EP2716912A1 - Balanced pressure dual pump - Google Patents
Balanced pressure dual pump Download PDFInfo
- Publication number
- EP2716912A1 EP2716912A1 EP12187673.4A EP12187673A EP2716912A1 EP 2716912 A1 EP2716912 A1 EP 2716912A1 EP 12187673 A EP12187673 A EP 12187673A EP 2716912 A1 EP2716912 A1 EP 2716912A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pump
- entity
- pressure
- outlet pressure
- dual outlet
- 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.)
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Classifications
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- 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
- F04C2/00—Rotary-piston machines or pumps
- F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C2/10—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
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- 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
- F04C11/00—Combinations of two or more machines or pumps, each being of rotary-piston or oscillating-piston type; Pumping installations
- F04C11/001—Combinations of two or more machines or pumps, each being of rotary-piston or oscillating-piston type; Pumping installations of similar working principle
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- 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
- F04C14/02—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations specially adapted for several machines or pumps connected in series or in parallel
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- 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
- F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
- F04C15/0042—Systems for the equilibration of forces acting on the machines or pump
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- 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
- F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
- F04C15/06—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
- F04C15/062—Arrangements for supercharging the working space
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- 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
- F04C2/00—Rotary-piston machines or pumps
- F04C2/30—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
- F04C2/34—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members
- F04C2/344—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
Definitions
- the present invention concerns a dual outlet pressure pump comprising a first pump entity and a second pump entity and more particularly a dual outlet pressure pump whereby a first pump rotor and a second pump rotor are operatively arranged on a common drive shaft to convey a fluid.
- the present invention further concerns a hydraulic control system for a continuously variable transmission of a vehicle, comprising a dual outlet pressure pump.
- variable displacement vane pumps have been considered for use as oil pumps for vehicle transmissions and engines.
- energy required to pressurize unneeded oil can be saved and thus energy efficiency of the pump, and the entire vehicle, can be improved.
- Single pump hydraulic systems are particularly inefficient in applications requiring high-pressure fluid because the single pump continues to deliver high flow, high pressure fluid even when only low flow is needed. This results in unnecessary consumption of power from the vehicle engine or battery and may tend to reduce the overall life of the pump.
- Multiple pump systems are designed to minimize this undesirable behavior by providing an additional pump that can be activated to deliver a required fluid flow rate or pressure depending upon the operating conditions.
- a hydraulic fluid supply system that utilizes a split-pressure configuration in cooperation with first and second pumps to continuously deliver variable flow, high-pressure fluid and fixed flow, low-pressure fluid, depending on the individual needs of two independent hydraulic circuits.
- a split-pressure hydraulic fluid supply circuit for supplying pressurized fluid to a multi-speed transmission.
- the split-pressure hydraulic fluid supply circuit includes a first pump, a second pump, a low-pressure circuit portion, and a high-pressure circuit portion.
- the first pump has both inlet and outlet ports, and is driven by the power source to provide a continuous flow of pressurized hydraulic fluid at a fixed rate.
- the second pump has an inlet port, an outlet port, and a regulator port, and is driven by the power source to provide a continuous flow of pressurized hydraulic fluid at variable rates.
- the low-pressure circuit portion includes a work circuit fluidly coupled to the first pump. The low-pressure circuit portion is adapted to supply all of the low-pressure hydraulic fluid needed by the multi-speed transmission.
- the high-pressure circuit portion includes a high-pressure work circuit fluidly coupled to the second pump. The high-pressure circuit portion is adapted to supply all of the high-pressure hydraulic fluid needed by the multi-speed transmission. No fluid coupling is provided between the high-pressure work circuit and the low-pressure work circuit.
- EP 2 441 985 A2 provides a hydraulic system for an automatic transmission which supplies oil from an oil reservoir to a high-pressure part and a low-pressure part, using a cascaded pump arrangement, which includes a first oil pump pumping up oil from the oil reservoir and supplying the oil to the low-pressure part, and a low-pressure regulating valve connected to a low-pressure part channel connecting the first oil pump with the low-pressure part, and controlling the pressure of the oil discharged from the first oil pump.
- a second oil pump receives the oil and supplies it to the high-pressure part of the hydraulic system.
- Object of the present invention is to provide pumps with the capability to provide fluids simultaneously at multiple pressure levels and flow rates.
- the pumps should combine improved wear resistance and longer service life with simplified construction and low cost and thereby improve known hydraulic control systems of said type in this respect.
- a dual outlet pressure pump comprising a first pump entity and a second pump entity, whereby a dual pump housing comprises a first pump rotor cavity and a second pump rotor cavity separated by a diaphragm with a bore and whereby a first pump rotor and a second pump rotor are operatively arranged on a common drive shaft to convey a fluid is provided.
