GB1565462A – Gear pump
– Google Patents
GB1565462A – Gear pump
– Google Patents
Gear pump
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Publication number
GB1565462A
GB1565462A
GB4254/77A
GB425477A
GB1565462A
GB 1565462 A
GB1565462 A
GB 1565462A
GB 4254/77 A
GB4254/77 A
GB 4254/77A
GB 425477 A
GB425477 A
GB 425477A
GB 1565462 A
GB1565462 A
GB 1565462A
Authority
GB
United Kingdom
Prior art keywords
chamber
gear pump
spool
gear
passages
Prior art date
1976-02-10
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.)
Expired
Application number
GB4254/77A
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.)
AlliedSignal Automotive Espana SA
Original Assignee
Bendiberica SA
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.)
1976-02-10
Filing date
1977-02-02
Publication date
1980-04-23
1977-02-02
Application filed by Bendiberica SA
filed
Critical
Bendiberica SA
1980-04-23
Publication of GB1565462A
publication
Critical
patent/GB1565462A/en
Status
Expired
legal-status
Critical
Current
Links
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Classifications
F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F04—POSITIVE – DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
F04C14/26—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels
Description
C 4 ( 21) Application No 4254177
\ ( 31) Convention Application No.
445 ( 11) ( 22) Filed 2 Feb 1977 021 ( 32) Filed 10 Feb 1976 in ( 33) Spain (ES) ( 44) Complete Specification published 23 April 1980 ( 51) INT CL ‘ F 04 C 2/14 15102 ( 52) Index at acceptance FIF 1 B 5 B 1 ER ( 54) GEAR PUMP ( 71) We, BENDIBERICA S A, of Balmes 243, Barcelona 6, Spain, a Spanish Body Corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: –
The invention relates to a hydraulic pump of the gear type.
A gear pump generally comprises a casing, provided with an inlet port communicating with an intake chamber and a delivery port communicating with a delivery chamber, and a drive gear which is controlled by an electric motor and which meshes with a driven gear The two gears are installed in respective bores in the casing and are in the flow path between the inlet and delivery ports Fluid flows from the intake chamber to the delivery chamber through the gaps between the longitudinal surfaces of the bores and the teeth of their respective gears.
In general the delivery of a gear pump of the type described is proportional to the speed of the pump, that is, to the rotational speed of the drive gear Where it is desirable to obtain a delivery of substantially constant value independent of the pump speed, the pump must have means for regulating its flow rate.
An object of the invention is to propose a gear pump whose delivery is regulated to a substantially constant value independent of the pump speed.
According to the invention there is provided a hydraulic gear pump comprising a casing provided with an inlet port communicating with and on the upstream side of an intake chamber, and a delivery port on the downstream side of a delivery chamber, and communicating with the latter through a venturi, a drive gear meshing with a driven gear, each gear being placed in a corresponding bore in the casing, the gears being placed in the flow path between the intake chamber and the delivery chamber, one of the gears containing a central bore to which lead passages connecting 50 the bore to the gaps between the adjacent teeth of the gear, a spool valve being slidable in the central bore, the movements of the spool being controlled by the pressure difference between the fluid pressure in 55 the delivery chamber, and an operating fluid pressure prevailing at or downstream of the neck of the venturi, so that the spool is held in a closed condition in which it blocks the route from the central bore 60 through the passages to the said gaps, as long as said pressure difference remains below a given level.
According to an optional feature of the invention, the spool comprises two bearing 65 surfaces defining with the central bore two end chambers and a central chamber, the end chambers being exposed respectively to the fluid pressure in the delivery chamber and to the operating pressure, the route 70 through the passages being blocked by one bearing surface of the spool when the latter is in its closed position, and the said route being open when the central chamber is opposite the passages due to 75 movement of the spool.
The invention will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 represents a section through a 80 gear pump embodying the invention; and Figure 2 is a section along a line 2-2 in Figure 1.
In the drawings a casing 10 comprises an inlet port 12 and a delivery port 14 The 85 casing contains two bores 16, 18 of identical diameters, with mutually parallel axes perpendicular to the axis of the inlet port.
