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
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/047—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement with actuating or actuated elements at the outer ends of the cylinders
• • 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
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/047—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement with actuating or actuated elements at the outer ends of the cylinders
  • F04B1/0474—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement with actuating or actuated elements at the outer ends of the cylinders with two or more serially arranged radial piston-cylinder units
• • 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
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/06—Control
  • F04B1/07—Control by varying the relative eccentricity between two members, e.g. a cam and a drive shaft

Definitions

• the present invention relates to a radial piston pump for displacing liquids, with a pump housing, two lateral inlet covers with a liquid inlet and outlet covers with a liquid outlet, a rotatable drive shaft axially mounted in the covers, a rotor which is seated on the drive shaft and rotates with it, at least two in Corresponding cylinder spaces in the rotor guided radial pistons and a cylindrical guide ring arranged around the rotor and the pistons.
• the invention relates in particular to a pump for supplying fuel to the engines of an aircraft.
• the invention is not limited to this preferred application, but can also be used in other areas for the transport or displacement of liquids.
• the conventional pumps for supplying fuel to an aircraft engine are driven directly by the engines. Since these engines, with the exception of the landing process, run at a constant speed, the pumps are also operated at a constant speed, so that the delivery volume of the fuel is constant over time and must be calculated so that it can meet the highest fuel consumption. However, this fuel consumption depends on the flight conditions and is essentially determined by the pilot using the control lever.
• This control lever acts on a control device which is connected downstream of the fuel pump and which determines the power and the fuel consumption.
• the control device also experiences sensor-controlled control depending on various flight parameters such as altitude, pressure, etc., as well as electrical control to refine the hydraulic control.
• the control device accordingly receives a fuel quantity that is constant over time and feeds the associated engine with a smaller fuel quantity that changes over time.
• the difference or excess amount of fuel is branched off by the control device and returned to the fuel tank.
• the present invention is therefore based on the object of providing a radial piston pump which only transports as much liquid as is required by the associated consumer and the liquid conveyed serves at the same time to cool the pump.
• the radial piston pump according to the invention has the features provided in the main claim. Further refinements of the invention result from the subclaims.
• the pump according to the invention is accordingly a volumetric, controllable construction.
• the required volume flow is brought to the required level by radially arranged displacement pistons distributed over two levels Pressure level of about 80 ° -10 5 Pa brought and centrally displaced from the pump.
• the overheating problems are solved by using the amount of liquid transported as a coolant. A certain proportion of the ingested liquids only fills the whole Pump interior and is then ejected from the pump into the consumer. Since this proportion can be determined arbitrarily by a suitable choice of the cross sections of the individual holes, the pump can be operated under optimal conditions.
• FIG. 1 is a perspective view of a radial piston pump according to the invention.
• Fig. 2 is an exploded perspective view of the pump towards the inlet cover.
• Fig. 3 is an exploded perspective view of the pump towards the outlet cover.
• FIG. 4 is an axial section through the pump according to the invention along the section line IV-IV of FIG. 5.
• 5 is a diagonal section through the left piston group of FIG. 4.
• Figures 6 and 7 are perspective views of the inside and the outside of the inlet cover.
• Figures 8 and 9 are perspective views of the inside and the outside of the outlet cover.
• Fig. 10 is a perspective view of the rotor without the piston.
• FIG. 11 is a perspective view of the adjustable guide bearings.
• Figures 12 and 13 are perspective views of the guide bearings seated on the guide ring.
