GB2554677A

GB2554677A - Vane pump

Info

Publication number: GB2554677A
Application number: GB1616779.3A
Authority: GB
Inventors: Guerrato Diego
Original assignee: Delphi International Operations Luxembourg SARL
Current assignee: Delphi International Operations Luxembourg SARL
Priority date: 2016-10-03
Filing date: 2016-10-03
Publication date: 2018-04-11
Anticipated expiration: 2036-10-03
Also published as: GB2554677B; KR102307758B1; GB201616779D0; WO2018065319A1; CN109804137A; KR20190057311A; CN109804137B

Abstract

A vane pump 12 whose rotor 20 is provided with a plurality of slots which each house a blade which is urged outwardly by a spring that is compressed at the inner end or the slot. The pump has an inlet 48 opening into a large volume chamber and an outlet 50 opening from a smaller volume chamber. The pump is characterised in that there is a second inlet (58, Figure 4) which opens in the inner end of slot so that fluid flows into the volume wherein the spring is compressed. The second opening may be curved and sized so that the slot can be filled over an extended angle of rotation. The opening may cover two thirds of the angle between consecutive slots. The rotor may be provided with grooves dug into the side face which open into the inner end of the slot so that fluid entering via the second opening can flow along them into the slot. These may be curved and of sized similarly to the second opening. Each blade may have sealing tips and a groove which allows flow along its length. Fuel injection equipment utilising such a vane pump is also disclosed.

Description

(54) Title of the Invention: Vane pump

Abstract Title: Pressure balancing vane pump (57) A vane pump 12 whose rotor 20 is provided with a plurality of slots which each house a blade which is urged outwardly by a spring that is compressed at the inner end or the slot. The pump has an inlet 48 opening into a large volume chamber and an outlet 50 opening from a smaller volume chamber. The pump is characterised in that there is a second inlet (58, Figure 4) which opens in the inner end of slot so that fluid flows into the volume wherein the spring is compressed.

FIG. 2

(continued on next page)

GB 2554677 A continuation (57) cont

The second opening may be curved and sized so that the slot can be filled over an extended angle of rotation. The opening may cover two thirds of the angle between consecutive slots. The rotor may be provided with grooves dug into the side face which open into the inner end of the slot so that fluid entering via the second opening can flow along them into the slot. These may be curved and of sized similarly to the second opening. Each blade may have sealing tips and a groove which allows flow along its length.

Fuel injection equipment utilising such a vane pump is also disclosed.

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CM

FIG.

X

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FIG. 2

FIG. 4

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FIG. 7

VANE PUMP

TECHNICAL FIELD

The present invention relates to a blade pump and more particularly to means for maintaining fluid pressure around the blades of the pump.

BACKGROUND OF THE INVENTION

In a blade pump, blades radially sliding in the slots of a rotor move in and out of their slots as a function of the rotation of the rotor. A fluid communication is provided to enable fluid to inwardly flow toward the bottom of the slot in order to compensate for pressure drops and spikes when the blade moves.

In diesel injection equipment, blade pumps are typically utilized as feed pump drawing fuel from a low pressure tank and delivering it to a high pressure pump. Under certain conditions of the engine equipment, for instance at high RPM and low atmospheric pressure, pressure spikes are observed around the blade generating cavitation erosion at the rotor and disturbing the blade displacements and the feed pump operation.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to resolve the above mentioned problems in providing a blade pump having a housing with an inner plate, an outer plate and a peripheral liner defining an inner space in which a rotor is adapted to rotate about a main axis. The rotor has a first face sliding against the inner plate, a second face sliding against the outer plate and a peripheral cylindrical face. The rotor is provided with a plurality of slots which open in said peripheral face, a blade being slidably arranged in each slot and, a spring being compressed at the bottom, or inner end, of said slot, against the inner end of the blade, outwardly biasing said blade so that, the blade protrudes outside the slot and the outer end of the blade slides against said liner of the housing thus defining a plurality of arcuate chambers between the peripheral face of the rotor, the liner and the outer end of the blades. The volume of said chambers cyclically varies between large and small as the rotor rotates.

