US3312169A

US3312169A - Pump

Info

Publication number: US3312169A
Application number: US426116A
Authority: US
Inventors: Harold B Schultz
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1965-01-18
Filing date: 1965-01-18
Publication date: 1967-04-04
Anticipated expiration: 1984-04-04
Also published as: GB1123570A; FR1464422A

Description

April 4, 1967 H. B. scHuLTz 3,312,169

- PUMP Filed Jan. 18, 1965 2 Sheets-Sheet 1 INVENTOR.

kw/4M April 4 1967 H. B. scHuL'rz 3,312,169

PUMP

.950 /4/6 ya 2524 0a 75a. 76

I N VENTOR.

HAROLD 5. SCh'l/LTZ H T TOE/VE Y of Delaware Filed 1an. 18, 1965, Ser.. No. 426,116 6 Claims. (Cl. 103-37) This invention relates to la hydraulic pump, and more particularly to a hydraulic pump which incorporates a pressure regulator and is provided with ported induction features.

` Several problems of varying degrees of severity have arisen in the early phases of development of high pressure, small displacement, hydraulic pumps. These included high speed piston float, failure to limit positively the maximum pump pressure, and poor pump priming characteristics caused by large clearance volume in the pumping chamber in combination with fluid aeration. It is, therefore, a principal object of my invention to provide an inexpensive, economical and practical pump solving all the aforesaid problems.

It is a further specific object of my invention to provide a pump with :a regulating valve which maintains a predetermined maximum output pressure.

It is yet another object of my invention to provide a pump having a smaller clearance volume for a pump inlet valve .arrangement by utilizing the principle of ported induction.

Yet, still another 'particular object of my invention lies in the provision of a pressure balanced cylinder assembly which moves out as Iaccumulator pressure acting on a small piston exerts a force great enough to overcome that of a regulating spring on the cylinder assembly whereby the inlet for the pump is always open whereby the displacement volume of the pump may be regulated in accordance with the needs of a system therewith associated.

Other objects and advantages of my invention will appear from the following description of the drawings in which:

FIGURE l is a schematic presentation of a power braking system utilizing a pump in accordance with the principles of my invention;

FIGURE 2 is a cross-sectional view of a pump embodying features in accordance with the principles of my invention; and

FIGURE 3 is ya cross-sectional view of a modified form of pump embodying principles of my invention.

Referring particularly to FIGURE l, `a power brake system as shown comprising a power brake control valve 19 having split fluid discharge ports 12 and 14 and a single inlet port 16 receiving fluid from a conduit 1S that is connected with :a fluid discharge side of an accumulator 20 which is connected to a pump 22 designed in accordance with the principles of my invention. As seen, the pump 22 is communicated to the accumulator by means of a conduit 24 and to a fluid reservoir 26 by means of a conduit 28. The fluid reservoir 26 is also communicated with the control valve in order to replenish fluid supply therewithin when the control valve is in the released attitude shown.

The control valve is operated by means of a brake pedal 30 connected thereto by means of push rod 32.

The fluid discharve ports 12 and 14 are communicated to wheel cylinders 34 and 36, respectively, of a front brake means 3S and a rear brake means 40, respectively.

The pump 22 is driven by means of a fan belt 42 from a vehicle engine (not shown) that rotates a pulley 44 keyed or otherwise axed to a pumpshaft46.

The fluid discharge conduit 24 is connected to the pump at a fluid discharge port 48; whereas the reservoir ired States Patent O ICC conduit 23 is connected to the pump 22 at a reservoir port 59. The pump may be mounted to the aforesaid engine by means of the

mounting flanges

52 and 54 formed on the pump housing.

Referring now to FIGURE 2, I show across section of my pump 22 showing it to be constructed generally from a tubular housing 56 having a radially open end 58 and an axially open end 60 which is threaded as at 62 to receive a plug 64. The radial opening is closed by means of a filler cap 66 held in place by ia split ring 68 which filler cap is formed with a means to receive conduit 28y to supply reservoir fluid to the cavity within housing 56. The housing is also provided with journal bearings (not shown) which receive the shaft 46 of the pulley 44. As seen in FIGURE 2, the shaft 46 is provided with an eccentric throw 79 on which 1a pitman 72 is journaled so that rotary motion for shaft 46 will transmit reciprocatory motion to pitman 72.

