US3554678A - High speed hydraulic pump - Google Patents

Abstract

THIS DISCLOSURE RELATES TO A HIGH SPEED, HIGH EFFICIENCY HYDRAULIC PUMP MADE FROM A PLURALITY OF PLATE-LIKE MEMBERS. A PUMP CAVITY FOR A PAIR OF INTERMESHING GEAR MEMBERS IS FORMED IN ONE OF THE PLATES. INLET AND OUTLET CONDUITS ARE PROVIDED TO EITHER SIDE OF THE PUMP CAVITY. A RECYCLE BYPASS LINE CONTAINING A PRESSURE CONTROLLED VALVE IS PROVIDED TO RECYCLE FLUID AT THE OUTLET SIDE OF THE PUMP TO THE INLET SIDE IN THE EVENT THAT BACK PRESSURE AT THE OUTLET EXCEEDS THAT OF THE INLET BY A PREDETERMINED AMOUNT. ALIGNING PINS EXTEND INTO OR THROUGH ALL OF THE PLATES TO ENSURE PRECISE ALIGNMENT OF THE PUMP PARTS THEREBY PERMITTING SMALLER TOLERANCES TO BE USED IN THE PUMP CAVITY. O-RING SEALS ARE PROVIDED BETWEEN EACH OF THE PLATES TO AVOID EXTERNAL LEAKAGE OUTSIDE THE CAVITY.

Description

United States Patent Ofiice 3,554,678 Patented Jan. 12, 1971 3,554,678 HIGH SPEED HYDRAULIC PUMP Edward J. Jackoboice and Gerrit H. Kruizenga, Grand Rapids, Mich., assignors' to Monarch Road Machinery Company, Grand Rapids, Mich., a corporation of Michigan Filed Oct. 16, 1968, Ser. No. 780,925

Int. Cl. F04c 1/08 US. Cl. 418-206 9 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a high speed, high efiiciency hydraulic pump made from a plurality of plate-like members. A pump cavity for a pair of intermeshing gear members is formed in one of the plates. Inlet and outlet conduits are provided to either side of the pump cavity. A recycle bypass line containing a pressure controlled valve is provided to recycle fluid at the outlet side of the pump to the inlet side in the event that back pressure at the outlet exceeds that of the inlet by a predetermined amount. Aligningfpins extend into or through all of the plates to ensure precise alignment of the pump parts thereby permitting smaller tolerances to be used in the pump cavity. O-ring seals are provided between each of the plates to avoid external leakage outside the cavity.

This invention relates to a high speed, high efliciency hydraulic. pump.

High speed hydraulic pumps heretofore developed reach a maximum operating speed of about 3,300 r.p.m. After that, the efficiency drops down and the pumps begin to become excessively overheated. Further, in order to operate most pumps efficiently, special and expensive hydraulic fluid is required.

It is an object of this invention to provide a high speed, high volume, and highly efiicient hydraulic pump.

It is a further object of this inventionto provide a high speed pump which operates efficiently with motor oil, transmission oil, and does not require expensive hydraulic fluid.

It is a further object of this invention to provide a pump which can operate at speeds in excess of 5,000 r.p.m. without excessive heat buildup.

Other aspects, objects, and the several advantages of this invention are apparent to one skilled in the art from a study of this disclosure, the drawings, and the appended claims.

According to the invention, there is provided a high speed, high volume hydraulic pump formed from a plurality of plate members including a base member, a cylinder plate member and a suction plate member. The cylinder plate is fixed between the base member and the suction plate member. A pump cavity is formed in the cylinder plate member and intermeshing gear means are provided within the pump cavity having close tolerances between the walls of the pump cavity and the outer portions of the gear means. A drive shaft extends through the base and engages one of the intermeshing gear means. An inlet conduit means is provided in the suction plate member, the inlet conduit communicating with the pump cavity at an intake side of the point of the meshing of the gear means. An outlet conduit communicates with the pump cavity at an opposite side of the meshing of the gear means so that liquid in the inlet conduit means will be pumped to the outlet conduit means as the gear means rotate within the pump cavity.

According to one aspect of the invention, axial aligning pins are provided in the base member and extend through the cylinder plate member and into at least a portion of the suction member thereby ensuring precise alignment of the base member and the suction plate member so that close tolerances can be maintained between the walls of the pump cavity and the outer portions of the gear means.

