Roller vane stage for a fuel pump - Patent Review 6099261

Claims

What is claimed is:

1. A roller vane stage for a fuel pump comprising:

an inlet plate, an outlet plate, and a spacer positioned therebetween, said spacer having an eccentric inner surface defining a rotor space therein, said inlet plate having at least one inlet port therethrough communicating with said rotor space, and said outlet plate having at least one outlet port therethrough communicating with said rotor space; and

a rotor mounted for rotation within said rotor space and having a plurality of lobes spaced circumferentially about said rotor and opening radially outwardly towards said eccentric inner surface, a roller associated with and movable within each said lobe, said rotor further having a driver slot adapted to be engaged by a driver tang of a motor of the fuel pump to rotate said rotor within said rotor space so as to pump fuel, said rotor having a predetermined thickness, said driver slot having a depth less than said rotor thickness such that said driver slot does not extend completely through said rotor.

2. The roller vane stage of claim 1 where said inlet plate has first and second inlet ports and said outlet plate has first and second outlet ports.

3. The roller vane stage of claim 2 where said second inlet port is spaced radially outwardly of said first inlet port and said second outlet port is spaced radially outwardly of said first outlet port.

4. The roller vane stage of claim 3 where said first and second inlet ports are arcuate in shape, said second outlet port is arcuate in shape, and said first outlet port is defined by a U-shaped section and an arcuate section intersecting the otherwise open end of said U-shaped section.

5. The roller vane stage of claim 4 where said first inlet port and said first outlet port are positioned to form a first pair of cooperating ports, and said second inlet port and said second outlet port are

positioned to form a second pair of cooperating ports.

6. The roller vane stage of claim 5 where said first inlet port has a trailing edge and a tapered extension disposed ahead of said trailing edge.

7. The roller vane stage of claim 1 where said rotor has five lobes.

8. The roller vane stage of claim 7 where each said lobe is U-shaped and each roller is cylindrical and sized to fit within said U-shaped lobe.

9. The roller vane stage of claim 8 where each said roller is solid.

10. The roller vane stage of claim 9 where said roller has a thickness and a diameter such that said thickness of said roller is no less than said diameter of said roller.

11. The roller vane stage of claim 10 where said thickness of said roller is twice said diameter of said roller.

12. The roller vane stage of claim 1 where said rotor has two driver slots adapted to be engaged by pair of driver tangs of the fuel pump motor.

13. The roller vane stage of claim 1 where said eccentric inner surface is defined by a first circular arc having a radius and by a second circular arc having a radius, said second circular arc being oppositely disposed of said first circular arc, said first and second arcs being interconnected by a plurality of circular arcs of differing radii, said first arc radius being greater than said second arc radius and each of said radii of said plurality of circular arcs, said second arc radius being smaller than said first arc radius and each of said radii of said plurality of circular arcs.

14. The roller vane stage of claim 13 where each said roller has a diameter, said rotor also having a radius, the difference between said radius of said first arc and said radius of said rotor being no greater than one-half of said roller diameter.

15. The roller vane stage of claim 14 where said second circular arc of said eccentric inner surface is bisected by a reference line intersecting the axis of said rotor, and said outlet port is sized such that as said rotor rotates, one of said lobes will be in fluid communication with said outlet port until said one lobe becomes tangent to the reference line.

16. The roller vane stage of claim 1 where said eccentric inner surface has a circular arc bisected by a reference line intersecting the axis of said rotor, and said outlet port is sized such that as said rotor rotates, one of said lobes will be in fluid communication with said outlet port until said one lobe becomes tangent to the reference line.

17. The roller vane stage of claim 1, wherein said rotor is mounted on a bearing, said bearing having a cap such that an armature of said motor of said fuel pump cannot extend completely therethrough.

