EP1557564A1 - Umkehrbare Pumpeneinheit zum Antrieb hydraulischer Zylinder - Google Patents

Umkehrbare Pumpeneinheit zum Antrieb hydraulischer Zylinder Download PDF

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Publication number
EP1557564A1
EP1557564A1 EP04250372A EP04250372A EP1557564A1 EP 1557564 A1 EP1557564 A1 EP 1557564A1 EP 04250372 A EP04250372 A EP 04250372A EP 04250372 A EP04250372 A EP 04250372A EP 1557564 A1 EP1557564 A1 EP 1557564A1
Authority
EP
European Patent Office
Prior art keywords
piston
pump assembly
cylinder
reservoir
pumping chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP04250372A
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English (en)
French (fr)
Other versions
EP1557564B1 (de
Inventor
Robert A. Rocky Mountain Parabolic Prod. Lt Wood
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SRAOSHA CONSULTING Inc
Original Assignee
Rocky Mountain Parabolic Products Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rocky Mountain Parabolic Products Ltd filed Critical Rocky Mountain Parabolic Products Ltd
Priority to EP20040250372 priority Critical patent/EP1557564B1/de
Publication of EP1557564A1 publication Critical patent/EP1557564A1/de
Application granted granted Critical
Publication of EP1557564B1 publication Critical patent/EP1557564B1/de
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B7/00—Piston machines or pumps characterised by having positively-driven valving
    • F04B7/04—Piston machines or pumps characterised by having positively-driven valving in which the valving is performed by pistons and cylinders coacting to open and close intake or outlet ports
    • F04B7/06—Piston machines or pumps characterised by having positively-driven valving in which the valving is performed by pistons and cylinders coacting to open and close intake or outlet ports the pistons and cylinders being relatively reciprocated and rotated

