US2797647A

US2797647A - Hydraulic pump

Info

Publication number: US2797647A
Application number: US404930A
Authority: US
Inventors: Burton S Floraday
Original assignee: Detroit Harvester Co
Current assignee: Detroit Harvester Co
Priority date: 1954-01-19
Filing date: 1954-01-19
Publication date: 1957-07-02
Anticipated expiration: 1974-07-02

Description

I July 2, 1957 s, FLORADAY 2,797,647

HYDRAULIC PUMP Original Filed Sept. 25, 1950 v 2 Sheets-Sheet l IN VEN TOR.

ATTORNEY B. S. FLORADAY HYDRAULIC PUMP Jul 2, 1957 Original Filed Sept. 25, 1950 2 Sheets-Sheet 2 INVENTOR.

Burfm J. Harm/4y BY MGM.

ATTORNEY United States HYDRAULIC PUMP September 25, 1950. This application January 19, 1954, Serial No. 404,930

2 Claims. (Cl. 103-173) This application is a substitute for Serial No. 186,539, filed September 25, 1950, and now abandoned.

This invention relates to hydraulic pumps and an object is to produce a new and improved hydraulic pump, which is simple and economical to construct, has relatively few operating parts thereby greatly to reduce maintenance cost, and the parts being so constructed and designed that they can be easily assembled.

Another object is to produce a hydraulic pump of the piston and cylinder type in which the piston stroke is very short but owing to the high speed, a relatively high volumetric output can be generated.

A further object is to produce an electric motor and hydraulic pump assembly, which can be readily constructed and assembled, occupies a minimum amount of space, and is particularly adapted for use in an automotive vehicle for providing hydraulic pressure means to operate regulators for windows, convertible tops, seat adjusters and the like.

A still further object is to produce a hydraulic pum mechanism, contained within a reservoir to which it is rigidly secured, the pump being directly connected to a rotary motor, and which is adapted to generate relatively high hydraulic pressure by a substantially vibratory piston action.

Other objects reside in details of construction and arrangement as will hereinafter appear, and for purposes of illustration but not of limitation, an embodiment of the invention is shown on the accompanying drawings, in which Fig. 1 is a plan view of the electric motor pump assembly;

Fig. 2 is an enlarged longitudinal sectional view of the pump showing its connection with the electric motor and the drive;

Fig. 3 is a transverse sectional view substantially on the line 3-3 of Fig. 2;

Fig. 4 is a transverse sectional view substantially on the line 44 of Fig. 2; and

Fig. 5 is a transverse sectional view substantially on the line 5-5 of Fig. 2.

The illustrated embodiment of the invention comprises an electric motor and pump assembly having an electric motor M, to one end of which is secured a pump generally designated at P. This affords an assembly, which is a self-contained unit, the motor being connected to operate the pump as will hereinafter appear. Fixed to one end of the housing of the motor by a series of screws 10 is a flanged plate 11, which has a peripheral flange 12 formed with a recess to receive an annular rubber gasket 13 against which the open end of a sheet metal pump housing or reservoir 14 abuts. The mouth of the reservoir is overlapped by the flange 12 and secured thereto by a series of screws 15, thereby securely to retain the reservoir or housing 14 in position in approximate axial alignment with the motor M. The central portion of the plate 11 is frusto-conical, as indicated at 16, with ice the forwardly extending apical portion flattened as indicated at 17, the central portion thereof being apertured to receive an extension 18 of the motor armature shaft. On the inner side of the flattened portion 17 is a washer 19, which bears against the nose portion 20 of the motor housing, and at the opposite side of the flattened portion 17 is a pair of washers 21. A rotating sleeve 22 is secured for rotation to the shaft extension 18 by a key 23 and bears against the innermost of the washers 21. The inner end portion of the sleeve 22 is reduced and pressed thereagainst is the inner race of a ball bearing unit 24, such unit being inclined relative to the sleeve 22 so that it is not coaxial therewith. Suitably secured, as by a press fit, to the outer race of the ball bearing unit 24 is the hub portion 26 of a sheet metal actuator 25, lips 27 being struck therefrom into engagement with the inner edge of the outer race properly to position the actuator. Integral with the actuator hub is a ring 28, which is cup-shaped in cross section, as indicated in Fig. 2, thereby to provide a concave-convex annulus opening in a direction toward the motor M. i