- Angular placement of elements of the first pump entity relative to elements of the second pump entity about a pump axis is such, that the radial force exerted by the fluid pressure in a first pump discharge region of the first pump rotor cavity upon the first pump rotor is opposed in direction to the radial force exerted by the fluid pressure in a second pump discharge region of the second pump rotor cavity upon the second pump rotor.
- a hydraulic control system for a continuously variable transmission of a vehicle comprising a dual outlet pressure pump.
- the dual outlet pressure pump comprises a first pump entity and a second pump entity which are any combination of either a hydraulic rotary vane pump or a hydraulic gear pump.
- Rotary vane pumps and gear pumps are known in many designs and can be configured in many combinations to adapt to specific requirements of hydraulic control system applications. Combinations of two pump entities of the same type, such as rotary vane pump with rotary vane pump or gear pump with gear pump are useful. Preferred are combinations of a rotary vane pump and a gear pump as either the first or second pump entity. This allows a pump designer to combine complementary strengths of both pump types.
- an analogous "operational plane of symmetry” is an imagined plane through the axis of rotation of the pump rotor and the axis of said circular cylindrical pump rotor cavity.
- the imagined "operational plane of symmetry” divides the pump rotor cavity into a lower pressure pump suction region comprising the pump suction port and a higher pressure pump discharge region comprising the pump discharge port.
- it is the combined fluid pressure of the moving compartments formed between vanes of the rotary vane pump in the higher pressure pump discharge region that exerts a significant radial force on the rotary vane pump rotor and thus on the pump shaft supporting the rotary vane pump rotor.
- a preferred embodiment of the dual outlet pressure pump comprising either a hydraulic rotary vane pump and/or a hydraulic gear pump as the first pump entity and the second pump entity, said first and second pump entities are angularly aligned about the pump axis such that a first pump "operational plane of symmetry" and the second pump “operational plane of symmetry” intersect at a pointed angle and the first pump discharge region of the first pump rotor cavity and the second pump discharge region of the second pump rotor cavity are provided in opposite larger quadrants of the intersecting first and second pump "operational planes of symmetry".
- first pump discharge region of the first pump rotor cavity and the second pump suction region of the second pump rotor cavity are hydraulically connected through a connection passage.
- connection passage allows pump fluid to pass from the lower pressure pump directly to the higher pressure pump.
- the internal pressure drops of the two pumps are adding up and the maximum pressure level achievable with the same first and second pump entities is higher than in the embodiment without said connection passage.
- connection passage comprises a connection passage inlet which is located in the area of highest pressure of the first pump discharge region of the first pump rotor cavity.
- either the first pump entity or the second pump entity of the dual outlet pressure pump is a variable displacement pump. This allows the relative pumping capacity of the first and second pump entities to be altered although both are driven by the same drive shaft.
- either the first pump entity or the second pump entity is a fixed displacement pump.
- Fixed displacement pumps feature simple construction and reliable operation.
- the first pump entity is a lower pressure higher capacity pump and the second pump entity is a higher pressure lower capacity pump.
- This combination of pump entities is particularly useful as in many hydraulic systems there is a relatively large and variable need for fluid at low pressure and an often intermittent and limited need for fluid at high pressure.
- the first pump entity is a rotary vane pump.
- Rotary vane pumps are available as variable capacity and low pressure types.
- the second pump entity is a gerotor pump. A small gerotor pump is a nearly perfect choice for a higher pressure lower capacity pump.
- the axial bore of diaphragm of the dual pump housing of the dual outlet pressure pump according to the invention may comprise a bearing for additional performance and increased operating life.
- FIG. 1 shows schematically multiple sectional views of an exemplary preferred embodiment of the dual outlet pressure pump comprising a variable displacement vane pump (VDVP) as a first pump entity 10 and a small gerotor pump (designated as boost pump BP in Figures 2 to 5 ) as second pump entity 20.
- VDVP variable displacement vane pump
- boost pump BP boost pump in Figures 2 to 5
- Three schematic sectional views are aligned along a pump axis 40.
- the sectional view 30 in the center of Fig. 1 shows the dual pump housing 17 comprising a first pump rotor cavity 36, a second pump rotor cavity 39 and diaphragm 37 having a bore 38.
- Pump shaft 15 is arranged to extend through the bore 38.
- a connection passage 33 fluidly connecting first pump rotor cavity 36 and second pump rotor cavity 39.
- Connection passage 33 has a carefully designed connection passage inlet 32 and connection passage outlet 34.
- FIG. 1 shows the variable displacement vane pump in a sectional view.
- the pump has a first pump suction port 11 arranged in a low pressure (0 bar) first pump suction region 42.
- First pump rotor 16 is equipped with several vanes to fit into slide 13 which is tensioned by spring 14.
- Slide 13 is movably arranged inside dual pump housing 17. By varying a fluid pressure in control port 18 the position of slide 13 can be changed and thus the volumetric pumping capacity of the VDP can be varied according to hydraulic control system requirements.
- Second pump entity 20 is shown in sectional view B.
