VARIABLE DISPLACEMENT PUMP WITH AXIAL DISPLACEMENT OF THE VANES

Abstract

The present disclosure relates to a variable displacement vane pump, in particular for oil, comprising a body having a cavity wherein a movable ring slides in the longitudinal direction over the rotor which rotates around an axis and which is provided with vanes which are radially supported on the inner surface of the fixed ring of fixed eccentricity relative to the rotation axis of the rotor, and with movement means in the longitudinal direction of the movable ring according to a pilot pressure between a position corresponding to the maximum volume of the plurality of chambers, the return elastic spring being in this position at its maximum length, and a predetermined end position corresponding to the minimum volume of the plurality of chambers, the return elastic spring being in this position at its minimum length by action of the displacement in the longitudinal direction of the movable wall which occurs simultaneously to the longitudinal displacement of the plurality of vanes and of the movable ring.

Claims

1. A variable displacement vane pump of the type having a body with a fixed ring fixed to said body, a rotor provided with a plurality of radial vanes, wherein each vane is adapted to slide radially in a corresponding slot in said rotor, wherein the vanes slide along the circular inner surface of said fixed ring, and wherein the rotation axis of the rotor is eccentric relative to the axis defined by the circular inner surface of the fixed ring, the displacement vane pump comprising: a movable ring adapted for sliding longitudinally along the rotor; and a fixed body that is not longitudinally slidable over the rotor, wherein each of the vanes is adapted for sliding longitudinally along the rotor in the corresponding slot in said rotor, passing through and sealing in openings of the side surface of the fixed body in one of the longitudinal tops of the vane, and sealing with a side surface of the movable ring in the other of the longitudinal tops of the vane, defining chambers between vanes of variable longitudinal length arranged among the side surface of the movable ring, side surface of the fixed body, outer surface of the rotor and circular inner surface of the fixed ring.

2. The variable displacement vane pump according to claim 1, wherein the fixed body is fixed to the rotor and rotates jointly with the rotor.

3. The variable displacement vane pump according to claim 1, wherein the fixed body and the rotor are formed by the same part.

4. The variable displacement vane pump according to claim 1, wherein the movable ring has the cross-section of a surface delimited by two non-concentric circumferences wherein one of the circumferences is completely contained by the other circumference.

5. The variable displacement vane pump according to claim 1, further comprising force means for longitudinally moving the movable ring and the vanes.

6. The variable displacement vane pump according to claim 1, wherein the force means comprise a return elastic spring for longitudinally moving the movable ring and the vanes up to their initial position.

7. The variable displacement vane pump according to claim 5, further comprising force means for applying longitudinal force on the movable ring for longitudinally moving the movable ring and the vanes in order to increasing the volume of said chambers.

8. The variable displacement vane pump according to claim 5, wherein the force means comprise a pilot chamber delimited by the side surface of the movable ring opposite to the side surface of the movable ring which seals with longitudinal tops of the vanes, wherein the pilot chamber comprises a channel for receiving pressure from an external pressure source.

9. The variable displacement vane pump according to claim 1, wherein the pilot chamber is connected to the pump outlet.

10. The variable displacement vane pump according to claim 1, wherein the force means are mechanically or electronically controlled.

11. The variable displacement vane pump according to claim 1, further comprising a wall which leans laterally against to the longitudinal top of the vanes passing through the fixed body, for applying longitudinal force to said vanes.

12. The variable displacement vane pump according to claim 11, further comprising force means for applying longitudinal force on said wall for longitudinally moving the movable ring and the vanes in order to decrease the volume of said chambers.

13. The variable displacement vane pump according to claim 1, wherein the fixed ring is of a more wear resistant material than the material of the pump body.

14. The variable displacement vane pump according to claim 1, wherein the pump is configured for pumping oil.

15. A vehicle including a variable displacement vane pump according to claim 1.

16. The vehicle of claim 15, wherein the variable displacement vane pump is a component of an engine of the vehicle.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0049] For an easier understanding of the present disclosure, drawings are herein attached, which represent preferred embodiments which, however, are not intended to limit the scope of the present disclosure.

[0050] FIG. 1: Schematic representation of the longitudinal section of the variable displacement vane pump in an embodiment of the disclosure in the maximum volume position of the plurality of chambers.

[0051] FIG. 2: Schematic representation of the cross-section of the variable displacement vane pump along line I-I in FIG. 1.

[0052] FIG. 3: Schematic representation of the cross-section of the variable displacement vane pump along line II-II in FIG. 1.

