US 3808814 A
A fluid transmission comprising a variable delivery, rotary pump and a fixed volume hydraulic motor. The rotary pump is operated to supply fluid to turn the hydraulic motor, and as the rotary pump fluid volumetric output is changed the speed of rotation of the hydraulic motor varies. Fluid output variations are accomplished by changing the chamber volume within which the rotor of the rotary pump turns. The chamber volume is varied by moving a pair of housing components having arcuate faces defining opposing chamber walls within which the pump rotor rotates. The pump rotor has a plurality of spaced sliding vanes radiating therefrom and as the rotor turns the vanes are forced outward to be in constant sealing engagement with the opposing arcuate chamber faces. In addition to controlling power output from the hydraulic motor, by directing a greater volume of fluid to the hydraulic motor than it is receiving from the rotary pump the hydraulic motor can be made to act as an opposing pump, to provide a braking action within the fluid transmission.
Description (OCR text may contain errors)
[ FLUID TRANSMISSION Robert W. Macy, II, 802 Second Ave., Rock Springs, Wyo. 82901 22 Filed! Mar. 20, 1972 21 Appl. No.: 235,910
1451 May 7, 1974 Primary ExaminerEdgar W. Geoghegan [5 7] ABSTRACT A fluid transmission comprising a variable delivery, rotary pump and a fixed volume hydraulic motor. The rotary pump is operated to supply fluid to turn the hydraulic motor, and as the rotary pump fluid volumetric output is changed the speed of rotation of the hydraulic motor varies. Fluid output variations are accom-- plished by changing the chamber volume within which the rotor of the rotary pump turns. The chamber volume is'varied by moving a pair of housing components having arcuate faces defining opposing chamber walls within which the pump rotor rotates. The pump rotor has a plurality of spaced sliding vanes radiating therefrom and as the rotor turns the vanes are forced outward to be in constant sealing engagement with the opposing arcuate chamber faces. In addition to controlling power output from the hydraulic motor, by directing a greater volume of fluid to the hydraulic motor than it is receiving from the rotarypump the hydraulic motor can be' made to act as an opposing pump, to provide a braking action within the fluid 6 Claims, 3 Drawing Figures  US. Cl "611/487, 418/31, 418/212, -60/D1G. 10  Int. Cl. F16h 39/46  Field of Search 60/325, 330, 445, 448, 60/465, 466, 479, 487, 489; 418/22, 31, 212, 210
 References Cited UNITED STATES PATENTS 466,661 1/1892 Duncan 60/487 2,141,170 12/1938 Centervall 418/31 2,232,428 2/1941 Benedek 60/465 2,323,926 7/1943 MCGlll 60/489 2,687,049 8/1954 Ebert 60/487 x 2,874,533: 2/1959 Schott 60/489 x 3,663,130 5/1972 Lincks 418/31 FOREIGN PATENTS OR APPLICATlONS transmission 216,525 11/1924 Great Britain 60/489 lOe k PATENTEDIAY 1 i974 SHEU 1 0F 2 FIG lOe
FIG 2 IOCN PATENTEDIAY 71914 v I 3.808.814
sum 2 or 2 FIG 3 1 FLUID TRANSMISSION BRIEF DESCRIPTION OF THE INVENTION 1. Field of the Invention This invention relates to fluid transmissions that utilize variable displacement pumps having a constant or variable speed input and hydraulic motors to produce a variable rotational work output.
2. Prior Art The use of variable displacement pumps to produce desired variations in output speed and torque of a hydraulic motor are well known. Rotary pumps capable of producing varied fluid flow outputs are disclosed by US. Pat. Nos. 2,631,544 and 2,752,851, for example. The pumps disclosed by these patents, like the present invention, obtain a variable output flow rate by varying their pump chamber volumes or the relative position of the pump rotor therein. The means disclosed in these prior patents for varying the pump chamber, or the rel.- ative position of the pump rotor therein, include arrangements that are expensive to produce and that do not provide smooth contact between-the rotor chamber and vanes of the rotor. Nor do any pumps to my knowledge incorporate two inlet and discharge ports that are opposite or 180 from each other to provide a balance thrust on the pump and hydraulic motor rotors. Consequently, undesirable wear of the vanes and of the rotor chamber occur and pressure cannot be maintained.
