TECHNICAL FIELD
Present disclosure relates to a rotor type pump. In particular, present disclosure relates to anouter rotor for a rotor-type pump.
BACKGROUND
Rotor-type pumps, hereinafter referred to as rotor pumps, are widely used for the purpose of supplying oil, such as lubricating oil in machine. A rotor pump generally has an annular outer rotor which and an annular inner rotor. The inner rotor is disposed eccentrically inside the outer rotor. The outer gear teeth of the inner rotor mesh partially with the inner gear teeth of the outer rotor. When the inner and the outer rotors are rotated, a pumping action occurs.
The outer rotor of the rotor pump is generally disposed rotatably in a pump casing. For facilitating the rotary movement of the outer rotor with respect to the inner rotor, an annular cavity is provided in the pump casing and the outer rotor is disposed in the annular cavity concentrically to achieve a rotary sliding motion between the pump casing and the outer rotor. The outer surface of the outer rotor is circular corresponding to the annular cavity. Such rotors are bulky difficult to manufacture as they require several machining processes to obtain a smooth outer surface for minimizing friction between the pump casing and the outer rotor. Also, during manufacturing of such outer rotors using a powder metallurgy process, undesired density variations may occur throughout the profile of the outer rotor. Present disclosure is directed to address the problems as discussed above and other associate problems.
SUMMARY
One or more shortcomings of conventional assemblies are overcome and additional advantages are provided through the provision of an assembly as claimed in the present disclosure. Additional features and advantages are realized through the assembly of the present disclosure.
An outer rotor for a rotor-type oil pump is disclosed. The outer rotor is configured to rotate about an axis, and the cross-section of the outer rotor taken along a plane perpendicular to the axis is of a uniform thickness wall forming the outer rotor.
In an aspect, an axial end of the outer rotor has a circular periphery about the axis.

In an aspect, the outer rotor is made by a powder metallurgy process.
In an aspect, the outer rotor has an axial length of 30mm to 300mm.
In an aspect, the wall has a thickness of 2.5 mm to 100mm.
It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
FIG. 1 illustrates a perspective view of a rotor-type oil pump having an outer rotor in accordance with an embodiment.
FIG. 2 illustrates a perspective view of the outer in accordance with an embodiment.
FIG. 3 illustrates a front view of the outer rotor of FIG. 2
FIG. 4 illustrates a cross-sectional view of the outer rotor taken along line 4-4 of FIG. 3.

FIG. 5 illustrates perspective view of an outer rotor in accordance with another embodiment of the present disclosure.
FIG. 6 illustrates a front view of the outer rotor of FIG. 5.
FIG. 7 illustrates cross-sectional view of the outer rotor of FIG. 5 taken along the line 7-7 of FIG. 6.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
It is to be noted that a person skilled in the art would be motivated from the present disclosure of an outer rotor, which may vary based on configuration of the outer rotor. However, such modifications should be construed within the scope of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a device, system, assembly that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more

constraints, preclude the existence of other elements or additional elements in the system or device.
FIG. 1 illustrates an oil pump (10) having a casing (12), an outer rotor (14) and an inner rotor (not shown). As shown, the outer rotor (14) is disposed in a circular cavity (16) defined in the casing (12). The outer rotor (14) is configured to rotate about an axis (18) (shown in FIG. 4). The casing (12) supports the outer rotor (14) in the circular cavity (16) and guides rotary motion of the outer rotor (14) by a relative sliding motion between the casing (12) and the outer rotor (14), as known in the art.
Referring to FIG. 1 and FIG. 2, the outer rotor (14) has an inner surface (20) and an outer surface (22). The inner surface (20) of the outer rotor (14) defines internal gears (24) and a cavity configured to receive the inner rotor eccentrically, as known in the art. The outer surface (22) is radially outwardly offset relative to the inner surface (20) by a uniform width throughout the periphery of the inner surface (20). As shown in FIG. 3, the inner surface (20) and the outer surface (22) define a wall (28) of uniform thickness throughout the cross section (taken along a plane perpendicular to the axis (18)) of the outer rotor (14).
As the outer surface (22) is uniformly offset to the inner surface (20), the outer surface (22) defines concave grooves (30) between two adjacent internal gears (24) on the inner surface (20). In the embodiment as shown in FIG. 5-7, one axial end (32) of the outer rotor (14) has the wall (28) extending radially from the concave grooves (30) to form a complete circular outer periphery at that axial end (32). The radius of the circular outer periphery is same as the radial extremity of the outer rotor (14), as shown in FIG. 6. The circular periphery at an axial end (32) may aid in stability of the outer rotor (14) during operation of the oil pump (10). In an alternate embodiment, both the axial ends (32) of the outer rotor (14) may be provided with circular outer periphery as described herein.
In the embodiment as shown in FIG. 1-7, the outer rotor (14) has an axial width of 3mm to 300mm, in an example axial width is 30 mm. Whereas, the thickness of the wall (28) forming the outer rotor (14) profile ranges from about 2.5mm to 100mm. The outer rotor (14) has five internal gears (24) and a radial dimension ranging from about 10mm to 500mm. It may be

understood that the outer rotor (14) as described herein is shown as an example. An alternate embodiment may have any number of gears, or any axial or radial dimensions, as required. Further, the outer rotor (14) may be made by any suitable material such as polymer, iron, steel, or any other metal or alloy.
The outer rotor (14) of the present disclosure may be manufactured using a powder metallurgy process. The outer rotor (14) of the present disclosure manufactured using powder metallurgy process has a uniform density throughout the outer rotor (14). A casting die having a casting cavity corresponding to the outer rotor (14) as described herein may be used for manufacturing of the outer rotor (14) of the present disclosure.
The outer rotor (14) of the present disclosure is light weight and easy to manufacture. Further, the overall contact area between the casing (12) and the outer rotor (14) is reduced. Hence, the friction between the outer rotor (14) and casing (12) is also reduced. Accordingly, the outer rotor (14) of the present disclosure provides for improved efficiency of the oil pump (10) by minimizing frictional losses.
Equivalents:
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such

phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

List of referral numerals: 10-Oil pump. 12-Casing. 14-Outer rotor. 16-Circualr Cavity. 18-Perpedicaulr axis. 20-Inner Surface of outer rotor. 22-Outer surface of outer rotor. 24-Internal gears. 28-Wall.
30-Concave Groove. 32-Axial end.

We claim:
1. An outer rotor (14) for a rotor-type oil pump (10), the outer rotor (14) configured to rotate about an axis (18), characterized in that, the cross-section of the outer rotor (14) taken along a plane perpendicular to the axis (18) is of a uniform thickness wall (28) forming the outer rotor (14).
2. The outer rotor (14) as claimed in claim 1, wherein an axial end (32) of the outer rotor (14) has a circular periphery about the axis (18).
3. The outer rotor (14) as claimed in claim 1, wherein the outer rotor (14) is made by a powder metallurgy process.
4. The outer rotor (14) as claimed in claim 1, wherein the outer rotor (14) has an axial length of ranging from about 30 mm to 300mm.
5. The outer rotor (14) as claimed in claim 1, wherein the wall (28) has a thickness ranging from about 2.5 mm to 100mm.
6. A rotor-type oil pump (10) having a rotor as claimed in claim 1.