Definitions

  • This invention relates to a reversible positive displacement piston pump particularly, but not exclusively, suited for driving double acting hydraulic cylinders.
  • the subject invention may have other uses it is particularly useful in applications where a pump is required to drive a single hydraulic cylinder to perform useful work.
  • the pump is connected to the cylinder using two tubes that connect between two ports on the cylinder and two ports on the pump.
  • An electric motor on the pump can be made to rotate in alternate directions and the resultant pumping action will expand or retract the cylinder according to the direction of rotation of the motor.
  • Such combinations of hydraulic pump and cylinder are used for applications such as cranes on trucks, portable log splitters and automatic pilots on ships. It is desirable in such systems that fluid flow from the cylinder to the pump be blocked when the pump is at rest as in this way any load placed on the hydraulic cylinder is restrained in position when the pump is not running.
  • the double acting hydraulic cylinder is constructed with the piston rod passing right through the piston and exiting through glands at both the mounting and the rod ends of the cylinder the fluid flow leaving and returning to the pump is exactly equal and the pump and cylinder can be constructed as a closed loop through which the fluid flows. In such a system no external reservoir is required.
  • the hydraulic cylinder is of the type with a single cylinder rod attached to the piston with this rod passing through a gland on one end of the cylinder only. No rod passes through the mounting end of the cylinder.
  • a quantity of fluid is fed into the mounting end of the cylinder less fluid will emerge from the rod end of the cylinder the difference being equal to the swept volume of the cylinder rod.
  • fluid is fed into the rod end of the cylinder a greater quantity will flow from the mounting end of the cylinder the difference being equal to the swept volume of the cylinder rod.
  • a system cannot be constructed as a closed loop and a means must be provided to introduce extra fluid into the loop as the cylinder expands and remove surplus fluid from the loop as the cylinder contracts.
  • Such fluid must be stored in a system reservoir and the level of fluid in this reservoir will drop as the cylinder expands and rise as the cylinder contracts.
  • the reservoirs that are used for this purpose may be an integral part of the pumping unit or a separate entity.
  • Simple gear pumps are frequently used in such applications but the nature of a gear pump is that it does not offer the capability to support a load on the cylinder when the pump is at rest and requires complicated spool valves to support a load and return fluid to the reservoir as the cylinder retracts.
  • the subject invention is simple and economical to manufacture. It has no gears and no spool valves, has the ability to hold a load on the cylinder when the pump is at rest, provides a simple means of returning fluid to the reservoir as the cylinder retracts and provides a simple means of supplying extra fluid to the cylinder as it expands.
  • Piston pumps having a single piston that reciprocates and rotates about a single axis are known in the prior art but the subject invention incorporates features that make such pumps simpler.
  • the devices shown in U.S. Patents 4,479,759, 5,161,491, and 3,083,895 all show pistons that reciprocate and rotate simultaneously but rely on grooves in the piston to accomplish this motion.
  • U.S. Patent 3,930,762 shows a device containing a piston that reciprocates and rotates simultaneously but which relies on a system of cams to produce such motion.
  • U.S. Patents 5,015,157 and 3,168,872 show devices containing a piston that reciprocates and rotates simultaneously but such motion is achieved by setting the drive motor axis at an angle to the axis of the piston.
  • U.S. Patent 4,902,208 discloses a pump suitable for driving a hydraulic cylinder that includes a rotating valve mechanism but the pumping action in this invention takes place in a separate cylinder at right angles to the rotating valve axis.
  • a pump assembly comprising piston and cylinder members in telescoping relationship with one another along an axis to define a single pumping chamber therebetween, means for reciprocating and rotating said piston and cylinder members relative to each other, and commutating valve means for establishing fluid flow into said pumping chamber during one portion of each revolution to charge said pumping chamber and for establishing fluid flow from said pumping chamber during the remainder of each revolution, said commutating valve means including a single radial port communicating with the pumping chamber and rotatable about the axis of said piston for independent fluid communication with first and second fixed ports spaced circumferentially from one another.
  • the pump assembly preferably includes a housing supporting the cylinder and also supporting an electric motor with a shaft so as the axis of rotation of the motor shaft coincides with the axis of rotation of the piston.
  • Any suitable means may be employed for coupling the motor shaft to the piston for rotating the piston, for example, a transverse pin in the motor shaft engaging with a slot provided in the end of the piston.
  • any suitable means may be employed for reciprocating the piston as it rotates, for example a single row ball bearing secured to the piston on an axis set at an angle to the piston where the single row ball bearing is restrained at one point on the outer circumference of the single row ball bearing from moving in the direction of the axis of the piston. In this way, the bearing oscillates when the piston is rotated and such oscillation causes the piston to reciprocate.
  • the cylinder member is preferably open except for the piston member to establish only one pumping chamber between the members with the commutating valve means for establishing fluid flow into the single pumping chamber during one half of each revolution to charge the pumping chamber and for establishing fluid flow from the pumping chamber during the second half of each revolution.
  • the arrangement of the porting is such that the first and second fixed ports alternatively communicate with the radial port so the fluid flows in one direction through the fixed ports upon rotation of the piston in one direction and through the fixed ports in the opposite direction when the direction of rotation of the piston is reversed.
  • the pump assembly preferably also provides a system reservoir that is connected to the pumping components by three passages.
  • the first and second of these passages are fitted with one way check valves which allow additional fluid to enter the pump exit ports as required when the attached hydraulic cylinder is expanding.
  • the third of these passages is fitted with a bleed device that allows surplus fluid to be returned to the reservoir when the attached hydraulic cylinder is contracting.
  • the single acting piston pump provides excellent sealing between the piston and the cylinder, and, as such a single acting piston pump cannot be driven by hydraulic pressure as a motor, the pump is essentially non reversing and any load on the hydraulic cylinder will be held for long periods without such a load causing significant movement in the hydraulic cylinder shaft.
  • a pump assembly comprising piston and cylinder members in telescoping relationship with one another along an axis to define a single pumping chamber therebetween, means for reciprocating and rotating said piston and cylinder members relative to each other, a pair of ports connectable to a hydraulic cylinder, means controlling fluid flow between the ports and the pumping chamber, and a reservoir for accommodating variations in the fluid flow produced in use of the pump assembly.
  • flow control means comprises valve means connectable between the pumping chamber and each port.
  • the valve means may comprise a pair of one way valves, one for each port, that allow flow of fluid from the reservoir and a bleed valve that allows flow of fluid to the reservoir.
  • a pump assembly comprising piston and cylinder members in telescoping relationship to with one another for reciprocating and rotating movement relative to one another along an axis to define a single pumping chamber therebetween, a housing supporting said piston member and also supporting an electric motor with a shaft on the same axis as said piston, a coupling means consisting of a transverse pin in said motor shaft engaging with a slot provided in the end of said piston, a means of causing said piston to reciprocate as it rotates consisting of a single row ball bearing secured to said piston on an axis set at an angle to said piston where said single row ball bearing is restrained at one point on the outer circumference of said single row ball bearing from moving in the direction of the axis of said piston, commutating valve means for establishing fluid flow into said closed pumping chamber during one portion of each revolution to charge said pumping chamber and for establishing fluid flow from said pumping chamber during the remainder of each revolution, said commutating valve means including a fluid passage extending from