The present invention attempts to solve these and other inherent problems associated with rotary pumps by providing a device requiring the interaction of a minimum number of easily constructed parts to achieve controlled pump chamber variations and by providing a smooth chamber in which the pump rotor and its vanes can revolve.
SUMMARY OF THE INVENTION It is a principal object of the present invention to provide a rotary pump for use in a fluid transmission such that fluid output can be varied to provide a variable volume of flow to turn a hydraulic motor from which an output power is derived and such that maximum life of the pump chamber and rotor vanes is obtained.
Another object is to provide a variable flow rotary pump having a volume output varied by changing the volume of the chamber in which the pump rotor of the rotary pump turns.
Still another object-is to provide a transmission that can act as a brake, resisting rotational forces applied to the output of the transmission.
Principal features of the present invention include a fluid transmission comprising a rotary pump and a hydraulic motor having fluid input and output ports coupled together directly, to provide a fluid flow therebetween.
A variable output speed of rotation from the hydraulic motor is obtained by varying the fluid flow from the rotary pump even though the rotor speed of the pump is constant. The varying fluid discharge from the rotary pump is achieved by changing the volume of the chamber in which the pump rotor of the rotary pump turns.
Opposing arcuate faces of a pair of blocks that are in overlapping engagement with one another, within the housing of the rotary pump, are arranged to make up the walls of the chamber in which the pump rotor turns.
The pair of blocks are positioned between sides of the rotary pump and slide with respect to the sides towards and away from each other, thereby enlarging o'r reducing the pump chamber. Spaced vanes radiate from around the periphery of the rotor to be in sliding engagement with the opposing arcuate faces of the pair of blocks. A mechanical linkage, operated from a point that is external to the fluid transmission, simultaneously moves the pair of blocks towards and away from each other.
A volume of fluid flowing from the pump to the hydraulic motor normally produces an opposite output rotation of the hydraulic motor from which useful work can be derived. Should however, a greater volume of fluid be present in the hydraulic motor than it is receiving from the pump, then the hydraulic motor will act as a pump. Further reduction of the volume of fluid moving between the rotary pump and hydraulic motor, such as when the size of the ports therebetween are reduced, blocks the outlet flow from the hydraulic motor. This blockage causes the fluid circulating within the hydraulic motor to exert a braking force opposing rotation of the hydraulic motor.
Excessive pressure accumulation within the fluid transmission is avoided by the installation of pressure relief valves in the ports between the rotary pump and the hydraulic motor. Fluid flow losses between the rotary'pump and hydraulic motor may be kept to a minimum by providing relatively short passages or ports between the cavities of the pump and motor. Further flow loss reduction can be effected by polishing or Teflon plated as being the best mode of the invention.
THE DRAWINGS FIG. lis a perspective view of the fluid transmission with the outer housing thereof broken away for clarity;
FIG. 2, a vertical sectional view taken on the line 22 of FIG. 1 and showing the interior of the rotary pump of the transmission; and
FIG. 3, a vertical section view taken along line 33 of FIG. 1 and showing the rotary pump and the coupled hydraulic motor of the transmission.
DETAILED DESCRIPTION Referring now to the drawings:
In the illustrated preferred embodiment of the invention, the fluid transmission has an outer housing shown generally at 10, within which there is included a rotary, variable delivery pumpshown generally at l l, and a hydraulic motor shown generally at 12, FIG. 3. As best shown in FIG. 3, the pump 11 and motor 12 are arranged in a side by side relationship and arrows indicate the direction of fluid flow therethrough. The pump 11 and motor 12 could of course be separate units linked by hydraulic lines, not shown.
The fluid transmission includes an inner casing 13, which is immersed in a suitable transmission fluid within housing 10. However, it should be apparent that other types of fluid reservoirs could be used since it is not necessary that the casing 13 be immersed in the fluid. If however, the inner casing 13 were not im mersed in the fluid then different sealing arrangements than those shown would have to be installed, to retain the fluid within the inner casing.