18. A roller vane stage for a fuel pump comprising:

an inlet plate, an outlet plate, and a spacer positioned therebetween, said spacer having an eccentric inner surface defining a rotor space therein, said inlet plate having at least one inlet port therethrough communicating with said rotor space, and said outlet plate having at least one outlet port therethrough communicating with said rotor space;

said eccentric inner surface being defined by a first circular arc having a radius and by a second circular arc having a radius, said second circular arc being oppositely disposed of said first circular arc, said first and second arcs being interconnected by a plurality of circular arcs of differing radii, said first arc radius being greater than said second arc radius and each of said radii of said plurality of circular arcs, said second arc radius being smaller than said first arc radius and each of said radii of said plurality of circular arcs; and

a rotor within said rotor space and having a plurality of U-shaped lobes spaced circumferentially about said rotor and opening radially outwardly towards said eccentric inner surface, and a solid, cylindrical roller associated with and movable within each said U-shaped lobe, each said roller having a thickness and a diameter, said thickness of said roller is not less than said diameter of said roller, said rotor being rotatably mounted within said rotor space for rotation about an axis, said rotor also having a radius, the difference between said radius of said first arc and said radius of said rotor being no greater than one-half the diameter of said rollers.

19. The roller vane stage of claim 18 where said inlet plate has first and second inlet ports and said outlet plate has first and second outlet ports.

20. The roller vane stage of claim 19 where said second inlet port is spaced radially outwardly of said first inlet port and said second outlet port is spaced radially outwardly of said first outlet port.

21. The roller vane stage of claim 20 where said first and second inlet ports are arcuate in shape, said second outlet port is arcuate in shape, and said first outlet port is defined by a U-shaped section and an arcuate section intersecting the otherwise open end of said U-shaped section.

22. The roller vane stage of claim 21 where said first inlet port and said first outlet port are positioned to form a first pair of cooperating ports, and said second inlet port and said second outlet port are positioned to form a second pair of cooperating ports.

23. The roller vane stage of claim 22 where said first inlet port has a trailing edge and a tapered extension disposed ahead of said trailing edge.

24. The roller vane stage of claim 18 where said rotor has five lobes.

25. The roller vane stage of claim 18 where said thickness of said roller is twice said diameter of said roller.

26. The roller vane stage of claim 18 where said second circular arc of said eccentric inner surface is bisected by a reference line intersecting the axis of said rotor, and said outlet port is sized such that as said rotor rotates, one of said lobes will be in fluid communication with said outlet port until said one lobe becomes tangent to the reference line.

27. The roller vane stage of claim 18 where said first circular arc and said second circular arc are interconnected by 16 circular arcs, each of said 16 circular arcs having a radius no greater than said radius of said first circular arc and no less than said radius of said second circular arc, and each said radius of said 16 circular arcs being different.

28. The roller vane stage of claim 18, wherein said rotor is mounted on a bearing, said bearing having a cap such that an armature of a motor of said fuel pump cannot extend completely therethrough.

29. A roller vane stage for a fuel pump comprising:

an inlet plate, an outlet plate, and a spacer positioned therebetween, said spacer having an eccentric inner surface defining a rotor space therein, said inlet plate having at least one inlet port therethrough communicating with said rotor space, and said outlet plate having at least one outlet port therethrough communicating with said rotor space; and

a rotor mounted for rotation about its axis within said rotor space and having a plurality of lobes spaced circumferentially about said rotor and opening radially outwardly towards said eccentric inner surface, and a roller associated with and movable within each said lobe;

said eccentric inner surface having a circular arc bisected by a reference line intersecting the axis of said rotor;

said outlet port being sized such that as said rotor rotates, one of said lobes will be in fluid communication with said outlet port until said one lobe becomes tangent to the reference line.

30. The roller vane stage of claim 29 where said inlet plate has first and second inlet ports and said outlet plate has first and second outlet ports.

31. The roller vane stage of claim 30 where said second inlet port is spaced radially outwardly of said first inlet port and said second outlet port is spaced radially outwardly of said first outlet port.

32. The roller vane stage of claim 31 where said first and second inlet ports are arcuate in shape, said second outlet port is arcuate in shape, and said first outlet port is defined by a U-shaped section and an arcuate section intersecting the otherwise open end of said U-shaped section.

33. The roller vane stage of claim 32 where said first inlet port and said first outlet port are positioned to form a first pair of cooperating ports, and said second inlet port and said second outlet port are positioned to form a second pair of cooperating ports.