- a second pump inner rotor 26 is operatively arranged on pump shaft 15 and thus forced to rotate with the pump shaft.
- This rotation entrains rotation of a second pump outer rotor in the same direction, which appears as counterclockwise rotation of both second pump rotors in view B. Said rotation transports fluid from second pump suction region 46 (15 bar) to second pump discharge region 48 where it is discharged at high pressure (30 bar) through second pump discharge port 22.
- first pump shaft force vector 19 normal to a first pump operational plane of symmetry 41 in view A and points out of the plane of Fig. 1 in view 30 (also not shown).
- Figs. 2 - 4 show a dual outlet pressure pump operatively arranged in a hydraulic control system according to the invention.
- the hydraulic control system controls a continuously variable transmission in various operating modes.
- Arrows indicate oil flow in a hydraulic line.
- Crosses on oil line indicate that oil pressure in the line is maintained at low to medium level by the VDP - typically no significant flow of oil from the pumps.
- FIG. 2 shows a schematic view of a hydraulic control system for a continuously variable transmission in an "Idle" state.
- a first pump entity 10 in this example a variable displacement pump VDP
- a second pump entity 20 in this example designated as boost pump BP
- VDP variable displacement pump
- boost pump BP boost pump
- drive unit 80 In "Idle" mode drive unit 80 is supposed to run at 600 rpm.
- the 600 rpm rotation of pump shaft 15 drives the VDP at approximately 50% of theoretical pump capacity V th .
- the VDP transports oil from oil reservoir 90 through oil filter 91 and oil intake line 92 into low pressure oil line 94.
- a small fraction of the oil passes through connection passage 33 to boost pump BP and is transported by the boost pump into high pressure oil line 96.
- boost pump BP boost pump
- high pressure oil line 96 In "Idle” state all of the oil of high pressure oil line 96 is recycled through oil bypass line 98 to oil intake line 92 because no high pressure oil is needed by primary pulley (PP) 65 and thus ratio control valve 55 is completely closed as shown in detail in insert 56.
- PP primary pulley
- Fig. 3 is a schematic view of a hydraulic control system for a continuously variable transmission in a "Speed UP" state of operation.
- Drive unit 80 is assumed to run at 1500 rpm.
- the ratio control valve 55 is now partially open and the VDP is filling the primary pulley 65 to increase the gear ratio.
- the boost pump assists the VDP in reaching and maintaining a desired (medium) pressure level in the primary pulley 65.
- Fig. 4 shows schematically the hydraulic control system of Figs. 2 and 3 in a "Constant Speed" state of operation.
- the VDP runs at a fraction of its V th and at a relatively low pressure.
- the primary and secondary pulleys are maintained at the appropriate level and lockup clutch 86 is engaged. Most of the oil is recycled over the bypass lines 98.
- Fig. 5 shows the hydraulic control system of Figs. 2 , 3 and 4 in a "Speed DOWN" state of operation.
- the VDP runs at a significant fraction of its theoretical pump capacity and part of the oil (at medium pressure) is recycled through bypass lines 98.
- the VDP fills the secondary pulley 66 through the cramping pressure control valve 58 to gradually decrease the gear ratio.
- the ratio control valve 55 controls the oil flow out of the primary pulley 65.
- FIG. 6 is a series of sectional views showing different embodiments of a variable displacement vane pump with enhanced discharge port as disclosed in US 8 118 575 B2 .
- "Gen I” designates an original design and "Gen II” and “Gen III” show proposed alternative designs of an enhanced discharge port of said variable displacement vane pump.
- the most preferable solution shown in “Gen III” requires much extra space in the pump discharge region.
- the invention thus allows a particularly compact construction and relatively low production costs for a dual outlet pressure pump in a hydraulic control system for a continuously variable transmission of a vehicle.
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Abstract
Description
- The present invention concerns a dual outlet pressure pump comprising a first pump entity and a second pump entity and more particularly a dual outlet pressure pump whereby a first pump rotor and a second pump rotor are operatively arranged on a common drive shaft to convey a fluid. The present invention further concerns a hydraulic control system for a continuously variable transmission of a vehicle, comprising a dual outlet pressure pump.
- It is well known to utilize one or more fixed displacement pumps in continuously variable and other automated transmissions of vehicles. More recently, also variable displacement vane pumps have been considered for use as oil pumps for vehicle transmissions and engines. By providing a suitable control mechanism to alter the capacity of the pump to provide only the amount of pressurized lubrication oil necessary for proper operation of the engine, energy required to pressurize unneeded oil can be saved and thus energy efficiency of the pump, and the entire vehicle, can be improved.
- Single pump hydraulic systems are particularly inefficient in applications requiring high-pressure fluid because the single pump continues to deliver high flow, high pressure fluid even when only low flow is needed. This results in unnecessary consumption of power from the vehicle engine or battery and may tend to reduce the overall life of the pump.