The pitman 72 is formed with a spherical surface 74 to receive a spherical rod end 76 for a piston 78.

The piston 78 is reciprocatorily arranged within a cylinder assembly that includes a cylinder block 80, a cylinder head 82 which is joined to the cylinder block as by the threads 34, a sleeve 86 formed with radially displaced axial openings 88 and a central opening 99 which is sized to slip over an annular base projection of the cylinder block S9 and abut upon a radial flange of the cylinder block, as seen. The aforesaid cylinder Aassembly is biased by means of -a spring 92 bearing upon a spring retainer bearing plate 94 which is operatively connected to the cylinder block to the right as viewed in FIGURE 2 to project from the plug 64.

The cylinder head 82 is formed with a discharge cavity 96 ahead of the innermost end of the cylinder block, which cavity is communicated by means of a tube 98 to a passage 100 in an annular fitting 102 positioned within an axial bore 104 within the plug 64, as by a bearing 106 and snap ring 108. The fitting 162 is provided with a peripheral seal 119 and an inner seal 112. The inner seal 112, as well as the bearing 106i, cooperates with the tube 98 to prevent fluid discharge pressure Ifrom leaking out of the passage 100 and to support the tube 9S in the plug 64.

In the constructions shown by FIGURES 2 and 3 l have equated the outer diameter of tube 98 to the outer diameter of piston 78. By virtue of the fact that these diameters are equal, any pressure in the pumping or discharge cavity 96 and passage 190 does not disturb a balanced condition created by biasing spring 92 against a piston 126.

It has been my experience that if one does not equate the diameters of the aforesaid members, then the designer is forced to utilize a large spring and a large piston to minimize :the unbalance effects caused by pumping. Therefore, I have been able to produce a compact and efficient pump Without utilizing spring loads which aggravate assembly problems.

The passage 100 is closed by means of a check valve 114 held thereagainst by a spring 116 that is compressed between the check valve 114 and a plastic fitting 118 abutting `the -axial end of the bore 164 in the plug 64. The fitting 118 is provided with radial passages 120 so that upon opening of the check valve 114 as by discharge pressure in passage 11MB greater than the compressive force of spring 116, fluid will flow outwardly into an annular chamber 122 which is open to an axial passage 124 through the plug 64 leading to the discharge port 48.

Centrally of the fitting 118 l have provided a pressure responsive member or piston 126 that is subjected to the pressure passing through check valve 114 at one end thereof and bears upon a cross pin 128 at the other end thereof.

The cross pin 128 is connected to the sleeve 86 by a tight fit therewith and to the plug 64 through an elongated slot 130. The cylinder block Sti is provided with a radial fluid inlet passage 132 which is located to communicate when assembled to the cylinder head 82 with a radial opening 134 in the cylinder head that is open to an inlet chamber 136 between the sleeve S6 and the cylinder block and cylinder head. As seen, the chamber 136 is communicated by means of axial openings 88 to a reservoir chamber 138 to be lled with a hydraulic fluid or the like.

In FIGURE 3 I -have shown a slight variation of the aforesaid pump assembly wherein a housing 55a is provided with

internal passages

13S, 140 and 142 so that fluid within the discharge chamber 12251 may be communicated to the pressure responsive member 12661 that is located remotely from the plug 64a and operative against a bearing plate 144 for pushing the sleeve 86a that is in abutment with cylinder block Stia against the compressive force of the spring 92a to function similarly to that of the pump of FIGURE 2 which will be explained below. The subscript a indicates similar elements as presented in FIGURE 2.

Two other features that distinguish the construction of FIGURE 3 from that of FIGURE 2 are the use of an additional spring retainer 146 to abut on the right face of the plug 64a and in the use of a spring clip 14S for retaining the spherical end 7dr: of the piston '78a to the pitman 72a, which connection in FIGURE 2 was by means of a simple snap t.

