US2935063A - Variable pressure fluid drive mechanism - Google Patents

Description

May 3, 1960 J. ZUBATY VARIABLE PRESSURE FLUID DRIVE MECHANISM INVENTOR. dZwgp/zZa qy I! AT TORNEY Corporation, Detroit, Mich., a corporation of Delaware Application September 16,1957, SerlalNo. 684,193; '3 Claims. '(Cl. 123-140 The invention relates to a fluid drive mechanism and more particularly to a mechanismof the Wobble plate type as used in fluid pumps. The drive and the controls therefor may be used with a pump of the type disclosed in my application Serial No. 633,456, entitled Variable Pressure Fluid Pump, and filed January 10, 1957.

The fluid drive includes an oscillating member whichimparts reciprocable motion to pump plungers which operate to pump fluid at a desired pressure and volume. It is often desirable to vary the delivery characteristics of such pumps in accordance with the load impressed on associated mechanisms such as internal combustion engines. A pump embodying theinvention has the pump actuating ring interconnected with a diaphragm responsive toenginevacuum so that sponse to the changes in the engine vacuum automatically adjust the stroke of the pump, thereby adjusting the delivery characteristics of the pump. A pump embodying the invention is sensitive to load on the engine since centrifugal force acting on the actuating ring and the vacuum caused by the action of a venturi tube at the engine air intake tend to balance each other. 7 During rotation, the oscillating member will tend to occupy a position normal to the axis of rotation due to centrifugal force. The degree of this tendency is proportional to the square of the speed of the drive shaft. The angle of tilt of the oscillating member is controlled by vacuum imposed by a venturi tube used on the engine intake. The depression tendency of the vacuum sensitive diaphragm is proportional to the square of the air mass flow. These two tendencies will be balanced and pump output depending on load without interference of speed will result.

In the drawing:

The figure illustrates a pump embodying the invention and having parts in section.

The pump illustrated includes a housing 10 with which a a web 12 is integrally formed. A hearing hub 14 is located centrally within web 12. Bearing 16 is received within hub 14 and provides a rotatable mount end and locating point for the end of drive shaft 18. A second bearing 20 is mounted on the other end of drive shaft 18 and is located in the bearing cap and seal 22. Cap 22 is, secured to a pump cover 24. Several stacked plates which may be separated by gaskets are positioned intermediate pump cover 24 and housing 10. These plates include a plunger guide plate 26, a pressure chamber plate 28, and a valve plate 30. Pump cover 24 may be provided with an inwardly extending sleeve 32 on which plates 26, 28, and 30 are piloted. The valve, passage, and chamber arrangement may be similar to that shown in the above identified application. The pressure chambers 27 may contain the piston springs 29 and be connected with the inlet 21 through inlet annulus 33 and inlet valves 35. Outlet valves 37 connect the chambers 27 with outlet annulus 39 and the outlet 41.

The pump diaphragm 34 is positioned intermediate plates 26 and 28 and is used both as a pump diaphragm and a gasket. Plunger guide plate 26 has plunger cylinmovement of the diaphragmxin rely spaced from that shaft.

ders 36 formed therein in which pump plunger pistons 38 are reciprocably received. These pistons engage dia-- phragm 34 at their outer ends and, when reciprocated,

cause the diaphragm to flex, thereby imparting pumpingaction to the diaphragm. Plunger pistons 38 may be integrally formed with plunger arms 40 which terminate at their ends opposite the pistons in rounded ends 42.. Sockets 44 are formed within actuating ring 46 and the ends 42 of the plunger arms 40 are received in the sockets- Actuating ring 46 is preferably mounted on the outerrace of bearing 48. The inner race of this bearing is secured to hub 50 of oscillating member 52. Hub 50 extends circumferentially about drive shaft 18 and is radial-- Actuating ring 46 may be: tilted relative to the axis of drive shaft 18 by pivotal. movement of oscillating member 52. Oscillating mem-- ber 52 is rotatably driven from drive shaft 18 through. drive pin 54 and driving member 56. Oscillating member 52 is pivotally attached to driving member 56 by hinge: 58. The axis of hinge 58 provides the pivot point for os-- cillating member 52 and actuating ring 46. Actuating ring 46 may be prevented from rotating with respect tohousing 10 by pin 64 which extends downwardly from web 12 and engages ring 46 in recess 66.