[0053] FIG. 4: Schematic representation of the cross-section of the variable displacement vane pump along line III-Ill in FIG. 1.

[0054] FIG. 5: Schematic representation of the cross-section of the variable displacement vane pump along line IV-IV in FIG. 1.

[0055] FIG. 6: Schematic representation of the longitudinal section of the variable displacement vane pump in an embodiment of the disclosure in the minimum volume position of the plurality of chambers.

[0056] FIG. 7: Schematic perspective representation of the partial longitudinal section of the variable displacement vane pump in an embodiment of the disclosure in the maximum volume position of the plurality of chambers.

[0057] FIG. 8: Schematic perspective representation of the partial longitudinal section of the variable displacement vane pump in an embodiment of the disclosure in the minimum volume position of the plurality of chambers.

[0058] FIG. 9: Schematic representation of a variable displacement pump wherein (A) represents a minimum volume position of the plurality of chambers and (B) represents a maximum volume position of the plurality of chambers in which the vanes pass through the fixed body.

[0059] FIG. 10: Schematic representation of a variable displacement pump wherein (A) represents a minimum volume position of the plurality of chambers and (B) represents a maximum volume position of the plurality of chambers in which the vanes pass through the side surface of the fixed body.

DETAILED DESCRIPTION

[0060] FIG. 1 schematically shows the longitudinal section of the vane pump wherein 1 represents a vane rotary pump or of variable displacement; 2 represents a support body, 3 represents a suction port in the support body, 4 represents a discharge port in the support body, 5 a fixed ring, 6 represents a suction port in the fixed ring, 7 represents a discharging port in the fixed ring; 8 represents an inner circular surface of the fixed ring, 9 represents a vane, 10 represents a rotor; 11 represents a side surface of the body; 12 represents a cap; 13 represents a side surface of the cap; 14 represents a movable ring; 15 represents an outer surface of the rotor; 16 represents a side surface of the movable ring; 17 represents a movable wall; 18 a side surface of the movable wall; 19 and 20 represent washers; 21 represents an elastic spring; 22 represents a side of the movable wall, 23 represents a side surface of the body, 24 represents an inner surface of the body, 25 represents an shaft, 26 represents an outer surface of the shaft, 27 represents a side surface of the rotor, 28 represents chambers, 29 represents a pilot chamber, 30 represents a side surface of the movable ring, 31 represents a side surface of the cap, 32 represents a channel, 33 and 34 represent surfaces of the slot in the rotor; 35 and 36 represent a means for reducing friction in the movable ring, 37 and 38 represent a means for reducing friction in the movable wall, 39 represents an axis around which the rotor rotates; 40 represents an axis defined by the inner circular surface of the fixed ring.

[0061] The present disclosure relates to a variable displacement vane pump (1) comprising a body (2) having a cavity wherein a movable ring (14) slides in the longitudinal direction over the rotor (10) which rotates around an axis (39) and which is provided with vanes (9) which are radially supported on the inner circular surface (8) of the fixed ring (5) of fixed eccentricity relative to the rotation axis of the rotor (10), and with movement means in the longitudinal direction of the movable ring (29) according to a pilot pressure between a position corresponding to the maximum volume of the plurality of chambers (28), the return elastic spring (21) being in this position at its maximum length, and a predetermined end position corresponding to the minimum volume of the plurality of chambers (28), the return elastic spring (21) being in this position at its minimum length by action of the displacement in the longitudinal direction of the movable wall (17) which occurs simultaneously with the longitudinal displacement of the plurality of vanes (9) and of the movable ring (14).

[0062] In an embodiment, the present vane rotary pump (1) with a displacement variation, in particular for oil, comprises a support body (2) with a suction port (3) which may be connected to the fluid reservoir and a discharging port (4) which may be connected to a circuit for dispensing the fluid itself.

[0063] A fixed ring (5) secured to the support body (2) with suction (6) and discharging ports (7) wherein on the inner circular surface (8) a plurality of vanes (9) slides, wherein each is adapted for radially and longitudinally sliding in the corresponding slot of the rotor (10) which rotates around the longitudinal shaft (39), this shaft being positioned eccentrically and fixed relative to the longitudinal axis (40) of the inner circular surface (8) of the fixed ring (5).

[0064] The rotor (10) is limited in its longitudinal movement by the support body (2) through the contact surface (11) and by the cap (12) through the surface (13), the cap (12) being fixed to the support body (2).

