US2775206A - Pump - Google Patents

Description

Dec. 25, 1956 LA VERN R. CONNELLY ,2 6

PUMP

Filed March 7, 1955 4 Sheets-Sheet l INVENTOR. LAVERNR. CONNELLY ATTORNEYS Dec. 25, 1956 LA VERN R. CONNELLY 2,775,206

ATTORNEYS LA VERN R. CONNELLY Dec. 25, 1956 PUMP 4 Sheets-Sheet 3 Filed March 7, 1955 .lllillll INVENTOR.

LAVERNRCONMELLY ATTORNEYS 1956 LA VERN R. CONNELLY 2,775,206

PUMP

4 Sheets-Sheet 4 Filed March 7; 1955 INVENTOR. LAVERNRCONNEL-LY Fig. 8

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ATTORNEYS United States Patent PUMP La Vern R. Connelly, Marshall, Mich., assignor to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application March 7, 1955, Serial No. 492,717 Claims. (Cl. 103-42) This invention relates to rotary pumps and pumping units of the positive displacement type adapted to be driven by a vehicle engine for supplying actuating fluid under pressure to a hydraulic power steering motor or other auxiliary device to be actuated.

This application is related, as to subject matter and ownership, to earlier applications Serial No. 261,654, filed December 14, 1951, now Patent No. 2,724,335, issued November 22, 1955, and Serial No. 383,318, filed September30, 1953. j A rotary pump being driven and used in this manner is subjectto operation at widely varying speeds. The output capacity of the pump must be suflicient to meet the requirements of the auxiliary device during low speed operation of the vehicle, and accordingly, the pressure and volume values of the pump delivery during high speed operation of the vehicle are usually considerably in excess of the requirements of the auxiliary device.

The auxiliary device is usually contained in a closedloop external circuit through which fluid is forced by the pump and the excess fluid is by-passed from the discharge side of the pump to the intake side thereof. The present invention is particularly concerned with valve control bypassing of this excess fluid and, as one of its objects, aims to provide a rotary pump having novel flow directing means incorporated therein by which the by-passed fluid is returned to the intake side of the pump with minimum turbulence and noise. Another object is to provide a rotary pump having novel flow directing means by which the by-passed fluid is returned to the intake side in a manner such that the velocity and direction of the stream of by-passed fluid will assist the flow of intake fluid into the intake port of the pump and such that the energy of thehigh velocity fluid be utilized in increasing the pressure head of the fluid in the intake at points downstream from the junction point of the stream of by-passed fluid with the stream of normal supply intake fluid.

Still another object is to provide a rotary pump having novel flow directing means for the purpose mentioned above and which comprises venturi means located in the intake passage and substantially opposite a junction port connecting the by-pass passage with the intake passage.

A further object is to provide a rotary pump with a flow directing means of the kind above indicated and comprising a venturi sleeve extending along the intake passage and having its external surface defining a deflecting surface against which the by-passed fluid impinges and providing with the wall of the intake passage a passage restriction through which the by-passed fluid must pass.

The invention can be further briefly summarized as consisting in certain novel combinations and arrangements of parts hereinafter described and more particularly set out in the claims hereof.

In the accompanying sheets of drawings, forming a part of this specification:

Fig. 1 is mainly an end elevation of a pumping unit embodying this invention, but with portions of the unit broken away;

Fig. 2 is a partial vertical axial section taken through the pumping unit as indicated by section line 2--2 of Fig. 1;

Fig. 3 is a transverse vertical section taken on the irregular section line 33 of Fig. 2 and showing the bypass valve means;

Fig. 4 is a top plan view of the pumping unit with the reservoir member omitted therefrom;

Fig. 5 is a partial transverse vertical section taken on section line 5-5 of Fig. 2 and showing the rotor chamber andthe gear type rotors thereinj Fig. 6 is a transverse horizontal section taken on section line fi6 of Fig. 4;

Fig. 7 is a transverse vertical section taken on section line 7-7 of Fig. 6;

Fig. 8 is an elevational view showing the flow directing insert in a detached relation; and,

Fig. 9 is an end view of the insert.