34. The roller vane stage of claim 33 where said first inlet port has a trailing edge and a tapered extension disposed ahead of said trailing edge.

35. The roller vane stage of claim 29 where said rotor has five lobes.

36. The roller vane stage of claim 35 where each said lobe is U-shaped and each roller is cylindrical and sized to fit within said U-shaped lobe.

37. The roller vane stage of claim 36 where each said roller is solid.

38. The roller vane stage of claim 37 where said roller has a thickness and a diameter such that said thickness of said roller is no less than said diameter of said roller.

39. The roller vane stage of claim 38 where said thickness of said roller is twice said diameter of said roller.

40. The roller vane stage of claim 29 where said eccentric inner surface is defined by a first circular arc having a radius and by a second circular arc having a radius, said second circular arc being oppositely disposed of said first circular arc, said first and second arcs being interconnected by a plurality of circular arcs of differing radii, said first arc radius being greater than said second arc radius and each of said radii of said plurality of circular arcs, said second arc radius being smaller than said first arc radius and each of said radii of said plurality of circular arcs;

wherein said bisected circular arc is said second circular arc.

41. The roller vane stage of claim 40 where said rotor has a driver slot adapted to be engaged by a driver tang of a motor of the fuel pump to rotate said rotor within said rotor space so as to pump fuel, said rotor having a predetermined thickness, said driver slot having a depth less than said rotor thickness such that said driver slot does not extend completely through said rotor.

42. The roller vane stage of claim 29, wherein said rotor is mounted on a bearing, said bearing having a cap such that an armature of a motor of said fuel pump cannot extend completely therethrough.

43. A fuel pump including a roller vane stage, an inlet for receiving fuel, an outlet for exhausting fuel, and a motor for drivingly engaging said roller vane stage, said roller vane stage comprising:

an inlet plate, an outlet plate, and a spacer positioned therebetween, said spacer having an eccentric inner surface defining a rotor space therein, said inlet plate having at least one inlet port therethrough communicating with said rotor space, and said outlet plate having at least one outlet port therethrough communicating with said rotor space;

a rotor mounted for rotation within said rotor space and having a plurality of lobes spaced circumferentially about said rotor and opening radially outwardly towards said eccentric inner surface, a roller associated with and movable within each said lobe, said rotor further having a driver slot adapted to be engaged by a driver tang of a motor of said fuel pump to rotate said rotor within said rotor space so as to pump fuel, said rotor having a predetermined thickness, said driver slot having a depth less than said rotor thickness such that said driver slot does not extend completely through said rotor.

44. The fuel pump of claim 43 where said inlet plate has first and second inlet ports and said outlet plate has first and second outlet ports.

45. The fuel pump of claim 44 where said second inlet port is spaced radially outwardly of said first inlet port and said second outlet port is spaced radially outwardly of said first outlet port.

46. The fuel pump of claim 45 where said first and second inlet ports are arcuate in shape, said second outlet port is arcuate in shape, and said first outlet port is defined by a U-shaped section and an arcuate section intersecting the otherwise open end of said U-shaped section.

47. The fuel pump of claim 46 where said first inlet port and said first outlet port are positioned to form a first pair of cooperating ports, and said second inlet port and said second outlet port are positioned to form a second pair of cooperating ports.

48. The fuel pump of claim 47 where said first inlet port has a trailing edge and a tapered extension disposed ahead of said trailing edge.

49. The fuel pump of claim 43 where said rotor has five lobes.

50. The fuel pump of claim 49 where each said lobe is U-shaped and each roller is cylindrical and sized to fit within said U-shaped lobe.

51. The fuel pump of claim 50 where each said roller is solid.

52. The fuel pump of claim 51 where said roller has a thickness and a diameter such that said thickness of said roller is no less than said diameter of said roller.

53. The fuel pump of claim 52 where said thickness of said roller is twice said diameter of said roller.

54. The fuel pump of claim 43 where said rotor has two driver slots adapted to be engaged by a pair of driver tangs of said fuel pump motor.