According to another aspect of this invention, a recycle conduit is provided in the base member, the recycle conduit communicating at one end with one side of the point of meshing of the gear means and at the other end with the opposite point of meshing of the gear means. Biased check valve means are provided in the recycle conduit to permit fluid to flow from the discharge side to the intake side when the pressure at the discharge side exceeds that of the intake side by a predetermined value.

In another aspect of the invention, O-rings are provided between each plate in the pump to seal oh the pump chamber against leakage.

In still another aspect of this invention, a removable wear plate is provided between the base and the cylinder plate member, the wear plate having a bearing surface for the gear means. The Wear plate can be replaced when the gear means wear down the surface of the wear plate.

In still another aspect of the invention, each gear means has eleven teeth which are frustro-conically shaped, the sides of each tooth being bowed outwardly.

The invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a pump which embodies the invention;

FIG. 2 is an exploded view of the pump shown in FIG. 1;

FIG. 3 is a top view of the pump shown in FIGS. 1 and 2 with the top plate member removed and generally seen along lines IIIIII of FIG. 6;

FIG. 4 is a sectional view of the pump shown in FIGS. 1 through 3 generally seen along lines IVIV of FIG. 6;

FIG. 5 is another sectional view of the pump shown in FIGS. 1 through 4 generally seen along lines V-V of FIG. 6;

;FIG. 6 is a side sectional view of the pump shown in FIGS. 1 through 5 as seen along lines VI-VI of FIG. 3; and

FIG. 7 is a sectional view taken along lines VIIVII of FIG. 3.

Referring now to the drawings, there is shown a high speed, high volume hydraulic pump. The pump has a power-driven shaft 12, a base 14, a wear or pressure plate 16, a cylinder plate 18 and a suction plate 20. An inlet line 22 is provided for supplying fluid to the pump which pumps the fluid through an outlet line 24 under pressure.

The power-driven shaft 12 is journalled in the base 14 and the suction plate 20. For this purpose, outer bearings 26 and inner bearings 28 have been provided in the base 14. Bearings 38 are provided in suction plate 20 for rotatably supporting the power-driven shaft 12 in suction plate 20. A washer seal 27 is provided between outer bearings 26 and inner bearings 28 to seal the pump chamber. The outer bearings 26 are provided to protect the seal 27 and to prevent the outer shaft from bending.

The shaft 12 has a longitudinal groove 32 and a pair of circumferential grooves 34 and 36. A first gear member 40 is secured to the power shaft 12 through a keyway 44 positioned in the longitudinal groove 32 and through a pair of retainer rings 62 which are positioned on either side of the first gear member 40 in the circumferential grooves 34 and 36. The keyway 44 locks in an axial groove in the inside surface of first gear means.

The first gear member 40 intermeshes with a second gear member 42 which is supported on an idler shaft 48 in a manner similar to that in which the first gear member 40 is fixed to the power-driven shaft 21. A keyway 46 is positioned in longitudinal groove 54 of the idler shaft 48 and is positioned in a longitudinal groove on the interior surface of the second gear member 42. Retainer rings 62 are positioned in circumferential grooves 50 and 52 of the idler shaft on either side of the second gear member 42 to fix the second gear member 42 longitudinally on the idler shaft 48.

The idler shaft 48 is journalled in base 14 at one end and at suction plate 20 at the other end. To this end, bearings 56 and 58 are provided in base 14 and bearings 60 are provided in suction plate 20.

The base 14 contains an axial bore 64 for the idler shaft 48 and for the bearings 56 and 58. A second axial bore 66 is provided for the power-driven shaft 12 and the bearings 26, 28, and 30. A third axial bore 68 and a forth axial bore 70 are provided for a recycle bypass line. Bore 68 communicates with bore 70 through radial bore 72 and port 74. The flow of fluid through the recycle line is blocked by ball 76 seated against port 74 by the pressure of spring 78 which is held by a threaded retainer plug 80. Threads 82 are provided in the radial bore 72 to threadably engage the retainer plug 80. By this device, the pressure on ball 76 can be adjusted. Therefore, the required differential pressure required to permit flow between bore 68 and 70 is adjustable.

The wear plate 16 contains an annular groove 92 in the bottom face to position an O-ring 86 for sealing the area between the base 14 and the wear plate 16.