The rotary pump 10 which will be presently described in detail is shown in the drawings as forming a part of a pumping unit 11 which supplies hydraulic fluid under pressure to a closed-loop external fluid circuit 12. The external fluid circuit 12 includes an auxiliary or accessory device which is operated by the hydraulic pressure being supplied by the pump 10 and may be a hydraulic power steering device 13 which is here shown only diagrammatically. The external fluid circuit also includes delivery and return conduit members or fittings 14 and 15 by which the rotary pump 10 is operably connected with such circuit.

The pumping unit 11 also includes a reservoir member 16 which is mounted on and supported directly by the rotary pump 10 and defines a reservoir chamber 17 adapted to contain a quantity of the hydraulic fluid. A fitting 18 extending into the reservoir 16 has an axial passage 19 through which fluid being returned from the external circuit 12 is directed into the reservoir chamber 17. The fitting 18 also forms a support for a substantially cylindrical strainer 20 which is disposed around this fitting and through which the returned fluid must pass in flowing into the reservoir chamber.

The rotary pump 10 is provided with a pump housing 22 which is formed by a pair of connected housing sections 22 and 22 The housing section 22 comprises a body member having a rotor chamber 23 therein. This housing section 22* is also provided with a pair of arcuately extending intake and discharge ports 24 and 25 which communicate with the rotor chamber 23 at one end thereof. The discharge port 25 is in the form of an arcuate pocket which can be conveniently referred to as a blind pocket inasmuch as this pocket does not have any intake or discharge passage connected therewith but communicates only with the pumping chambers 35. The housing section 22 forms a cover for the rotor chamber 23 and contains a pair of arcuately extending intake and discharge ports 26 and 27 which communicate with the rotor chamber 23 at the opposite end thereof.

As shown in the drawings, the rotary pump 10 also includes a shaft 28 having its outer end rotatably supported in the housing section 22 by a bushing 29 mounted in the latter. The inner end of the shaft 28 is rotatably supported by a bushing 30 mounted in the housing section 22 As shown in Fig. 2, the inner end of the shaft projects beyond the bushing 30 and also we tends through an annular packing 31 which is mounted in I the housing section 22 adjacent the bushing. The inner end of the shaft 28 is adapted for connection with an available rotating part from which the rotary pump is to valve seat 41. chamber is in communication with the discharge port be driven. The housing section 22 is provided with a flange 32 adapted for connection with an available support on which the rotary pump 10 is to be mounted.

The pump 10 also includes rotor means operable in the rotor chamber 23 for producing a pumping action ported by a cylindrical liner or "bushing 36 mounted in the rotor chamber 23. The inner rotor member 34 is mounted on .the shaft 28 and is connected therewith by the :key 37.

The housing section 22 is provided with an intake passage 38 extending in depending relation from the reservoir chamber 17 and which connects the reservoir chamber with the intake port 24. The housing section 22 is also provided with a return fluidpassage 15 which connects the .return conduit 15 of the external fluid circuit with the passage 19 leading into the reservoir chamber 17. The housing section 22 contains a valve chamber 39which extends in spanning relation to the intake and discharge ports 26 and 27 of this housing member and which contains a suitable by-pass valve means, such as the valve assembly 40 here shown and which will be further described presently.

As shown in Fig. 3, the valve chamber 39 is provided .at an intermediate point thereof with an internal annular Inwardly of the valve seat 41 this valve chamber 39 defines a dash pot cylinder44. The extreme outer end portion of the valve chamber 39 defines a spring chamber and delivery passage 45 through which the pumped fluid being supplied to the external fluid circuit 12 is delivered. The outer end of the valve chamber is closed by the fitting or conduit member 14 which has .a passage 14 therein connecting the delivery passage 45 with the external fluid circuit.