55. The fuel pump of claim 43 where said eccentric inner surface is defined by a first circular arc having a radius and by a second circular arc having a radius, said second circular arc being oppositely disposed of said first circular arc, said first and second arcs being interconnected by a plurality of circular arcs of differing radii, said first arc radius being greater than said second arc radius and each of said radii of said plurality of circular arcs, said second arc radius being smaller than said first arc radius and each of said radii of said plurality of circular arcs.

56. The fuel pump of claim 55 where each said roller has a diameter, said rotor also having a radius, the difference between said radius of said first arc and said radius of said rotor being no greater than one-half the diameter of said rollers.

57. The fuel pump of claim 56 where said second circular arc of said eccentric inner surface is bisected by a reference line intersecting the axis of said rotor, and said outlet port is sized such that as said rotor rotates, one of said lobes will be in fluid communication with said outlet port until said one lobe becomes tangent to the reference line.

58. The fuel pump of claim 42 where said eccentric inner surface has a circular arc bisected by a reference line intersecting the axis of said rotor, and said outlet port is sized such that as said rotor rotates, one of said lobes will be in fluid communication with said outlet port until said one lobe becomes tangent to the reference line.

59. The roller vane stage of claim 42, wherein said rotor is mounted on a bearing, said bearing having a cap such that an armature of said motor of said fuel pump cannot extend completely therethrough.

60. A roller vane stage for a fuel pump comprising:

an inlet plate, an outlet plate, and a spacer positioned therebetween, said spacer having an eccentric inner surface defining a rotor space therein, said inlet plate having at least one inlet port therethrough communicating with said rotor space, and said outlet plate having at least one outlet port therethrough communicating with said rotor space;

a rotor mounted for rotation within said rotor space and having a plurality of U-shaped lobes spaced circumferentially about said rotor and opening radially outwardly towards said eccentric inner surface, said rotor further having a driver slot adapted to be engaged by a driver tang of a motor of the fuel pump to rotate said rotor within said rotor space so as to pump fuel, said rotor having a predetermined thickness, said driver slot having a depth less than said rotor thickness such that said driver slot does not extend completely through said rotor; and

a cylindrical roller associated with and movable within each said U-shaped lobe, said roller has a thickness and a diameter such that said thickness of said roller is not less than said diameter of said roller.

61. The roller vane stage of claim 60 where each said roller is solid.

62. The roller vane stage of claim 60 where said thickness of said roller is twice said diameter of said roller.

63. A fuel pump including a roller vane stage, an inlet for receiving fuel, an outlet for exhausting fuel, and a motor for drivingly engaging said roller vane stage, said roller vane stage comprising:

an inlet plate, an outlet plate, and a spacer positioned therebetween, said spacer having an eccentric inner surface defining a rotor space therein, said inlet plate having at least one inlet port therethrough communicating with said rotor space, and said outlet plate having at least one outlet port therethrough communicating with said rotor space;

a rotor mounted for rotation within said rotor space and having a plurality of U-shaped lobes spaced circumferentially about said rotor and opening radially outwardly towards said eccentric inner surface, said rotor further having a driver slot adapted to be engaged by a driver tang of a motor of the fuel pump to rotate said rotor within said rotor space so as to pump fuel, said rotor having a predetermined thickness, said driver slot having a depth less than said rotor thickness such that said driver slot does not extend completely through said rotor; and

a cylindrical roller associated with and movable within each said U-shaped lobe, said roller has a thickness and a diameter such that said thickness of said roller is not less than said diameter of said roller.

64. The roller vane stage of claim 63 where each said roller is solid.

65. The roller vane stage of claim 63 where said thickness of said roller is twice said diameter of said roller.

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention relates to fuel pumps and, more particularly, to a high pressure roller vane stage of a motor vehicle fuel pump.

II. Description of Prior Art

An automobile generally will have an engine which derives its power from the internal combustion of fuel, such as gasoline. That same automobile will also have a tank in which fuel that is to be consumed by the engine is stored. The fuel stored in the tank is transferred to the engine by means of a fuel delivery system which commonly includes a fuel pump located in or around the tank and a fuel line leading from the fuel pump to the engine. One conventional fuel pump design uses an electric motor to drive to a high pressure roller vane stage to produce the necessary pumping action.

