Patent Grant
8133045
The present disclosure relates to fluid pumps, and more particularly, to fluid pumps having mechanical rotor assemblies.
Rotary fluid devices are used for a variety of purposes such as to transfer fluid (i.e., water, oil, etc.) from one location to another (e.g., a pump) or to convert fluid pressure into torque (e.g., a motor). Most rotary fluid devices include a rotating component. The rotating component cooperates with other components of the rotary fluid device to achieve its pumping or motoring purpose.
The rotating component includes precise dimensions and is precisely placed in the rotary fluid device. As a result of these precise dimensions and the precise placement of the rotating component in the rotary fluid device, assembly and disassembly of the rotary fluid device often requires the use of specialized tools. While specialized tools can be readily employed in a manufacturing facility, the use of specialized tools in the field makes field serviceability of the rotary fluid device very difficult. Therefore, there is a current need for an improved rotating component that does not require the use of special tools for assembly.
An aspect of the present disclosure relates to rotary fluid device having a housing that defines a pumping chamber, a shaft disposed in the housing, and a rotor disposed in the pumping chamber and engaged with the shaft. The rotor includes a body which defines a bore that includes an oblique tapered surface. A pivot line is disposed along the tapered surface. The pivot line is a circumferential line at which the rotor pivots.
Another aspect of the present disclosure relates to a method for manufacturing a rotor. The method includes turning an outer peripheral surface of the rotor. A bore is formed in the rotor. The bore includes an oblique tapered surface that has a pivot line disposed along the tapered surface, wherein the pivot line is a circumferential line at which the rotor pivots.
Another aspect of the present disclosure relates to a method for assembling a rotary fluid device, the method includes installing a rotor over a shaft into a pumping chamber of a housing. The rotor defines a bore having an oblique tapered surface with a pivot line disposed along the tapered surface, wherein the pivot line is a circumferential line. An end plate defining a center opening is mounted to the housing. The end plate includes an outer race of a bearing disposed in the center opening for engaging the shaft.
Another aspect of the present disclosure relates to a rotor. The rotor includes a body which defines a bore that includes an oblique tapered surface. The tapered surface of the rotor includes a first taper portion and a second taper portion that intersect. A pivot line is disposed along the tapered surface at the intersection of the first taper portion and the second taper portion. The pivot line is a circumferential line at which the rotor pivots.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Reference will now be made in detail to the exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like structure.
Many fluid pumps include rotating kits that transport or pump fluid from one location to another location. In order for these rotating kits to operate efficiently, small dimensional tolerances are required to minimize potential leakage between the rotating kits and the fluid pump. However, as a result of these small dimensional tolerances, the assembly of the rotating kit in the pump is difficult. The small dimensional tolerances require the rotating kit to be precisely placed within a pump chamber of the pump such that axial ends of the rotating kit do not contact surfaces adjacent to the rotating kit when the fluid pump is fully assembled. If the axial ends of the rotating kit contact the surfaces adjacent to the rotating kit, excessive wear of the rotating kit, decreased mechanical efficiency of the pump, and potential galling at the interface between the axial end of the rotating kit and the adjacent surface may result. As a result of these potential assembly issues, fluid pumps having rotating kits with small dimensional tolerances are not easily serviceable in the field as specialty tools for assembling the rotating kit in the pump chamber are often required.
In order to minimize the likelihood of contact between the axial ends of the rotating kit and the surfaces adjacent to the rotating kit, a self-aligning rotating kit will be described. The self-aligning rotating kit aligns itself in the pump chamber, which allows the rotating kit to be assembled and serviced in the field. In addition, the self-aligning feature of the rotating kit allows the rotor to be fitted within the pumping chamber without the need of expensive assembly tools and complicated assembly techniques, which allows for the self-aligning rotating kit to be less expensively and more efficiently manufactured and serviced.
Referring now to
In the subject embodiment, the rotary fluid device 10 includes a housing, generally designated 12, having a fluid inlet 14 and a fluid outlet 16. The rotary fluid device 10 further includes a shaft 18 and an end plate, generally designated 20, connectedly engaged with the housing 12.
Referring now to
The first portion 28 of the stepped bore 26 is adapted to receive a radial lip seal 32. In the subject embodiment, the radial lip seal 32 is retained in the first portion 28 of the stepped bore 26 through a press-fit/friction-fit engagement.
