Piston pump with pistons, crank rods, and ball joints

Abstract

A system includes a crank, a motor coupled to rotate the crank, a swash plate coupled with the crank, a plurality of cylinders, a plurality of pistons moveable in the cylinders, and a plurality of cranks rods. The crank rods couple the pistons by ball joints with the swash plate. Rotation of the crank causes reciprocating movement of the swash plate, the crank rods, and the pistons, and the reciprocating movement of the pistons pumping a fluid through the fluid inlet to the fluid outlet.

Description

BACKGROUND

[0001] Automobile seats and other types of seats often include features to add to the comfort of the seat occupant. For example, seats are known to have inflatable air bladders to provide support and massaging effects. One or more air pumps are used to inflate the bladders. One type of compact air pump design is a diaphragm pump. Such a pump includes multiple pumping chambers and a diaphragm in each of the chambers. A motor actuates the diaphragm such that on a downstroke the diaphragm increases a working volume in the chamber to draw air into the chamber. On the upstroke, the diaphragm decreases the working volume to discharge the air through an outlet.BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The various features and advantages of the present disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

[0003] FIG. 1 illustrates a system including a pump.

[0004] FIG. 2 illustrates an expanded view of a pump.

[0005] FIG. 3A illustrates an expanded view of a piston of the pump.

[0006] FIG. 3B illustrates an over-molded seal of a piston.

[0007] FIG. 3C illustrates a double lip seal on a piston.

[0008] FIG. 3D illustrates an o-ring seal on a piston.

[0009] FIG. 4 illustrates reciprocation of the pump.

[0010] FIG. 5 illustrates another example piston of the pump.

[0011] FIG. 6 illustrates an expanded view of the piston of FIG. 5.

[0012] FIG. 7 illustrates a linear guide in the pump.DETAILED DESCRIPTION

[0013] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. However, it will be apparent to one of ordinary skill in the art that the various described embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

[0014] “One or more” includes a function being performed by one element, a function being performed by more than one element, e.g., in a distributed fashion, several functions being performed by one element, several functions being performed by several elements, or any combination of the above.

[0015] It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first contact could be termed a second contact, and, similarly, a second contact could be termed a first contact, without departing from the scope of the various described embodiments. The first contact and the second contact are both contacts, but they are not the same contact.

[0016] The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,”“including,”“comprises,” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0017] As used herein, the term “if” is, optionally, construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” is, optionally, construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.

[0018] FIG. 1 shows a system 20 and, more particularly, a piston pump for providing air to inflatable bladders in a seat, such as the seat of a vehicle for a massage effect. In general, the system 20 has a motor section 22 and a pump section 24 that is driven by the motor section 22 to pump air from pump outlet 25. In one example, the motor 22 is an electric motor. It is to be appreciated that although the examples are based upon implementation as an air pump for seats, the system 20 is not limited to air and may be implemented for pumping other fluids and for use in end-use applications other than seats.

[0019] FIG. 2 illustrates an expanded view of one example of the system 20. The system 20 includes a crank 26 that is mechanically coupled with a motor shaft 28 of the motor section 22. The motor section 22 is coupled through the motor shaft 28 to rotate the crank 26. A swash plate 30 is coupled with the crank 26. For instance, the swash plate 30 is coupled through a bushing 32 to the crank 26. A crank refers to the hardware between the motor shaft 28 and the swash plate that translates rotational motor shaft movement to reciprocating movement in an axial direction.

[0020] There are a plurality of cylinders 34 that are associated with one or more fluid inlets 36 and one or more fluid outlets 38. In this example, there are multiple fluid outlets 38 that combine to feed the pump outlet 25. Pistons 40 are moveable in respective cylinders 34. Crank rods 42 couple the pistons 40 with the swash plate 30. For example, the crank rods 42 are coupled by ball joints 44 to the swash plate 30. For instance, as shown in FIG. 3, the crank rod 42 includes a ball 43a and the swash plate 30 includes a corresponding socket 43b that forms a ball-and-socket joint, i.e., the ball joint 44.