As will be hereinafter described, the actuator 25 is in the nature of a wobble plate which effects to and fro reciprocatory or vibratory movement of the pistons to effect the pumping action. A metallic cylinder block 29 tween the end of the flange 30 and the closed end wall of the reservoir 14. A series of screws 32 connect the flange 30 in fluid-tight relation to the end wall of the reservoir 14.

Formed in the cylinder block'29 is a series of transverse cylinders 33 for receiving reciprocatory pistons 34. In this instance, six cylinders are formed in the block 29 and a piston mounted in each of these cylinders for reciprocatory action in directions lengthwise or axially of the reservoir 14. The pistons 34 may be of any desired construction, but in this instance are of molded nylon, and each is formed with a flexible skirt 35 at the forward end thereof, the inner end being formed with a series of longitudinal grooves 36 to reduce the frictional contact between the piston and cylinder as much as possible. In the rear end portion of each piston is an integral rearwardly extending boss 37 integrally connected with the piston skirt by radial arms 38. Fixed to the central portion of each of the bosses 37 is a metallic pin 39, which has an intermediate collar 40 disposed at the inner end portion of the piston and forming an abutment for the inner face of the wobble plate 25. Each of the pins 39 extends through an opening in the annulus 28 and disposed on the inner or cupped side of the annulus is a substantially hemispherical block 41 through which the pin 39 projects. A spring metal fastener 42 retains each block 41 on its pin and in abutting engagement with the wobble plate.

The above arrangement is such that as the motor extension shaft 18 rotates, the actuator 25 wobbles back and forth, thereby imparting slight reciprocatory movement to the pistons 34 successively. This wobble action thus imparts almost vibratory movement to the pistons within their respective cylinders for effecting the desired pumping action.

Formed in the cap plate 30' is an annular row of fluid inlet openings 43 which, at predetermined times, enables liquid from the reservoir 14 to be sucked or drawn into the respective cylinder when the piston therein moves inwardly or away from the closure plate 30. Clamped Patented July 2, 1957 edge portion of the rubber ring '44 provides inlet valve flaps 46, which flex inwardly into the cylinder upon the retracting or inward stroke of the respective piston, thereby to allow liquid to be drawn in from the reservoir 14, but close when the respective piston advances creating pressure against the inner side of the valve flap 46.

When pressure is generated within each cylinder, the liquid therein is forced therefrom through an outlet'opening 47in the plate 30', past a valve flap 48 and into an outlet chamber 49, 'which communicates with the several outlet openings. Leading from the chamber '49 is a common outlet tube fitting 50. The rubber outlet valves 48 close when the respective piston retracts or when negative pressure is created on the inner side of each of the flaps 48. The flaps '48 form an integral part of a rubber disc 51 which is clamped between a clamping plate 52 and the outer face of the closure plate 30, the screws 45 passing through the plate 52 as well as the rubber disc 51. Thus it will be understood that there are as many outlet openings 47 as there are cylinders in the cylinder block 29 and that each outlet opening 47 is coveredby a resilient flap which is free at one end and is integrally joined and clamped in place at its outer end, each outlet flap or valve 48 opening to discharge liquid from one of the cylniders and closing when the respective piston retracts.