The two bores 16, 18 partly overlap Inside the bores there are respective gears 20, 22 90 PATENT SPECIFICATION
If) 1 565462 1 565 462 with identically shaped teeth which mesh in the space defined by the overlap between the two bores 16, 18 This space communicates with the inlet port 12 by way of an intake chamber 24 and with the delivery port 14 by way of a delivery chamber 26.
The gear 20 is rotated by a motor (not shown) and is termed the drive gear It rotates the gear 22, which is termed the driven gear Figure 1, which is a section along a line 1-1 in Figure 2, shows that the delivery chamber 26 is connected to the delivery port by way of a venturi 28.
A bore 30 is formed in the driven gear 22 The bore 30 is coaxial with the bore 18 and with the gear 22 The gear 22 contains radial passages 32 which are equispaced round the axis of the bore 30 in a plane perpendicular to the latter, and which enable the bore 30 to communicate with the bore 18 and therefore with the chambers 24,26 The passages 32 connect the central bore 30 to the gaps between the adjacent teeth of the gear 22 A spool generally designated 33 is slidable in the bore 30 The spool has a central rod 34 which runs along the axis of the bore 30, and on which there are two bearing surfaces 36, 38 which, with the bore 30, define first and second end chambers 40, 42 and a central chamber 44 A spring 46 situated in the chamber 42 urges the spool 33 to the left in Figure 1 When the spool is in the idle position, the spring 46 biases it so that the bearing surface 38 blocks the radial passages 32, with the result that the bores 18, 30 do not communicate.
The driven gear 22 has journals 47, 49 which rotate respectively in a bearing 48 and in the casing A passage 50 formed in the casing 10, in the bearing 48 and in the journal 47 of the driven gear 22 connect the first end chamber 40 to the delivery chamber 26 Similarly, a passage 52 formed in the casing 10 and in the journal 49 of the gear 22 connects the neck 54 of the venturi 28 to the end chamber 42.
A further passage 56, containing an excess pressure valve 58, connects the delivery port 14 to the chamber 24.
The apparatus just described operates as follows.
The drive gear 20 rotates the driven gear 22 Fluid is thus trapped between the walls of the bores 16, 18 and the teeth of the respective pinions 20, 22 and flows from the intake chamber to the delivery chamber as indicated by solid arrows in Figure 2 The close engagement of the meshing gear teeth prevents the fluid from returning to the intake chamber Pressure is then generated in the delivery chamber, on account of the resistance due to the venturi 28 This pressure is transmitted to the first end chamber 40 and is exerted on the spool 33, counteracting the spring 46 Similarly, the pressure in the neck 54 of the venturi 28 is transmitted to the end chamber 42 by way of the passage 52 The pressure obtained in the neck 54 of the 70 venturi 28 is the lower pressure prevailing between the delivery chamber 26 and the delivery port 14 This pressure is termed the operating pressure Also, the operating pressure is a function of the flow rate in 75 the venturi.
When the flow rate of the pump is below its rated value, the pressures in the end chambers 40, 42 are such that the pressure difference between the two chambers is too 80 small to overcome the force of the spring 46 The spool remains in its idle position.
The route through the radial passages 32 is now blocked.
When the flow rate becomes equal to 85 or greater than its rated value, the pressure difference between the chambers 40, 42 is sufficient to overcome the force of the spring 46 The spool 33 is then moved to the right in Figure 1, possibly into its limit 90 position Fluid can now flow through the radial passages 32, producing a transfer of fluid from the delivery chamber to the intake chamber.
In response to an increase in the flow 95 rate, therefore, the pressure difference between the end chambers 40, 42 varies to cause excess fluid to return by way of the central chamber 44 and passages 32, so giving a constant flow rate at the delivery 100 port.
In a variant (not shown) of the embodiment which has just been described, the passage 52 is omitted and replaced by a passage in the casing connecting the end 105 chamber 42 to the delivery port The apparatus is less sensitive to variations in the flow rate, but still functions satisfactorily since it also is operated by a pressure difference representing the speed of the 110 motor.