The valve assembly 40 is operable in the valve chamber 39 as a bypass valve means which controls the flow of by-passed fluid from the valve chamber through the passage 43. This valve assembly comprises a volume control valve member 46 and a pressure relief valve member 47. The volume control valve member 46 is a hollow valve member having an axial passage 48 therein and also having radial flow control orifices 49 through which the axial passage is connected with the discharge port 27. At an intermediate point thereof, the valve member 46 is provided with a valve plunger portion 50 which cooperates with ;the valve seat 41. At its inner end, the valve member 46 is provided with a dash pot plunger 51 which is operable in the dash pot cylinder 44. A compression spring 52, located in the delivery passage 45 and disposed between the fitting 14 and the outer end of the valve member 46, acts on this valve member-tending to shift the same in a direction to cause closing movement of the valve plunger portion 50 in relation to the valve seat 41.

At a point adjacent its outer end, the axial passage 48 of the volume control valve member 46 is provided with an internal annular valve seat 53. The volume con:

trol valve member 46 is also provided with radial by-pass .ports 54 adjacent this internal valve seat 53 and which .theouter end portion of the axial passage 48 of the valve member 46 and includes a valve plunger portion 55 which cooperates with the internal annular valve seat 53. A compression spring 56 located in the axial passage 48 of the valve member 46 acts on the pressure relief valve member 47 and urges the same in an outward direction to a position engaging the valve seat 53 for closing the by-pass ports 54.

A spring ring 57 mounted in the valve member 46 retains the pressure relief valve member 47 in the axial passage 48 and forms a stop against which the pressure relief valve member is adapted to be held by the compression spring 56. The pressure relief valve member 47 has an axial passage 58 therein. The axial passage 58 connectes the delivery passage 45 with the discharge port 27 through the axial passage 48 and the radial flow control orifices 49 of the valve member 46.

The valve assembly 40 is more fully disclosed and claimed in copending patent application Serial No. 261,655, filed December 14, 1951. For the purposes of the present invention, it is sufficient to explain that the valve assembly 40 is responsive to the pressure of the spring 52 and the fluid pressure differential across the orifices 49. When the pump 10 is being driven at a relatively high rate of speed, the resultant effect of these pressures causes the valve assembly 40 to be shifted toward the left in opposition to the spring 52 to thereby move the edge 50 of the valve plunger portion 50 past the shoulder 41 of the internal valve seat 41 to thereby cause opening of the volume control valve member 46 for by-passing pumped fluid from the discharge port 27 to the by-pass passage 43 for return to the intake side of the pump. The amount of fluid which is thus bypassed for return to the intake side of the pump is dependent upon the extent of this opening movement of the valve member 46 and will be such that the rate at which pumped fluid will be supplied to the external fluid circuit 12 through the delivery passage 45 will be automatically maintained at. a desired substantially constant va ue.

The pressure relief valve member 47 is responsive to the pressure of the spring 56 and to the fluid pressures acting on opposite ends of this valve member. When the pump 10 is'being operated at higher pressure the resultant eifect of these forces causes the pressure relief valve member 47 to be shifted towards. the right in opposition to the spring 56 to cause an opening movement of the valve plunger portion 55 relative to the by-pass ports 54 for by-passing pumped fluid from the delivery passage 45 to the by-pas's passage 43 for return to the intake side of the pump. The amount of fluid thus by-passed through the bypass ports 54 will depend upon the extent of this opening movement of the pressure relief valve member 47 and will be such that the maximum pressure of the fluid being supplied to the external fluid circuit 12 will be automatically maintained at a desired substantially constant safe pressure value.

In accordance with the present invention, the pumped fluid which is by-passed through the passage 43 by the functioning of the valve members 46 and 47 is returned to the intake side of the pump in a novel manner which Will now be described and by which turbulence in the intake fluid and noise resulting therefrom will be prevented or kept at a minimum, and also by which the velocity of the by-passed fluid can be used to assist the flow of intake fluid to the intake port 24. .The by-pass passage 43 accordingly extends between and connects the valve chamber 39 and the intake passage 38.