  • a pump assembly 10 constructed in accordance with the subject invention, is shown in Fig. 1 as it would be connected in a typical application to a double acting hydraulic cylinder in order to raise a load.
  • Two tubes from the cylinder connect to ports 1 and 2.
  • reservoir cap 3 and drive motor 4 Also shown is reservoir cap 3 and drive motor 4
  • FIG. 2 A half sectional side elevation of the pump assembly 10 is shown in Fig. 2 where the section is made along the axis of the piston member 5.
  • Pump housing 11 includes a reservoir 24 with vented filler cap 3.
  • Piston member 5 is in a telescoping relationship with cylinder 6 to define a pumping chamber 7 therebetween.
  • the cylinder 6 is closed except for the piston 5 to define or establish only one pumping chamber 7 between the members 5 and 6 so that the piston member 5 is single acting.
  • Housing 11 incorporates cylinder 6 and also secures a drive means comprising an electric motor 4 that rotates a shaft 9. Housing 11 secures the axis of shaft 9 in exact alignment with the axis of piston 5 and cylinder 6. Motor shaft 9 enters a recess in the end of piston 5.
  • Pin 8 inserted at right angles into shaft 9 engages with slot 12 cut across the end of piston 5.
  • Slot 12 is provided in the end of piston 5 to enable the rotation of shaft 9 to be transmitted to piston 5 by pin 11 acting in slot 9. Slot 12 also allows piston 5 movement along the axis of cylinder 6 without disrupting the rotational connection between shaft 9 and piston 5.
  • a commercially available single row ball bearing 13 is mounted on a cylindrical surface formed on the end of piston 5.
  • the cylindrical surface on which single row ball bearing 13 mounts has an axis inclined at an angle to the main axis of piston 5.
  • the single row ball bearing 13 is secured to the piston 5 by means of a retaining ring 14.
  • a passage 38 allows fluid to flow from the reservoir into cavity 39 in order to lubricate single row ball bearing 13.
  • Fluid seal 40 prevents fluid escaping along motor shaft 9 from cavity 39.
  • a cylindrical pin 15 is secured in housing 11 with the axis of said pin 15 intersecting the axis of piston 5 at right angles.
  • Cylindrical pin 15 presents a cylindrical surface to the edge of single row ball bearing 13.
  • a spring loaded plunger arrangement consisting of ball 16 and spring 17 applies pressure to the edge of single row ball bearing 13 and forces single row ball bearing 13 against the cylindrical surface of pin 15. The action of plunger 15 and spring 16 acting on single row ball bearing 13 restricts the movement of the surface of single row ball bearing 13 in contact with the cylindrical surface of pin 14 along an axis parallel with the axis of piston 5.
  • cylindrical surface formed by pin 15 in contact with single row ball bearing 13 can be replaced by similar cylindrical surface formed as part of pump housing 11.
  • a cylindrical surface on the pin 15 or housing 11 may not always be required and it will be understood the invention is not limited thereto.
  • plunger 16 and spring 17 can be replaced by a spring of another nature which provides a means of keeping single row ball bearing 13 in contact with a cylindrical surface such as that provided by pin 15.
  • cylindrical pin 15, plunger 16, and spring 17 can be replaced as in FIG 6. with a fork 41, having a slot 42 into which single row ball bearing 13 locates.
  • Fork 41 has a spherical outer surface that is restrained but free to swivel in a spherical or cylindrical socket such as 43 in housing 11.
  • Fig 3 is a cross sectional view along line A-A in Figure 2 and shows a commutating valve means for delivering fluid to the pumping chamber 7 and for receiving fluid from pumping chamber 7.
  • the commutating valve means includes a passage 18 which connects pumping chamber 7 to a radial port 19 which is rotatable with piston 5.
  • passage 18 is omitted and radial port 19 is extended to the end of piston 5 to communicate directly with pumping chamber 5.
  • Housing member 11 includes first and second fixed or stationary ports 20 and 21 spaced circumferentially from one another and diametrically opposite one another on the axis of piston 5 so that the axis of ports 20 and 21 is at right angles to the axis of the cylindrical surface formed by pin 15.
  • the ports 20 and 21 independently communicate with the radial port 19 during rotation of piston 5 relative to housing 11.
  • the ports 20 and 21 extend through passages 22 and 23 respectively into threaded ports 1 and 2 which may be utilised for hose or hydraulic tubes leading away from the pump to a hydraulic cylinder.
  • the stationary or fixed ports 20 and 21 are aligned relative to the piston 5 with radial port 19 for alternatively communicating with the radial port 19. Consequently fluid will flow from port 20 through the radial port 19 and passage 18 to pumping chamber 7 and from pumping chamber 7 back through passage 18, radial port 19 and out through second port 21 upon rotation of piston 5 in one direction, but will flow in the opposite direction from fixed port 21 through radial port 19 and passage 18 to the pumping chamber 7 and out of pumping chamber 7 through passage 18 to fixed port 20 when the rotation of the piston is in the opposite direction.
  • Passages 22 and 23 extend into reservoir 24.
  • a one way ball check valve consisting of ball 25 and spring 26 allows fluid from reservoir 24 to flow into exit port 1 but not return.
  • a one way ball check valve consisting of ball 27 and spring 28 allows fluid from reservoir 24 into exit port 2 but not return.
  • reservoir 24 could be remotely mounted and connected by a single tube that connected between such a remotely mounted reservoir and a common connection on the pump assembly from which passages 22,23 and 35 extended.
  • a passage 29 connects outlet ports 1 and 2.
  • Two balls 30 and 31 that are a loose fit in passage 29 are placed in the centre of passage 29 and restrained from moving outwards towards outlet port 1 by retaining ring 32 and restrained from moving outwards towards port 2 by retaining ring 33.
  • a rubber O ring 36 seals ball 31 against the walls of passage 29 and prevents fluid flowing past ball 31.
  • balls 30 and 31 are pressed towards port 2 and ball 31 is in contact with retaining ring 33 a rubber O ring 34 seals ball 30 against the walls of passage 29 and prevents fluid from flowing past ball 30.
  • a passage 35 connects the centre of passage 29 to reservoir 24.
  • retaining rings 32 and 33 may be replaced by another stopping means such as a pin that arrests the movement of balls 30 and 31 in the desired positions.
  • Figure 4 shows the relative position of the components of the invention when the pump is rotating in the direction of the arrow shown and smaller arrows in the figure indicate the direction of fluid flow.
  • the pump is connected as shown in Fig. 1.
  • the swept volume of the cylinder rod exiting the hydraulic cylinder creates a condition where more fluid is exiting port 1 than is entering port 2.
  • a partial vacuum thus develops in port 1 and additional fluid is drawn from reservoir 24 past check ball 25 and spring 26 to make up the extra fluid required.
  • Figure 5 shows the relative position of the components of the invention when the pump is rotating in the direction of the arrow shown and smaller arrows in the figure indicate the direction of fluid flow.
  • the pump is connected as shown in Fig. 1.
  • the swept volume of the cylinder rod entering the hydraulic cylinder creates a condition where more fluid is entering port 1 than is exiting from port 2.
  • balls 30 and 31 are forced by said pressure against retaining ring 32.
  • Rubber O ring seal 36 acting against ball 31 seals passage 29 to prevent pressurised fluid escaping from port 2 to passage 35. Excess fluid entering port 1 from the hydraulic cylinder can however flow past loose fitting ball 30 and flow up passage 35 to the reservoir.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
  • Details Of Reciprocating Pumps (AREA)
EP20040250372 2004-01-23 2004-01-23 Umkehrbare Pumpeneinheit zum Antrieb hydraulischer Zylinder Expired - Fee Related EP1557564B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP20040250372 EP1557564B1 (de) 2004-01-23 2004-01-23 Umkehrbare Pumpeneinheit zum Antrieb hydraulischer Zylinder

