8 is a view looking in the direction of the arrows 8-8 in FIG. 1;

FIG. 9 is a View looking in the direction of the arrows 99 in FIG. 1 and showing inlet passages; and

FIG. 10 is a view looking in the direction of the ar rows 1010 in FIG. 1 and showing outlet and inlet ports.

The pump depicted in FIG. 1 of the drawings comprises a casing with a hollow or drive portion generally indicated at 10 and a pump valve portion generally indidicated at 12. The pump portion 10 is hollow as at 14 to serve as a sump chamber for a lubricant 16 as well as ice to house a part of a driving mechanism for a wobble plate. The hollow casing has two threaded openings 18 and 20 by means of which the entire pump structure may be joined by suitable bolts to a support. An opening 22 is formed in the side wall of the hollow portion 10 and through which opening a drive shaft 24 extends. The exterior end of the shaft is recessed as at 26 for the reception of atongue on a driving member (not disclosed) which is adapted to rotate the shaft 24. Two plugs 28 and 30 are utilized on the hollow portion 10 for filling and draining the sump chamber. The hollow portion 10 and valve portion 12 are provided with a common wall 32 which is joined by two screws 34 and six bolts 37 to the portion 10. The screws 37 are of suflicient length to pass through the valve portion 12 of the pump casing, the wall 32 and into the rim of the hollow portion 10. Three bolts 36 aid in attaching the wall 32 and the parts of the portion 12 closely together. The wall 32 is apertured as at 38 for the retaining of a ball bearing 40. The portion 10 is recessed at 42 for the retaining of a ball bearing 44. The shaft 24 is journaled in the two bearings 40 and 44 and is integrally provided with a pulley 46 which is annularly grooved to receive a spring belt 48. The latter also passes around a grooved pulley 50 preferably immersed in lubricant 16 and rotatably mounted on the portion 11} by means of a pivot screw 52. An intermediate portion 54 of the shaft 24 is tightly fitted within a sleeve member 56 which is tightly fitted between the inner race of a bearing 58 and the shaft. The portion 54 is coaxial with the bearings 40 and 42 but the outer surface of the sleeve member 56 is made cylindrical with its axis intersecting the shaft axis within the plane of a pumping diaphragm 59.

Surrounding the bearing 58 for rotation with the outer race thereof is an annular wobble plate 60. Integral with the wobble plate are three plungers 62 which are equally spaced about the axis of the bearing 58. Three shallow round pockets 64 are formed in the plate 32 loosely to receive the three plungers.

The valve portion 12 is made in four parts 66, 68, 70 and 72, all of which are substantially cylindrical. Seals between these parts are afforded by suitable gaskets 74, 76 and 78. The gasket 59 constitutes pumping diaphragm means with reference to its main function but it also serves as a sealing gasket around each of the pockets 64 and between the valve portion 12 and the plate 32. A gasket 80 forms a seal between the latter and a marginal portion of the main body of the portion 10.

Shallow pockets 82 are formed in the part 66, each pocket being in substantial registry with a pocket 64 in the plate 32 and combining to form a cylinder. The material of the diaphragm 59 is flexible and resistant to wear and is as used in conventional fuel pump diaphragms. Because of its flexibility it may be deformed for pumping action, the extent of deformation being as seen in FIG. 1. One diaphragm may be used for each pocket 82 or cylinder, but it is preferred to employ one diaphragm 59 serving for all pockets or cylinders and thereby promoting ease of assembly. A spring 91 is used in combination with a protector plate 93 for maintaining contact between the diaphragm and a plunger in each of the three cylinders. If desired, a low intake pressure may be used to maintain this contact and the spring 91 with its plate could be omitted.

The part 66 is provided with three recesses 86 triangularly communicating by means of grooves 88 best seen in FIG. 6. Each recess 86 communicates with a pocket 82 by means of a port 90 and this port is controlled by a spring-biased valve 92. Each valve is held in its closed position by means of a leaf spring 94 fixed to the part 66 by a screw 96. Conveniently, two of the leaf springs are located within the grooves 88 with one of them extending into a side groove 98 in order to permit sufiicient leeway for the corresponding leaf spring 94 to operate.

