EP0045928A1 - Power transmission - Google Patents
Power transmission Download PDFInfo
- Publication number
- EP0045928A1 EP0045928A1 EP19810106075 EP81106075A EP0045928A1 EP 0045928 A1 EP0045928 A1 EP 0045928A1 EP 19810106075 EP19810106075 EP 19810106075 EP 81106075 A EP81106075 A EP 81106075A EP 0045928 A1 EP0045928 A1 EP 0045928A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- flow
- inlet
- pump
- control valve
- fluid
- 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
Links
Images
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
Definitions
- This invention relates to hydraulic systems and particularly to hydraulic systems such as power steering systems which utilize a fixed displacement pump driven by a prime mover that operates at variable speeds.
- the system operates at a predetermined constant'volume controlled by a flow control valve.
- the flow control valve also provided the fluid mechanics for replenishing the flow directed to the power steering booster by bypassing some of the fluid to the inlet of the pump when the pump is operated at higher speeds.
- the restricted size of the passage for replenishing the flow by fluid returning from the power booster it is common that there may be excessive inlet vacuum and cavitational damage especially at larger control flows and at cold temperatures when the fluid is very viscous.
- Typical systems are shown in United States Patents 2,880,674 and 3,207,077.
- the present invention is intended to provide a hydraulic system which will adequately provide hydraulic fluid at the lower speeds before the flow control valve begins to bypass fluid, which will permit an increased control discharge flow range, which will lower the sound level of operation of the pump, which will produce less wear associated with cavitation, which will permit more effective use of the shaft seals because of the lesser tendency to draw vacuum, and which will increase the pressure of the inlet due to the normal replenishing by the flow control valve.
- an auxiliary passage extends from the reservoir and communicates with the inlet of the pump upstream from the system flow drawn from the reservoir by opening of the flow control valve and normally isolated during low speed operation from the bypass flow by the flow control valve thereby providing auxiliary flow to the inlet.
- the single drawing is a partly schematic view of a hydraulic system embodying the invention.
- the hydraulic system comprises a fixed displacement pump 10 driven by a prime mover such as the engine of an automotive vehicle to supply-fluid through an orifice 11 to a steering booster 12 such as a linear or rotary hydraulic motor.
- a prime mover such as the engine of an automotive vehicle
- a steering booster 12 such as a linear or rotary hydraulic motor.
- the return of fluid through a line 13 is to a reservoir 14.
- Fluid from the reservoir normally flows through a line 15 and a passage 16 to the inlet 17 of the pump.
- a flow control valve 18 comprising a spool 19 having spaced lands 20, 21 is provided in a bore 22 and is operable in accordance with well known practive to bypass the fluid when the volume exceeds a predetermined rate.
- a line 23 extends from the outlet of the pump and has an orifice 24 therein to the spring end of the spool.
- the land 21 moves to the broken line position causing a portion of the fluid to flow through line 25 between the land 21 and the edge of the bore into the inlet 17.
- the passage 16 aspirates further hydraulic fluid flow through the inlet thereby supplementing the flow of fluid to the pump at the higher speed.
- an auxiliary passage 26 is provided and communicates as shown diagrammatically by a line 27 with the reservoir 14. Passage 26 functions to provide supplemental flow of hydraulic fluid to the inlet 17 at the lower speeds. It is noted that the passage 26 is located upstream from the passage 16 and is hydraulically isolated from the fluid applied to the flow control valve when the flow control valve is in closed position.
- a hydraulic system embodying the invention provides improved filling at the inlet at the lower speeds before the flow control valve begins to bypass the discharge volume, lowers the sound level, reduces the wear and maintenance that might be caused by vacuum and cavitational damage.
- the additional passage also functions to increase the pressure at the inlet supplementing the supercharging normally provided by the flow control valve.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Details And Applications Of Rotary Liquid Pumps (AREA)
- Power Steering Mechanism (AREA)
- Reciprocating Pumps (AREA)
- Control Of Positive-Displacement Pumps (AREA)
Abstract
Description
- This invention relates to hydraulic systems and particularly to hydraulic systems such as power steering systems which utilize a fixed displacement pump driven by a prime mover that operates at variable speeds.
- In hydraulic systems utilizing fixed displacement pumps driven by variable speed prime movers such as utilized in power steering systems for automotive vehicles, the system operates at a predetermined constant'volume controlled by a flow control valve. The flow control valve also provided the fluid mechanics for replenishing the flow directed to the power steering booster by bypassing some of the fluid to the inlet of the pump when the pump is operated at higher speeds. However, in such a system, at the lower speeds, because of the restricted size of the passage for replenishing the flow by fluid returning from the power booster, it is common that there may be excessive inlet vacuum and cavitational damage especially at larger control flows and at cold temperatures when the fluid is very viscous. Typical systems are shown in United States Patents 2,880,674 and 3,207,077.
- Accordingly, the present invention is intended to provide a hydraulic system which will adequately provide hydraulic fluid at the lower speeds before the flow control valve begins to bypass fluid, which will permit an increased control discharge flow range, which will lower the sound level of operation of the pump, which will produce less wear associated with cavitation, which will permit more effective use of the shaft seals because of the lesser tendency to draw vacuum, and which will increase the pressure of the inlet due to the normal replenishing by the flow control valve.
- In accordance with the invention, an auxiliary passage extends from the reservoir and communicates with the inlet of the pump upstream from the system flow drawn from the reservoir by opening of the flow control valve and normally isolated during low speed operation from the bypass flow by the flow control valve thereby providing auxiliary flow to the inlet.
- The single drawing is a partly schematic view of a hydraulic system embodying the invention.