- Multiple pump systems are designed to minimize this undesirable behavior by providing an additional pump that can be activated to deliver a required fluid flow rate or pressure depending upon the operating conditions.
- In
US 8 128 377 B2 a hydraulic fluid supply system is disclosed that utilizes a split-pressure configuration in cooperation with first and second pumps to continuously deliver variable flow, high-pressure fluid and fixed flow, low-pressure fluid, depending on the individual needs of two independent hydraulic circuits. In one embodiment of the disclosed invention, a split-pressure hydraulic fluid supply circuit for supplying pressurized fluid to a multi-speed transmission is provided. The split-pressure hydraulic fluid supply circuit includes a first pump, a second pump, a low-pressure circuit portion, and a high-pressure circuit portion. The first pump has both inlet and outlet ports, and is driven by the power source to provide a continuous flow of pressurized hydraulic fluid at a fixed rate. The second pump has an inlet port, an outlet port, and a regulator port, and is driven by the power source to provide a continuous flow of pressurized hydraulic fluid at variable rates. The low-pressure circuit portion includes a work circuit fluidly coupled to the first pump. The low-pressure circuit portion is adapted to supply all of the low-pressure hydraulic fluid needed by the multi-speed transmission. The high-pressure circuit portion includes a high-pressure work circuit fluidly coupled to the second pump. The high-pressure circuit portion is adapted to supply all of the high-pressure hydraulic fluid needed by the multi-speed transmission. No fluid coupling is provided between the high-pressure work circuit and the low-pressure work circuit. -
EP 2 441 985 A2 provides a hydraulic system for an automatic transmission which supplies oil from an oil reservoir to a high-pressure part and a low-pressure part, using a cascaded pump arrangement, which includes a first oil pump pumping up oil from the oil reservoir and supplying the oil to the low-pressure part, and a low-pressure regulating valve connected to a low-pressure part channel connecting the first oil pump with the low-pressure part, and controlling the pressure of the oil discharged from the first oil pump. A second oil pump receives the oil and supplies it to the high-pressure part of the hydraulic system. - The known systems using multiple pumps to provide hydraulic fluid at different pressure levels and flow rates help to save energy but are often complicated in design and expensive to manufacture. Simplified and more affordable designs suffer from increased wear on components.
- Object of the present invention is to provide pumps with the capability to provide fluids simultaneously at multiple pressure levels and flow rates. The pumps should combine improved wear resistance and longer service life with simplified construction and low cost and thereby improve known hydraulic control systems of said type in this respect.
- The object is achieved by a dual outlet pressure pump with the features of
claim 1. - According to the invention, a dual outlet pressure pump comprising a first pump entity and a second pump entity, whereby a dual pump housing comprises a first pump rotor cavity and a second pump rotor cavity separated by a diaphragm with a bore and whereby a first pump rotor and a second pump rotor are operatively arranged on a common drive shaft to convey a fluid is provided. Angular placement of elements of the first pump entity relative to elements of the second pump entity about a pump axis is such, that the radial force exerted by the fluid pressure in a first pump discharge region of the first pump rotor cavity upon the first pump rotor is opposed in direction to the radial force exerted by the fluid pressure in a second pump discharge region of the second pump rotor cavity upon the second pump rotor.
- By not simply stacking pump entities of known design onto a common drive shaft, but instead consciously placing and aligning pump elements such as pump suction ports and pump discharge ports or eccentric pump rotor cavities, vibrations and wear of dual outlet pressure pump components can be significantly reduced. Many different types and of asymmetric pumps of widely differing capacities can be successfully combined by following the principles outlined in the present invention.
- The object is further achieved by a hydraulic control system for a continuously variable transmission of a vehicle, comprising a dual outlet pressure pump.
- The directional terms "axial" and "radial" in the context of the present invention always relate to the axis of the rotating pump shaft.
- Refinements of the invention are given in the subclaims, the description and the enclosed drawings.
- Preferably the dual outlet pressure pump comprises a first pump entity and a second pump entity which are any combination of either a hydraulic rotary vane pump or a hydraulic gear pump.
- Rotary vane pumps and gear pumps are known in many designs and can be configured in many combinations to adapt to specific requirements of hydraulic control system applications. Combinations of two pump entities of the same type, such as rotary vane pump with rotary vane pump or gear pump with gear pump are useful. Preferred are combinations of a rotary vane pump and a gear pump as either the first or second pump entity. This allows a pump designer to combine complementary strengths of both pump types.
- Many of the abovementioned rotary vane pumps and gear pumps can be said to comprise an "operational plane of symmetry". In an internal gear pump such as a gerotor pump an imagined plane through the axis of rotation of a gerotor pump inner rotor and the axis of rotation of a gerotor pump outer rotor is fixed with respect to the gerotor pump housing. This imagined "operational plane of symmetry" divides the pump rotor cavity into a lower pressure pump suction region comprising the pump suction port and a higher pressure pump discharge region comprising the pump discharge port. It is the fluid pressure in the higher pressure pump discharge region that exerts a significant radial force on the gerotor pump inner rotor and thus on the pump shaft supporting the gerotor pump inner rotor.