More simply stated, in the embodiment of FIGURE 2 We pull the sleeve 36; whereas in the embodiment of FIGURE 3 we push the sleeve 36a.

In operation, the shaft 46 is rotated by pulley 44 through drive belt 42 to reciprocate the eccentric 70 and thereby reciprocate piston 78 within the cylinder block and cylinder head. As seen, the piston 78 never fully opens the radial port 132 in the cylinder block and in the rest position, or rearward position, as shown, allows fluid to enter through the cylinder head into the cylinder block ahead of the piston. Upon moving inwardly of the cylinder block, the piston closes off the inlet and pressurizes the uid brought therein until sufcient pressure is reached to open a discharge valve 150 against its spring 152 whereupon fluid will pass through the tube 98 into the passage 100. Until the pressure in t-he accumulator builds up to a predetermined amount, the fluid within the passage 10G will open the check valve 114 to ow through lthe plug 64 to the accumulaton However, when a predetermined pressure in the accumulator has been reached, the pressure responsive member 126 will be caused to move to the left to push |the pin 128 and pull the cylinder 86 to the left also. This has the effect of reducing the displacement Volume 0f the piston 78 as the cylinder block is caused to move to a position where the inlet 132 and companion inlet 134 in the cylinder head 82 is held open for an increasing portion of the pumping cycle. When accumulator pressure reaches system pressure, the induction port (132 and 134 combined) is held open for the full pumping cycle and pump displacement is reduced to zero.

I claim:

1. A pump comprising:

a housing having an internal bore which is threaded at one end thereof;

a reciprocating piston operatively connecte-d in said housing at the end opposite that which is threaded;

a cylinder assembly operatively connected to said housing by said threads thereon including,

a threaded plug member having a discharge passage and a discharge port communicated therewith which is communicated with an annular discharge chamber, said plug also having an elongated slot therein,

a sleeve operatively connected to said plug by a cross pin that extends through said elongated slot of said plus,

a cylinder block and head assembly operatively connected to said plug by a spring that causes abutting relationship of said block with said sleeve, said cylinder block and head assembly having an internal bore receiving said reciprocating piston, said internal Ibore of said cylinder block and head assembly being open radially to a chamber formed within said sleeve about said cylinder block and head assembly which radial opening is located to be open by said piston when said piston is at the bottom of its reciprocatory motion to allow fluid to enter said bore ahead of said piston,

a discharge valve means operatively associated with said bore in said cylinder block and head assembly which is operable upon the creation of a predetermined pressure within said bore to discharge iiuid from said cylinder block and head assembly, and

a tubular means of equal diameter as said piston, said tubular means operatively connecting said cylinder block and head assembly t-o said annular chamber in said plug.

2. A pump according -to claim 1 and fur-ther comprising a pressure responsive member operatively connected to said pin and to said annular chamber in said plug so as to compress said spring holding said cylinder block and head assembly to said plug whenever the pressure acting upon said pressure responsive means is greater than the compressive resistance of said spring to thereby move said radial port of said cylinder block and head assembly forwardly of said piston whereupon said port will be held open for an increasing portion of the pumping cycle to reduce the displacement of said pump until the displacement of said pump is reduced to zero when said radial port is open for the full pumping cycle.

3. A pump comprising:

a housing having a reservoir supply port and an axially located internal bore with a radially displaced passage open at one end to said axial bore and at the other end to a closed chamber within said housing;

a plug aixed to an open end of said bore affixed to said housing closing an open end of said bore, said plug having an axial passage and a radial passage leading from said axial passage to said passage communicated with the radial displaced passage in said hous- 111g;

a cylinder block and head assembly having an axial discharge tube and a radial inlet port, which cylinder block and head assembly is biased by a spring away from said plug;

a sleeve for limiting the projection of said cylinder block and head assembly from said plug;

a piston of equal external diameter as said tube, said piston being reciprocatorily arranged within said housing for pressurizing a luid in said cylinder block and head assembly, said piston having a maximum retractile position which would open said radial port to allow fluid to enter said cylinder block and head assembly;

a pressure responsive means responsive to the discharge pressure of said cylinder block and head assembly for positioning said cylinder block and-head assembly within said housing, which pressure responsive means is located in said closed chamber of said housing and operatively connected to said sleeve in opposition to said spring.