The part 66 also includes a port 100 connecting each pocket 82 with a port 102 in the part 68. A port 104 also passes through the part 68 and communicates with one of the recesses 86. The port 104 is in alignment and communicates with a port 106 passing through the part 70. This port in turn communicates with a port 108 formed in the part 72 and leading to a threaded port 110 for connection with a suitable discharge conduit.

The part 70 has three recesses 112, each of which communicates with a port 102 in the part 68. A port 114 is formed in part 70 for each of the recesses 112. Also formed in the part 70 is a continuous groove 116 (FIG. 9) which connects the three ports 114. Springbiased valves 118 are mounted in the recesses 112 to control the ports 114. These valves are similar to the valves 92.

The part 72 not only has a discharge port 108 in communication with the port 106, but it also has an inlet port 120 which communicates with the groove 116. An enlarged threaded opening 122 is provided in the part 78 for the connection of an inlet or feed line to the port 120.

In the operation of the device shown in FIG. 1, and assuming that the sump chamber in the portion contains lubricating oil, the shaft 24 is driven with the result that the plate 60 wobbles with an accompanying nonrotative reciprocatory movement of each of the plungers 62. Each of the latter is provided with a smooth and curved surface in contact with the diaphragm 59 and, because of the peculiar configuration of the sleeve 56, each plunger will be moved substantially along the axis of a pocket 64 and its aligned recess 82. When a plunger 62 moves to the left into the position as viewed in FIG. 1, a suction will occur to open the corresponding valve 118 and admit liquid by way of a port 100 to the corresponding recess or pumping chamber 82. The latter will become pressurized when the corresponding plunger 62 subsequently moves to the right. This will constitute a pumping stroke and result in the closing of the corresponding inlet valve 118 and the opening of the corresponding outlet valve 92. With the opening of the latter the fluid will flow through the corresponding port 90 for discharge by way of the ports 104, 106, 108 and the threaded connection 110.

From the above description of the structure in FIG. 1, it will be seen that the one-piece wobble plate 60 will cause consecutive pulses in pressure to discharge the fluid. It will also be seen that there is no appreciable relative movement between the surface of the diaphragm 59 and the slightly rounded surface of each plunger 62 to cause Wear.

FIGS. 2 and 2a depict a modification of the pumping device while retaining the unitary construction of the wobble plate. In FIG. 1 the wobble plate does not rotate whereas in FIG. 2 a wobble plate is provided which rotates and wobbles. FIG. 2 shows an annular wobble plate 200 which is provided with three plungers integral therewith. One of these plungers is designated as 202 in FIG. 2 and bears against a pumping diaphragm 204. The pump casing is again divided into two main portions 206 and 208 which are suitably attached together with a sealing gasket 210 interposed between the margins thereof. The pump drive part 206 is in the form of a cup, the bottom of which is provided with a bushing 212 and a sealing means 214 within which is mounted a protruding drive shaft 215. The latter is kerfed as at 217 to facilitate a driver attachment. Within the interior of part 206 the shaft 215 is provided with a disk portion 220 the hub of which is annularly grooved to accommodate a lubrication spring pulley 222 similar to the pulley '48 utilized in the structure of FIG. 1. This wire spring also passes around a pulley 224 journaled within the part 206 on a screw 226. A roller 228 is pivoted on a projection 230 formed on one side of the disk 220 opposite a counterweight 232. Coaxial with the shaft 215 is mounted a short stub shaft 234 having a rounded end constituting a stop limiting the movement of the shaft 215 to the right as viewed in FIG. 2.