- In accordance with the invention as shown in Fig. 1, the hydraulic system comprises a fixed displacement pump 10 driven by a prime mover such as the engine of an automotive vehicle to supply-fluid through an orifice 11 to a
steering booster 12 such as a linear or rotary hydraulic motor. In a normal system, the return of fluid through aline 13 is to a reservoir 14. Fluid from the reservoir normally flows through a line 15 and apassage 16 to theinlet 17 of the pump. Aflow control valve 18 comprising aspool 19 having spacedlands bore 22 and is operable in accordance with well known practive to bypass the fluid when the volume exceeds a predetermined rate. Aline 23 extends from the outlet of the pump and has an orifice 24 therein to the spring end of the spool. When the volume exceeds a predetermined rate, theland 21 moves to the broken line position causing a portion of the fluid to flow throughline 25 between theland 21 and the edge of the bore into theinlet 17. Thepassage 16 aspirates further hydraulic fluid flow through the inlet thereby supplementing the flow of fluid to the pump at the higher speed. Such systems are old and shown in the aforementioned United States Patents 2,880,674 and 3,207,077 which should be referred to for details of construction. - In accordance with the invention, an
auxiliary passage 26 is provided and communicates as shown diagrammatically by aline 27 with the reservoir 14.Passage 26 functions to provide supplemental flow of hydraulic fluid to theinlet 17 at the lower speeds. It is noted that thepassage 26 is located upstream from thepassage 16 and is hydraulically isolated from the fluid applied to the flow control valve when the flow control valve is in closed position. - Thus, a hydraulic system embodying the invention provides improved filling at the inlet at the lower speeds before the flow control valve begins to bypass the discharge volume, lowers the sound level, reduces the wear and maintenance that might be caused by vacuum and cavitational damage. The additional passage also functions to increase the pressure at the inlet supplementing the supercharging normally provided by the flow control valve.
Claims (4)
said flow control valve (18) being operable when the flow exceeds a predetermined value to permit flow from the bypass flow passage (25) toward the inlet and aspirate flow from the system flow return to the inlet.
said flow control valve comprising a spool (19) in said bore having first and second lands (20,21),
said second land controlling the flow from said bypass flow passage (25) to the inlet upstream of the system flow return passage,
said auxiliary passage (26) intersecting said bore (22) between said lands (20,21) and isolated from said bypass flow return by said flow.control valve when said flow control valve is in position preventing flow from said bypass flow control . passage to said inlet.
directing fluid extending from the reservoir (14) to the inlet of the pump (20) upstream from the system flow return (16) drawn from the reservoir (14) by the flow control valve (18) and normally isolating said fluid during low speed operating from the bypass flow by the flow control valve thereby providing auxiliary flow to the inlet.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17736980A | 1980-08-11 | 1980-08-11 | |
US177369 | 1980-08-11 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0045928A1 true EP0045928A1 (en) | 1982-02-17 |
EP0045928B1 EP0045928B1 (en) | 1985-11-21 |
Family
ID=22648334
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19810106075 Expired EP0045928B1 (en) | 1980-08-11 | 1981-08-04 | Power transmission |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0045928B1 (en) |
JP (1) | JPS5752686A (en) |
AU (1) | AU545989B2 (en) |
CA (1) | CA1160538A (en) |
DE (1) | DE3172983D1 (en) |
IN (1) | IN153744B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1674729A2 (en) * | 2004-12-22 | 2006-06-28 | Kayaba Industry Co., Ltd. | Pump device |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3253607A (en) * | 1964-06-10 | 1966-05-31 | Trw Inc | Combination pump and flow regulator |
US3644065A (en) * | 1970-03-18 | 1972-02-22 | Bosch Gmbh Robert | Apparatus for filling the suction chamber of a pump at high-pump speeds |
GB2019940A (en) * | 1978-05-01 | 1979-11-07 | Ford Motor Co | Rotary positive-displacement fluidmachines |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5629510Y2 (en) * | 1977-02-18 | 1981-07-14 |
-
1981
- 1981-06-10 IN IN625/CAL/81A patent/IN153744B/en unknown
- 1981-06-15 CA CA000379723A patent/CA1160538A/en not_active Expired
- 1981-06-15 AU AU71850/81A patent/AU545989B2/en not_active Ceased
- 1981-07-14 JP JP56109923A patent/JPS5752686A/en active Granted
- 1981-08-04 EP EP19810106075 patent/EP0045928B1/en not_active Expired
- 1981-08-04 DE DE8181106075T patent/DE3172983D1/en not_active Expired
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3253607A (en) * | 1964-06-10 | 1966-05-31 | Trw Inc | Combination pump and flow regulator |
US3644065A (en) * | 1970-03-18 | 1972-02-22 | Bosch Gmbh Robert | Apparatus for filling the suction chamber of a pump at high-pump speeds |
GB2019940A (en) * | 1978-05-01 | 1979-11-07 | Ford Motor Co | Rotary positive-displacement fluidmachines |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1674729A2 (en) * | 2004-12-22 | 2006-06-28 | Kayaba Industry Co., Ltd. | Pump device |
EP1674729A3 (en) * | 2004-12-22 | 2012-10-17 | Kayaba Industry Co., Ltd. | Pump device |
Also Published As
Publication number | Publication date |
---|---|
JPS5752686A (en) | 1982-03-29 |
EP0045928B1 (en) | 1985-11-21 |
AU7185081A (en) | 1982-02-18 |
JPH0138708B2 (en) | 1989-08-16 |
IN153744B (en) | 1984-08-18 |
AU545989B2 (en) | 1985-08-08 |
DE3172983D1 (en) | 1986-01-02 |
CA1160538A (en) | 1984-01-17 |
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Owner name: DR. ING. A. RACHELI & C. |
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