[0021] Referring again to FIG. 2, a top cover 46 secures a valve plate 48 and reed valves 50 on the cylinders 34. The body of the cylinder 34 is secured to a lower housing 52, such as by clamps 54. There is a rubber seal 49 in between the valve plate 48 and the cylinder 34 to seal the piston chambers at the cylinder 38.

[0022] Activation of the motor section 22 causes the motor shaft 28 to rotate. Rotation of the motor shaft 28 drives rotation of the crank 26, and rotation of the crank 26 causes reciprocating movement of the swash plate 30, the crank rods 42, and the pistons 40, which is indicated at movement arrows M in FIG. 4. Reciprocating movement refers to substantially linear axial movement back-and-forth along a direction parallel or approximately parallel to the axis of rotation of the motor shaft 28, which is parallel to a central axis A of the system 20. The reciprocating movement of the pistons 40 draws air through the fluid inlets 36, into the cylinders 34, and then from the cylinders 34 through the fluid outlets 38 to the pump outlet 25, which is represented by flow F. For example, on a downstroke of the piston 40, air is drawn into the cylinder 34 and on an upstroke of the piston 34 the air in the cylinder 34 is discharged to the outlet 38.

[0023] Some pump designs utilize a diaphragm in the cylinders, and the diaphragm is actuated to pump the air. Such diaphragms, however, are usually thin-walled elastomer structures in which a fold or convolution in the wall rolls as the diaphragm is moved. While effective for pumping, the thin-walled elastomer structure of the diaphragm often lacks durability, particularly if there is non-linear movement during the pumping stroke, which can cause undue stress on portions of the fold of the diaphragm. As will be discussed in further detail below, the disclosed pistons 40 are relatively rigid, eliminate diaphragms, and enable strict linear reciprocation that facilitates good durability.

[0024] FIG. 3A illustrates a piston 40 in which a head 40a of the piston 40 is a separate piece from the crank rod 42. For instance, the head 40a is a molded plastic piece or metallic piece that carries a seal ring 40b that seals against the sides of the cylinder 34 to prevent air from escaping around the piston 40. In this example, the seal 40b is a separate piece that is assembled onto the head 40a, but it is to be understood that the seal 40b may alternatively be integrated as an over-molded seal. The head 40a may be rigidly coupled with the crank rod 42, or may be coupled in a ball joint 44 as described above. That is, the crank rod 42 may be have a ball joint 44 at both ends, one coupling the crank rod 42 to the head 40a and the other coupling the crank rod 42 to the swash plate 30. The ball joint or joints 44 enable transfer of the linear reciprocating movement to the head 40a without causing tilting of the head 40a. For instance, insofar as there is any lateral movement at the crank rod 42, such as from the swash plate 30, the ball joint 44 permits a degree of freedom to pivot to take up the lateral movement instead of translating the lateral movement through the crank rod 42 to the head 40a. In this manner, only linear movement is transferred to the head 40a and the head 40a is prevented from tilting. Thus, in comparison to diaphragm designs, the system 20 eliminates the diaphragm and facilitates reduction in tilting.

[0025] The piston 40 is not limited to the design above, and the type of seal may be varied. For example, as shown in FIG. 3B, the seal 140b may be over-molded on the perimeter of the head 40a. In another alternative shown in FIG. 3C, the seal 240b is a double lip seal 240b disposed in a seal groove 241 in the head 40a. In yet another example shown in FIG. 3D, the seal 340b is an o-ring disposed in an o-ring groove 341 in the head 40a.

[0026] Another example of the piston 40 is shown in FIG. 4. The piston 40 is also shown in isolation in FIG. 5 and in an expanded view in FIG. 6. In this example, the piston 40 is a multi-piece construction that includes a base piece 45a, a cap piece 45b, and a seal 45c captured between the base piece 45a and the cap piece 45b. The base piece 45a and the cap piece 45b may be molded plastic or metallic pieces, while the seal 45c may be an elastomer, a low-friction plastic, or fluoropolymer material. The seal 45c is annular, defines a cavity 45d, and circumscribes a central opening 45e. The cap piece 45b includes a pin 45f. The cap piece 45b nests in the cavity 45d and the pin 45f extends through the opening 45e and engages a pin hole 45g in the base piece 45a to secure the cap piece 45b and the base piece 45a together, with the seal 45c trapped between. As shown in FIG. 4 the edge lip of the seal 45c seals against the side of the cylinder 34. The base piece 45a and the cap piece 45b provide rigidity, while the seal 45c provides flexibility needed for sealing. In this example, the crank rod 42 is integrated with the base piece 45a.

