Field of the invention

This invention relates to a balanced variable vane pump.

This invention relates to a drive mechanism for a balanced variable vane pump.

In particular this invention relates to a drive mechanism for the CAM-ring of the
balanced variable pump.

Background of the invention

Pumps find use in a wide range of industries and in a wide range of operation. Rotary pumps are one of the popular types of pumps. A vane pump is one such type of rotary pump. A vane pump usually has pluralities of vanes which are accommodated within the rotor of the pump. The rotor is eccentrically located in a chamber and rotates within the chamber. The vanes which are accommodated in the rotor are usually spring loaded. As the rotor rotates within the chamber the vanes trap the fluid between the surface of the rotor and the surface of the cavity. As the rotor rotates at least a number of vanes of the pluralities vanes get compressed while others get decompressed. During compression and decompression of the vanes the springs provide the required resistance to the vanes.

Furthermore, balanced vane pumps and variable vane pumps are known in the state of the art. Balanced vane pumps ensure that the pressure variations during the operation of the vane are balanced. While variable vane pumps allow for variable flow during the operation of the vane pump. Variable vane pumps usually have a CAM-ring which can be adjusted while the pump is in operation such that the output flow of the vane pump can be varied.

In accordance with this invention we will focus on the mechanisms used to move the CAM-ring for varying the output flow of the balanced variable vane pump. Known in the prior art are vane pumps which have oscillating or linearly moving CAM-ring. Some of the mechanisms to move the CAM-ring known in the state art are mentioned below.

US patent number 7108493 discloses a variable displacement pump with a rotating CAM-ring. The CAM-ring in accordance with the disclosure is provided with a plurality of actuating surfaces. A piston type arrangement is used to move the CAM-ring such that the output flow from the balanced variable vane pump can be varied.

US patent number 7726948 discloses a variable displacement pump with a movable CAM-ring. A solenoid valve and a pressure regulating valve are used such that output flow and pressure of the variable displacement pump can be varied.

In accordance with this there is provided a balanced variable vane pump, with a drive mechanism which is used to impart motion to the CAM-ring. The advantage of providing a drive mechanism is that the force required in moving the CAM-ring is reduced. This reduces the overall cost of the system. The drive mechanism provides a stable profile in case of dynamic vibrations. Such drive mechanism makes the CAM-ring pressure balanced, which makes the overall system easier to control. Further, the drive mechanism also helps in very precise control over the movement of the CAM-ring.

Brief description of the accompanying drawings

Different modes of the invention are disclosed in detail in the description and
illustrated in the accompanying drawing:

Figure 1 illustrates balanced variable vane pump in accordance with this invention;

Figure 2 illustrates the balanced variable vane pump with a first embodiment of the drive mechanism;

Figure 3 illustrates the balanced variable vane pump with a second embodiment of the drive mechanism;

Figure 4 illustrates the balanced variable vane pump with a third embodiment of the drive mechanism.

Detailed description of the invention

Figure 1 illustrates the balanced variable vane pump 10 in accordance with this invention. The balanced variable vane pump 10 comprises at least a rotor 12 adapted to accommodate pluralities of vanes 14 and the rotor 12 rotates in a CAM chamber 18 formed within the CAM-ring 16. The balanced variable vane pump 10 is characterized by the CAM-ring 16 being provided with teeth 20 on at least a part of the outer circumference of the CAM-ring 16 and a drive mechanism 22 adapted to engage the teeth 20 on the outer circumference of CAM-ring 16 to impart movement to CAM-ring 16. The drive mechanism 22 which imparts movement to the CAM-ring 16 comprises a gear assembly 24 and a drive 26. The gear assembly 24 engages with the teeth 20 on at least a part of the outer circumference of the CAM-ring 16. The drive 26 is adapted to impart motion to the gear assembly 24. In accordance with one embodiment of the balanced variable vane pump 10, the drive mechanism 22 is integrated with the balanced variable vane pump 10 to form one single unit. In accordance with another embodiment of the balanced variable vane pump 10, the drive mechanism 22 is separate from the balanced variable vane pump 10 to form two separate units.

The gear assembly 24 may be at least one chosen from a group of gear assemblies such as linear gear assemblies, rotary gear assemblies and the like. The gear assembly 24 may be at least one chosen from a group of gear assemblies such as rack and pinion, spur, worm and the like. The drive 26 is a motor. The drive 26 is adapted to impart translator/ or rotary motion to the gear assembly 24 in dependence of the gear assembly chosen from the group of gear assemblies.