A conventional combustion engine, or other power source, not shown, is used to turn a rotor shaft 14 that is journaled through wall 13a of casing 13 and through wall 100 of housing 10, FIG. 3. A piston ring type seal 17 surrounds the shaft 14 within wall 13a of casing 13 to keep fluid from leaking out of the casing around the shaft 14. The end of shaft 14 extending through a bearing 19a in the side a of the transmission housing 10 is then adapted to be connected to the power source. Fluid is maintained within the transmission housing 10 by the inclusion of lip type oil seals 14b and 23b around the input and output shafts l4 and 23. Covers 16 held in place by bolts 16a fit over and maintain oil seals 14a and 23b to walls 10a and 10b. A key 20, positioned in a keyway 14a of shaft 14, couples the shaft to a rotor 15, for simultaneous rotation. The other end of shaft 14 is journaled in an enlarged coupling end 21a of hydraulic motor output shaft 23 by a bearing 22. The enlarged coupling end 21 is journaled within a partition 25 that separates the pump 1 1 from the motor 12, by a bearing 24. Bearings 19a and 22 allow shaft 14 to freely rotate and bearing 24 and a bearing 19b in the wall 10b of housing 10 andthrough which shaft 23 is journaled allow the shaft 23 to freely rotate. A piston ring type seal 26 on the shaft 23 engages the wall 13b of casing 13 to prevent fluid loss from the interior of the casing along shaft 23.
As best shown in FIGS. 2 and 3, radiating vanes 27 are slidablymaintained in the rotor 15 and project out- .wardly from the periphery thereof to slidably engage the rotor chamber wall formed by opposing arcuate faces 28a and 29a of blocks 28and 29, FIG. 2. Vanes 27 are slidable within grooves 15a, that radiate outwardly from the rotor 15. As will be further explained, when rotor 15 is rotated, the vanes slide in grooves 15a and the centrifugal force, imported, holds them against the wallof the rotor chamber. A spring or pressure oil passage, not shown, may be provided in each groove 15a in conventional fashion, between the rotor 15 and the vane 27 to further bias the vane out of the groove and into sliding engagement with the opposing arcuate faces 28a and 29a of blocks 28 and 29. Alternatively, other known vane biasing arrangements could be used in lieu of vanes 27 to generate fluid flow within the pump 11.
The volume of fluid discharged by the pump 11 is dependent upon the volumetric size of the chamber and the surface area of the vanes 27 rotated therewithin. Consequently, movement of the blocks 28 and 29 with respect to the rotor 15 to increase or decrease the pump chamber volume will cause greater or lesser projection of the vanes 27 from rotor 15. Blocks 28 and 29 are slidably sandwiched between the casing wall 13a and the partition 25, and the top 130 and bottom 13d of casing 13.
The opposing faces 28a and 29a of blocks 28 and 29 are arcuately formed and have a slightly larger radius than does the outermost periphery of rotor 15 so as to allow operating clearance at the points of tangency of the blocks 28 and 29. Each arcuate face is therefor in proximate contact with the rotor 15 about its entire arc surface when the blocks 28 and 29 are moved inward to a point of close proximity to rotor 15 and the vanes are forced fully into grooves 151;. When the blocks are so positioned the rotor chamber is essentially eliminated. However, as the faces 28a and 29a of the blocks are moved apart the size of the rotor chamber increases. As the faces move apart, the vanes 27 which move outward from the rotor 15 maintain a sliding engagement with the arcuate faces 28a and 29a, as the rotor turns.
The arcuate faces 28a and 29a of the blocks 28 and 29 are formed such that there is a smooth transition from one arcuate surface to the other. Thus, each arcuate face terminates in a feathered edge 30, FIG. 2, at one end and has an elongate surface forming a tangential extension 31 of the arcuate face on its other end. When the blocks 28 and 29 are moved from or towards each other the feathered edge 30 of each block is in sliding engagement with the elongate surface forming a tangential extension of the arcuate face of the other block. Close fitting, smooth joints are thereby formed between the feathered edges 30 and tangential extensions 31.- When the shaft 14 within rotor 15 is turned in the proper direction by its coupled power source,
i.e., clockwise in FIG. 2, the ends of vanes 27 slide off of the feathered edge of one block and onto the tangential surface of the other block. Thus, the vane tops do not engage any abrupt shoulders and minimum wear occurs to vanes and to the rotor chamber. Furthermore, with the vanes sweeping from the feathered edges onto the tangential extensions, there is very little chance for fluid being pumped to move between the sliding surfaces of the blocks. Thus, if the transmission is not fully immersed in the fluid being pumped, little if any of the fluid can be lost between the sliding blocks.
