WO2008106198A1

WO2008106198A1 - Stamped steel lamination process to produce gerotor inner and outer rotors for pump applications

Info

Publication number: WO2008106198A1
Application number: PCT/US2008/002648
Authority: WO
Inventors: Robert J. Mack
Original assignee: Borgwarner Inc.
Priority date: 2007-02-28
Filing date: 2008-02-28
Publication date: 2008-09-04

Abstract

The present invention is an improved approach to manufacturing a gerotor pump using several laminas attached together to form a solid, which are laid adjacent to each other. The present invention is a pump having a first pump element and a second pump element. The first pump element is operably associated with the second pump element such that a pumping action is created between the first pump element and the second pump element, and at least one of either the first pump element or second pump element are made of a plurality of lamina laminated together to form said at least one of said first pump element or said second pump element.

Description

STAMPED STEEL LAMINATION PROCESS TO PRODUCE GEROTOR INNER AND OUTER ROTORS FOR PUMP APPLICATIONS

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a PCT International Application which claims benefit of United States Patent Application No. 60/903,915 filed on February 28, 2007. The disclosure of the above application is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the manufacture of gerotor pumps; more specifically, the present invention relates to a stamped steel lamination manufacturing process for producing an inner gerotor and an outer gerotor used in a gerotor pump.

BACKGROUND OF THE INVENTION

Gerotor pumps are generally known. Gerotor pumps typically consist of an inner gerotor and an outer gerotor. There is also a series of lobes on the outer diameter of the inner gerotor, and a series of lobes on the inner diameter of the outer gerotor. The lobes of the inner gerotor are intermittently in mesh with the lobes of the outer gerotor. The reason the lobes of the inner gerotor are intermittently in mesh with the lobes of the outer gerotor is because the inner gerotor is smaller in diameter compared to the outer gerotor. The inner gerotor and the outer gerotor have the same linear velocity at the point where the inner gerotor and the outer gerotor are in mesh, and the outer gerotor rotates at a slower linear velocity relative to the inner gerotor at all other locations. Also, the reduced size of the inner gerotor creates a space in between the lobes of the inner gerotor which are not in mesh with the lobes of the outer gerotor; this space is used for pumping fluid, as well as allowing the lobes of the inner gerotor to be in mesh with the lobes of the outer gerotor on an intermittent basis. Gerotor pumps are manufactured in several ways. Most commonly, inner gerotors and outer gerotors are manufactured using a powdered metal process. While many attempts have been made to improve the manufacturing process used to create gerotor pump components, powdered metallurgy processes remain the most common and cost effective. Due to the operating conditions of the gerotor pump, as well as strength and durability requirements, the approach used to manufacture a gerotor pump is limited to processes which can meet or exceed the various strength and durability requirements, while at the same time remain cost feasible. Accordingly, there exists a need for an improved method of manufacture of gerotor pumps which has cost advantages over powdered metallurgy, yet provides proper strength, durability, and meets tolerance requirements.

SUMMARY OF THE INVENTION

The present invention is an improved approach to manufacturing a gerotor pump using several laminas attached together to form a solid, which are laid adjacent to each other. The present invention is a pump having a first pump element and a second pump element. The first pump element is operably associated with the second pump element such that a pumping action is created between the first pump element and the second pump element, and at least one of either the first pump element or second pump element are made of a plurality of lamina laminated together to form said at least one of said first pump element or said second pump element. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

Figure 1 is a side view of a gerotor pump having an inner gerotor and an outer gerotor, according to the present invention;

Figure 2 is a sectional side view of a gerotor pump prior to having a stake point installed, according to the present invention; and

Figure 3 is a sectional side view taken along line 3-3 of Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

A gerotor pump according to the present invention is shown in Figure 1 generally at 10. The pump 10 includes a first pump element, which in this embodiment is an inner gerotor 12 having lobes 14, and a second pump element, which in this embodiment is an outer gerotor 16 having lobes 18. Both the inner gerotor 12 and the outer gerotor 16 are made of at least one lamina, more preferably, the inner gerotor 12 has a first plurality of lamina, and the outer gerotor 16 has a second plurality of lamina (best seen in Figures 2 and 3). In this embodiment, both the inner gerotor 12 and the outer gerotor 16 have a first lamina 20, at least one middle lamina made of a second lamina 22, a third lamina 24, and a fourth lamina 26, and an end lamina made of a fifth lamina 28. Both the inner gerotor 12 and the outer gerotor 16 having at least one stake point 30 for connecting the laminas 20,22,24,26,28 together during assembly.