Claims (9)
WHAT WE CLAIM IS: –
1 A hydraulic gear pump comprising a casing provided with an inlet port communicating with and on the upstream side 115 of an intake chamber, and a delivery port on the downstream side of a deliverv chamber, and communicating with the latter through a venturi, a drive gear meshing with a driven gear, each gear being 120 placed in a corresponding bore in the caning, the gears being placed in the flow path between the intake chamber and the delivery chamber, one of the gears containing a central bore to which lead 125 passages connecting the bore to the gaps between the adjacent teeth of the gear, a spool valve being slidable in the central bore, the movements of the spool being controlled by the pressure difference be 130 1 565 462 tween the fluid pressure in the delivery chamber, and an operating fluid pressure prevailing at or downstream of the neck of the venturi, so that the spool is held in a closed condition in which it blocks the route from the central bore through the passages to the said gaps, as long as said pressure difference remains below a given level.
2 A gear pump as claimed in Claim 1, wherein the spool is slidable inside the driven gear.
3 A gear pump as claimed in Claim 1 or Claim 2, wherein said spool comprises two bearing surfaces defining with the central bore two end chambers and a central chamber, the end chambers being exposed respectively to the fluid pressure in the delivery chamber and to the operating pressure, the route through the passages being blocked by one bearing surface of the spool when the latter is in its closed position, and the said route being open when the central chamber is opposite the passages due to movement of the spool.
4 A gear pump as claimed in any of the preceding claims, wherein the passages are situated in a plane perpendicular to the axis of the central bore.
A gear pump as claimed in any of 30 the preceding claims, wherein the passages are radial.
6 A gear pump as claimed in any of the preceding claims, wherein an excess pressure valve is situated between the outlet 35 orifice and the inlet orifice.
7 A gear pump as claimed in any of Claims 1 to 6, wherein the operating pressure is obtained from the neck of the venturi 40
8 A gear pump as claimed in any of Claims 1 to 6, wherein the operating pressure is obtained at the delivery port.
9 A gear pump substantially as hereinabove described, with reference to the 45 figures of the accompanying drawings.
For the Applicants:
F J CLEVELANDS & COMPANY Chartered Patent Agents, 40/43 Chancery Lane, London WC 2 A 1 JQ.
Printed for Her Majesty’s Stationery Office by The Tweeddule Press Ltd, Berwick-upon-Tweed, 1980 Published at the Patent Office, 25 Southampton Buildings, London, WC 2 A IAY, from which copies may be obtained
GB4254/77A
1976-02-10
1977-02-02
Gear pump
Expired
GB1565462A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
ES445021A
ES445021A1
(en)
1976-02-10
1976-02-10
Gear pump
Publications (1)
Publication Number
Publication Date
GB1565462A
true
GB1565462A
(en)
1980-04-23
Family
ID=8470886
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB4254/77A
Expired
GB1565462A
(en)
1976-02-10
1977-02-02
Gear pump
Country Status (5)
Country
Link
US
(1)
US4138204A
(en)
DE
(1)
DE2705584A1
(en)
ES
(1)
ES445021A1
(en)
FR
(1)
FR2341052A1
(en)
GB
(1)
GB1565462A
(en)
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
GB2312476A
(en)
*
1996-04-24
1997-10-29
Sauer Sundstrand Ltd
Pressure balance control in gear pumps
Families Citing this family (13)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US4298316A
(en)
*
1978-05-01
1981-11-03
Ford Motor Company
Power steering pump
US4322988A
(en)
*
1980-02-05
1982-04-06
Hill Charles S
Fluid braked planetary transmission
US4393651A
(en)
*
1980-09-02
1983-07-19
Chandler Evans Inc.