As the arcuate faces 28a and 29a are separated, pump inlet port 33 and pump outlet port 32 of pump 11 are exposed. These diametrically spaced ports are formed through the partition 25 between the pump. 11 and motor 12. Fluid flow losses between the pump and motor are kept to a minimum by providing a narrow partition 25 so that the length of ports 32 and 33 is small, and by polishing or Teflon coating the interior surfaces of the ports. Another inlet port 34 is provided into the pump 11 through the wall 13a of the casing 13 in alignment with each outlet port 32. Fluid can therefor be supplied to the pump 11 as a return fluid from the motor 12 through inlet 33 or from the static fluid reservoir that surrounds the pump and motor through inlet port 34 within housing 10. Adequate fluid is available through the inlet ports 33, FIG. 2, and 34 to insure efficient pump operation at all positions of the blocks 28 and 29.
Movements of blocks 29 and 28 are controlled and synchronized by a mechanical linkage operating through rods 35, FIGS. 1 and 2. Rods 35 are threaded into the blocks on the sides opposite the arcuate faces and extend slidably through opposite ends of casing 13, within the housing 10. Holes 18 through ends 13e and 13f allow free movement of fluid into and out of casing 13 and prevent formation of a vacuum or a fluid accumulation in the casing that would hinder movement of the blocks 28 and 29. The rods 35 are part of a mechanical linkage that simultaneously moves the blocks towards or away from each other. The linkage further includes arms 36 which are pivotally connected at 37, intermediate their lengths to pivot mounts 38 on the casing 13. Each arm 36 is pivotally connected at one end, through a clevis coupling 39, to the end of a rod 35 projecting from casing 13. The other ends of the arms 36 are each pivotally connected through an elongate slot 40 to a pin 41 on a traveling block 42. The traveling blocks 42 are reversely threaded onto a shaft 43 such that rotation of the shaft in one direction will move the blocks in opposite directions therealong. As the blocks move, the arms 36 are pivoted to move the rods 35 and blocks 28 and 29, attached thereto, within casing 13.
A bearing 44 in the wall f of housing 10 journals the shaft 43 and packing seals 44a prevent leakage of transmission fluid from the housing along the shaft. Any conventional control, not shown can be coupled to shaft 43 to provide for remote operation of the transmission.
It should be understood that other types of controls that will synchronize the movement of the sliding blocks such as hydraulic, vacuum, or electrical arrangements could be substituted for the mechanical arrangement herein described. Also, these controls and the mechanical control described can be equipped with an override arrangement connected to a maximum power indicator, such that as a maximum output power is reached, the control arrangement is moved to reduce the volumetric output from the pump.
The volumetric output from the pump is decrease until the maximum power indicator indicates that an overload is not being imposed on the power source, whereupon the controls are moved to increase the volumetric pump output to the set flow desired by the operator. Examples of some maximum power indicators include maximum fuel rack travel, maximum fuel rail pressure, maximum turbocharge boost pressure, lowered inlet manifold vacuum, and maximum amperage flow.
Fluid discharged by pump 11, as shown on FIG. 3, moves through the pump outlet port 32 into the motor 12 to act on spaced vanes 45. The vanes radiate from the periphery of a motor rotor 46 and the impinging fluid turns the rotor within a chamber formed by partition 25 and the side 13b, top 13c, bottom 13g, and ends 132 and l3fof the casing 13. 1
Motor rotor 46 is fixed to the output shaft 23 by a key 47 inserted into aligned keyways 23a in shaft 23, and
46a in the motor rotor. As previously noted, shaft 23 extends through the wall 13b of casing 13 and wall 10b of housing 10 and is journaled therein by an oil seal 23b.