The wear plate 16 has axial bores 88 and 90 for permitting passage of power-driven shaft 12 and idler shaft 48 respectively.

The base 14 contains aligning pins 96 and 98 on opposite sides, the aligning pins extending axially parallel to the power shaft 12. The base also contains a plurality of circumferentially spaced threaded bores 100. For simplicity, only two of such bores have been shown (FIG. 5). However, in practice, a plurality of such bores will be spaced about the periphery of the base 12.

The wear plate contains peripheral axial bores 102 and 104 which are aligned with the aligning pins 96 and 98 respectively. Peripheral axial bores 105 are provided, which bores communicate with the threaded bores 100 of base 12. Central axial bores 106 and 108 are also provided for communicating with bores 70 and 68 respectively. An indented slot 107 in the top face of wear plate 16 communicates with axial bore 106. A second indented slot 109 in the top face plate of wear plate 16 communicates with axial bore 108.

An annular groove 94 is formed in the top face of the wear plate 16 for the purpose of seating O-ring 112.

A central pump cavity 114 is axially bored in cylinder plate 18. The pump cavity 114 conforms to the outer periphery of the rotating gear members 40 and 42 except at the points where the gear members intermesh. At that intermeshing point, an inlet lobe 114a is formed at one side of the point where the gears intermesh and an outlet lobe 114b is formed on the opposite side of the pump cavity from the inlet lobe 114a and where the gears intermesh.

Axial bores 116 and 118 are provided at the periphery of the cylinder plate 18 for alignment with the aligning pins 96 and 98 respectively. Axial bores 120 are provided around the periphery of the cylinder plate 118, which bores 120 communicate with the bores 105 and the threaded bores 100.

An annular groove 122 is provided in the top face of the cylinder plate 118 for seating an O-ring 126 to seal the area between the top plate 20 and the cylinder plate 18. To this end, a second annular groove 124 is provided in the bottom face of the top plate 20. The O-ring 26 is also seated in this groove 124.

The suction plate 20 contains an axial bore 128 for receiving the top of aligning pin 96 and an axial bore 130 for receiving the top of the aligning pin 98. Axial bores 132 are also provided in the top plate 18 around the periphery thereof. The bores 132 communicate with the bores 120 of the cylinder plate, with bores 105 of the wear plate 16, and with threaded bores 100' of the base 12. Fastening bolts 142 extend through bores 132, 120, 105 and threadably engage the threaded bores 100 of base 12. In this manner, the base 14, the wear plate 16, the cylinder plate 18 and the top plate 20 can be securely fastened together.

The suction plate 20 is also provided with an inlet bore 134, an outlet bore 136, communicating with the inlet lobe 114a and the outlet lobe 114b respectively. An axial bore 138 is provided for idler shaft 48 and bearing 60. Another axial bore is provided for the power shaft 12 and the bearings 38.

OPERATION In operation, rotational power is supplied to shaft 12 causing rotation of the first and second gear members 40 and 42 in a direction illustrated by the arrows in FIG. 1 and FIG. 3. Any suitable fluid can be supplied to inlet line 22. The fluid will pass through inlet bore 134 and into the inlet lobe 114a. The rotation of the gear members 40 and 42 will carry the fluid around the periphery of the central pump cavity 114 between the teeth. As the fluid reaches the outlet lobe 1141), the fluid is pushed from between the teeth by the intermeshing of the gear members 40 and 42. To this end, the indented slot 107 is provided to facilitate the movement of the fluid from between the teeth as the gears intermesh and into the outlet lobe area 114b. As is illustrated in FIG. 3, the intermeshing of the teeth of the gear members 40 and 42 substantially fill the space between the teeth thereby forcing substantially all of the fluid into the outlet lobe 114b. As the pressure in the outlet lobe builds up, the fluid will flow upwardly through the outlet bore 136 and into the outlet line 24.

When there is a certain amount of back pressure in the outlet line 24, the pressure will build up in the outlet lobe 114b. This pressure will be transmitted to the spring biased ball 76 in port 74 through bores 106 and 68. When the pressure in the outlet lobe 114b exceeds that of the inlet lobe 114a by a predetermined amount, then the pressure will force the ball 76 away from the seat at port 74 thereby permitting flow of fluid from the outlet lobe 114b to the inlet lobe 114a through bores 106, 68, port 74, bores 72, 70 and 109. The pressure differential required to cause recycle can be adjusted by adjusting the threaded retainer plug 80 within the bore 78. With the use of the aligning pin 96 and 98, the central pump cavity 114 and the first and second gear members 40 and 42 can be machined to much closer tolerances. This means that the pump will operate much more efliciently, especially at high speeds.