The blade pump is further provided with an inlet opening in a large volume chamber and, an outlet opening in the small volume chamber so that in use, a fluid entering the inlet fills a large volume and is compressed and pushed toward the outlet.

The blade pump is further provided with a second inlet opening in the inner end of the slot so that, in use, said fluid flows into the chamber via the first inlet and, into the volume wherein a spring is compressed via the second opening.

Also, the second inlet extends over an angular width enabling, in use, the inner end of the slot to be filled over an extended rotational angle of the rotor.

Said angular width is substantially two third of the angle between two consecutive slots.

Also, said second opening has an arcuate shape.

Also, the rotor is further provided with grooves dug in its first side face, each groove opening at an entry end in the inner end of the slot and extending in said first side face toward a closed end so that, in use, fluid entering via said second inlet flows into said groove toward the inner end of the slot while said inner end is no longer facing said second inlet.

Also, the groove extends over an angular width W enabling, in operation of the pump, the inner end of the slot to be filled over an extended time.

The angular width of the groove is substantially two third of the angle between two consecutive slots.

Also, each blade is having an outer end with two sealing tip edges, sliding against the liner and, a fluid communication channel extending through the blade from its inner end, where said channel opens in the inner end of the slot where the spring is compressed, to the outer end where said channel opens between said tip edges.

The invention further extends to a fuel pump assembly adapted to be arranged in a fuel injection equipment, said fuel pump assembly comprising a feed pump for drawing fuel from a low pressure tank and for delivering it to a high pressure pump, said feed pump being a blade pump as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now described by way of example with reference to the accompanying drawings in which:

Figure 1 is a section of a diesel pump comprising a blade pump and a high pressure pump.

Figure 2 is an axial section of the blade pump of figure 1 adapted to rotate about a main axis XI.

Figure 3 is a magnified view of a portion of figure 2, said view detailing the area of a blade in an axial XI section.

Figure 4 is a radial section of the blade pump of figure 2, said section enabling view of a first side face of the pump.

Figure 5 is a magnified view of figure 4 of an inlet area arranged in said first side face.

Figure 6 is a magnified view detailing the blade in an radial XI section.

Figure 7 is a 3D view of a rotor of the pump of figure 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In an internal combustion engine provided with a direct fuel injection equipment, a pump assembly 10 represented on figure 1 is adapted to draw fuel from a low pressure tank, to pressurize and to deliver said fuel to a high pressure reservoir from which it is distributed to fuel injectors.

The fuel pump assembly 10, which in the example chosen is a diesel pump, comprises a transfer pump 12 and a high pressure pump 14, both pumps being fixed to a cambox 16. A camshaft 18, adapted to rotate in said cambox 16, imparts rotational movement to the transfer pump 12 and reciprocal linear movements to one or more pistons of the high pressure pump 14.

The transfer pump 12 now described is a blade pump 12 represented and described in reference to the figures 2 to 7.

The typical blade pump 12 has a housing with peripheral walls defining an inner space S in which a rotor 20 rotates about a main axis XI. The peripheral walls comprise an inner plate 22, also identified as distribution plate 22, transverse to said main axis XI, an outer plate 24 also transverse to said main axis XI and, a peripheral liner 26 that defines a cylindrical track.

The rotor 20 has a cylindrical shape and it has a first face 28 adapted to slide against the inner face of the inner plate 22 of the housing, a parallel second face 30 adapted to slide against the inner face of the outer plate 24 of the housing and, a peripheral cylindrical face 32 distant from the liner 26.

The rotor 20 is provided with a plurality of slots 34 radially extending from an outer opening 36 in the peripheral face 32 to an inner end 38 closer to the axis XI. In each slot 34 is slidably arranged a blade 40 extending from an inner end 42 close to the inner end 38 of the slot, to an outer end 44 protruding from the slot through the outer opening 36 in the peripheral face of the rotor. Each blade 40 is outwardly pushed by a spring 46 compressed between the inner end 38 of the slot and an inner end 42 of the blade, the outer end 44 of the blade being biased in contact and sliding, in use, against the liner 26 of the housing. The main axis XI and the liner axis X2 being offset, the arrangement of the rotor in the housing defines between the peripheral face 32 of the rotor, the liner 26 of the housing and the outer end 44 of the blades, a plurality of arcuate chambers C which, in use as the rotor rotates, volume cyclically varies between a large volume and a small volume.