Pressure relief valves 49 and 50 are respectively mounted on the top and bottom of casing 13 and are connected to pump and motor discharge ports 32 and 33, so that excess high pressure developed therein can be safely relieved. Fluid discharged from the relief valve 50 is circulated within the housing 10 through a channel 51 formed in the bottom of casing 13.
Should the output shaft 23 be turned faster than the input shaft 14, or should it be desired to use the motor as a brake, gate valves 52 opposite to ports 33 in center plate 25 are arranged to slide in one or more guides 52a oncasing 13. Valves 52 open and close input ports 53 through wall 13b of the casing to admit fluid therethrough. Gates 52 are connected to the rod 54 of a hydraulic cylinder 55 controlled from without the transmission. When the gate 52 is opened, the rotation of rotor 46 tends to pump fluid from the reservoir discharging it out through pump inlet port 33. By moving the blocks 28 and 29 inwardly the size of the passage between the motor and pump is reduced causing a decrease of the flow into the rotary pump thereby providing a filled condition within the hydraulic motor. This filled state tends to restrict rotation of the motor rotor thereby curtailing output rotation of shaft 23. It can be seen that gate valves 52 can be effectively used as a governor, responsive to the speed of output shaft 23 and that any conventional speed sensing device arranged to regulate flow to and from cylinder 55 through lines 56 and 57 in response to sensed speed of the output shaft can be used.
The sides, ends, top and bottom of both the housing 10 and the casing 13 are sealingly joined together by an arrangement of bolts, nuts and screws as shown in FlGS. l-3.
Shown herein, the variable delivery rotary pump of the invention is connected to turn a hydraulic motor. It should be obvious that the rotary pump could also be connected to a gear motor, a swash plate piston type motor, or a like motor arrangement without departing from the scope of this invention. The variable delivery rotary pump of the invention is therefor highly versatile and useful in that it has applications ranging from a utilization in a bicycle transmission to a transmission of a large earth mover.
Although a preferred form of my invention has been herein disclosed, it is to be understood that the present disclosure is made by way of example and that variations are possible without departing from the scope of the hereinafter claimed subject matter, which subject matter I regard as my invention.
1. A fluid transmission comprising a rotary pump including a housing divided by a partition into a pair of compartments,
a pump rotor,
a pair of blocks movable towards-and away-from each other in one compartment of the housing, each said block including an arcuate face in opposing relationship to the arcuate face of the other block, and said blocks and said housing defining a pump rotor chamber in which said pump rotor is journaled;
spaced vanes on the rotor and radiating therefrom.
into sliding engagement with the arcuate faces and said housing;
an input shaft journaled through the housing and connected to the pump rotor, whereby rotation of said input shaft will rotate said rotor;
- a motor rotor in the other compartment, wall means surrounding the periphery of the motor rotor and the sides thereof and forming a motor rotor chamber;
vanes extending radially outwardly from the motor rotor to engage the wall means;
an output shaft fixed to the rotor and journalled through the housing, whereby rotation of said motor rotor will rotate said output shaft;
input port means through the housing to the pump rotor chamber the size of said input port means being varied according to the relative positions of said blocks;
port means through the partition forming an outlet of the pump chamber and an inlet to the motor chamber, whereby fluid forced through the port means from the pump chamber acts on the motor rotor to rotate it within the motor rotor chamber; and
port means through the partition whereby fluid forced from the motor rotor chamber is forced into the pump rotor chamber, the size of said port means through the port chamber being varied according to the relative positions of said blocks.
2. A fluid transmission as in claim 1, further including a fluid reservoir supplying fluid to the inlet port means.
3. A fluid transmission as in claim 1, wherein the movable blocks each include a tangential extension at one end of its arcuate faces, a feathered edge at the other end of the arcuate face in sliding engagement with the tangential extension of the other block; and wherein the vanes radially spaced around the pump rotor are 8 adapted to project into sliding engagement with the arcuate faces and tangential extensions.
4. A fluid transmission as in claim 3, further including the housing is immersed in the reservoir.