US3835647A - Multiple speed hydraulic drive circuit - Google Patents

Multiple speed hydraulic drive circuit Download PDF

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Publication number
US3835647A
US3835647A US00221343A US22134372A US3835647A US 3835647 A US3835647 A US 3835647A US 00221343 A US00221343 A US 00221343A US 22134372 A US22134372 A US 22134372A US 3835647 A US3835647 A US 3835647A
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Prior art keywords
valve
motor
pump
pumps
drive circuit
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US00221343A
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English (en)
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T Huffman
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ICM ACQUISITIONS Inc A DE CORP
Hydreco Inc
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General Signal Corp
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Priority to US00221343A priority Critical patent/US3835647A/en
Priority to CA156,378A priority patent/CA969068A/en
Priority to AU49882/72A priority patent/AU4988272A/en
Priority to DE2262450A priority patent/DE2262450A1/de
Priority to JP48011534A priority patent/JPS4883602A/ja
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Publication of US3835647A publication Critical patent/US3835647A/en
Assigned to CONTINENTAL ILLINOIS NATIONAL BANK AND TRUST COMPANY OF CHICAGO reassignment CONTINENTAL ILLINOIS NATIONAL BANK AND TRUST COMPANY OF CHICAGO SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ICM ACQUISTIONS INC.
Assigned to CONTINENTAL ILLINOIS NATIONAL BANK AND TRUST COMPANY OF CHICAGO reassignment CONTINENTAL ILLINOIS NATIONAL BANK AND TRUST COMPANY OF CHICAGO SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ICM ACQUISITIONS, INC., A CORP. OF DE
Assigned to HYDRECO, INC. reassignment HYDRECO, INC. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). EFFECTIVE DATE: SEPTEMBER 11, 1987 Assignors: ICM ACQUISTIONS INC.
Assigned to ICM ACQUISITIONS, INC., A DE. CORP. reassignment ICM ACQUISITIONS, INC., A DE. CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: GENERAL SIGNAL CORPORATION, A NY CORP.
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F16H61/4148—Open loop circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
    • F15B11/0426—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in" by controlling the number of pumps or parallel valves switched on
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
    • F15B13/0422—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with manually-operated pilot valves, e.g. joysticks
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F16H61/44—Control of exclusively fluid gearing hydrostatic with more than one pump or motor in operation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F16H61/44—Control of exclusively fluid gearing hydrostatic with more than one pump or motor in operation
    • F16H61/444—Control of exclusively fluid gearing hydrostatic with more than one pump or motor in operation by changing the number of pump or motor units in operation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F15B2211/20584—Combinations of pumps with high and low capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/255—Flow control functions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F15B2211/50527—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves using cross-pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50536—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using unloading valves controlling the supply pressure by diverting fluid to the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5151—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve
    • F15B2211/5154—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve being connected to multiple ports of an output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7058—Rotary output members