Fuel control method and apparatus
US4741675A
(en)
*
1986-08-04
1988-05-03
Hydreco, Incorporated
Flow control system for a hydraulic pump
US4746276A
(en)
*
1987-02-27
1988-05-24
Dana Corporation
Gear pump having conditional dry valve closure structure
DE19638335C2
(en)
*
1996-09-19
2000-07-20
Bosch Gmbh Robert
Feed pump
DE19927400A1
(en)
*
1998-06-24
1999-12-30
Luk Fahrzeug Hydraulik
Hydraulic advancing unit, eg for use in vehicles
GB2380524B
(en)
*
1998-06-24
2003-06-11
Luk Fahrzeug Hydraulik
Hydraulic delivery device
CZ211498A3
(en)
*
1998-07-03
2000-02-16
Jihostroj A. S.
Hydraulic speed governor of aircraft adjustable
US6729855B2
(en)
*
2002-02-01
2004-05-04
S & S Cycle, Inc.
Oil pump and gears
WO2005057013A1
(en)
*
2003-12-10
2005-06-23
Dieter Voigt
Engine speed-dependent pressure regulation of oil pumps
GB2452493B
(en)
*
2007-09-05
2012-05-23
Bamford Excavators Ltd
Pumping apparatus
CN111577568B
(en)
*
2020-06-02
2023-01-17
威海东椿电子有限公司
Synchronous belt constant delivery pump and method
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Priority date
Publication date
Assignee
Title
US2481646A
(en)
*
1943-08-18
1949-09-13
Western Electric Co
Variable delivery gear pump
US2629326A
(en)
*
1945-02-20
1953-02-24
Harold C White
Pump
US3120814A
(en)
*
1959-10-21
1964-02-11
Mueller Otto
Variable delivery and variable pressure vane type pump
US3153508A
(en)
*
1961-08-04
1964-10-20
Gen Turbine Corp
Vehicle mounted air compressor
DE1255369B
(en)
*
1963-02-20
1967-11-30
Danfoss As
Device on a pressure control valve
US3427980A
(en)
*
1965-03-22
1969-02-18
Rolls Royce
Gear pump
DE1751061C3
(en)
*
1968-03-27
1974-07-04
Michael Dipl.-Ing. Rolle May (Schweiz)
Externally ignited internal combustion engine charged by means of an exhaust gas turbocharger
US3527548A
(en)
*
1969-04-10
1970-09-08
Vilter Manufacturing Corp
Screw compressor with capacity control
NO142094B
(en)
*
1969-07-25
1980-03-17
Hydraulik Brattvaag As
HYDRAULIC SYSTEM.
US3751190A
(en)
*
1971-11-15
1973-08-07
Fiat Spa
Self regulating fluid pump
DE2219587A1
(en)
*
1972-04-21
1973-10-25
Teves Gmbh Alfred
VINGE CELL PUMP
DE2339872A1
(en)
*
1973-08-07
1975-02-20
Bosch Gmbh Robert
Pump or rotor gearwheel unit – has pressur medium fed between gearwheel teeth without connection between feed chamber and outflow chamber
CH566505A5
(en)
*
1974-04-09
1975-09-15
Von Roll Ag
1976
1976-02-10
ES
ES445021A
patent/ES445021A1/en
not_active
Expired
1977
1977-02-02
GB
GB4254/77A
patent/GB1565462A/en
not_active
Expired
1977-02-07
US
US05/766,315
patent/US4138204A/en
not_active
Expired – Lifetime
1977-02-09
FR
FR7703669A
patent/FR2341052A1/en
active
Granted
1977-02-10
DE
DE19772705584
patent/DE2705584A1/en
not_active
Withdrawn
Cited By (2)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
GB2312476A
(en)
*
1996-04-24
1997-10-29
Sauer Sundstrand Ltd
Pressure balance control in gear pumps
GB2312476B
(en)
*
1996-04-24
1999-12-08
Sauer Sundstrand Ltd
Pressure balance control in gear pumps
Also Published As
Publication number
Publication date
DE2705584A1
(en)
1977-08-11
US4138204A
(en)
1979-02-06
FR2341052A1
(en)
1977-09-09
FR2341052B1
(en)
1980-06-20
ES445021A1
(en)
1977-06-01
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Legal Events
Date
Code
Title
Description
1980-07-09
PS
Patent sealed [section 19, patents act 1949]
1987-09-16
PCNP
Patent ceased through non-payment of renewal fee