The Wobble plate 200 is centrally apertured snugly to receive the outer race of a ball bearing 240. A cylindrical sleeve 242 is snugly fitted within the inner race of the ball bearing 240 and is provided with a flange 244 engaging one side of the inner race of the hearing. The sleeve 242, together with the inner race of the bearing, is held in non-rotative relation on a short shaft portion 260 which is part of a lever 262. The latter is pivoted on a shaft 264 which in turn extends into opposite sides of a sleeve or tubular journal 266. The free end of the shaft portion 260 is threaded as at 268 to receive a washer 270 and a nut 272. This nut and washer serves to hold the inner race of the bearing 240 and the sleeve 242 in non-rotative relation on the lever 262. The protruding end of the lever 262 is perforated as at 274 for connection with one end of a spring 276. The other end of the spring is connected to an I-bolt 278 adjustably supported on a projection 280 formed on the pump body part 203. Adjustment of the I-bolt and tension in the spring 276 is by means of a nut 282.

The sleeve 266 is apertured as at 284 not only to receive the lever 262 but also to permit a slight swinging motion of the latter about the axis of the shaft 264. It also bears a projection 286 for retaining a stop screw 288 which is held in an adjustable position by means of a nut 290. One end of the stop screw 283 extends toward the lever 262 to limit the motion of the latter in one direction. The sleeve member 266 is held to the part 208 by screws 209 shown in FIG. 2a.

An inner end portion of the sleeve 266 is reduced in diameter to accommodate a bushing 291 upon which is rotatably mounted a cylindrical rotor 292. The latter is provided with three spaced pumping chambers 294 each of which is cylindrical and in alignment with a plunger 202. Each pumping chamber 294 communicates by means of a bore 261 with an arcuate slot 263 or 265 depending upon the rotative position of the rotor. The two arcuate slots are formed in the part 208 and one of them communicates by means of a passage 269 with a conduit connection 269'. The other slot is connected by means of a passage 271 to a conduit connection 271'. Each bore 261 is adapted consecutively to register with the slots 263 and 265 but its diameter is smaller than the land 273 or 277 separating the slots in order to prevent connecting the slots during rotation.

A coiled spring 289 is interposed between the outer race of the ball bearing 240 and a part 279 of the rotor 292.

The pumping diaphragm 204 is tightly clamped between the two main parts of the rotor by means not shown. The rotor part 279 has an annular rim 281 which is notched as at 263 for the loose reception of the roller 228. It is also notched as at 285 to eliminate contact with the counterweight 232.

If the shaft 215 is rotated, the roller 228 will bring about rotation of the rotor 292 on and with respect to the bushing 291. The plungers 202 with the wobble plate 200, will be rotated by the rotor part 279. If the arm 262 is held in its position, as illustrated, the plungers 202 and diaphragm will be rotated without any displacement or pump discharge taking place because of lack of distortion of the diaphragm. If, however, the lever were permitted to move with a pull of the spring 276 the tension in the spring 276 being suitably adjusted, the wobble plate 200 will be tilted with its axis intersecting the plane of the diaphragm 204 (at axis of shaft portion 260) and the plungers will move to flex that portion of the pumping diaphragm traversing each pumping chamber 294. As a result, liquid will enter through one of the arcuate ports 263 or 265 (dependent upon which direction the rotor 292 is driven), be compressed in a pumping chamber 294 and be discharged through the other arcuate port 265 or 263.

By adjustment of the nuts 282 and 290, the pump displacement or volume of fluid discharge can be determined. When a predetermined discharge pressure is exceeded and the lever 262 is permitted movement within limits, the spring 276 will yield. Both the pressure of the fluid and of the spring 276 insures a proper seal between the abutting and radial surfaces through which the rotor 292 and the part 279 contact. The two arcuate slots 263 and 265 correspond to the suction and pressure zones of the Wobble plate depending upon the direction of rotation of the rotor. These slots have no relation to the number of plungers 202. There may be several plungers simultaneously in the suction phase or pressure phase. When three plungers are used in a particular pump, it is clear that two of them will be on suction stroke and one on its pressure stroke or vice versa.