As illustrated in FIGS. 6 and 7, the thickness of the first and second gear members is substantially the same as the thickness of the cylinder plate 18. The upper face of the wear plate 16 and the lower face of the suction plate 20 therefore provides bearing surfaces for the bottom and top respectively of the first and second gear members 40 and 42. After extensive use of the pump, the bearing surfaces can be machined or the wear plate 16 and/or the top plate 20 can be replaced without replacing the entire pump.

The use of the O-ring seals between each of the plates maximizes the tightness of the pump cavity to thereby prevent external leakage of the fluid used in the pump.

In the preferred embodiment of the invention illustrated in the drawings and heretofore described, each gear member 40 and 42 contains eleven teeth equally spaced about the periphery. Each tooth is generally frusto-conically shaped and spaced at the base from an adjacent tooth a distance substantially equal to the width of each tooth at the peak. By this construction, substantially complete removal of the fluid between the gear teeth is effected. It has further been found that the elficiency and speed of operation can be improved by providing each tooth with sides bowed outwardly toward adjacent teeth. This construction is seen more clearly in FIG. 3.

As an example of suitable gears, the following specifications are given: H.O.B. ll, 1 2D.P., 14 /2P.A., 1.211 plus .000 minus .001 over 0160 pins.

SPECIFIC EXAMPLE A pump constructed according to the invention and as set forth in the preceding specification was tested according to the following procedure: the pump was connected to a three inch by six inch double acting hydraulic cylinder having a 42.36 cubic inch displacement. Transmission oil type A at 80 F. was used in the system; The gear size was A inch. Various back pressures were set on the cylinder and the time to completely displace the piston in the cylinder was measured. The power input was measured. The following is a tabulation of the results of th1s test:

TYPE FLUID: TRANSMISSION OIL TYPE A Displace Back per pressure Volume Percent Time second p.s.i.a. (gaL/min.) efiiciency (sec.) (cu. in.)

As can be seen from the above table, the pump 0perated at high efficiencies (up to 62.2%) at back pressures up to 1500 p.s.i. and at speeds of 5.1 cu. in./sec. The pump according to the invention is thus able to move efficiently high volumes of liquid at hydraulic back pressures at high speeds.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, the drawings, and the appended claims without departing from the spirit of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A high speed, high volume hydraulic pump formed from a plurality of plate members including a base member, a cylinder plate member, and a suction plate member, said cylinder plate member being fixed between said base member and said suction plate member; a pump cavity formed in said cylinder plate member; intermeshing gear means within said pump cavity having close tolerances between the walls of said pump cavity and outer portions of said gear means; a drive shaft extending through said base and rigidly fixed on one of said intermeshing gear means; an outlet conduit means in said suction plate member communicating with said pump cavity at an intake side of the point of meshing of said gear means; an outlet conduit communicating with said pump cavity at an opposite point of meshing of said gear means, so that liquid in said inlet conduit means can be pumped to said outlet conduit means as said gear means rotates within said pump cavity, the improvement which comprises: axial aligning pins in said base member extending through said cylinder plate member and into at least a portion of said suction plate member, thereby ensuring precise alignment of said base member, said cylinder plate member, and said suction plate member, whereby close tolerances can be maintained between the walls of said pump cavity and the outer portions of said gear means, and O-ring seal means between each of said plate members to seal off said pump cavity to prevent leakage of fluid from said pump cavity.

2. The high speed, high volume hydraulic pump of claim 1 further comprising: a recycle conduit in said base member communicating at one end with said one side of the point of interengagement of said gear means, and at the other end with said opposite point of engagement of said gear means; and biased check valve means in said recycle conduit to permit fluid to flow from said discharge side to said intake side when the pressure at said discharge side exceeds that of said intake side by a predetermined value.

3. The high speed, high volume hydraulic pump of claim 1, wherein said gear means have a thickness substantially the same as said cylinder plate, and further comprising a wear plate member between said cylinder plate and said base member, said wear plate forming a bearing surface for said gear means, whereby said wear plate member can be replaced or machined as said bearing surface wears to maintain close tolerances within said pump cavity.