- In the case of a rotary vane pump having a circular cylindrical pump rotor cavity an analogous "operational plane of symmetry" is an imagined plane through the axis of rotation of the pump rotor and the axis of said circular cylindrical pump rotor cavity. In this example again the imagined "operational plane of symmetry" divides the pump rotor cavity into a lower pressure pump suction region comprising the pump suction port and a higher pressure pump discharge region comprising the pump discharge port. But here it is the combined fluid pressure of the moving compartments formed between vanes of the rotary vane pump in the higher pressure pump discharge region that exerts a significant radial force on the rotary vane pump rotor and thus on the pump shaft supporting the rotary vane pump rotor.
- A preferred embodiment of the dual outlet pressure pump comprising either a hydraulic rotary vane pump and/or a hydraulic gear pump as the first pump entity and the second pump entity, said first and second pump entities are angularly aligned about the pump axis such that a first pump "operational plane of symmetry" and the second pump "operational plane of symmetry" intersect at a pointed angle and the first pump discharge region of the first pump rotor cavity and the second pump discharge region of the second pump rotor cavity are provided in opposite larger quadrants of the intersecting first and second pump "operational planes of symmetry".
- In a further preferred embodiment of the inventive dual outlet pressure pump the first pump discharge region of the first pump rotor cavity and the second pump suction region of the second pump rotor cavity are hydraulically connected through a connection passage.
- Said connection passage allows pump fluid to pass from the lower pressure pump directly to the higher pressure pump. The internal pressure drops of the two pumps are adding up and the maximum pressure level achievable with the same first and second pump entities is higher than in the embodiment without said connection passage.
- In a preferred embodiment of the dual outlet pressure pump said connection passage comprises a connection passage inlet which is located in the area of highest pressure of the first pump discharge region of the first pump rotor cavity. By locating the connection passage inlet close to the point of highest pressure of said connection passage inlet flow characteristics of the first pump entity can be significantly improved. Zones of reverting flow of high pressure fluid are minimized whereby pump friction is reduced. Guiding pump fluid through a streamlined connection passage inlet right through the diaphragm of the dual pump housing solves many common problems in hydraulic pump outlet design and allows for a very compact dual outlet pressure pump scheme.
- According to a further embodiment of the invention either the first pump entity or the second pump entity of the dual outlet pressure pump is a variable displacement pump. This allows the relative pumping capacity of the first and second pump entities to be altered although both are driven by the same drive shaft.
- In a further embodiment of the invention either the first pump entity or the second pump entity is a fixed displacement pump. Fixed displacement pumps feature simple construction and reliable operation.
- In another preferred embodiment of the dual outlet pressure pump the first pump entity is a lower pressure higher capacity pump and the second pump entity is a higher pressure lower capacity pump. This combination of pump entities is particularly useful as in many hydraulic systems there is a relatively large and variable need for fluid at low pressure and an often intermittent and limited need for fluid at high pressure.
- Preferably the first pump entity is a rotary vane pump. Rotary vane pumps are available as variable capacity and low pressure types. Also preferably is the second pump entity is a gerotor pump. A small gerotor pump is a nearly perfect choice for a higher pressure lower capacity pump.
- The axial bore of diaphragm of the dual pump housing of the dual outlet pressure pump according to the invention may comprise a bearing for additional performance and increased operating life.
- The invention is described below as an example with reference to the drawings.
- Fig. 1
- shows multiple sectional views of a dual pump according to the present invention.
- Fig. 2
- is a schematic view of a hydraulic control system for a continuously variable transmission in an "Idle" state.
- Fig. 3
- is a schematic view of a hydraulic control system for a continuously variable transmission in a "Speed UP" state of operation.
- Fig. 4
- is a schematic view of a hydraulic control system for a continuously variable transmission in a "Constant Speed" state of operation.
- Fig. 5
- is a schematic view of a hydraulic control system for a continuously variable transmission in a "Speed DOWN" state of operation.
- Fig. 6
- shows several embodiments of a variable displacement vane pump with enhanced discharge port as known in the prior art.