The second portion 30 of the stepped bore 26 is adapted to receive a first bearing set 34. In the subject embodiment, the first bearing set 34 is a ball bearing. It will be understood, however, that the scope of the present disclosure is not limited to the first bearing set 34 being a ball bearing. The first bearing set 34 is retained in the second portion 30 of the stepped bore 26 through a press-fit/friction-fit engagement.
The end plate 20 of rotary fluid device 10 includes a first end surface 40 and a second end surface 42. The end plate 20 is connectedly engaged with the housing 12 through a plurality of fasteners 44. In the subject embodiment, the fasteners 44 provide tight sealing engagement between the first end surface 40 of the end plate 20 and the second end 24 of the housing 12. It will be understood, however, that the scope of the present disclosure is not limited to the first end surface 40 of the end plate 20 being engaged to the second end 24 of the housing 12 as there could be additional plates, such as wear plates or spacer plates, or rotating kits disposed between the end plate 20 and the housing 12.
In the subject embodiment, the end plate 20 defines a center bore 46 that extends from the first end surface 40 through the second end surface 42 of the end plate 20. Disposed within the center bore 46 is a second bearing set, generally designated 48, and a lip seal 50. In the subject embodiment, the second bearing set 48 is a needle bearing having an outer race 52 and an inner race 54. The outer race 52 of the second bearing set 48 is retained in the center bore 46 through a press-fit/friction-fit engagement. The inner race 54 of the second bearing set 48 is retained on the shaft 18 through a press-fit/friction fit engagement. It will be understood, however, that the scope of the present disclosure is not limited to the second bearing set 48 having an inner race 54 as the shaft 18 can be manufactured to the hardness and surface finish requirements for the second bearing set 48.
Referring now to
In the subject embodiment, the second end 24 of the housing 12 defines the pumping chamber 62. It will be understood, however, that the scope of the present disclosure is not limited to the housing 12 defining the pumping chamber 62. In the subject embodiment, the pumping chamber 62 defines an inner surface 66 that is generally cylindrical in shape. It will be understood, however that the scope of the present disclosure is not limited to the inner surface 66 of the pumping chamber 62 being cylindrical in shape as the inner surface 66 could have a cam-shaped surface, which is similar to the inner surface of a vane-type pump.
The pumping chamber 62 defines a longitudinal axis 68 (shown as a dashed and dotted line in
Referring now to
The rotor 64 is rotatably disposed in the pumping chamber 62 such that the first axial end 72 is adjacent to an end wall 82 of the housing 12 and the second axial end 74 is adjacent to the first end surface 40 of the end plate 20. In the subject embodiment, the rotor 64 rotates about an axis 83 (shown in
During rotation of the rotor 64 about the axis 83, which is generally aligned with the central axis 70 of the rotary fluid device 10, each of the rollers 80 rotates about a center axis 84 (shown as a dashed line in
In the subject embodiment, the inner surface 66 of the pumping chamber 62, the rotor 64, and the rollers 80 cooperatively define a plurality of contracting and expanding volume chambers 86. As the rotor 64 rotates about the central axis 70, the expanding volume chambers 86 are in fluid communication with the fluid inlet 14 of the fluid rotary device 10 while the contracting volume chambers 86 are in fluid communication with the fluid outlet 16.
Referring now to
Referring now to
In the subject embodiment, the axial location 104 of the pivot line 106 is disposed an axial distance W104 from the first axial end 72. This axial distance W104 is less than or equal to the total width W of the rotor 64 as measured from the first axial end 72 to the second axial end 74. In the subject embodiment, and by way of example only, the axial distance W104 is in the range of about 0% to about 100% of the width W of the rotor 64. In another embodiment, and by way of example only, the axial distance W104 is in the range of about 25% to about 75% of the width W of the rotor 64. In another embodiment, and by way of example only, the axial distance W104 is in a range of about 33% to about 67% of the width W of the rotor 64. In another embodiment, and by way of example only, the axial distance W104 is in a range of about 45% to about 55% of the width W of the rotor 64. In another embodiment, and by way of example only, the axial distance W104 is in a range of about 48% to about 52% of the width W of the rotor 64. In another embodiment, and by way of example only, the axial distance W104 is about 50% of the width W of the rotor 64.