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20040250372 EP1557564B1 (de) 2004-01-23 2004-01-23 Umkehrbare Pumpeneinheit zum Antrieb hydraulischer Zylinder

Publications (2)

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EP1557564A1 true EP1557564A1 (de) 2005-07-27
EP1557564B1 EP1557564B1 (de) 2008-07-16

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EP20040250372 Expired - Fee Related EP1557564B1 (de) 2004-01-23 2004-01-23 Umkehrbare Pumpeneinheit zum Antrieb hydraulischer Zylinder

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107620739A (zh) * 2017-10-12 2018-01-23 广州奥姆特机电设备制造有限公司 一种可切换双向流道的水泵座

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3083895A (en) * 1961-02-28 1963-04-02 Besly Welles Corp Compressor
US4902208A (en) * 1983-09-22 1990-02-20 Wood R A Ray Pump having piston and cylinder rotatable respectively about spaced axes transverse to the reciprocating axis
US5015157A (en) * 1990-01-10 1991-05-14 Dennis Pinkerton Pump with multi-port discharge

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3083895A (en) * 1961-02-28 1963-04-02 Besly Welles Corp Compressor
US4902208A (en) * 1983-09-22 1990-02-20 Wood R A Ray Pump having piston and cylinder rotatable respectively about spaced axes transverse to the reciprocating axis
US5015157A (en) * 1990-01-10 1991-05-14 Dennis Pinkerton Pump with multi-port discharge

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107620739A (zh) * 2017-10-12 2018-01-23 广州奥姆特机电设备制造有限公司 一种可切换双向流道的水泵座
CN107620739B (zh) * 2017-10-12 2024-04-09 广州奥姆特机电设备制造有限公司 一种可切换双向流道的水泵座

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Publication number Publication date
EP1557564B1 (de) 2008-07-16

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