4. A high 'speed, high volume hydraulic pump according to claim 1, wherein each of said gear means has eleven.

equally spaced teeth, each tooth being generally frustroconically shaped, each tooth being spaced at the base from an adjacent tooth a distance substantially equal to the width of each tooth at the peak.

5. A high speed, high volume hydraulic pump according to claim 4 wherein the sides of each tooth are bowed outwardly toward adjacent teeth.

6. A high speed, high volume hydraulic pump according to claim 1, wherein each of said gear means has a plurality of equally spaced teeth, each tooth being generally frustro-conically shaped, each tooth being spaced at the base from an adjacent tooth a distance substantially equal to the width of each tooth at the peak, and the sides of each tooth are bowed outwardly toward adjacent teeth.

7. A high speed, high volume hydraulic pump formed from a plurality of plate members including a base member, a cylinder plate member, and a suction plate member, said cylinder plate member being fixed between said base member and said suction plate member; a pump cavity formed in said cylinder plate member; intermeshing gear means within said pump cavity having close tolerances between the walls of said pump cavity and outer :portions of said gear means; a drive shaft extending through said base and engaging one of the said intermeshing gear means; an inlet conduit means in said suction plate member communicating with said pump cavity at an intake side of a point of meshing of said gear means; an outlet conduit communicating with said pump cavity at an opposite point of meshing of said gear means, so that liquid in said inlet conduit means can be pumped to said outlet conduit means as said gear means rotate within said pump cavity; the improvement which comprises:

a recycle conduit in said base member communicating at one end with said one side of a point of meshing of said gear means, and at the other end with said opposite point of meshing of said gear means; and

biased check valve means in said recycle conduit to permit fluid to flow from said discharge side to said intake side when the pressure at said discharge side exceeds that of said intake side by a predetermined value.

8. A high speed, high volume hydraulic pump formed from a plurality of plate members, said pump comprising:

a base member, a wear plate member, a cylinder plate member, and a suction plate member, said wear plate member being in face to face contact with said base member, said cylinder plate member being fixed between said wear plate member and said suction plate member;

a pump cavity formed in said cylinder plate member;

intermeshing gear means within said pump cavity having close tolerances between the walls of said pump cavity and outer portions of said gear means, said gear means including a plurality of equally spaced teeth, each tooth being generally frustro-conically shaped, with the sides thereof bowed outwardly toward adjacent teeth, each tooth being spaced at the base from an adjacent tooth a distance substantially equal to the width of each tooth at the peak;

a drive shaft extending through said base and rigidly engaging one of the said intermeshing gear means;

an inlet conduit means in said suction plate member communicating with said pump cavity at an intake side of a point of meshing of said gear means;

an outlet conduit communicating with said pump cavity at an opposite point of meshing of said gear means, so that liquid in said inlet conduit means Will be pumped to said outlet conduit means as said gear means rotates within said pump cavity;

axial aligning pins in said base member extending through said wear plate member and said cylinder plate member and into at least a portion of said suction plate member thereby ensuring precise alignment of said base member, said wear plate member,

said cylinder plate member and said suction plate member, whereby close tolerances can be maintained between said walls of said pump cavity and the outer portions of said gear means;

a recycle conduit in said base member communicating at one end with said one side of a point of meshing of said gear means, and at the other end with said opposite point of meshing of said gear means;

biased check valve means in said recycle conduit to permit fluid to flow from said discharge side to said intake side when the pressure at the discharge side exceeds that of said intake side by a predetermined value;

said gear means having a thickness substantially the same as that of said cylinder plates; and

O-ring seal means between each of said plate members to seal off said pump cavity to prevent external leakage of fluid from said pump cavity.

9. A high speed, high volume hydraulic pump according to claim 8 further comprising indented slots formed in said wear plate at either side of meshing of said gear means to permit pressure relief at those points.

References Cited UNITED STATES PATENTS 1,912,737 6/1933 Svenson 103l26(BY) 2,395,824 3/1946 Herman l03l26(M) 2,842,006 7/1958 Edman 103126(H) 3,096,719 7/1963 McAlvay 103-126(H) 3,128,710 4/1964 Blomgren et a1. 103-126(BY) 3,170,408 2/1965 Hill et a1 l03l26(BY) MARK NEWMAN, Primary Examiner W. J. GOODLlN, Assistant Examiner

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