An initial manual adjustment of the oscillating member 52 may be obtained by threading tapered adjusting.

cillatingmember 52. The tapered end of screw 62 may I contact bevel surface 60 which is formed on one side of driving member 56 adjacent screw 62. When the screw 62 is moved inwardly, the minimum tilt angle obtainable between oscillating member 52 and driving member 56 is increased.

The pump is preferably controlled during engine operation by vacuum sensed at a venturi throat in the engine air intake system. A typical system of this type is shown in application Serial No. 591,889, filed June 18, 1956, in the name of John Dolza and assigned to the common assignee. A vacuum sensitive diaphragm 70 is provided for this purpose. Cover plate 72 may be suitably secured to pump housing 10 so that web 12 and the cover plate form a space divided by diaphragm 70 to define atmospheric chamber 74 and vacuum chamber 76. Vacuum chamber 76 is connected with the engine air intake venturi throat 77 through appropriate conduits 79 connected to vacuum inlet 78. Spring 80 may be mounted between web 12 and diaphragm 70 to resist movement of the diaphragm when vacuum is increased within chamber 76 and to return the diaphragm to its neutral position when the vacuum approaches atmospheric pressure.

Control arm 82 may be rigidly attached to diaphragm '70 and extend in a generally perpendicular direction from the diaphragm through an aperture 84 formed in web 12. A bellows seal 86 may be secured in aperture 84 to permit longitudinal movement of arm 82 while effectively sealing vacuum chamber 76 from the interior of the pump. End 88 of control arm 82 may be threaded into or otherwise attached to actuating ring 46. When diaphragm 70 is moved under the influence of increased vacuum in chamber 76, arm 82 is moved in a direction generally parallel to drive shaft 18 and actuating ring 46 is pivoted about hinge 58. Since the engine air intake venturi throat vacuum is a function of the second power of engine air mass flow and the centrifugal forces acting on members 52 and 56 are a function of the second power of engine speed, these forces tend to balance each other, thereby making the pump sensitive to engine load. Since the speed of drive shaft 18 is directly proportional to engine speed, the centrifugal forces acting on members 52 and 56 are also sensitive to speed of that shaft.

Patented May3, 1960 a What is claimed is: 1. Ina fiuid pump of the wobble plate type, a housing, a drive shaft rotatably mounted in said housing, internal ea. n e. me ns d i n sa sh an a l:

latable mernber s filtd tq said, energ s rot'ati' with, fm eans permitting angular movement of said oscil seams latable merriber relative tothe axis of said shaft, a wobble plate actuating member secured for oscillatory mov ement with said osc illatable member relative totthe axis'of said shaft, and differential pressure. means ior adjusting the angular relationshipof said member relative to said shaft, said dilferential pressure means being sensitive 'to the secpistons disposed,concentrically, about saidrdrive shaftv and nd power of the air mass flow ofsaid engine means, said oscillatable member. when rotating havinga centrifug'al force component sensitive to the second power .of the speed of said drive shaft and opposingsaid differential.

pressure means whereby said memb are angularly adactuated by oscillatory movement .of said actuating ring, and meansv for tilting said actuatingsring and said oscillating member relativeto said drivingfmember on said drive shaft, said tilting means including a diaphragm sensitive to a differential pressure, said diiferential pressure being directly proportional to the second power of the air mass passing throughthe; intake of said engine, said oscillating member exerting a component of centrifugal iusted relative to said drive shaft in direct proportion to I V the load on said engine means.

2.'A vacuum controlled variable pressure pump having a tiltable actuating ring and reciprocable pistons driven by said ring, a drive for said ring, a chamber formed in one end of said pump for having a diaphragm extending therethrough, one side of said diaphragm being sensitive to vacuum proportional to the second power of a load characteristic of said ring drive, connecting means interconnecting said diaphragm and said ring, said ring drive exerting a component of centrifugal force on said ring acting opposite to the force of said vacuum on said diaphragm transmitted through said connecting means to said ring whereby said ring is tilted in direct proportion to the load' on said drive.

3. A wobble plate fluid pump having a drive shaft, an

force proportional to the second power of the speed of said driveshaft on said-actuatingring in opposition to the force of said difierentialpressure exerted on said it diaphragm References Cited in the file of this patent UNITED f stares PATENTS

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