In such roller vane stages, low-pressure fuel from the tank is pulled into the roller vane stage through one or more inlet ports, and exhausted under high-pressure out one or more outlet ports into the fuel line. One particular roller vane stage includes a disk shaped inlet plate carrying the inlet port(s), a disk-shaped outlet plate carrying the outlet port(s) and a spacer position therebetween. The spacer has a central aperture or opening therethrough with an eccentric inner surface which defines a rotor space. A circular rotor element is rotatably mounted in the rotor space for rotation about the centroid or axis of the rotor. The rotor rotates within the spacer aperture so as to cooperate with the eccentric surface to pull fuel into the rotor space through the inlet port(s) in the inlet plate and to exhaust same out of the outlet port(s) in the outlet plate.

There are generally two different pumping actions taking place in such a roller vane stage design. In particular, the rotor has a plurality of lobes located circumferentially about its periphery such that each lobe opens radially outwardly toward the eccentric inner surface. A roller is associated with and movable within each lobe. The outer periphery and thus the lobe openings of the rotor pass closer to a smaller radius section of the eccentric surface and further from a larger radius section. The rotor spins to thereby produce pumping action. Consequently, as the rotor rotates about its axis within the rotor space, a respective lobe passes along changing radius sections of the eccentric inner surface of the spacer such that fuel is sucked into the lobe from a first or central inlet port as the lobe-roller combination rotates from a smaller radius section of the eccentric surface to a larger radius section, and fuel is exhausted therefrom out of a first or central outlet port as the roller is forced back into the lobe as the lobe-roller combination rotates from the larger radius section to the smaller radius section. Additionally or alternatively, a void in an area defined adjacent a segment of the rotor outer periphery located between two successive lobes increases in size as the rotor passes from the smaller radius section of the eccentric surface

to the larger radius section to thereby suck fuel into the void through a second or outer inlet port. Similarly, the void shrinks as the rotor segment passes from the larger radius section to the smaller radius section to thereby exhaust the fuel out of a second or outer outlet port. Successive rotation of the lobes and the outer periphery provides for a continuous conversion of low-pressure fuel coming from the tank to high-pressure fuel supplied to the engine.

To rotate the rotor element, driver slots are usually punched or otherwise formed completely through the rotor element to either side of the rotational axis thereof. An electric motor is provided with driver tangs that drivingly engage the driver slots to spin the rotor upon actuation of the motor.

Fuel pumps equipped with these high pressure roller vane stages suffer from various problems such as high vibration, excessive noise, undesirable pressure pulse, and fluid cavitation. It is believed that the excessive noise and vibration cause many consumers to register complaints with automotive service departments. As the problems are believed to originate from the roller vane stage design itself, there is no readily available repair the service department can offer. Recognizing that the roller vane stage design itself may be the source of the problems, the service department may refused to replace the fuel pump. Even if the service department replaces the fuel pump, this action may not solve the problems, and depending on the condition of the replacement fuel pump, may accentuate the noise and vibration problems. In addition, fuel pumps based upon such roller vane stages also suffer from undesirable pressure loss and excessive fuel heating. It has been suggested that increasing the rotation speed of the rotor, or providing a larger pump stage, might relieve some of these problems. However, such remedial measures may increase the electrical demands on the motor and generate increased noise and vibration of the fuel delivery system. Consequently, such remedial measures are believed to be unacceptable solutions, and other more effective solutions are desired.

SUMMARY OF THE INVENTION

The present invention provides a roller vane stage for a fuel pump, such as for use in motor vehicles, which overcomes the above-mentioned drawbacks. In accordance with one aspect of the present invention, I have come to believe that the open driver slots in the rotor provide a source of pressure loss between the inlet and outlet sides of the roller vane stage in that fuel may leak through the rotor along the motor driver tangs. To this end, and in accordance with this aspect of the invention, I overcome this problem by closing off one end of the driver slots such that there is no through-path for fuel along the motor driver tangs. More particularly, where the rotor has a predetermined thickness, ends of the driver slots have a depth less than the thickness of the rotor such that the driver slots do not extend completely through the rotor. As a consequence, I believe that my rotor can rotate at relatively lower speeds than prior art devices, yet can develop comparable fuel flow and pressures thereby reducing noise, vibration and the electricity demand of the motor.