Definitions

  • the circuit preferably employs two fixed displacement pumps of different capacities, and a pair [52] US. Cl 60/486, 91/6, 60/493 f pilot Operated comm] valves which Selectively [51] Int. Cl. Fl5b 15/18 cause the output of either or both pumps to be deliv Field of Search 60/52 R, 52 HE; 91/6 ered to the drive motor.
  • the control valves are so arranged that they may be incorporated in a single, con- References Cited ventional valve body, and that neither has to be sized UNITED STATES PATENTS to handle the combined outputs of both pumps.
  • the simplest circuit includes a single fixed displacement pump, and a two-position selector valve which either unloads the pump or delivers its output to the drive motor.
  • This arrangement affords only a single driving speed; therefore, the elevator operates efficiently only in a very limited range of vehicle speeds. Moreover, since the driving direction cannot be reversed, dislodgment of objects caught in the elevator can be difficult.
  • the object of this invention is to provide an improved hydraulic drive circuit which accommodates a wider range of ground speeds than the prior proposals which employ fixed displacement pumps, and which is more economical than the hydrostatic tansmission proposal in the sizes required for high power applications.
  • the new circuit includes a drive motor which is selectively supplied with the output of either or both of a pair of fixed displacement pumps depending upon the positions of a pair of control valves.
  • the pumps have different capacities, so the circuit affords a choice of three driving speeds.
  • One of the pumps is connected with the motor through a check valve and is selectively loaded and unloaded by one of the control valves, which also is arranged to selectively open and close a return path leading from the motor.
  • the second valve controls a supply path from the other pump to the motor as well as an additional return path from the motor to a fluid reservoir.
  • neither control valve is required to handle the combined outputs of the two pumps, and both valves can be incorporated in a conventional tandem (i.e., series-parallel circuit) valve body having the usual Y-shaped coring for the open center path.
  • the drive motor is reversible
  • the second control valve takes the form of a conventional three-position directional control valve which is adapted to reverse the direction of flow through the motor.
  • both control valves are of the pilot operated type and are operated by a remote control system having a single actuating lever which determines the positions of both control valves. This embodiment, therefore, facilitates dislodgment of objects stuck in the elevator, reduces operator effort, and allows considerable freedom in locating and arranging circuit components.
  • FIG. 1 is a schematic diagram of the improved drive circuit.
  • FIG. 2 is a sectional view taken on line 22 of FIG.
  • FIG. 3 is a sectional view taken on line 3-3 of FIG.
  • FIG. 4 is a cross sectional view of the control valve assembly used in the FIG. 1 circuit.
  • the drive circuit includes a reversible, rotary hydraulic motor 11 which drives the elevator (not shown), a pair of engine-driven, fixed displacement pumps 12 and 13 of unequal capacities, and a fluid reservoir or tank 14.
  • Motor 11 is provided with a pair of ports Ila and 11b, either of which may serve as the supply port while the other serves as the return port, and which are connected to the service lines 15 and 16, respectively.
  • These lines are equipped with criss cross relief valves 17 and 17a which serve to prevent cavitation and reduce shocks when motor 11 is stopped or reversed.
  • the smaller supply pump 12 is connected with service line 15 through a conduit 18 containing a check valve 19, and is selectively loaded and unloaded by a two-position control valve 21 which is connected with conduit 18 at a point upstream of the check valve via branch conduit 22.
  • valve 21 also controls a motor return path leading from service line 16 to tank 14 through conduit 23.
  • Valve 21 is biased by spring 24 to the illustrated position, in which it unloads pump 12 and closes conduit 23, and is shifted to the second position, in which it loads pump 12 and opens conduit 23, by a piloted pressure motor 25 which is actuated by a remote control system 26.
  • the larger supply pump 13 is selectively unloaded, or loaded and connected with one or the other of the service lines 15 and 16, by a three-position control valve 27 which also is adapted to establish a return path from the remaining service line to tank 14.
  • Valve 27' is biased to the illustrated neutral position by a pair of centering springs 28 and 29 and is shifted to one or the other of two motor-actuating positions by a pair of opposed piloted pressure motors 31 and 32 under the control of system 26. In its neutral position, valve 27 unloads pump 13 to tank 14 and isolates the service lines 15 and 16 from both of these components and from each other, whereas in each of the actuating positions the unloading path is closed, one service line is connected to pump 13, and the other service line is connected to tank l4.
  • valve 27 is connected with pump 13 through control valve 21, this path is continuously open. Therefore, the functions of valve 27 are not affected by actuation of valve 21.
  • the remote control system 26 comprises a pilot valve 33 which is supplied with hydraulic fluid at a relatively low, constant pressure on the order of 250 psi. by a source 34, such as the power steering circuit of the vehicle, and which contains a pair of valving units 35 and 35a which serve to pressurize and vent the piloted pressure motors of control valves 21 and 27, respectively, in accordance with the position of a common actuating lever 36.
