Patent Application
20090274564
This patent disclosure relates generally to pump assemblies and, more particularly, to floating cup pump assemblies utilizing a plurality of piston elements disposed around a first rotating surface and a plurality of complimentary cup elements disposed around a second rotating surface in angled relation to the piston elements. The cup elements reciprocate relative to the piston elements during rotation.
Pumping devices utilizing a plurality of piston elements mounted around a first rotor and a plurality of complimentary cup elements projecting away from a swash plate in angled relation to the piston rotor are generally known. United States Patent Application No. 2006/0222516 in the name of Achten, having a publication date of Oct. 5, 2006, discloses one such device. Embodiments of pumps described in this reference include a centrally disposed rotor having a plurality of pistons projecting away from both sides of the rotor. A pair of cooperating drum plates disposed outboard from the rotor support an arrangement of cup elements or drum sleeves adapted to house distal portions of the pistons. The rotor supporting the pistons rotates around a first axis of rotation. The drum plates rotate in angled relation to the first axis. The rotor supporting the pistons is rotated in tandem with the drum plates during operation. Due to the angle between the rotor and the drum plates, the cups are caused to stroke along the length of the corresponding piston elements such that the volume occupied by the piston elements is alternately increased and decreased during the rotational cycle. Thus, fluid introduced into a cup element when the complimentary piston is in a substantially withdrawn position may be pressurized and expelled as the cup is pushed inwardly during the rotational cycle.
In the noted reference, each of the drum plates housing the cup elements rotates around a convex centering surface or ball guide. In order to balance forces generated within the pump, the drum plates on either side of the central rotor are mounted and operated with substantial symmetry. A lack of symmetry leads to the pump operating in an unbalanced condition. Such unbalanced operation may degrade performance and introduce stresses which can cause damage. The need to maintain a substantially matched arrangement of drum plates in the prior device gives rise to a relatively complex initial construction process to ensure the desired matched angle and spacing on each side of the central rotor. Carrying out this initial construction may require a relatively high level of skill. Accordingly, an alternative construction which promotes balanced operation while reducing complexity is desirable.
The disclosure describes, in one aspect, a floating cup pump structure having a swashplate structure including a first side and an opposing second side facing away from the first side. A first plurality of cup elements projects away from the first side of the swashplate structure and a second plurality of cup elements projects away from the second side of the swashplate structure. The swashplate structure is positioned between a first group of piston elements mounted on a first rotatable piston support and a second group of piston elements mounted on a second rotatable piston support. At least one member of the first group of piston elements is adapted to engage a complimentary cup element projecting away from the first side of the swashplate structure. At least one member of the second group of piston elements is adapted to engage a complimentary cup element projecting away from the opposing side of the swashplate structure. The swashplate structure is angled relative to at least one of the rotatable piston supports.
In another aspect, this disclosure describes a method for pumping a fluid. The method includes providing a fluid to a pump having a tilted swashplate structure. A first plurality of cup elements projects away from a first side of the swashplate structure and a second plurality of cup elements projects away from a second side of the swashplate structure facing away from the first side. The first plurality of cup elements engages a first plurality of piston elements and the second plurality of cup elements engages a second plurality of piston elements. At least a portion of the fluid is introduced into the first plurality of cup elements and the second plurality of cup elements. The first plurality of cup elements and the second plurality of cup elements are reciprocated relative to the engaged piston elements, and the fluid is expelled in a pressurized state.
This disclosure relates to a floating cup pump assembly incorporating a swashplate structure with cup elements projecting away from a first side and an opposed second side of the swashplate structure. The swashplate structure is positioned between a first group of engaged piston elements and a second group of engaged piston elements. The swashplate structure is tilted to define angled backing support surfaces for carriers supporting the cup elements. The piston elements rotate around a first axis and the carriers supporting the cup elements follow the rotational movement of the piston elements. Due to the angled backing support provided by the swashplate structure, the cups are pushed around a second axis in angled relation to the first axis thereby causing the cups to reciprocate relative to the piston elements.
Reference will now be made to the drawings, wherein like reference numerals designate like elements in the various views.