4. A pump comprising: a housing having an internal bore with an outlet passage;

a cylinder block and head assembly within said housing, said assembly having an inlet port, a pressure responsive discharge valve and an outlet tube of a predetermined outside diameter operatively connected to the head on the opposite side thereof as the cylinder block with the discharge valve interposed;

a piston operatively connected to the housing and mounted for reciprocation within the cylinder block and head assembly for developing a uid pressure 6. A pump according to claim 4 wherein the operative therein, said piston having a diameter equal to the connection between said pressure responsive mem'ber and predetermined outside diameter of said outlet tube; said sleeve utilizes said spring to position said sleeve as a spring between said housing and said cylinder block well as said assembly within said bore.

and head assembly to position said assembly in said 5 bore; References Cited by the Examiner a means operatively connected to said outlet passage UNITED STATES PATENTS `and said assembly in opposition to said spring to regulate the position of said inlet port, which means 1g; 'llzazram includes a check valve to prevent outlet pressure from returning to said cylinder block and head as- 10 3160102 12/1964 Budzlch 10?*37 3,205,832 9/1965 Daub 103-37 sembly during retractile motion of said piston. 5. A pump according to claim 4 wherein said means LAURENCE V EFNER Pfl-mary Examiner consists of a pressure responsive member and a sleeve operatively connected to said member.

Claims

1. A PUMP COMPRISING: A HOUSING HAVING AN INTERNAL BORE WHICH IS THREADED AT ONE END THEREOF; A RECIPROCATING PISTON OPERATIVELY CONNECTED IN SAID HOUSING AT THE END OPPOSITE THAT WHICH IS THREADED; A CYLINDER ASSEMBLY OPERATIVELY CONNECTED TO SAID HOUSING BY SAID THREADS THEREON INCLUDING, A THREADED PLUG MEMBER HAVING A DISCHARGE PASSAGE AND A DISCHARGE PORT COMMUNICATED THEREWITH WHICH IS COMMUNICATED WITH AN ANNULAR DISCHARGE CHAMBER, SAID PLUG ALSO HAVING AN ELONGATED SLOT THEREIN, A SLEEVE OPERATIVELY CONNECTED TO SAID PLUG BY A CROSS PIN THAT EXTENDS THROUGH SAID ELONGATED SLOT OF SAID PLUG, A CYLINDER BLOCK AND HEAD ASSEMBLY OPERATIVELY CONNECTED TO SAID PLUG BY A SPRING THAT CAUSES ABUTTING RELATIONSHIP OF SAID BLOCK WITH SAID SLEEVE, SAID CYLINDER BLOCK AND HEAD ASSEMBLY HAVING AN INTERNAL BORE RECEIVING SAID RECIPROCATING PISTON, SAID INTERNAL BORE OF SAID CYLINDER BLOCK AND HEAD ASSEMBLY BEING OPEN RADIALLY TO A CHAMBER FORMED WITHIN SAID SLEEVE ABOUT SAID CYLINDER BLOCK AND HEAD ASSEMBLY WHICH RADIAL OPENING IS LOCATED TO BE OPEN BY SAID PISTON WHEN SAID PISTON IS AT THE BOTTOM OF ITS RECIPROCATORY MOTION TO ALLOW FLUID TO ENTER SAID BORE AHEAD OF SAID PISTON, A DISCHARGE VALVE MEANS OPERATIVELY ASSOCIATED WITH SAID BORE IN SAID CYLINDER BLOCK AND HEAD ASSEMBLY WHICH IS OPERABLE UPON THE CREATION OF A PREDETERMINED PRESSURE WITHIN SAID BORE TO DISCHARGE FLUID FROM SAID CYLINDER BLOCK AND HEAD ASSEMBLY, AND A TUBULAR MEANS OF EQUAL DIAMETER AS SAID PISTON, SAID TUBULAR MEANS OPERATIVELY CONNECTING SAID CYLINDER BLOCK AND HEAD ASSEMBLY TO SAID ANNULAR CHAMBER IN SAID PLUG.