  • Valve unit 35 includes a spool 37 which is equipped with a conventional centering spring and detent assembly 38, and which is formed with a land 39 which controls communication between an outlet chamber 41, which is joined to piloted motor 25, and supply and exhaust chambers 42 and 43, respectively.
  • valve unit 35 is a double-acting unit, so spool 37 includes another land 44 which controls communication between a second outlet chamber 45 and the supply and exhaust chambers 42 and 46.
  • control valve 21 incorporates only a single actuating motor, this added capability of unit 35 is not needed, and the outlet port of chamber 45 is sealed by a plug 47.
  • Valve unit 35a is identical to unit 35, but its full double-acting capability is needed. Therefore, outlet chamber 41a is connected with piloted motor 31, outlet chamber 45a is connected with opposed motor 32, and the second detented actuating position of spool 37a (i.e., the position of the right of neutral) is utilized.
  • the spools 37 and 37a of the two pilot valve units are shifted by the common actuating lever 36 which includes a plate 49 containing a pair of aligned slots 51 and 51a in which the spherical heads 52 and 52a of the spools are held captive. Plate 49 also is provided with a third slot 53 in which is retained the spherical head 54 of a fixed pivot 55.
  • Lever 36 is biased to the illustrated neutral position, in which it is parallel with spools 37 and 37a, by the centering springs associated with those spools, and can be tilted about fixed pivot head 54 to one of the following four actuating positions labeled in FIG. 2:
  • lever 36 In order to drive the elevator in the forward direction at the lowest of the three available speeds, lever 36 is tilted to position L. This action raises the pressure in pilot valve outlet chamber 41 and in the connected piloted motor 25, so the latter now shifts control valve 21 to its second position to thereby load the small pump 12 and open a return path for motor port 11!).
  • the output of pump 12 is now delivered to motor 11 via conduit 18, check valve 19, service line 15 and port 11a, and the fluid exhausting from port 11b is returned to tank 14 via service line 16 and return conduit 23. Therefore, motor 11 will now drive the elevator at a low speed proportional to the delivery rate of pump 12.
  • pilot spool 37 will return to the illustrated neutral position under the action of its centering spring to thereby again vent piloted motor 25 and allow spring 24 to return control valve 2 to its neutral position. This action unloads pump 12 and closes return conduit 23. Simultaneously, pilot spool 37a is shifted to its first actuating position, so outlet chamber 41a and piloted motor 31 are pressurized by source 34, and chamber 45a and motor 32 remain vented. Therefore, motor 31 will shift control valve 27 to the actuating position in which it connects pump 13 with service line 15, and opens a return path from service line 16 to tank 14. Since the check valve 19 prevents the escape of oil from line 15 through the unload ing path established by valve 21, the full output of large pump 13 will be delivered to motor 11, and the latter will now drive the elevator at a higher speed.
  • the highest output speed of motor 11 is developed by shifting lever 36 to position F. in this mode of operation, the pilot valve outlet chambers 41 and 410 are pressurized, so piloted motors 25 and 31 set both of the control valves 21 and 27, respectively, to their second positions. As a result, both of the pumps 12 and 13 are loaded, and their combined outputs are delivered to motor 11. In contrast to the previous modes of operation, the return flow from motor 11 is delivered to tank 14 along two parallel paths; one leading through conduit 23 and control valve 21, and the other leading through control valve 27. Inasmuch as the flow rate through motor 11 now equals the sum of the outputs of the two pumps, the driving speed will equal the sum of the low and medium speeds.
  • lever 36 In the event it becomes necessary to reverse the elevator, lever 36 is shifted to position R. This movement of the actuator allows spool 37 to return to its neutral position, thereby causing control valve 21 to unload pump 12 and block return conduit 23, and simultaneously shifts spool 37a to the right to the second actuating position in which it isolates outlet chamber 45a from exhaust chamber 46a and opens communication between the outlet chamber and supply chamber 420. Since piloted motors 31 and 32 are now vented and pressurized, respectively, control valve 27 is moved to the left to the position in which large pump 13 is connected with service line 16, and service line is connected with tank 14. Inasmuch as these connections reverse the direction of flow through motor 11, the motor now drives the elevator in reverse. Its speed, of course, is proportional to the output of pump 13, and thus is the same as during forward operation at medium speed.
  • the two control valves 21 and 27 take the form of sliding plunger valves, and, together with the relief valve 56 for large pump 13, they are incorporated in the conventional tandem circuit valve body 57 shown in FIG. 4.
  • the body 57 is cored to provide a C-shaped exhaust manifold 58, which communicates with an exhaust port 59 and has legs 61 and 62 which interconnect the annular chambers 63-66 located at opposite ends of the plunger bores 67 and 68.
  • the body also is cored to provide a central unloading path which includes a yshaped section 69 leading from inlet port 71 to the annular chambers 72 and 73 encircling bore 67, a second y-shaped section 74 connecting the central annular chamber 75 of bore 67 with the annular chambers 76 and 77 encircling bore 68, and a downstream portion 78 leading from the central chamber 79 of bore 68 to the exhaust manifold.