In the exemplary construction illustrated in
As shown, the first cup elements 18 matedly engage distal portions of a plurality of complementary first piston elements 20. The second cup elements 19 matedly engage distal portions of a plurality of complementary second piston elements 21. The first piston elements 20 extend away from a first rotatable piston support 22. The second piston elements 21 extend away from a second rotatable piston support 23. As illustrated, the first rotatable piston support 22 and the second rotatable piston support 23 are disposed radially about rotatable the shaft assembly 12 in generally opposing relation to one another on either side of the swashplate structure 14. According to the illustrated construction, the first piston elements 20 have a generally hollow, frusto-conical configuration with an increased diameter distal portion and a fluid passageway 26 running along the length from the distal portion to a proximal portion held at the first rotatable piston support 22. Likewise, the second piston elements 21 have a generally hollow, frusto-conical configuration with an increased diameter distal portion and a fluid passageway 27 running along the length from the distal portion to a proximal portion held at the second rotatable piston support 23. However, other suitable constructions may likewise be utilized as desired. It is to be understood that while the cross-sectional view of
In the illustrated construction of
According to the exemplary construction, the first carrier plate 44 is supported radially in this angled orientation by a first curved surface support element 40 alternatively referred to as a “ball guide” which is arranged about the rotatable shaft assembly 12. Likewise, the second carrier plate 45 is supported radially in this angled orientation by a second curved surface support element 41. As best illustrated through joint reference to
By way of example only, and not limitation, it is contemplated that each of the first curved surface support element 40 and the second curved surface support element 41 may have a substantially unitary construction formed by techniques such as casting, powder metallurgy, or other suitable formation techniques using metal alloys or other materials adapted to withstand substantial cyclical stresses. However, it is likewise contemplated that portions may be formed separately and thereafter joined together if desired. According to one contemplated practice, the first curved surface support element 40 and/or the second curved surface support element 41 may be formed separately from components of the rotatable shaft assembly 12 such that the first curved surface support element 40 and/or the second curved surface support element 41 is non-integral with the rotatable shaft assembly 12. Accordingly, the first curved surface support element 40 and/or the second curved surface support element 41 may be held in separable relationship relative to the rotatable shaft assembly 12. That is, the first curved surface support element 40 and/or the second curved surface support element 41 may be subject to nondestructive removal from the rotatable shaft assembly 12 upon disassembly of the pump assembly 10. Of course, the first curved surface support element 40 and/or the second curved surface support element 41 may also be formed in integral relation with the rotatable shaft assembly 12 by techniques such as casting, machining or the like.
By way of example only, and not limitation,
As shown in
In the illustrated construction, the first carrier plate opening 60 is surrounded by a first beveled or curved engagement surface 62 adapted to engage the convex exterior support surface of the first curved surface support element 40 in substantially complimentary relation. Likewise, the second carrier plate opening 61 is surrounded by a second beveled or curved engagement surface 63 adapted to engage the convex exterior support surface of the second curved surface support element 41 in substantially complimentary relation. As the rotatable shaft assembly 12 rotates during operation, the first carrier plate 44 and the second carrier plate 45 are likewise caused to rotate due to circumferential pushing action by the first piston elements 20 and the second piston elements 21. During this rotation, the swashplate structure 14 does not rotate but may carry out a dynamic wobbling motion in the axial direction as forces are applied and relieved during different stages of the rotational cycle. During this wobbling motion portions of the first beveled engagement surface 62 move axially along the first curved surface support element 40 and portions of the second beveled engagement surface 63 move axially along the second curved surface support element 41. Thus, the first curved surface support element 40 and the second curved surface support element 41 provide radial support while nonetheless permitting the first carrier plate 44 and the second carrier plate 45 to wobble in concert with the swashplate structure 14 to accommodate forces applied to opposing faces of the swashplate structure 14 during operation.
Referring jointly to
Regardless of whether or not piston rings 74 are utilized, the first cup elements 18 circumferentially surround distal portions of corresponding first piston elements 20 such that the first piston elements 20 cooperate with interior boundary walls of the first cup elements 18 to define a plurality of variable volume first compression chambers 80. Likewise, the second cup elements 19 circumferentially surround distal portions of corresponding second piston elements 21 such that the second piston elements 21 cooperate with interior boundary walls of the second cup elements 19 to define a plurality of variable volume second compression chambers 81. As rotatable shaft assembly 12 rotates around the first axis 13, a corresponding circumferential rotation is imparted to the first rotatable piston support 22 and to the second rotatable piston support 23. As the first rotatable piston support 22 and the second rotatable piston support 23 rotate around the first axis 13, the first piston elements 20 and the second first piston elements 21 impart a circumferential pushing force to the engaged first cup elements 18 and second cup elements 19 thereby causing the first carrier plate 44 and the second carrier plate 45 to rotate circumferentially. Due to the orientation of the swashplate structure 14, the first carrier plate 44 and the second carrier plate 45 rotate around the second axis 15 in angled relation to the first axis 13. Due to the different axis of rotation, during the rotational cycle, the first cup elements 18 reciprocate relative to the first piston elements 20 and the second cup elements 19 reciprocate relative to the second piston elements 21. This reciprocating action gives rise to changes in the volumetric capacity of the first compression chambers 80 and the second compression chambers 81. In this regard, the volumetric capacity cycles progressively between a high capacity filling stage with the first piston elements 20 and the second piston elements 21 substantially withdrawn as shown in the upper left and lower right portions of
The industrial applicability of the pump assembly described herein will be readily appreciated from the foregoing discussion. Pump assemblies consistent with the present disclosure may be used to convey fluids through various systems in an efficient manner while maintaining proper operative relation of the various components. By way of example only, and not limitation, exemplary fluids conveyed by the pump assembly may include lubricants, hydraulic fluids, cooling fluids and the like.
In practice, a pump assembly consistent with this disclosure may be utilized in environments such as industrial equipment, transportation vehicles and the like where substantial durability is required. In such environments, a self-balancing swashplate structure supporting an arrangement of cup elements engaging piston elements on either side of the swashplate structure may tend to balance forces and promote stability of operation.
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to examples herein are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure or claims more generally. Accordingly, this disclosure contemplates the inclusion of all modifications and equivalents of the subject matter recited in the appended claims as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is contemplated unless otherwise indicated herein or otherwise clearly contradicted by context.