In utilizing the by-passed fluid for the purposes just mentioned above, the present invention provides a flow directing means in the pump housing 22 by which the bypassed fluid is directed along the intake passage 38 in a downstream direction, that is, toward the rotor chamber 23. This flow directing means is preferably in the form of a venturi section insert 61 located in the housing section 22 and extending axially in the intake passage 38. The insert 61 is here shown as being an externally fluted open-ended sheet metal sleeve having a relatively tight engagement in the intake passage 38 and whose upper end 61 communicates with the reservoir chamber 17. The lower end 61 extends transversely of a junction port 62 located in the side wall of the intake passage 38 and through which port the by-pass passage 43 communicates with the intake passage.

The lower end 61* of the insert extends fully across the junction port 62 and cooperates with the continuous side wall of the intake passage 38 in defining a restricted annular venturi space or pocket 63 whose lower end is in communication with the intake passage and faces in the downstream direction of the latter, that is, opens toward the rotor chamber 23. The portion of the insert 61 which is located opposite the junction port 62 forms a deflecting means for the by-passed fluid entering the intake passage 38 through the junction port, such that this by-passed fluid will be deflected or directed toward the rotor chamber 23. By reason of the insert 61 and theventuri space 63 provided annularly externally of the inserta suitable restriction is provided efliective to produce a high velocity stream with a corresponding drop in pressure at the venturi throat to help draw fluid from the reservoir through passage 61 of the insert.

The by-passed fluid enters the intake passage 38 through the junction port 62 as a velocity stream and when this velocity stream has been deflected in the downstream direction by the insert 61 so as to pass through the confined annular space 63, the energy of this bypassed fluid will be utilized in accelerating the flow of intake fluid toward the rotor chamber 23 through the passage 61 of the insert and through the intake passage 38. i The Walls of the intake passage 38 are continuous throughout the portion of this passage extending from the junction port 62 to the rotor chamber 23, such that the intake fluid will be confined therein and the energy of the by-passed fluid will be utilized in creating a pressure head in this portion of the by-pass passage tending to accelerate the filling of the pumping chambers 35 with a solid body of intake fluid.

When the by-passed fluid enters the intake passage 38 through the port 62, it is desirable that the mingling or confluence of the stream of by-passed fluid with the stream of intake fluid, take place with minimum disturbance or noise-producing turbulence. To assist in achieving this desired result, the external wall of the insert 61 located opposite the junction port 62, is curved for facilitating a smooth passage of the by-passed fluid into space 63 from whence it passes to mingle with the intake fluid.

In addition to the arrangement of insert 61 in passage 38 and the communication of by-pas's passage 43 with passage 38 by way of confined space 63 adjacent the outlet end of passage 61 in the venturi insert, for pressurizing the intake to chambers 35, means for providing intercommunication of the by-passed fluid by way of chamber portion 39 with intake port 26 is had through a predetermined limited size passage 64. Furthermore the depth of port 26 is made shallow and the communication of passage 64 with port 26 is purposely had at the extreme end of the port timing.

By so limiting the size of passage 64 assistance is given to insert 61 and space 63 in developing the restriction effective to cause a build-up in back pressure so as to reduce any tendency for the fluid to separate at the flow control valve opening point.

From the foregoing detailed description and the accompanying drawings, it will now be readily understood that this invention provides novel flow directing means in a positive displacement rotary pump, and in a pumping unit embodying such a rotary pump, by which fluid being by-passed from the discharge side of the pump to the intake side can be mingled smoothly and with minimum turbulence and noise with the stream of intake fluid. Likewise, it will be seen that this novel flow directing means alsoprovides for utilizing the by-passed fluid as a high velocity stream for assisting the flow of intake fluid to the intake port for maintaining the latter substantially filled at all times and preventing the formation of a vacuum or void condition therein, and for utilizing the energy of the high velocity by-passed fluid for increasing the pressure head of the intake fluid at points downstream from the junction point of the bypass passage with the intake passage. Additionally, it will be understood that this flow directing means is employed in the form of an open ended insert sleeve mounted in the pump housing so as to extend along the intake passage for a portion of the length thereof and with the lower end portion of the insert cooperating with the by-pass passage as a deflecting means eifective on the stream of by-passed fluid and to provide a venturi passageway communicating the by-pass with the fluid intake passage adjacent to the inlet of the rotor chamber.