The first taper portion 100 includes an inner diameter Ø72 at the first axial end 72 of the rotor 64. As the first taper portion 100 extends along the axis 83 from the first axial end 72 to the axial location 104, the inner diameter Ø72 of the first taper portion 100 decreases to the inner diameter Ø106 of the pivot line 106. In the subject embodiment, the first taper portion 100 is shaped generally as a truncated right circular cone. It will be understood, however, that the scope of the present disclosure is not limited to the first taper portion 100 being generally conical in shape.
The second taper portion 102 includes an inner diameter Ø74 at the second axial end 74 of the rotor 64. As the second taper portion 102 extends along the axis 83 from the second axial end 74 to the axial location 104, the inner diameter Ø74 of the second taper portion 102 decreases to the inner diameter Ø106 of the pivot line 106. In the subject embodiment, the second taper portion 102 is shaped generally as a truncated right circular cone. It will be understood, however, that the scope of the present disclosure is not limited to the second taper portion 102 being generally conical in shape.
In the subject embodiment, and by way of example only, the inner diameter Ø72 of the first axial end 72 of the rotor 64 is about equal to the inner diameter Ø74 of the second axial end 74. It will be understood, however, that the scope of the present disclosure is not limited to the inner diameter Ø72 of the first axial end 72 being about equal to the inner diameter Ø74 of the second axial end 74.
The inner diameter Ø106 of the pivot line 106 is sized for a close clearance fit with the outer diameter of the shaft 18. This close clearance fit prevents the rotor 64 from moving radially with respect to the shaft 18 during rotation of the rotor 64 and the shaft 18.
In the subject embodiment, the first taper portion 100 defines a first conical opening 110 having a first conical angle α1. The first conical angle α1 is defined as the angle between the two lines that generate the truncated right circular conical shape of the first taper portion 100. In the subject embodiment, and by way of example only, the first conical angle α1 is in the range of about 0.1 to about 30 degrees. In one embodiment, and by way of example only, the first conical angle α1 is in the range of about 3 to about 5 degrees. In another embodiment, the first conical angle α1 is about 4 degrees.
The second taper portion 102 defines a second conical opening 112 having a second conical angle α2. The second conical angle α2 is defined as the angle between the two lines that generate the truncated right circular conical shape of the second taper portion 102. In the subject embodiment, and by way of example only, the second conical angle α2 is in the range of about 0.1 to about 30 degrees. In one embodiment, and by way of example only, the second conical angle α2 is in the range of about 3 to about 5 degrees. In another embodiment, the second conical angle α2 is about 4 degrees.
In the subject embodiment, the first conical angle α1 of the first taper portion 100 is about equal to the second conical angle α2 of the second taper portion 102. It will be understood, however, that the scope of the present disclosure is not limited to the first conical angle α1 of the first taper portion 100 being about equal to the second conical angle α2 of the second taper portion 102.
With the inner diameter Ø106 of the pivot line 106 being in close clearance fit with the shaft 18 and with the inner diameters Ø72, Ø74 of the first and second taper portions 100, 102 at the first and second axial ends 72, 74, respectively, being larger than the inner diameter Ø104 of the axial location 104, the central bore 90 of the rotor 64 allows for angular misalignment of the rotor 64 on the shaft 18. As will be described in greater detail subsequently, this allowance for angular misalignment provides for ease of assembly/reassembly of the rotary fluid device 10.
Referring now to
With the tapered surface 98 of the central bore 90 formed, a key broach is used to broach the notch 92. In one embodiment, after the notch 92 has been broached, the rotor 64 is ready to be assembled in the rotary fluid device 10. In another embodiment, after the notch 92 has been broached, the rotor 64 is heat treated. Following the heat treat process, the rotor 64 is sent to a grinding operation where the outer periphery, the slots 78, and the first and second axial ends 72, 74 of the rotor 64 are ground.