  • a central unloading path which includes a yshaped section 69 leading from inlet port 71 to the annular chambers 72 and 73 encircling bore 67, a second y-shaped section 74 connecting the central annular chamber 75 of bore 67 with the annular chambers 76 and 77 encircling bore 68, and a downstream portion 78 leading from the central chamber 79 of bore 68 to the exhaust manifold.
  • Each valve bore is also provided with a pair of annular outlet chambers 81, 82 or 83, 84 which communicate with service ports 81a, 82a, 83a and 84a, respectively; the ports 81a and 82a being connected to branch conduit 22 and return conduit 23, respectively, and the ports 83a and 84a being connected with service lines 15 and 16, respectively.
  • the control valve 21 of FIG. 4 includes a solid valve plunger 85 formed with three axially spaced peripheral grooves 86-88 which define four valve lands 89, 91, 92 and 93, and is biased by a pair of springs 24 to the illus-' trated neutral position in which groove 86 interconnects chambers 63' and 81, and lands 92 and 93 isolate outlet chamber 82.
  • Plunger 85 is moved to its second or actuating position by the piloted motor 25, which includes the left end of the plunger, and in this position lands 89 and 91 isolate outlet chamber 81, and groove 88 interconnects chambers 64 and 82.
  • groove 87 interconnects chambers 72, 73 and 75, so control valve 27 always is able to receive oil from pump 13 via inlet port 71 and the open center path regardless of the position of valve plunger 85.
  • the preferred control valve 27 includes a conventional threeposition hollow valve plunger 94 formed with three lands 95, 96 and 97 which are separated by a pair of peripheral grooves or necks 98 and 99.
  • the plunger contains two axial bores 101 and 102, each of which is intersected by a pair of axially spaced radial passages 103 and 104 or 105 and 106.
  • the arrangement of the parts is such that e a. in the illustrated neutral position, lands and 97 isolate outlet chambers 83 and 84, and plunger necks 98 and 99 connect chamber 79 with chambers 76 and 77, respectively, and thereby complete the open center unloading path;
  • a hydraulic drive circuit comprising a. a hydraulic motor (11) having first and second ports (11a, 11b);
  • a first control valve (21) connected with the first pump (12), the second motor port (110) and the reservoir (14) and having a neutral position in which it unloads the first pump to the reservoir and isolates the second motor port from both of these components, and a second position in which it closes the unloading path and connects the second motor port with the reservoir;
  • a second control valve (27) connected with the second pump (13), the reservoir (14) and the motor ports (11a, 11b) and having a neutral position in which it unloads the second pump to the reservoir and isolates the motor ports from both of these components, and a second position in which it closes the unloading path and connects the first (11a) and second (11b) motor ports with the second pump and reservoir, respectively.
  • the means for preventing reverse flow through the conduit means (18) is a check valve (19).
  • the second control valve (27) has a third position in which it closes the unloading path for the second pump and connects the first and second motor ports (11a, 11b) with the reservoir (14) and the second pump (13), respectively.
  • a drive circuit as defined in claim 2 in which the second pump (13) is connected with the second control valve (27) via a passage in the first control valve (21) which is open in both of said positions of the first tral position, valve. b. a second position (L) in which it sets the first valve 5.
  • a drive CiICUit as defined in claim 4 in which the (21) to second position and the second valve (27) two control valves (21, 27) are sliding plunger units into neutral position, Corporated in a Common valve body having s c. a third position (M) in which it sets the first valve Shaped coring 78, which defines an p cell (21) to neutral position and the second valve (27) ter unloading path for the second pump (13) when to second position both valves are in neutral position.
  • both control valves (21, 27) are operated by mechanism employing a common actuating lever (36), the lever havmg a. a first position in which it sets both valves to neu- 15 tra l position, b. a second position (L) in which it sets the first valve (21) to second position and the second valve (27) to neutral position,
  • a drive circuit as defined in claim 7 in which a. the control valves (21, 27) are operated by piloted pressure motors (25 and 31, 32); and
  • the common lever (36) positions a pair of pilot valves (35, 35a) which selectively pressurize and vent the piloted pressure motors of the first and c. a third position (M) in which it sets the first valve control 2 7 i l x 21 to position and the Second valve (27) 10.
  • a drive circuit as defined in claim 8 in which to second position, and a. the control valves (21, 27) are operated by piloted d. a fourth position (F) in which it sets both valves to Pressure mOtOrS and and second position.
  • the common lever (36) positions a pair of pilot 8.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Operation Control Of Excavators (AREA)
US00221343A 1972-01-27 1972-01-27 Multiple speed hydraulic drive circuit Expired - Lifetime US3835647A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US00221343A US3835647A (en) 1972-01-27 1972-01-27 Multiple speed hydraulic drive circuit
CA156,378A CA969068A (en) 1972-01-27 1972-11-14 Multiple speed hydraulic drive circuit
AU49882/72A AU4988272A (en) 1972-01-27 1972-12-11 Multiple speed hydraulic drive circuit
DE2262450A DE2262450A1 (de) 1972-01-27 1972-12-20 Schaltkreis fuer einen hydraulikantrieb
JP48011534A JPS4883602A (enrdf_load_stackoverflow) 1972-01-27 1973-01-27