I claim:

1. A pump having a portion forming a plurality of cylinders, pumping diaphragm means arranged in a given plane partially defining a pumping chamber at one end of each of said cylinders, pressure actuated valve means for admitting and discharging fluid in sequence to and from said pumping chamber, a unitary wobble plate having a given axis and comprising a plunger for and extending within each of said cylinders, said plunger contacting said diaphragm means, and means for imparting a wobble movement to said wobble plate and its plungers substantially about a point at which said axis intersects said plane.

2. A pump having a rotary portion forming a plurality of cylinders, said portion including diaphragm means extending across said cylinders to determine a pumping chamber in the end of each of said cylinders, inner ports in said rotary portion each leading to one of said pumping chambers, fixed means upon which said rotary portion is journaled for rotation on one fixed axis and including an inlet and outlet port adapted to communicate with said inner ports in sequence upon rotation of said rotary portion, a wobble plate having a movable axis extending in the same general direction as said fixed axis and being adapted to rotate with said rotary portion, plungers joined to said plate and extending into said cylinders and contacting said diaphragm means, means for rotating said rotary portion and plungers, and means for changing the angularity of the said one fixed axis of said rotary portion with respect to the movable axis of said wobble plate whereby displacement of the said diaphragm means by said plungers may be varied.

3. A pump having a portion forming cylinders, diaphragm means in a general plane traversing said cylinders to determine pumping chambers in the latter, a unitary wobble plate including multiple plungers symmetrically arranged about a center line of said plate and extending into said cylinders, said plungers having curved surfaces engaging the side of said diaphragm means opposite said pumping chambers, means for actuating said wobble plate and its plungers substantially about a point in said plane to eflect pumping action by displacement of said diaphragm means by said plungers with substantially no relative motion between the said curved surfaces of said plungers and said engaged side of said diaphragm means, and valved ports to control the fluid flow to and from said pumping chambers during said pumping action.

4. A pump such as set forth in claim 3, including means for changing the relative angularity of the center line of the wobble plate with respect to the axes of the cylinders whereby the pump output from the pumping chambers may be regulated.

5. A pump such as set forth in claim 3, including a support for said portion, a lever pivoted to said support, said wobble plate being journaled on an end portion of said lever, and the arrangement being such that the pump output may be changed by pivotly moving said lever.

6. A pump such as set forth in claim 3, including a journal as a support for said cylinder forming portion, a lever pivoted intermediate its length to said journal, said wobble plate being journaled on one end of said lever, means for yieldingly holding said lever in a given angular position with respect to said support, and the arrangement being such that the pump discharge pressure is determined by the said yielding holding means.

7. A pump such as set forth in claim 3, including a tubular journal as a fixed support upon which said cylinder forming portion is mounted for rotation, a lever pivoted within said journal, said wobble plate being journaled on one end of said lever, adjustable means for holding said lever in any one of a range of positions with respect to said general plane, and the arrangement being such that the displacement of said diaphragm means in each of said cylinders upon rotation of the wobble plate is determined by the position selected for said lever.

8. A pump having a portion with a plurality of cylinders formed therein, pumping diaphragm means mounted in a given plane and a plurality of plungers, the crosssectional area of each of said cylinders being completely traversed by said diaphragm means and substantially traversed by one of said plungers, said cylinders and one side of said diaphragm means defining pumping chambers, said plungers contacting the other side of said diaphragm means and being joined to constitute a unitary Wobble plate having a given axis, means mounting said wobble plate for a wobble movement of the latter about a point at which said axis intersects said given plane, valved ports at one end of said portion and communicating with said pumping chamber, and rotative means arranged at the other end of said portion to impart said wobble movement to said plate and consequent fiexure of said diaphragm to effect pumping action sequentially to and from said pumping chambers by way of said valved ports.

References Cited in the file of this patent UNITED STATES PATENTS 1,871,816 Miller Aug. 16, 1932 2,052,737 Zubaty Sept. 1, 1936 2,311,939 Goode Feb. 23, 1943 2,752,852 Offut July 3, 1956 2,809,868 Thompson Oct. 15, 1957 FOREIGN PATENTS 782,231 Great Britain Sept. 4, 1957 945,304 France Nov. 22, 1948

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