Each of the laminas 20,22,24,26,28 can be formed from a material, such as steel, using any preferred manufacturing process, such as stamping, laser cutting, electronic discharge machining (EDM), wire cut, hydro cut, or the like. Any type of process can be used, provided the proper tolerances are met, and no secondary operation is required after the lamina 20,22,24,26,28 are assembled to achieve the proper surface finish. - A -

The inner gerotor 12 also includes a flat portion 32 which is used for contacting a corresponding flat potion on a shaft (not shown). The shaft is used for providing rotational force to the inner gerotor 12, the function of which will be described later. Figure 2 shows a sectional side view of an inner gerotor 12, prior to the stake point 30 being driven into the first lamina 20.

Figure 3 shows a sectional side view of one of the stake points 30 in the inner gerotor 12. However, the stake point 30 shown in Figure 3 is similar to the stake points 30 used in both the inner gerotor 12 and the outer gerotor 16. During assembly, the laminas 20,22,24,26,28 are positioned such that all of the lobes 14 of the inner gerotor 12 (or the lobes 18 of the outer gerotor 16, if the outer gerotor 16 is being assembled) are aligned. Once the lobes 14 of the inner gerotor 12 are aligned, a force, through a process such as staking or the like, is applied at the stake point 30, causing the material in each of the laminas 20,22,24,26 to shift and change position from what is shown in Figure 2, to what is shown in Figure 3. The fifth lamina 28 has an aperture 34 which is used for allowing the material in each of the first four laminas 20,22,24,26 to displace at each stake point 30. While staking is preferable, other methods of securing the lamina 20,22,24,26,28 together into a single unit can be utilized, providing the strength, durability, and tolerance can be maintained.

When the laminas 20,22,24,26,28 are assembled together, a force is applied (such as impact loading) to the first lamina 20 at the stake point 30. As the force is applied, a portion of the material 36 in the first lamina 20 will become displaced and forced into the second lamina 22. This will cause a portion of the material 38 in the second lamina 22 to be forced into the third lamina 24, a portion of the material 40 in the third lamina 24 to be forced into the fourth lamina 26, and a portion of the material 42 in the fourth lamina 26 to be forced into the aperture 34 in the fifth lamina 28. The aperture 34 must be aligned with the stake point 30 to allow the material in each of the first four laminas 20,22,24,26 to displace properly. Once the force is applied to the stake point 30, the fit between each of the laminas 20,22,24,26,28 due to the displacement of the material 36,38,40,42 will cause the laminas 20,22,24,26,28 to remain together as a single unit. The outer gerotor 16 is assembled in the same manner as the inner gerotor 12. Once assembled, the inner gerotor 12 is placed in a position such that the outer gerotor 16 circumscribes the inner gerotor 12, and the lobes 14 of the inner gerotor 12 are partially in mesh with the lobes 18 of the outer gerotor 16 as shown in Figure 1. Only some of the lobes 14 are in mesh with the lobes 18 because the inner gerotor 12 is smaller than the outer gerotor 16, this leaves a space 44 located in between the inner gerotor 12 and the outer gerotor 16 which is used to pump fluid.

In operation, as the inner gerotor 12 is driven by the shaft, the lobes 14 engaged with the lobes 18 will drive the outer gerotor 16 to rotate as well. As the inner gerotor 12 and outer gerotor 16 rotate, the space 44 will expand and contract, creating a pumping action which is used to pump fluid. This type of pump 10 can be used to pump various types of fluid, such as, but not limited to, engine oil, transmission fluid, transfer case fluid, or other types of fluids. While it has been described that the inner gerotor 12 and the outer gerotor 16 have five laminas 20,22,24,26,28, it is within the scope of the invention that different numbers of laminas can be used to assemble a gerotor pump.

The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Claims

CLAIMS What is claimed is:

1. A pump, comprising: a first pump element; a second pump element, said first pump element operably associated with said second pump element such that a pumping action is created between said first pump element and said second pump element; and at least one of said first pump element or said second pump element further comprising a plurality of lamina laminated together forming said at least one of said first pump element, or said second pump element.

2. The pump of claim 1 , each of said first pump element and said second pump element further comprising laminas.

3. The pump of claim 2, further comprising a space formed by said first pump element and said second pump element, and when said first pump element and said second pump element rotate, said space will create a pumping action.

