Claims:We Claim

1. A variable displacement vane pump (10), said variable displacement vane pump (10) comprising:
a housing (12) comprising a bore (14) extending there through, and a spring chamber (16) defined opposite to said bore (14);
a reaction ring (18) positioned within said housing (12) and abutting against a spring (20) that is positioned within said spring chamber (16);
a cylindrical rotor (22) positioned within said reaction ring (18) and eccentrically defined with reference to a center of said reaction ring (18) such that a first displacement between a first portion (24) of the cylindrical rotor (22) from said reaction ring (18) is greater than a second displacement between an opposite second portion (26) of said cylindrical rotor (22) from said reaction ring (18);
a plurality of vanes (28) extending from said cylindrical rotor (22) to said reaction ring (18), a space between said cylindrical rotor (22) and said reaction ring (18) containing fuel that is adapted to be compressed during a rotation of said reaction ring (18); characterized in that
a control rod (30) extending through the bore (14) that is defined in said housing (12), a first end of said control rod (30) in contact with said reaction ring (18), and wherein a translation of said control rod (30) in the direction of said reaction ring (18) causes said reaction ring (18) to compress against said spring (20), thereby causing a reduction in the second displacement between said cylindrical rotor (22) and said reaction ring (18), thereby allowing the fuel that is present in the space between said cylindrical rotor (22) and said reaction ring (18) to be compressed to a higher pressure than it were previously possible before the translation of said control rod (30) in the direction of said reaction ring (18).

2. A variable displacement vane pump (10) in accordance with Claim 1 further comprising a flexible diaphragm (32) secured to an opposite second end of said control rod (30), and wherein said flexible diaphragm (32) is adapted to be compressed to facilitate translating said control rod (30) in the direction of said reaction ring (18).

3. A variable displacement vane pump (10) in accordance with Claim 2 further comprising a casing (34) circumscribing said flexible diaphragm (32), said casing (34) containing a magneto rheotic fluid (36), and wherein a change in a state of the magneto rheotic fluid (36) from a liquid state to a semi solid state causes said flexible diaphragm (32) to be compressed to facilitate translating said control rod (30) in the direction of said reaction ring (18).

4. A variable displacement vane pump (10) in accordance with Claim 3 further comprising a plurality of solenoid coils (38) that are secured to said casing (34) circumscribing said flexible diaphragm (32), and wherein the energization of the plurality of solenoid coils (38) causes the magneto rheotic fluid (36) that is present within said casing (34) to transform from the liquid state to the semi solid state.

5. A variable displacement vane pump (10) in accordance with Claim 4 further comprising an engine control unit (40) in electronic communication with said plurality of solenoid coils (38), said engine control unit (40) adapted to energize said plurality of solenoid coils (38), thereby causing the magneto rheotic fluid (36) that is present within said casing (34) to transform from the liquid state to the semi solid state.
6. A variable displacement vane pump (10) in accordance with Claim 4 wherein said engine control unit (40) is adapted to de-energize said plurality of solenoid coils (38), thereby causing the magneto rheotic fluid (36) that is present within said casing (34) to transform from the semi solid state to the liquid state, thereby resulting in the translation of the control rod (30) in a direction opposite to said reaction ring (18), thereby resulting in an increase in the second distance between said cylindrical rotor (22) and said reaction ring (18).
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to a vane pump, and more specifically to a mechanism for varying a displacement between vanes of a vane pump by means of a magneto rhetoric fluid.

Background of the invention
[0002] US 20100282204 A1 describes a variable displacement vane pump. The variable displacement vane pump includes but is not limited to inlet and outlet ports in a pump body, a drive shaft rotatably mounted in the pump body, a rotor driven by the drive shaft and radially extending vanes slidably disposed in the rotor. A slide is pivotally disposed on a pivot and has a central axis eccentric to the axis of the rotor. Chambers are defined by the rotor, the vanes and the slide that are successively connected to the inlet and outlet ports. A resilient member is pivotally engaged with the slide and acts on the slide to urge the slide in one direction.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic diagram of a vane pump in one embodiment of the invention.