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00221343A US3835647A (en) 1972-01-27 1972-01-27 Multiple speed hydraulic drive circuit

Publications (1)

Publication Number Publication Date
US3835647A true US3835647A (en) 1974-09-17

Family

ID=22827417

Family Applications (1)

Application Number Title Priority Date Filing Date
US00221343A Expired - Lifetime US3835647A (en) 1972-01-27 1972-01-27 Multiple speed hydraulic drive circuit

Country Status (5)

Country Link
US (1) US3835647A (enrdf_load_stackoverflow)
JP (1) JPS4883602A (enrdf_load_stackoverflow)
AU (1) AU4988272A (enrdf_load_stackoverflow)
CA (1) CA969068A (enrdf_load_stackoverflow)
DE (1) DE2262450A1 (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3895490A (en) * 1973-02-27 1975-07-22 Poclain Sa Control circuit for a pressurized fluid engine
US4367624A (en) * 1979-02-20 1983-01-11 Kabushiki Kaisha Komatsu Seisakusho Control system for hydraulic actuator
US4840031A (en) * 1987-05-05 1989-06-20 Fluid Regulators Corp. Control system for fluid pressure operated actuator
US5353684A (en) * 1992-03-19 1994-10-11 Friedrich Wilh, Schwing, Gmbh Hydraulic control device for working cylinders with unequal piston speeds
US5823284A (en) * 1994-09-22 1998-10-20 Central Mechanical Ltd. Utility vehicle
US20230089947A1 (en) * 2020-03-13 2023-03-23 Hydac Mobilhydraulik Gmbh Control device

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5066908A (enrdf_load_stackoverflow) * 1973-10-23 1975-06-05
NL8201638A (nl) * 1982-04-20 1983-11-16 Jacobus Hendrikus Van Leusden Hijswerktuig.
JPS61201969A (ja) * 1985-03-05 1986-09-06 Hitachi Constr Mach Co Ltd 油圧パイロツト回路
GB9506500D0 (en) * 1995-03-30 1995-05-17 Brown David Hydraulics Ltd An improved joystick arrangement

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3895490A (en) * 1973-02-27 1975-07-22 Poclain Sa Control circuit for a pressurized fluid engine
US4367624A (en) * 1979-02-20 1983-01-11 Kabushiki Kaisha Komatsu Seisakusho Control system for hydraulic actuator
US4840031A (en) * 1987-05-05 1989-06-20 Fluid Regulators Corp. Control system for fluid pressure operated actuator
US5353684A (en) * 1992-03-19 1994-10-11 Friedrich Wilh, Schwing, Gmbh Hydraulic control device for working cylinders with unequal piston speeds
US5823284A (en) * 1994-09-22 1998-10-20 Central Mechanical Ltd. Utility vehicle
US20230089947A1 (en) * 2020-03-13 2023-03-23 Hydac Mobilhydraulik Gmbh Control device
US11801725B2 (en) * 2020-03-13 2023-10-31 Hydac Mobilhydraulik Gmbh Control device

Also Published As

Publication number Publication date
CA969068A (en) 1975-06-10
JPS4883602A (enrdf_load_stackoverflow) 1973-11-07
DE2262450A1 (de) 1973-08-09
AU4988272A (en) 1974-06-13

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