In accordance with a further aspect of the invention, I have come to believe that some of the problems of the prior art devices are caused by the movement of the roller within the lobe during rotation of the rotor. In one instance, the roller, which typically has a circular cross-section, may rotate or spin about its axis within the lobe as the rotor rotates. Moreover, the roller may tend to spin in different directions depending upon its location along the spacer eccentric inner surface. For example, when the roller is in rolling engagement with the eccentric inner surface, the roller will spin in a clockwise direction where the rotor rotates counter-clockwise. When not in rolling engagement, however, the roller may stop spinning and possibly begin spinning in the opposite direction depending somewhat on the local fluid dynamics. Additionally, the roller may move radially within the lobe when not being forced by fluid pressure against the eccentric surface of the spacer. Such uncontrolled or erratic movements of the roller within the lobe may cause several undesirable conditions such as the generation of heat, noise, and vibration.

I have discovered that such uncontrolled and erratic movements of the roller may be overcome, at least in part, by constraining the roller within the lobe. In particular, I have found that the central outlet port of prior roller vane stages was configured such that a roller that was ceasing fluid communication with the central outlet port still had space within its respective lobe to move radially unconstrained and away from the inner surface of the space. Because the roller was no longer in communication with the central outlet port, fluid pressure was not available to force the roller against the eccentric surface. Indeed, it is believed that the roller would sweep part way between the pumping aspect of the eccentric surface and the suction aspect with little or no restriction on the roller's motion within its respective lobe, such that it could stall or be caused to spin in a direction opposite to that which is desired such that when it is again pressed out by fluid motion against the eccentric surface, it will be forced to change direction resulting in noise, heat and the like. To overcome such problems, and in accordance with the principles of the present invention, the central outlet port has a portion shaped such that fuel pressure is applied to a roller leaving the pumping section until that roller fills the lobe, minimizing the unrestrained movement of the roller. As such, the roller is continually constrained within its respective lobe up against the eccentric surface of the spacer. This aspect of the invention is believed to reduce or eliminate the reciprocating radial motion and the uncontrolled motion of the roller within the lobe, and thereby reducing the generation of heat, noise, and vibration.

In accordance with another aspect of this invention, I have come to believe that the rollers of prior art devices may experience a pinching effect between the rotor lobe and the eccentric surface of the spacer. It is believed that such a pinching effect increases wear of the rotor, the roller and the eccentric surface and increases the torque demand of the electric motor and thus its electrical demand. In this regard, in prior devices, there was at least one area of rotation of the rotor across the larger radius section of the eccentric surface where more than half of the roller could project out of the lobe beyond the periphery of the rotor. When more than half of the roller projects out of the lobe beyond the periphery of the rotor, the roller may experience a pinching effect between the junction of the lobe opening and the periphery of the rotor and the eccentric surface. I have resolved such problems by appropriate dimensioning of the roller and/or rotor such that the diameter of each roller, where the roller is circular in cross-section, and the radius of the rotor are selected such that the difference between the radius of the largest radius arc of the eccentric surface and the radius of the rotor is not greater than one half the diameter of the roller. As a consequence, as the rotor passes across the largest radius of the eccentric surface, the roller may not project out of the lobe by an amount that exceeds one-half of its diameter. Accordingly, the pinching effect is reduced or eliminated.

By virtue of the foregoing, there is thus provided a roller vane stage which reduces noise, vibration, fuel heating, cavitation, and fuel pressure pulsation problems associated with the prior art roller vane stages for fuel pumps. These and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is an exploded, perspective view of a roller vane stage in accordance with the principles of the present invention;

FIG. 2 is an outlet side plan view of the roller vane stage of FIG. 1 with the outlet plate removed for clarity and the outlet ports shown in phantom;

FIG. 3 is a cross-sectional view along l