Referring now to
The key 94 is then inserted into the groove 96 of the shaft 18. With the key 94 disposed in the groove 96 of the shaft 18, the rotor 64 is inserted into the pumping chamber 62 such that the first axial end 72 of the rotor 64 is adjacent to the end wall 82 of the housing 12 and the notch 92 is engaged with the key 94. As previously stated, the central bore 90 of the rotor 64 allows for angular misalignment. Therefore, the axis 83 of the rotor 64 does not need to be precisely aligned with the central axis 70 of the rotary fluid device 10 when the rotor 64 is inserted into the pumping chamber 62 of the housing 12. As the inner diameter Ø106 of the pivot line 106 is in close clearance fit with the outer diameter of the shaft 18 and as the inner diameters Ø72, Ø74 of the first and second axial ends 72, 74 of the rotor 64 are greater than the inner diameter Ø106 of the pivot line 106, the rotor 64 is free to pivot at pivot point disposed along the pivot line 106 and/or points disposed within an area outlined by the pivot line 106. As the pivot line 106 is disposed in the plane 108, which is normal to the plane of rotation, the phrases “pivot at the pivot line 106”, “line at which the rotor pivots”, and derivatives thereof, as used in the specification and the claims will be understood to mean that the rotor pivots at pivot points disposed along the pivot line 106 and/or pivot points within an area outlined by the pivot line 106. In the subject embodiment, the rotor 64 can pivot at the pivot line 106 by about one-half the first conical angle α1 or about one-half the second conical angle α2 depending on which conical angle is smaller.
If the rotor 64 is angularly misaligned from the central axis 70 during installation, engagement of the end plate 20 to the housing 12 will pivot the rotor 64 at the pivot line 106 so as to rotationally balance the rotor 64 in the pumping chamber 62. In the subject embodiment, and by way of example only, the engagement of the end plate 20 to the housing 12 pivots the rotor 64 such that the axis 83 of the rotor 64 is generally aligned with the central axis 70.
With the rotor 64 disposed in the pumping chamber 62, the rollers 80 are inserted into the slots 78 defined by the rotor 64. The end plate 20 having the lip seal 50 and the outer race 52 of the second bearing set 48 disposed in the center bore 46 is mounted to the housing 12 such that the shaft 18 extends through the center bore 46. The fasteners 44 are then inserted through the end plate 20 and into the housing 12 and tightened to a predetermined torque.
The tapered surface 98 of the central bore 90 of the rotor 64 allows the rotor 64 to be self-aligning. This feature is potentially advantageous as it provides for improved assembly/reassembly of the rotary fluid device 10, which improves the serviceability of the rotary fluid device 10. As assembly/reassembly of the rotor 64 does not require the use of precision tools to properly align the axis 83 of the rotor 64 to the central axis 70 of the rotary fluid device 10, the rotary fluid device 10 can be easily disassembled and reassembled in the field.
In addition, the pivot line 106 of the tapered surface 98 can minimize the amount of wear between the rotor 64 and the shaft 18. As the pivot line 106 of the tapered surface 98 is a circumferential line, as opposed to a circumferential surface, the pivoting of the rotor 64 at the pivot line 106 minimizes wear between the pivot line 106 and the shaft 18. Wear resulting from the interfacing of mating or adjacent components creates material particles or contaminants. These material particles can create detrimental effects (e.g., galling, seizing, etc.) in the rotary fluid device 10 due to the tolerances associated with the assembly of the rotary fluid device 10. By having the pivot line 106 formed as a circumferential line as opposed to a surface, the amount of wear is reduced as the pivoting of the rotor 64 at the pivot line 106 does not create interference between the shaft 18 and the pivot line 106.
As previously stated, the second bearing set 48 includes an outer race 52 disposed in the center bore 46 of the end plate 20 and an inner race 54 disposed on the shaft 18. The outer and inner races 52, 54 of the second bearing set 48 are engaged such that the inner race 54 rotates within the outer race 52. As the outer and inner races 52, 54 are not in tight-fit engagement with each other, the outer and inner races 52, 54 can be separated without the use of a hydraulic press. This feature is potentially advantageous as it provides access to the rotor assembly 60 without the need for specialized tools.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2335284 | Kendrick | Nov 1943 | A |
| 2657638 | English | Nov 1953 | A |
| 2737121 | Badalini | Mar 1956 | A |
| 3316852 | Sadler | May 1967 | A |
| 3373693 | McKittrick | Mar 1968 | A |
| 4645430 | Carleton | Feb 1987 | A |
| Number | Date | Country |
|---|---|---|
| 59196986 | Nov 1984 | JP |
| 1752992 | Aug 1992 | SU |
| Number | Date | Country | |
|---|---|---|---|
| 20090238706 A1 | Sep 2009 | US |