-
Figure 1 shows schematically multiple sectional views of an exemplary preferred embodiment of the dual outlet pressure pump comprising a variable displacement vane pump (VDVP) as afirst pump entity 10 and a small gerotor pump (designated as boost pump BP inFigures 2 to 5 ) assecond pump entity 20. Three schematic sectional views are aligned along apump axis 40. Thesectional view 30 in the center ofFig. 1 shows thedual pump housing 17 comprising a firstpump rotor cavity 36, a secondpump rotor cavity 39 anddiaphragm 37 having abore 38.Pump shaft 15 is arranged to extend through thebore 38. Also shown is aconnection passage 33 fluidly connecting firstpump rotor cavity 36 and secondpump rotor cavity 39.Connection passage 33 has a carefully designedconnection passage inlet 32 andconnection passage outlet 34. - View A of
Fig. 1 shows the variable displacement vane pump in a sectional view. The pump has a firstpump suction port 11 arranged in a low pressure (0 bar) firstpump suction region 42.First pump rotor 16 is equipped with several vanes to fit intoslide 13 which is tensioned byspring 14.Slide 13 is movably arranged insidedual pump housing 17. By varying a fluid pressure incontrol port 18 the position ofslide 13 can be changed and thus the volumetric pumping capacity of the VDP can be varied according to hydraulic control system requirements. - Assumed is a rotary motion of
pump shaft 15 whereby the upper part ofshaft 15 moves into the plane ofFig. 1 inview 30. This rotation ofpump shaft 15 appears as clockwise rotation ofrotor 16 in view A. Fluid is transported from first pump suction region to first pump discharge region 44 (15 bar) and may be discharged through firstpump discharge port 12. Alternatively or simultaneously the fluid is transported throughconnection port 33 to a secondpump suction port 21 and a secondpump suction region 46 by the combined action offirst pump entity 10 andsecond pump entity 20.Second pump entity 20 is shown in sectional view B. A second pumpinner rotor 26 is operatively arranged onpump shaft 15 and thus forced to rotate with the pump shaft. This rotation entrains rotation of a second pump outer rotor in the same direction, which appears as counterclockwise rotation of both second pump rotors in view B. Said rotation transports fluid from second pump suction region 46 (15 bar) to secondpump discharge region 48 where it is discharged at high pressure (30 bar) through secondpump discharge port 22. - The high pressure fluid in second
pump discharge region 48 exerts a force on second pumpinner rotor 26 whereby the force is determined by the pressure difference between secondpump discharge region 48 and second pump suction region 46 (30 bar - 15 bar = 15 bar) and the diameter of second pumpinner rotor 26. Said force is transmitted to pumpshaft 15 and is shown as second pumpshaft force vector 29 normal to a second pump operational plane ofsymmetry 45 in view B and points into the plane ofFig. 1 in view 30 (not shown). - The force exerted by intermediate pressure (15 bar) fluid in the
discharge region 44 of the first pump is shown as first pumpshaft force vector 19 normal to a first pump operational plane ofsymmetry 41 in view A and points out of the plane ofFig. 1 in view 30 (also not shown). -
Figs. 2 - 4 show a dual outlet pressure pump operatively arranged in a hydraulic control system according to the invention. The hydraulic control system controls a continuously variable transmission in various operating modes. Arrows indicate oil flow in a hydraulic line. Crosses on oil line indicate that oil pressure in the line is maintained at low to medium level by the VDP - typically no significant flow of oil from the pumps. -
Figure 2 shows a schematic view of a hydraulic control system for a continuously variable transmission in an "Idle" state. A first pump entity 10 (in this example a variable displacement pump VDP) and a second pump entity 20 (in this example designated as boost pump BP) are operatively arranged on acommon pump shaft 15 which is driven by adrive unit 80 which is typically the crankshaft of a combustion engine of a vehicle. In "Idle"mode drive unit 80 is supposed to run at 600 rpm. The 600 rpm rotation ofpump shaft 15 drives the VDP at approximately 50% of theoretical pump capacity Vth. The VDP transports oil fromoil reservoir 90 throughoil filter 91 andoil intake line 92 into lowpressure oil line 94. A small fraction of the oil passes throughconnection passage 33 to boost pump BP and is transported by the boost pump into highpressure oil line 96. In "Idle" state all of the oil of highpressure oil line 96 is recycled throughoil bypass line 98 tooil intake line 92 because no high pressure oil is needed by primary pulley (PP) 65 and thusratio control valve 55 is completely closed as shown in detail ininsert 56. - In "Idle" state part of the low pressure oil flow passes through
valve compartment 50 throughtorque converter 85 intolubrication section 87 and back tooil reservoir 90. Part of the low pressure oil passes throughcheck valve 54 andoil return line 99 to theoil reservoir 90. A small amount of low pressure oil maintains belt cramping pressure insecondary pulley 66. Another small part of the low pressure oil is recycled to the VDP under control ofbypass valve 52 from where it is directed to controlport 18 of the VDP which in turn controls flow rate of the VDP. -
