US2277160A - Pump construction - Google Patents

Description

March 24, 1942.

C. W. SHAW PUMP CONSTRUCTION Filed April 19, 1940 INVENTOK C/are/meyl \Yfian ATTORNEY.

atented I CONSTRUCTION Clarence W. Shaw, Grosse Yointc Woods, Mich, assignor to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application April 19, 1940, Serial No. 330,521

1 Claim.

This invention relates to vehicle oil pumps in general, but more particularly concerns a pump gear or vaned wheel parts therein for moving the fluid supply, and which were not especially critical of the accuracy of the inlet and outlet pump ports cast therein. More recently, a pump construction has found favor with automotive engineers and others because of its general emciency compared to other known pumps and its increased efllciency at low speeds. Such a pump mechanism is based upon two rotors or gears, one within and eccentric to the other, having tooth divisions, with contours on each out- 103-126) cored out of a boss cast integral with the engine block, the casting of the crescent shaped inlet and outlet ports, which heretofore have been integral with and countersunk in the rotor pocket, may not be cast within the limits required to provide suitable inexpensive port shapes. This difilculty has been overcome in the present invention by casting a pump boss on the engine block, operating upon the boss to form the pump pocket therein concurrently with the machining operations performed upon the engine block casting, and then introducing a separately cast 'or suitably blanked steel porting plate insert into the pump pocket. Thereafter the pump rotors, shaft, and cover plate are added to complete the assembly.

Accordingly, the primary object of the present invention is the provision of an engine block lined or generated by the tooth form of the other at regular angular motion, i. e. steady angular motion as the two rotors turn at speeds inversely proportional to the number of teeth to provide rotor chambers separated by travelling tooth contacts for performing pressure functions. A pump such as described above while providing improved results is rather critical in the accuracy required to form the porting arrangement therefor, and care must be exercised in the machining operations performed upon the pump housing which is integral with the inlet and outlet ports countersunk therein.

In the adaptation of this pump construction to automotive vehicles it has been proposed to cast the pump housing integral with the engine cylinder block with a view, as aforementioned, to producing a more economical unit. In this procedure the machining operations ordinarily performed upon a separate pump casting would be combined with and made incidental to the operations performed upon the engine block casting. Intensive investigation has revealed that while the accurate porting arrangement required by this pump construction can be performed readily upon a small separate pump casting it is not commercially feasible to make the necessary port coring operations upon a casting the size of an engine cylinder block. That is to say, while the pump rotor pocket could be readily having a pump housing or pocket cast integral therewith and adapted to receive a separate pump porting plate insert in the pocket. Among the objects of the invention are the provision of a separately formed pump porting plate cast or blanked from steel including a locating pin thereon for suitably indexing and restraining the port plate in a pump pocket into which it may be introduced, and that is cast integral with an engine block; the provision in an engine block construction as above described providing integral fluid passages to and from the pump pocket, including means for receiving the operating parts of the pump in associated relation with the engine mechanism, and cover means, for retaining the pump mechanism in the engine block, readily accessible from the exterior of the block.

Further and other objects and advantages reside in the novel combination and arrangement of parts to be hereinafter described when considered in conjunction with the drawing forming a part of this specification and pointed out with particularity in the appended claim.

In the drawing like reference characters denote corresponding parts throughout the several views, and in which:

Fig. 1 is a vertical sectional view through a portionof an engine block illustrating one form of this invention with a pump housing cast integral therewith and including a separate porting plate; and

Fig. 2 is an elevational view of the pump boss cast integral with theblock of Fig. 1, showing the pump cover. removed to expose the rotors therein; and

plate removed, revealing the countersunk pump pocket cored in the pump boss; and

Fig. 4 is an elevational view of one form of separate porting plate insert and locating pin for indexing the same when introduced into the pump pocket of Fig. 3; and

Fig. 5 is a vertical sectional view of the porting plate of Fig. 4, illustrating the ports therethrough, and taken substantially on the line 5-5 thereof.

Now having reference to the drawing, and particularly Fig. 1, there is shown an engine block, generally designated l0, which has an oil sump or crankcase secured therebelow. Projecting from a lower wall of the block III, adjacent the oil sump II, at any suitable angle is a boss |2 which has been cast integral with the engine block. Concurrently with the operations performed upon the engine block casting the boss I2 is cored out to provide a countersunk pump pocket1|3 therein. From the countersunk face of the pump pocket extend inwardly a pair of passages l4 and I5, which may be holes readily drilled along with the other operations performed upon the block, and provide the inlet and outlet for oil to and from the pump, respectively. Communicating with the inlet passage H is another passage |6 drilled in the block and in the ceiling over the oil sump, from whence extends an oil pipe conduit secured thereto at its upper end by a fitting l8 and having its lower end extended deep down into the oil sump II with a filter screen l9 over the pipe end to strain the oil inducted thereinto. The outlet passage l5 communicates with a rifle drilled oil gallery or is shown a separately cast passage 20 which conducts lubricant under pressure to the several parts-of the engine such as the camshaft bearings, crankshaft bearings, tappets, connecting rods, etc. (not shown).