[0065] The movable ring (14) is in radial contact with the inner circular surface (8) of the fixed ring (5) and with the outer surface (15) of the rotor (10). The plurality of vanes (9) are in simultaneous contact in the longitudinal direction with the side surface (16) of the movable ring (14) and with the side surface (18) of the movable wall (17).

[0066] The plurality of vanes maintains the radial positioning by action of the radial contact with the washers (19, 20) and the inner circular surface (8) of the fixed ring (5).

[0067] The movable wall (17) is in contact with the return elastic spring (21) through the side surface (22), the fixed end of the elastic spring (21) being supported on the side surface (23) of the pump body (2). The movable wall (17) is in radial contact with the pump body (2) through the surface (24) and with the shaft (25) through the surface (26).

[0068] The outer (15) and side (27) surfaces of the rotor (10) together with the inner circular surface (8) of the fixed ring (5) of two successive vanes (9) and the side surface (16) of the movable ring (14) form the volume of each of the plurality of chambers (28) carrying the fluid from the suction port (3) to the discharging port (4) by action of the rotor rotation movement (10) fixed to the shaft (25) receiving the rotational movement external to the pump (1).

[0069] The longitudinal movement means (29) of the movable ring (14) according to a pilot pressure between a position corresponding to the maximum volume of the plurality of chambers (28), the return elastic spring (21) being in this position at its maximum length, and a predetermined end position corresponding to the minimum volume of the plurality of chambers (28), the return elastic spring (21) being in this position at its minimum length by action of the longitudinal displacement of the movable wall (17) occurring simultaneously to the longitudinal displacement of the plurality of vanes (9) by action of the surface (16) of the movable ring (14).

[0070] The movement means (29) comprising a pilot chamber (29) delimited by the surfaces (31) of the cap (11), by the side surface (30) of the movable ring (10), by the inner circular surface (8) of the fixed ring (5) and by the outer surface (15) of the rotor (10), the movable ring (14) being adapted for longitudinally sliding in said pilot chamber (29) due to the pilot pressure present in this pilot chamber (29). The pilot pressure comes from a source external to the pilot chamber (29) through the channel (32).

[0071] The guiding means (8, 15) for the longitudinal displacement of the movable ring (14) comprise the inner circular surface (8) of the fixed ring (5) and the outer surface (15) of the rotor (10). The guiding means (33, 34) for longitudinal and radial displacement of the plurality of vanes (9) comprise the surfaces (33, 34) of the plurality of rotor slots (10). The longitudinal guiding means (24, 26) of the movable wall (17) comprise the surface (24) of the pump body (2) and the surface (26) of the shaft (25).

[0072] The variation of flow carried by the plurality of chambers (28) between the suction port (3) and discharging port (4) at a given rotation of the rotor (10) is carried out by varying the pilot pressure in the pilot chamber (29) acting on the side surface (30) of the movable ring (14), causing a longitudinal force thereon, which being greater or less than the force exerted by the return elastic spring (21) in contact with the movable wall (17) causes longitudinal and simultaneous sliding in the movable ring (14) of the plurality of vanes (9) and of the side wall (17), the sliding towards the cap (12) increases the distance between the side surface (16) of the movable ring and the side surface (27) of the rotor (10) up to a maximum, and consequent increase of the volume of the plurality of chambers (28). The sliding towards the elastic spring (21) decreasing the distance between the side surface (16) of the movable ring (14) and the side surface (27) of the rotor (10) and consequent volume decrease of the plurality of chambers (28) thereby changing the flow carried from the suction port (3) to the discharging port (4) per each rotation of the rotor (10).

[0073] The movable ring (14) is provided with means (35, 36) adapted for reducing friction effects and improving the tightness between the pilot chamber (29) and the plurality of chambers (28). The movable wall (17) is provided with means (37, 38) adapted for reducing friction effects.

[0074] The pilot pressure in the pilot chamber (29) may or may not derive from the available pressure next to the discharging port (4) of the pump (1), it being controllable by means of an auxiliary device of mechanical or electronic programmable origin and which may or may not be integrated in the pump body (2) itself.

[0075] The return elastic spring (21) tends to move the movable wall (17), plurality of vanes (9) and movable ring (14) into the end position of the movable ring (14) next to the cap (12) maximizing the volume of the chambers (28) and hence the flow of the pump (1) in the event of absence or low pilot pressure.

[0076] Although the present disclosure has only shown and described particular embodiments of the solution, one skilled in the art shall know how to introduce modifications and replace some technical features for equivalents, depending on the requirements of each situation, without departing from the scope of protection defined by the appended claims. The embodiments are combinable. The following claims further define preferred embodiments.