The blade pump 12 further comprises an inlet 48 and an outlet 50, both provided in the inner plate 22 of the housing, the inlet 48 opening in a first chamber Cl that volumes increases and, the outlet 50 opening in a second chamber C2 which volume decreases. The offset between the main axis XI and the liner axis X2 is set so the top of the rotor 20 is almost tangent to the liner and so the chamber at the top has a volume almost null while the volume of the chamber at the bottom is maximum.

In use fuel fills the first chamber Cl and, as the rotor 20 rotates about the main axis XI, said fuel is moved toward the outlet 50 and compressed. Exiting via the outlet 50, the fuel is delivered to the high pressure pump 14. Also as visible in figure 4 and magnified in figure 6, each blade 40 is provided with a double tip edge 52, 54 and with an inner channel 56 radially extending between the inner end 42 of the blade, where said channel opens in the spring compartment and, the outer end 44 of the blade, where said channel 52 opens between said two tip edges 52, 54, each of said tip edges 52, 54 sliding against the liner 26. In use, the blades 40 cyclically slide in and out of their respective slot 34 and, fuel flows through said channel 56 avoiding pressure drops and pressure spikes in the inner end 38 of the slots.

The inlet 48 and the outlet 50 are, as visible in the rear view of figure 4, elongated and arcuate openings diametrically opposed and arranged to cover an angular width that, in the exemplary embodiment chosen of a blade pump having four blades at 90° from each other, is approximately 90°. The rotor 20 rotating in the clockwise direction of figure 4, the narrowing tail of the first chamber Cl is visible through the inlet 48 while the narrowing head of the second chamber C2 is visible through the outlet 50.

The blade pump 12 is further provided with a second inlet 58 radially and inwardly arranged parallel to the first inlet 48. In the embodiment presented, said second inlet 58 also has an elongated and arcuate shape and also an angular width W58 of 90°. In other embodiments the second inlet 58 can be a simple hole. The radial distance between the first inlet 48 and the second inlet 58 is substantially the length of the slot 34 so that, as the first inlet 48 fills the first chamber Cl, the second inlet 58 directly fills in the spring compartment at the inner end 38 of the slot bypassing the channel 56.

Furthermore, the rotor 20 of the blade pump is provided with arcuate grooves 60 dug in the first face 28 of the rotor and extending from a large entry 62 opening in the inner end 38 of each slot toward a distant closed pointy end 64. As visible in the 3D view of figure 7, the grooves 60 extend on an arc of approximately slightly shorter than 80° at a substantially constant radial distance from the main axis XI and they have a shape narrowing as approaching said pointy end 64. As shown on the figures 4 and 5, the groove 60 passes in front of the second inlet 58 and, when a slot 34 exits the openings of the first 48 and second 58 inlets, the groove 60 continues to face the second inlet 58 keeping open a fluid communication from said second inlet 58 to the inner end 38 of the slot. In combining the angular width W58 of the second inlet 58 and the angular width W60 of the groove 60, in use, the inner end 38 of the groove remains in fluid communication with the inlet for an extended time corresponding roughly to a rotation of the rotor of about 170°. In a general case of a pump having N blades spread every 360°/N, the angular width W58 of the second inlet opening 58 is approximately of said angle 360°/N and, the angular width W60 of the groove 60 is slightly shorter than said angle 360°/N. Other embodiments are possible for the grooves 60 that instead of a narrowing shape may have a constant width. Also, in the figures, the grooves 60 follow the slots 34 meaning that, in use, the slot 34 passes first in front of the inlet and, the groove 60 follows.