In order to connect the pump mechanism with an operable part of the engine a third passage 2| also is drilled inwardly of the boss l2, from the face of the countersunk pocket |3 therein, into the hollow interior of the block l0 and which serves as a journal for pump shaft 22, upon the inner end of which is fixed a spiral gear 23 that meshes with a complementary gear 25 on the camshaft 24 of the engine to be driven thereby. Upon the outer end of the pump shaft 22 a pump rotor 26 is press-fitted, or, in this instance, as best shown in Fig. 2, is fixed by the key 28. Surrounding the male pump rotor 26 is a female rotor 2'! which has'a running fit in the pocket l3.

It will be apparent that the female rotor 21 has one more internal cavity or tooth than the number of complementary shaped teeth on the male rotor 26 and are so dimensioned relative to each other that the male rotor which is mounted eccentric with respect to the female rotor, moves the same ahead of it progressively and continuously forming suction and compression phases which are accurately timed with respect to the separate porting plate insert, about to be described, and thus provides a continuous flow of lubricant under pressure when being driveryby the engine camshaft 24 through gear 23 on the pump shaft 22. The female and male rotors are provided with contours, such that the teeth of each in theory wipe or make continuous travelling contact over those of the other during rotation. Since the pump frotors or operation thereof form no part of this invention the above provides a brief description of the actual pump operation suflicient for the purposes of this specification.

Figs. 3, 4, and 5 there 7 ported plate, generally designated 30, which is arranged to be seated in the countersunk pocket l3 of the engine block boss l2, overlying the inlet and outlet passages and |5 therein and indexed relative thereto by the pin 3|, on the plate 30, in serted in'the blind hole 32, in the countersunk pocket I3. The ports 33 and 34 extended through the plate 30, and communicating with engine block the inlet and outlet passages l5 and I6 adjacent one face and the rotor parts 25 and Now having reference to 21 on the opposite face, are substantially crescent shaped and accurately cast, machined or blanked to secure the proper timed correlation between the rotor parts. A further circular through opening 35 in the ported plate 30 provides a running fit for the pump shaft 22 threaded therethrough. Obviously, of course, the shape of the ports 33 and 34 may vary according to the requirements desired in the finished pump to meet certain operating conditions and the specific form shown is merely for purposes of illustration. In some instances it may be possible to blank the ported plate 30 accurately out of steel or other suitable metal, andthe particular type of separate ported plate used whether cast and machined, or blanked from sheet metal, is immaterial for the purposes of this invention.

In assembly, the porting plate 30 is seated in the countersunk pocket ll, of the engine block boss I 2, and properly indexed with respect to the eccentricity of the rotors and registering with the underlying inlet and outlet passages l4 and H by the locating pin 3| and blind hole 32 for receiving and stationarily retaining the same. The pump shaft 22 with attached gear 23 is journalled in the drilled passage 2| of the block and threaded through the opening 35 in the ported plate 30. The driving rotor 28 is then keyed or fixed on the end of the shaft and meshed with driven rotor 21. Upon the outer face of the engine boss I2 is an annular countersunk rubber-like gasket 31 over which in sealing relation is a cover member 38 retained in place by any suitable fastening means 39- From the foregoing disclosures it will be apparent there has been provided an engine block cast with an integral pump boss thereon which may be cored out and operated upon incidental to the usual machining operations performed upon the block in a most economical manner, that is adapted to receive a novel separately cast or prefabricated pump Porting plate and other necessary pump parts, and which accomplishes among other things the objects and advantages of the invention first enumerated. It is to be understood, however, the specific form of the tration, as many other fonnal modifications and mechanical equivalents will present themselves in actual practice, which will come within the spirit and substance of the broad invention as defined by the scope of the following claim.

What I claim is:

In an engine block construction, a pump boss cast integral therewith and adapted to be operated upon incidental to machining operations performed upon the block in reducing it to finished form-so as to provide a counterbore including inlet and outlet passages therein, a shaft bore terminating in said counterbore, a shaft housed in the shaft bore including a driv'e connection upon the inner end adapted to be meshed with a driving means in the engine, an inlet conduit in registration with the inlet passage in aid counterbore, matched male and female toothed pump rotor parts adapted to be inserted in said counterbore with said male rotor secured to-said shaft for rotation of said rotors by said driving means in eccentric relation to each other thereby forming chambers which. expand and contract, and a separately fabricated porting plate adapted for insertion in said counterbore including means to restrain said porting plate in indexed relation to the eccentricity between said rotor parts and

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