Fig. 3 is a schematic view of a hydraulic control system for a continuously variable transmission in a "Speed UP" state of operation.Drive unit 80 is assumed to run at 1500 rpm. During "Speed UP" the VDP runs at 100% of Vth. Theratio control valve 55 is now partially open and the VDP is filling theprimary pulley 65 to increase the gear ratio. The boost pump assists the VDP in reaching and maintaining a desired (medium) pressure level in theprimary pulley 65. -
Fig. 4 shows schematically the hydraulic control system ofFigs. 2 and3 in a "Constant Speed" state of operation. The VDP runs at a fraction of its Vth and at a relatively low pressure. The primary and secondary pulleys are maintained at the appropriate level and lockup clutch 86 is engaged. Most of the oil is recycled over the bypass lines 98. -
Fig. 5 shows the hydraulic control system ofFigs. 2 ,3 and4 in a "Speed DOWN" state of operation. The VDP runs at a significant fraction of its theoretical pump capacity and part of the oil (at medium pressure) is recycled through bypass lines 98. The VDP fills thesecondary pulley 66 through the crampingpressure control valve 58 to gradually decrease the gear ratio. Theratio control valve 55 controls the oil flow out of theprimary pulley 65. -
Figure 6 is a series of sectional views showing different embodiments of a variable displacement vane pump with enhanced discharge port as disclosed inUS 8 118 575 B2 . "Gen I" designates an original design and "Gen II" and "Gen III" show proposed alternative designs of an enhanced discharge port of said variable displacement vane pump. The most preferable solution shown in "Gen III" requires much extra space in the pump discharge region. By using a variable displacement vane pump and providing a connection passage and a connection passage inlet according to the present invention flow behavior and friction is improved significantly without the extra space requirement of the "Gen III" solution. - The invention thus allows a particularly compact construction and relatively low production costs for a dual outlet pressure pump in a hydraulic control system for a continuously variable transmission of a vehicle.
-
- 10
- First Pump Entity
- 11
- First Pump Suction Port
- 12
- First Pump Discharge Port
- 13
- Slide
- 14
- Spring
- 15
- Pump Shaft
- 16
- First Pump Rotor
- 17
- Dual Pump Housing
- 18
- Control Port (of VDP)
- 19
- First Pump Shaft Force Vector
- 20
- Second Pump Entity / Boost Pump (BP)
- 21
- Second Pump Suction Port
- 22
- Second Pump Discharge Port (30 bar)
- 23
- Second Pump (GeRotor) Outer Rotor
- 26
- Second Pump (GeRotor Inner) Rotor
- 29
- Second Pump Shaft Force Vector
- 30
- Sectional View of Dual Pump
- 32
- Connection Passage Inlet
- 33
- Connection Passage
- 34
- Connection Passage Outlet
- 36
- First Pump Rotor Cavity
- 37
- Diaphragm
- 38
- Axial Bore
- 39
- Second Pump Rotor Cavity
- 40
- Pump Axis
- 41
- First Pump Operational Plane of Symmetry
- 42
- First Pump Suction Region
- 44
- First Pump Discharge Region
- 45
- Second Pump Operational Plane of Symmetry
- 46
- Second Pump Suction Region
- 48
- Second Pump Discharge Region
- 50
- Valve Compartment
- 52
- Bypass Valve
- 54
- Check Valve
- 55
- Ratio Control Valve
- 56
- Expanded Sectional View of Ratio Control Valve
- 58
- Cramping Pressure Control Valve
- 65
- Primary Pulley (PP)
- 66
- Secondary Pulley (SP)
- 80
- Drive Unit
- 85
- Torque Converter (T/C)
- 86
- Lockup Clutch
- 87
- Lubrication Section
- 90
- Oil Reservoir
- 91
- Oil Filter
- 92
- Oil Intake Line
- 94
- Low Pressure Oil Line (Plow)
- 96
- High Pressure Oil Line (Phigh)
- 98
- Oil Bypass Lines
- 99
- Oil Return/Dump Lines
- CVT
- Continuously Variable Transmission
- LHPA
- Local High Pressure Area
- NEDC
- New European Driving Cycle (Standard/Richtlinie ECE)
- TCU
- Transmission Control Unit
- VD(V)P
- Variable Displacement (Vane) Pump
- Vth
- Percentage of Theoretical Pump Capacity
Claims (13)
- A dual outlet pressure pump comprising a first pump entity (10) and a second pump entity (20), whereby a dual pump housing (17) comprises a first pump rotor cavity (36) and a second pump rotor cavity (39) separated by a diaphragm (37) with an axial bore (38) and whereby a first pump rotor (16) and a second pump rotor (26) are operatively arranged on a common drive shaft (15) to convey a fluid,
characterized in that
the angular placement of elements of the first pump entity (10) relative to elements of the second pump entity (20) about a pump axis (40) is such, that the radial force exerted by the fluid pressure in a first pump discharge region (44) of the first pump rotor cavity (36) upon the first pump rotor (16) is opposed in direction to the radial force exerted by the fluid pressure in a second pump discharge region (48) of the second pump rotor cavity (39) upon the second pump rotor (26). - The dual outlet pressure pump as claimed in claim 1,
characterized in that