4. The pump of claim 1 , said at least one of said first pump element or said second pump element further comprising: a first lamina; at least one middle lamina adjacent to said first lamina; an end lamina adjacent to said at least one middle lamina, said end lamina having at least one aperture; and at least one stake point operably associated with said first lamina, said at least one middle lamina, and said end lamina, for connecting said first lamina, said at least one middle lamina, and said end lamina.

5. The pump of claim 4, said at least one stake point further comprising: a portion of said first lamina is displaced in said at least one middle lamina; a portion said at least one middle lamina is displaced in said aperture of said end lamina; and said portion of material in said first lamina displaced in said at least one middle lamina connects said first lamina to said at least one middle lamina, and said portion of material in said at least one middle lamina displaced in said aperture in said end lamina connects said at least one middle lamina to said end lamina.

6. The pump of claim 5, wherein said material in said first lamina displaced in said at least one middle lamina is adjacent to said portion of material of said at least one middle lamina displaced in said aperture of said end lamina.

7. A gerotor pump, comprising: an inner gerotor pump element; an outer gerotor pump element circumscribing said inner gerotor pump element; at least one of said inner gerotor pump element and said outer gerotor pump element made of a first lamina adjacent to at least one middle lamina, and an end lamina adjacent to said at least one middle lamina; and said first lamina, said at least one middle lamina, and said end lamina being cut in the shape of said at least one of said inner gerotor pump element or said outer gerotor pump element and laminated together to form said at least one of said inner gerotor pump element or said outer gerotor pump element.

8. The gerotor pump of claim 7, wherein both of said inner gerotor pump element and said outer gerotor pump element are formed of lamina.

9. The gerotor pump of claim 7, wherein said first lamina, said at least one middle lamina, and said end lamina of said inner gerotor pump element are held together by a series of stake points located in proximity to a series of lobes, said series of lobes being formed in said inner gerotor pump element, and said first lamina, said at least one middle lamina, and said end lamina of said outer gerotor pump element are held together by a series of stake points located in proximity to a said series of lobes formed in said outer gerotor pump element.

10. The gerotor pump of claim 9, said series of stake points further comprising: a portion of material of said first lamina protruding into said at least one middle lamina; a portion of material of said at least one middle lamina protruding into said end lamina; and said portion of material of said first lamina protruding into said at least one middle lamina is adjacent to said portion of material of said at least one middle lamina protruding into said end lamina.

11. The gerotor pump of claim 10, further comprising: an aperture formed in said end lamina; and said aperture in said end lamina receives said portion of material of said at least one middle lamina offset into said end lamina.

12. The gerotor pump of claim 7, further comprising a space formed between said inner gerotor pump element and said outer gerotor pump element, wherein said space between said inner gerotor pump element and said outer gerotor pump element will pump fluid as said inner gerotor pump element and said outer gerotor pump element rotate.

13. A gerotor pump, comprising: an innergerotor made of a first plurality of laminas having a plurality of lobes; an outer gerotor made of a second plurality of laminas, said outer gerotor circumscribing said inner gerotor and having a plurality of lobes operably associated with said plurality of lobes of said inner gerotor; at least one stake point holding said first plurality of laminas of said inner gerotor together; and at least one stake point holding said second plurality of laminas of said outer gerotor together, and when said inner gerotor rotates, said plurality of lobes from said inner gerotor will transfer rotational force to said plurality of lobes of said outer gerotor, causing said outer gerotor to rotate.

14. The gerotor pump of claim 13, wherein said first plurality of laminas and said second plurality of laminas are further comprised of: a first lamina; at least one middle lamina adjacent to said first lamina; and an end lamina adjacent to said at least one middle lamina on the opposite side of said at least one middle lamina as said first lamina, wherein said first lamina, said at least one middle lamina, and said end lamina are connected to form either of said inner gerotor or said outer gerotor.

15. The gerotor pump of claim 14, said least one stake point further comprising: a portion of material in said first lamina received by said at least one middle lamina, joining said first lamina and said at least one middle lamina; an aperture formed as a portion of said end lamina; a portion of material in said at least on middle lamina received in said aperture in said end lamina, joining said at least one middle lamina and said end lamina; and when said first lamina is joined to said at least one middle lamina, said at least one middle lamina is joined to said end lamina, said first lamina, said at least one middle lamina, and said end lamina function as a single component.

16. The gerotor pump of claim 15, wherein said portion of material in said first lamina received by said at least one middle lamina contacts said portion of material in said at least one middle lamina received by said aperture in said end lamina.

17. The gerotor pump of claim 15, at least one stake point for connecting said first plurality of laminas further comprising: a portion of material in each of said first plurality of laminas is offset, connecting said plurality of laminas together.