LIST OF REFERENCES

XI main axis

S inner space

C chamber

Cl first chamber - inlet chamber C2 second chamber - outlet chamber

W58 angular width of the inlet W60 angular width of the groove fuel pump assembly transfer pump - blade pump high pressure pump cambox camshaft rotor inner plate of the housing outer plate of the housing liner first face of the rotor second face of the rotor peripheral face of the rotor slot outer opening inner end blade inner end of the blade outer end of the blade spring inlet outlet tip edge tip edge blade inner channel second inlet groove large entry of the groove pointy end of the groove - closed end

Claims

CLAIMS:

1. Vane pump (12) having a housing with an inner plate (22), an outer plate (24) and a peripheral liner (26) defining an inner space (S) in which a rotor (20) is adapted to rotate about a main axis (XI), the rotor (20) having a first face (28) sliding against the inner plate (22), a second face (30) sliding against the outer plate (24) and a peripheral cylindrical face (32), the rotor (20) being provided with a plurality of slots (34) which open in said peripheral face (32), a blade (40) being slidably arranged in each slot (34) and, a spring (46) being compressed at the bottom, or inner end (38), of said slot, against the inner end (42) of the blade, outwardly biasing said blade (40) so that, the blade protrudes outside the slot (34) and the outer end (44) of the blade slides against said liner (26) of the housing thus defining a plurality of arcuate chambers (C, Cl, C2) between the peripheral face (32) of the rotor, the liner (26) and the outer end (44) of the blades, the volume of said chambers (C, Cl, C2) cyclically varying between large and small as the rotor (20) rotates;

the blade pump (12) being further provided with an inlet (48) opening in a large volume chamber (Cl) and, an outlet (50) opening in the small volume chamber (C2) so that in use, a fluid entering the inlet (48) fills a large volume and is compressed and pushed toward the outlet (50), characterized in that the blade pump (12) is further provided with a second inlet (58) opening in the inner end (38) of the slot so that, in use, said fluid flows into the chamber (Cl) via the first inlet (48) and, into the volume wherein a spring is compressed via the second opening (58).

2. Vane pump (12) as claimed in the preceding claim wherein the second inlet (58) extends over an angular width (W) enabling, in use, the inner end (28) of the slot to be filled over an extended rotational angle of the rotor.

3. Vane pump (12) as claimed in claim 2 wherein said angular width is substantially two third of the angle between two consecutive slots.

4. Vane pump (12) as claimed in any one of the preceding claims wherein said second opening (58) has an arcuate shape.

5. Vane pump (12) as claimed in any one of the preceding claims wherein the rotor (20) is further provided with grooves (60) dug in its first side face (28), each groove (60) opening at an entry end (62) in the inner end (38) of the slot and extending in said first side face toward a closed end (64) so that, in use, fluid entering via said second inlet (58) flows into said groove (60) toward the inner end (38) of the slot while said inner end (38) is no longer facing said second inlet (58).

6. Vane pump (12) as claimed in claim 5 wherein said groove (60) extends over an angular width (W60) enabling, in operation of the pump (12), the inner end (38) of the slot to be filled over an extended time.

7. Vane pump (12) as claimed in claim 6 wherein said angular width (W60) of the groove is substantially two third of the angle between two consecutive slots (34).

8. Vane pump (12) as claimed in any one of the preceding claims wherein each blade (40) is having an outer end (44) with two sealing tip edges (52, 54) sliding against the liner (26) and, a fluid communication channel (56) extending through the blade (40) from its inner end (42), where said channel (56) opens in the inner end (38) of the slot where the spring (46) is compressed, to the outer end (44) where said channel (52) opens between said tip edges (52, 54).

9 Fuel pump assembly (10) adapted to be arranged in a fuel injection equipment, said fuel pump assembly (10) comprising a feed pump (12) for drawing fuel from a low pressure tank and for delivering it to a high pressure pump (14), said feed pump being a blade pump (12) as claimed in any one of the preceding claims.

Intellectual

Property

Office

Application No: GB 1616779.3 Examiner: Nicholas Wigley