the first pump entity (10) and the second pump entity (20) are any combination of either a hydraulic rotary vane pump or a hydraulic gear pump. - The dual outlet pressure pump as claimed in claim 2,
characterized in that
the first pump entity (10) and the second pump entity (20) are angularly aligned about the pump axis (40) such that a first pump operational plane of symmetry (41) and a second pump operational plane of symmetry (45) intersect at a pointed angle and the first pump discharge region (44) of the first pump rotor cavity (36) and the second pump discharge region (48) of the second pump rotor cavity (39) are provided in opposite larger quadrants of the intersecting first and second pump operational planes of symmetry. - The dual outlet pressure pump as claimed in any of the preceding claims,
characterized in that
the first pump discharge region (44) of the first pump rotor cavity (36) and a second pump suction region (46) of the second pump rotor cavity (39) are hydraulically connected through a connection passage (33). - The dual outlet pressure pump as claimed in claim 4,
characterized in that
said connection passage (33) comprises a connection passage inlet (32) which is located in the area of highest pressure of the first pump discharge region (44) of the first pump rotor cavity (36). - The dual outlet pressure pump as claimed in any of the preceding claims,
characterized in that
the first pump entity (10) is a lower pressure pump and the second pump entity (20) is a higher pressure pump. - The dual outlet pressure pump as claimed in any of the preceding claims,
characterized in that
either the first pump entity (10) or the second pump entity (20) is a variable displacement pump. - The dual outlet pressure pump as claimed in any of the preceding claims,
characterized in that
either the first pump entity (10) or the second pump entity (20) is a fixed displacement pump. - The dual outlet pressure pump as claimed in any of the preceding claims,
characterized in that
the first pump entity (10) is a lower pressure higher capacity pump and the second pump entity (20) is a higher pressure lower capacity pump. - The dual outlet pressure pump as claimed in any of the preceding claims,
characterized in that
the first pump entity (10) is a rotary vane pump. - The dual outlet pressure pump as claimed in any of the preceding claims,
characterized in that
the second pump entity (20) is a gerotor pump. - The dual outlet pressure pump as claimed in any of the preceding claims,
characterized in that
the axial bore (38) of diaphragm (37) of the dual pump housing (17) comprises a bearing. - A hydraulic control system for a continuously variable transmission of a vehicle, comprising a dual outlet pressure pump as claimed in claim 1.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP12187673.4A EP2716912A1 (en) | 2012-10-08 | 2012-10-08 | Balanced pressure dual pump |
PCT/JP2013/005955 WO2014057649A2 (en) | 2012-10-08 | 2013-10-07 | Balanced Pressure Dual Pump |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP12187673.4A EP2716912A1 (en) | 2012-10-08 | 2012-10-08 | Balanced pressure dual pump |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2716912A1 true EP2716912A1 (en) | 2014-04-09 |
Family
ID=47010356
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP12187673.4A Withdrawn EP2716912A1 (en) | 2012-10-08 | 2012-10-08 | Balanced pressure dual pump |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP2716912A1 (en) |
WO (1) | WO2014057649A2 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010026767A1 (en) * | 2000-03-27 | 2001-10-04 | Masatoshi Takagi | Trochoid gear type fuel pump |
US20020053829A1 (en) * | 1998-04-22 | 2002-05-09 | Denso Corporation | Pump equipment and method for assembling same |
US8118575B2 (en) | 2008-04-25 | 2012-02-21 | Magna Powertrain Inc. | Variable displacement vane pump with enhanced discharge port |
US8128377B2 (en) | 2007-04-03 | 2012-03-06 | GM Global Technology Operations LLC | Split-pressure dual pump hydraulic fluid supply system for a multi-speed transmission and method |
EP2441985A2 (en) | 2010-10-12 | 2012-04-18 | Hyundai Motor Company | Oil supply system of automatic transmission |
-
2012
- 2012-10-08 EP EP12187673.4A patent/EP2716912A1/en not_active Withdrawn
-
2013
- 2013-10-07 WO PCT/JP2013/005955 patent/WO2014057649A2/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020053829A1 (en) * | 1998-04-22 | 2002-05-09 | Denso Corporation | Pump equipment and method for assembling same |
US20010026767A1 (en) * | 2000-03-27 | 2001-10-04 | Masatoshi Takagi | Trochoid gear type fuel pump |
US8128377B2 (en) | 2007-04-03 | 2012-03-06 | GM Global Technology Operations LLC | Split-pressure dual pump hydraulic fluid supply system for a multi-speed transmission and method |
US8118575B2 (en) | 2008-04-25 | 2012-02-21 | Magna Powertrain Inc. | Variable displacement vane pump with enhanced discharge port |
EP2441985A2 (en) | 2010-10-12 | 2012-04-18 | Hyundai Motor Company | Oil supply system of automatic transmission |
Also Published As
Publication number | Publication date |
---|---|
WO2014057649A3 (en) | 2014-06-26 |
WO2014057649A2 (en) | 2014-04-17 |
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