• FIGS. 1-10 show a preferred exemplary embodiment of a radial piston pump according to the invention for supplying an aircraft engine with fuel.
• the invention is not limited to this preferred application.
• the pump is arranged in a cylindrical pump housing 20.
• This housing is laterally closed by an inlet cover 22 and an outlet cover 24.
• a drive shaft 30 is rotatably mounted in the connecting pieces 26 and 28. This shaft 30 is driven at a constant speed of e.g. 8600 rpm driven by the aircraft engine via a reduction gear, not shown.
• a control device 32 is provided with which, as will be described below, the pump is controlled and the amount of fuel conveyed can be changed continuously.
• the structure of the radial piston pump is explained in more detail below, in particular with reference to FIGS. 2 to 5.
• the drive shaft 30 carries a rotor 34 which is fixedly connected to it and shown individually in FIG. 10 and has a number of radial bores or cylinder spaces 36 in which there are radially movable pistons 38.
• the rotor 34 comprises a right and a left group of five cylinder spaces 36r and 361, respectively, in which the right pistons 38r and the left pistons 381 are located.
• the number of pistons 38 and cylinder spaces 36 or the number of groups can also be larger or smaller.
• the pump must have at least two opposing pistons.
• pistons of one group are angularly offset in relation to the pistons of the other group.
• the pistons 38r are offset by 36 ° with respect to the pistons 381, that is to say that when a piston 381 of the left group, as shown in FIG. 5, is oriented to the south, a corresponding piston 38r the right group is oriented to the north. This ensures optimal balancing during rotation.
• each cylinder space 36 there is a compression spring 42 (see FIGS. 4 and 5) which is clamped between the base surface of the cylinder space 36 and the piston 38, preferably in a corresponding bore in the piston and accordingly acts on the piston 38 radially outwards.
• the rotor 34 is located in a cylindrical guide ring 44 on the inner surface of which the individual pistons 38r and 381 of each group are supported under the action of their springs 42.
• the top surface of the individual pistons 38 is a cylindrical surface with a smaller radius of curvature than that of the guide ring 44. Accordingly, there is only a linear tangential contact between the guide ring 44 and the individual pistons, as can be seen from FIGS. 4 and 5.
• the top surface of the pistons 38 could also be spherical and the contact with the guide ring accordingly punctiform. The reason for this is that in the pump according to the invention the top surface of the pistons is not a working surface but only a guide surface.
• the working surface of the individual pistons is namely, as can be seen below, the base surface of the individual pistons 38 facing the axis of rotation of the rotor 34.
• the rotor 34 is traversed from one side surface to the other by ten axially parallel bores 46. Each of these bores 46 crosses a corresponding cylinder space 36 and alternately forms the intake connection and the displacement connection with the individual pistons 38.
• the guide ring 44 is drum-shaped with two lateral annular radial walls which are formed in the vicinity of the drive shaft 30 as guide flanges 48, 50 which extend axially on both sides.
• the guide ring must be made in two parts due to a separation, not shown.
• the rotor 34 is coupled in the direction of rotation to the guide ring 44, so that both parts are driven together by the drive shaft 30 about their respective central axes.
• the clutch consists of driver pins 52 provided on the two radial inner sides of the guide ring 44, which engage in corresponding recesses 54 in the rotor 34 provided between the individual cylinder spaces 36. Accordingly, there are also ten driving bolts 52 and ten recesses 54. Each driving bolt 52 is surrounded by a driving ring 56, the outer diameter of which, as will be understood later, must be at least twice the central offset smaller than the inner diameter of the corresponding recess. These driver rings 56 are axial spacers between the rotor 34 and the guide ring 44.
• the guide ring 44 is radially displaceable relative to the rotor 34.
• the two guide flanges 48, 50 are rotatably mounted in two lateral guide bearings 58, 60.
• the two guide bearings 58, 60 have parallel flats 62 on two opposite sides, by means of which they rotate on corresponding inner flats 64 in the side edge 66 of the inlet cover 22 and in the side edge 68 of the outlet cover 24 are held in the housing and can be moved radially in a direction parallel to the flats 62, 64.
• the radial adjustment of the guide bearings 58, 60 and consequently of the guide ring 44 takes place via two lateral spacer bolts 70, 72 guided radially through the housing 20 and the side edges 66, 68 of the covers.