Although the flow directing means of this invention and the rotary pump and pumping un-it embodying the same have been illustrated and described herein to a somewhat detailed extent, it will be understood, of course, that the invention is not to be regarded as being limited correspondingly in scope but includes all changes and modifications coming within the terms of the claims hereof.

Having thus described my invention, I claim:

1. In a rotary pump, a housing having therein a rotor chamber, two intake passages and a discharge passage communicating with said rotor chamber, rotor means operable in said rotor chamber for producing a pumping action, said housing also having a valve chamber communicating with the discharge passage and a by-pass passage connecting aid valve chamber with the intake passages through a junction port on one axial side of the rotor chamber and through a limited opening in the opposite axial side of the rotor chamber, valve means in said valve chamber and operable to by-pass pumped fluid through said by-pass passage, the first intake passage on said one axial side of the rotor chamber having a side wall which is substantially continuous and imperforate between said junction port and said rotor chamber for confining in said first intake passage the fluid being supplied thercthrough to said rotor chamber, and flow directing means comprising an open-ended sheet metal insert sleeve extending along said first intake passage and having spaced ribs extending longitudinally of said sleeve, one end of said sleeve having a relatively tight engagement in said intake passage and the wall of said sleeve adjacent its other end being spaced from the wall of said first intake passage to provide a venturi and defining with the latter a deflecting space opening toward said rotor chamber and with which said by-pass passage communicates through said port.

2. In a rotary pump, a housing having therein a rotor chamber and intake and discharge passages communicating with said rotor chamber, rotor means operable in said rotor chamber for producing a pumping action, said housing also having a valve chamber communicating with the discharge passage and a by-pass passage connecting said valve chamber with the intake passage through a junction port, valve means in said valve chamber and operable to by-pass pumped fluid through said by-pass passage, said intake passage having a substantially continuous side wall between the junction of said by-pass passage therewith and said rotor chamber for confining the fluid being supplied to said rotor chamber, and flow directing means comprising an insert sleeve extending along said intake passage in transverse relation to said junction point to a point adjacent said rotor chamber, ribbed portions forming a part of the external surface of said sleeve cooperating with said side wall of said intake pasage to provide a venturi intermediate said junction port and said rotor chamber.

3. A pumping unit as defined in claim 2 wherein a second intake passage means is provided, providing for communication between said fluid by-passing means and said rotor chamber axially opposite from the communication of the first intake passage means with said rotor chamber, said second intake passage mean being of predetermined limited size such that in cooperation with the venturi space a build-up in back pressure is attained effective to reduce any tendency for a separation of the fluid at the point of by-pass.

4. A pumping unit according to claim 3 wherein said second intake passage means communicates with said rotor chamber at the extreme end of the port timing of the pump unit.

5. In a pumping unit of the character described, a housing having therein a rotor chamber and intake and discharge ports communicating with said rotor chamber, means defining a reservoir chamber supported directly by said housing at an elevation above said rotor chamber, rotor means operable in said rotor chamber for producing a pumping action, said housing also having intake passage means therein connecting said reservoir chamber with said intake port for supplying fluid to the 3 latter, said intake passage means having a substantially continuous and imperforate side wall for confining in said intake passage means the fluid being supplied therethrough to said intake port, means for by-passing pumped fluid from said discharge port to said intake passage means including a by-pass passage communicating with said intake passage means through a junction port in the side wall means of the latter, and flow directing means comprising an open-ended externally ribbed insert sleeve having its upstream end relatively tightly engaged in said intake passage means adjacent said reservoir chamber and its downstream end extending fully across 'said junction port and defining externally thereof with said side wall an intervening venturi space with which said junction port communicates and Whose open end ,faces in the downstream direction of said intake passage References Cited in the file of this patent UNITED STATES PATENTS 1,806,287 Forrest May 19, 1931: 1,814,613 Woody July 14, 1931 2,724,335 Eames Nov. 22, 1955

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