Detailed description of the embodiments
[0004] Figure 1 illustrates a variable displacement vane pump 10. The variable displacement vane pump 10 comprises a housing 12 comprising a bore 14 extending there through, and a spring chamber 16 defined opposite to the bore 14. A reaction ring 18 is positioned within the housing 12 and abutting against a spring member 20 that is housed within the spring chamber 16. A cylindrical rotor 22 is positioned within the reaction ring 18 and eccentrically defined with reference to a center of the reaction ring 18 such that a first displacement between a first portion 24 of the cylindrical rotor 22 from the reaction ring 18 is greater than a second displacement between an opposite second portion 26 of the cylindrical rotor 22 from the reaction ring 18. A plurality of vanes 28 extends from the cylindrical rotor 22 to the reaction ring 18, a space between the cylindrical rotor 22 and the reaction ring 18 containing fuel that is adapted to be compressed during a rotation of the reaction ring 18. A control rod 30 extends through the bore 14 that is defined in the housing 12, a first end of the control rod 30 in contact with the reaction ring 18, and wherein a translation of the control rod 30 in the direction of the reaction ring 18 causes the reaction ring 18 to compress against the spring member 20, thereby causing a reduction in the second displacement between the cylindrical rotor 22 and the reaction ring 18, thereby allowing the fuel that is present in the space between the cylindrical rotor 22 and the reaction ring 18 to be compressed to a higher pressure than it were previously possible before the translation of the control rod 30 in the direction of the reaction ring 18.

[0005] In the exemplary embodiment, a variable displacement vane pump 10 is illustrated in Figure 1. The variable displacement vane pump 10 comprises a housing 12. The housing 12 comprises a bore 14 extending there through. A spring chamber 16 is defined opposite to the bore 14. More specifically, the spring chamber 16 is a U-shaped spring chamber that houses a spring member 20 therein, and that is positioned within the spring chamber 16 such that a first end of the spring member 20 abuts against an end wall of the spring chamber 16 while an opposite second end of the spring member 20 faces the free end of the U-shaped spring chamber 16. A reaction ring 18 is positioned within the housing 12 and abuts against the spring member 20 that is positioned within the spring chamber 16. In the exemplary embodiment, the reaction ring 18 is positioned within the housing 12 such that a portion of the outer circumference of the reaction ring 18 abuts against the second end of the spring member 20.

[0006] A cylindrical rotor 22 that is positioned within the reaction ring 18 and eccentrically defined with reference to a center of the reaction ring 18. More specifically, the cylindrical rotor 22 is positioned eccentrically within the reaction ring 18 such that a first displacement between a first portion 24 of the cylindrical rotor 22 from the reaction ring 18 is greater than a second displacement between an opposite second portion 26 of the cylindrical rotor 22 from the reaction ring 18. Since the first displacement between the first portion 24 of the cylindrical rotor 22 from the reaction ring 18 is greater than the second displacement between the opposite second portion 26 of the cylindrical rotor 22 from the reaction ring 18, the fuel that enters into the space between the vanes from the first portion 24 of the cylindrical rotor 22 and the reaction ring 18 gets compressed when the vanes 28 rotate and reaches the opposite second portion 26, and therein delivered to an engine. The rotation of the vanes 28 from the first portion 24 to the opposite second portion 26 causes the fuel to be compressed due to the reduction in the volume of the fuel flowing from the first portion 24 to the opposite second portion 26 and therein delivered to the engine.

[0007] A plurality of vanes 28 extends from the cylindrical rotor 22 to the reaction ring 18. More specifically, a first end of each of the plurality of vanes 28 is secured to the cylindrical rotor 22 while the opposite end of each of the plurality of vanes 28 is secured to the reaction ring 18. Therefore, the rotation of the cylindrical rotor 22 causes a rotation of the plurality of vanes 28. As the plurality of vanes 28 rotates, a space between the cylindrical rotor 22 and the reaction ring 18 containing fuel is adapted to be compressed during a rotation of the cylindrical rotor 22 from the first portion 24 to the opposite second portion 26.

[0008] A control rod 30 extends through the bore 14 that is defined in the housing 12. A first end of the control rod 30 is in contact with the reaction ring 18, and wherein a translation of the control rod 30 in the direction of the reaction ring 18 causes the reaction ring 18 to compress against the spring member 20. The translation of the reaction ring 18 due to the translation of the control rod 30 in the direction of the reaction ring 18, thereby compressing against the spring member 20 causes a reduction in the second displacement between the cylindrical rotor 22 and the reaction ring 18. The reduction in the second displacement between the cylindrical rotor 22 and the reaction ring 18 allows the fuel that is present in the space between the cylindrical rotor 22 and the reaction ring 18 to be compressed to a higher pressure than it were previously possible before the translation of the control rod 30 in the direction of the reaction ring 18.