• the guide bearings 58, 60 are effective on the opposite side of the spacer bolts exposed by compression springs 74, 76.
• the radial adjustment of the spacer bolts 70, 72, against the action of the springs 74, 76, takes place via the control device 32.
• this can consist of an eccentric shaft 78 with two lateral cams 80, 82 and one that is rotatably mounted on the outside of the housing 20 Rocker arm 84 exist. When the lever 84 is tilted, the spacer bolts 70, 72 are adjusted radially.
• the axis of the guide ring 44 moves as shown in FIG. 5 at the set distance from the rotor axis.
• the rotor 34 now becomes rotated about its own axis and the guide ring 44 also about its own axis.
• the individual pistons 38 rotate with the guide ring 44 about its axis.
• the pistons 38 are also guided by the rotor 34, there is a relative movement between the individual pistons 38 and the rotor 34, although the individual pistons 38 do not move radially during rotation. Because there is no typical piston movement, mass balancing is not necessary. Balancing of the rotating parts is only necessary due to different manufacturing tolerances.
• the rotation in the cylinder spaces 36 results in a change in the size of the space at the center, which corresponds to twice the distance between the axes of the rotor 34 and the guide ring 44.
• the room size is smallest on the south side and largest on the north side.
• An essential point of the radial piston pump according to the invention is the flow of fuel through the pump because this flow provides both cooling and lubrication of the pump.
• the inlet cover 22 (see FIGS. 6 and 7) comprises a central hub 86 facing the rotor with an axial kidney-shaped slot 88.
• This slot 88 forms a connection to the individual axial bores 46 in the rotor 34 during the rotation of the rotor 34 Angular position is such that the slot 88 is on the left suction side described with reference to FIG. 5.
• the hub 86 also includes a number of radial openings 90 which connect the slot 88 to the pump interior.
• the cover also includes a ring of axial openings 92 which also lead to the pump interior.
• the outlet cover 24 (see FIGS. 8 and 9) likewise comprises a central hub 94 directed towards the rotor, but here with two opposite axial kidney-shaped slots 96, 98, the slot 96 being connected to the pump interior via radial openings 100, but not to the pump interior Outlet spout 28.
• the individual axial bores 46 also come into connection one after the other with the two slots 96, 98.
• the slots are arranged at an angle so that, based on FIG. 5, the slot 96 is located on the suction side and slot 98 on the displacement side.
• Fig. 4 the flow in Fig. 4 is indicated by arrows.
• the fuel flows into the pump on the left-hand side through the inlet connector 26 and the inlet cover 22.
• the fuel flowing through the axial openings 92 fills the pump interior and flows around all components. This proportion of fuel accordingly cools down and lubricates the individual components.
• cooling is a very important point because pumps can generate a lot of heat depending on the drive power and ambient temperature. Since the cooling or the removal of heat was carried out by the fuel, the cooling in the radial piston pump according to the invention is proportional to the throughput.
• cold medium is drawn in from the right-hand side and warmer medium is sucked in and discharged again from the right-hand side during the inlet process, the warmer medium being always at the center of rotation due to the centrifugal force and thus being displaced first from the operating space.
• the setting of the ratio of cold medium to warm medium can be done via the Cross-sections of the axial bores are made on both sides of the rotor.
• All wear parts such as bearings, intake and exhaust control etc. are made of silicon carbide, which means that an extremely long service life can be expected.
• FIGS. 4 and 5 are on a scale of 1: 1. In such a pump with 10 pistons with a diameter of 20 mm and a stroke change of 2 mm by the control device 84, at a speed of 8600 rpm. a throughput of 6480 L per hour is achieved.
• the high speed of the pump also saves huge reduction gears with the space and weight required for this.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Reciprocating Pumps (AREA)

Priority Applications (1)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8180932

Family Applications (1)

Country Status (1)

Cited By (4)

Citations (3)

• 2001
  • 2001-09-14 EP EP01203499A patent/EP1293667A1/fr not_active Withdrawn

Patent Citations (3)

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