Figure 2 illustrates the balanced variable vane pump 10 with a first embodiment of the drive mechanism 22. In accordance with this embodiment, the gear assembly 24 used is a linear gear assembly such as a rack and pinion type gear assembly. The drive 26 is a linear drive which provided forward and backward translator/ motion to the gear assembly 24. The gear assembly 24 in this case forms the rack of the gear assembly 24 while the CAM-ring 16 whose teeth engage the gear assembly 24 forms the pinion of the gear assembly. The working of this embodiment can be explained as follows. When there is requirement to vary the flow of the balanced variable vane pump 10, the drive 26 is activated such that the gear assembly moved in a forward or reverse direction. As the gear assembly 24 translates, the inlets 28 and the outlets 30 of the pump 10 are re-aligned with the CAM-ring 16. Depending on the area of the inlets 28 and outlets 30 of the which are aligned with the CAM-ring 16, the flow is varied.

Figure 3 illustrates the balanced variable vane pump 10 with a second embodiment of the drive mechanism 22. In accordance with this embodiment, the gear assembly used is a rotary gear assembly such as a spur gear assembly 24. The drive 26 (not shown in the figure) is a rotary drive. The working of this embodiment can be explained as follows.

The drive 26 is activated such that gear assembly 24 rotates. The rotation realigns the inlets 28 and outlets 30 of the pump with the CAM-ring 16. Depending on the area of the inlets 28 and outlets 30 which are aligned with the CAM-ring 16, the flow is varied.
Figure 4 illustrates the balanced variable vane pump 10 with a third embodiment of the drive mechanism 22. In accordance with this embodiment, the gear assembly used is a rotary gear assembly such as worm gear assembly 24. The drive 26 is a rotary drive. The working of this embodiment can be explained as follows. The drive 26 is activated such that gear assembly 24 rotates. The rotation realigns the inlets 28 and outlets 30 of the pump with the CAM-ring 16. Depending on the area of the inlets 28 and outlets 30 which are aligned with the CAM-ring 16, the flow is varied.

It must be understood that the embodiments of the balanced variable vane pump and the embodiments of the drive mechanism as explained above are only illustrative and do not limit the scope of the invention in terms of the types of gear assemblies or drive that can be used to make the balanced variable vane pump operate. Many modifications to the embodiments explained above are envisioned and lie within the scope of this invention.

WE CLAIM:

1. A balanced variable vane pump (10) comprising at least a rotor (12) adapted to accommodate pluralities of vanes (14) and CAM-ring (16), said rotor (12) adapted to rotate in a CAM chamber (18) formed within the CAM-ring (16), characterized in that balanced variable vane pump (10)

said CAM-ring (16) being provided with teeth (20) on at least a part of the outer circumference of said CAM-ring (16); and

a drive mechanism (22) adapted to engage said teeth (20) on said outer circumference of said CAM-ring (16) to impart movement to said CAM-ring (16).

2. A balanced variable vane pump (10), wherein said drive mechanism (22) is integrated into said balanced variable vane pump (10) as a single unit.

3. A balanced variable vane pump (10), wherein said drive mechanism (22) is separate from said balanced variable vane pump (10) to form two separate units.

4. A drive mechanism (22) for a balanced variable vane pump (10), said drive mechanism (22) adapted to impart movement to a CAM-ring (16) of said balanced variable vane pump (10), said drive mechanism (22) comprising:

a gear assembly (24); and

a drive (26); said gear assembly (24) adapted to engage teeth (20) provided on at least a part of the outer circumference of said CAM-ring (16); and

said drive (26) adapted to impart motion to said gear assembly (24) such that movement of gear assembly (24) results in movement of said CAM-ring (16).

5. A drive mechanism (22) as claimed in claim 4, wherein said gear assembly (24) is at least one chosen from a group of gear assemblies such as linear gear assemblies, rotary gear assemblies and the like.

6. A drive mechanism (22) as claimed in claim 4, wherein said gear assembly (24) is at least one chosen from a group of gear assemblies such as rack and pinion, spur, worm and the like.

7. A drive mechanism (22) as claimed in claim 4, wherein said drive (26) is a motor.

8. A drive mechanism (22) as claimed in claim 4, 5 and 6, wherein said drive (26) is adapted to impart translatory or rotary motion to the gear assembly (24) in dependence of said gear assembly 24 chosen from the group of gear assemblies.