[0009] In an exemplary embodiment, the variable displacement vane pump 10 comprises a flexible diaphragm 32 that is secured to an opposite second end of the control rod 30. The flexible diaphragm 32 is adapted to be compressed to facilitate translating the control rod 30 in the direction of the reaction ring 18. Since the flexible diaphragm 32 is secured to the opposite second end of the control rod 30, the compression of the flexible diaphragm 32 causes a translation of the control rod 30 in the direction of the reaction ring 18. A casing 34 circumscribes the flexible diaphragm 32 such that the flexible diaphragm 32 is located within the casing 34. The casing 34 contains a magneto rheotic fluid 36 that surrounds the flexible diaphragm 32. The magneto rheotic fluid 36 maintains a liquid state under normal conditions, and changes its state from the liquid state to a semi solid state when an electric field has been passed through it. The extent to which the change in the state of the magneto rheotic fluid 36 occurs from the liquid state to the semi solid / solid state is directly proportional to the magnitude of the electric field that has been passed through it by the solenoid coils 38. A change in the state of the magneto rheotic fluid 36 from the liquid state to the semi solid state/solid state causes the flexible diaphragm 32 to be compressed thereby facilitating translating the control rod 30 in the direction of the reaction ring 18. More specifically, the change in the state of the magneto rheotic fluid 36 causes a reduction in the free volume of the casing 34. The reduction in the free volume of the casing 34 causes the flexible diaphragm 32 to be compressed.

[0010] The variable displacement vane pump 10 further comprises a plurality of solenoid coils 38 that are secured to the casing 34 circumscribing the flexible diaphragm 32. The energization of the plurality of solenoid coils 38 causes the magneto rheotic fluid 36 that is present within the casing 34 to transform from the liquid state to the semi solid state/solid state. The degree of transformation of the magneto rheotic fluid 36 that is present within the casing 34 from the liquid state to the semi solid state/solid state is directly proportional to the degree of energization of the plurality of solenoid coils 38 that is caused by the engine control unit 40.

[0011] The variable displacement vane pump 10 further comprises an engine control unit 40 in electronic communication with the plurality of solenoid coils 38. The engine control unit 40 is adapted to energize the plurality of solenoid coils 38, thereby causing the magneto rheotic fluid 36 that is present within the casing 34 to transform from the liquid state to the semi solid state/solid state. Therefore, the engine control unit 40 controls the degree of energization of the plurality of solenoid coils 38, which in turn controls the degree of solidification of the magneto rheotic fluid 36 that is present within the casing 34. In the exemplary embodiment, the engine control unit 40 is adapted to de-energize the plurality of solenoid coils 38, thereby causing the magneto rheotic fluid 36 that is present within the casing 34 to transform from the semi solid state to the liquid state. The transformation of the magneto rheotic fluid 36 from the semi solid state to the liquid state results in the translation of the control rod 30 in a direction opposite to the reaction ring 18 thereby causing an increase in the second displacement between the cylindrical rotor 22 and the reaction ring 18.

[0012] A working of the variable displacement vane pump 10 is described as an example. The rotation of the cylindrical rotor 22 causes a rotation of the plurality of vanes 28. As the plurality of vanes 28 rotates, a space between the cylindrical rotor 22 and the reaction ring 18 containing fuel is adapted to be compressed during a rotation of the reaction ring 18. This is because the space between the cylindrical rotor 22 and the reaction ring 18 decreases during the rotation of the reaction ring 18. The reduction in the space between the cylindrical rotor 22 and the reaction ring 18 causes the fuel that is contained between the cylindrical rotor 22 and the reaction ring 18 to be compressed. As the engine control unit 40 transmits an energizing current to the plurality of solenoid coils 38, the plurality of solenoid coils 38 get energized. Due to the energization of the plurality of solenoid coils 38, the magneto rheotic fluid that is contained within the casing 34 converts from the liquid state to a semi-solid state/solid state, wherein the degree of conversion from the liquid state to the semi-solid state/solid state is proportional to the degree of energization of the solenoid coils 38 by the engine control unit 40. The conversion of the magneto rheotic fluid from the liquid state to the semi-solid state/solid state causes a reduction in the free volume of the casing 34. The reduction in the free volume of the casing 34 causes the flexible diaphragm 32 to be compressed. The compression of the flexible diaphragm 32 causes the translation of the control rod 30 in the direction of the reaction ring 18. The translation of the control rod 30 in the direction of the reaction ring 18 causes the reaction ring 18 to compress against the spring member 20 that is within the spring chamber 16. The translation of the reaction ring 18 due to the translation of the control rod 30 in the direction of the reaction ring 18, thereby compressing against the spring member 20 causes a reduction in the second displacement between the cylindrical rotor 22 and the reaction ring 18. The reduction in the second displacement between the cylindrical rotor 22 and the reaction ring 18 allows the fuel that is present in the space between the cylindrical rotor 22 and the reaction ring 18 to be compressed to a higher pressure than it were previously possible before the translation of the control rod 30 in the direction of the reaction ring 18.

[0013] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.