'It will be understood that the disc or annulus 51 is a one-piece structure, the outer peripheral edge portion of which is clamped but the inner edge portion of which is free to flex to form the valve action, such free edge portion'being referred to as the valve flap portion 48. Centrally of the inner side of the clamping plate 52 is an annulus 53 providing a seal between the clamping plate and the central portion of the closure plate 30'. A central aperture 54 registers with an aperture 55 in the clamping plate and an aperture 56 in the closure plate 30, these apertures opening into a cavity 57 in the hub of the cylinder block 29. Within the cavity 57 is a ball valve'58, which is urged against the central portion of the rubber disc 44 by a coil spring 59. The inner end of the cavity 57 communicates through a smaller passage 60 with a plurality of laterally extending passages 61 in a spacer block 61a, which communicates with the interior of the reservoir 14. Thus it will be seen that in the event that the pressure in the outlet chamber 49 exceeds a predetermined maximum, the ball 58 will be unseated, thereby to serve as a pressure release enabling excess liquid to return to the interior of the reservoir 14.

In the side wall of the reservoir 14 is an inlet tube fitting 62. It is contemplated that this pump assembly may be used to advantage in a closed hydraulic system, liquid entering the reservoir through the tube fitting 62 and being discharged through the tube fitting 50. Each of these fittings is adapted to receive a rubber hose. For filling and replenishing the liquid within the reservoir 14, an inlet opening is provided in the side wall of the reservoir, the same being closed by a screw plug 63.

From the above description, it will be manifest that the pump is directly driven by the electric motor M and that from the rotation of the motor shaft, the several pistons are rapidly reciprocated to and fro within their respective cylinders. The piston movement is very slight but is sufiicient successively to draw in liquid from the reservoir 14 past the rubber inlet valve of one of the cylinders, and subsequently force the liquid therefrom past the outlet valve flap 48. This almost vibratory movement of the several pistons thus creates a hydraulic pressure in the outlet chamber '49 and thus the liquid under pressure is forced therefrom through the outlet t'ube or fitting 50. Thus although the individual pistons force but a slight amount of liquid under pressure from the respective cylinders, in the aggregate and due to the speed -'of rotation-of the actuator 25, a relatively high volumetric output is obtained. As above explained, in the event that the pressure in the outlet line becomes excessive, this pressure is relieved by the unseating of the ball valve 58 allowing excess liquid to be returned to the reservoir 14.

The pump has been designed particularly from the standpoint of a large quantity production. The parts can be readily produced in the main from stampings and die castings and due to the extreme simplicity of the construction and assembly, the cost is relatively low. Furthermore, the ease with which the pump unit can be attached to the electric motor M greatly reduces the time and labor of assembly.

It is to be understood that numerous changes in details of construction, arrangement and operation may be effected without departing from the spirit of the invention especially as defined in the appended claims.

I claim:

1. A hydraulic pump comprising a housing providing aliquid reservoir and having side walls and end closures, a cylinder block within said housing and spaced from said side walls to provide a liquid passage communicating .with the reservoir, a plate closing one end of said block and spaced from the adjacent end closure of the housing,'wall means cooperating with said plate and adjacent housing end closure to form an outlet chamber fluid-tightly sealed from the rest of the housing, pistons reciprocable in the cylinder block, inlet ports in said plate providing communication between said liquid passage and the cylinders respectively, a single rubber-like ring anchored at its outer edge between the closure plate and cylinder block and with its inner edge portion covering the several inlet openings thereby to provide flap portions flexible into the respective cylinder to admit liquid therein upon the retracting movement of the piston but flexible to close the respective opening upon pressure stroke of the piston, rubber-like flap valves for the outlet ports, and means to clamp said last valves to the outer side of said closure plate.

2. The organization as claimed in claim 1, in which the outlet chamber forming means comprises a flange rigid with the closure plate spaced inwardly from the periphery thereof, the inlet ports being arranged between said flange and the edge portion of the plate, and the outlet ports being arranged inwardly of said flange.

References Cited in the file of this patent UNITED STATES PATENTS 947,536 Wenkel Jan. 25, 1910 1,033,679 Diaz July 23, 1912 1,290,994 Holley Jan. 14, 1919 2,423,373 Chandler July 1, 1947 2,672,819 Widmer Mar. 23, 1954