[0027] As shown in an axial view in FIG. 7, the system 20 also includes a linear guide 56. The guide 56 includes a pair of parallel spaced-apart guide rails 56a / 56b that define a channel 58 there between, and a guide follower 60 rides in, and is slidable along, the channel 58. The rails 56a / 56b run parallel to the central axis A of the system 20. In the illustrated example, the rails 56a / 56b are on the housing 52 or on the housing body that forms the cylinders 34, and the follower 60 is on a lobe of the swash plate 30, though it is to be understood that that alternatively the follower 60 may be on the housing and the rails on the swash plate 30. The follower 60 rides along the channel 58 as the swash plate 30 reciprocates, and the engagement of the follower 60 between the rails 56a / 56b limits rotational movement of the swash plate 30 to thereby facilitate maintaining the desired linear reciprocating movement with little or no rotational or lateral movement that might affect the piston 40. As shown, the follower 60 includes a pair of spaced-apart spring arms 60a / 60b that ride between the rails 56a / 56b. The spring arms 60a / 60b provide flexibility so that the engagement of the follower and rails 56a / 56b is not fully rigid, in which case it might be more susceptible to binding. The flexibility of the spring arms 60a / 60b also permits minor rotational or lateral movement, but not so much as to affect the piston 40.

[0028] Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.

[0029] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.

Claims

1. A system comprising:a crank;a motor coupled to rotate the crank;a swash plate coupled with the crank;a plurality of cylinders, each of the cylinders comprising an associated fluid inlet and an associated fluid outlet;a plurality of pistons, each of the pistons moveable in a respective one of the cylinders; andand a plurality of crank rods, the crank rods coupling the pistons by ball joints with the swash plate, and rotation of the crank causing reciprocating movement of the swash plate, the crank rods, and the pistons, the reciprocating movement of the pistons pumping a fluid through the fluid inlet to the fluid outlet.

2. The system as recited in claim 1, wherein the pistons are multi-piece constructions that each comprise a base piece, a cap piece, and a seal captured between the base piece and the cap piece.

3. The system as recited in claim 2, wherein the seal includes a cavity into which the cap piece nests.

4. The system as recited in claim 3, wherein the seal circumscribes a central opening, and the cap piece includes a pin that extends through the central opening and engages a pin hole in the base piece.

5. The system as recited in claim 2, wherein the seal is circular and seals against side walls of the cylinder.

6. The system as recited in claim 1, further comprising a housing around the swash plate, and a linear guide limiting rotational movement of the swash plate.

7. The system as recited in claim 6, wherein linear guide includes guide rails and a guide rail follower slidable along the guide rails.

8. The system as recited in claim 7, wherein the guide rail follower includes a pair of spring arms that ride between the guide rails.

9. The system as recited in claim 1, wherein each of the ball joints includes a ball on one of the crank rod or the swash plate and a socket on the other of the crank rod or swash plate.

10. The system as recited in claim 1, further comprising reed valves on the cylinders.

11. A system comprising:a crank;an electric motor coupled to rotate the crank;a swash plate coupled with the crank;a housing disposed around at least the swash plate;a cylinder block comprising a plurality of cylinders, and fluid inlets and fluid outlets associated with the cylinders;a plurality of valves controlling flow through the fluid inlets and the fluid outlets;a plurality of pistons, each of the pistons moveable in a respective one of the cylinders; andand a plurality of crank rods, the crank rods coupling the pistons by ball joints with the swash plate, activation of the motor causing rotation of the crank, and rotation of the crank causing reciprocating movement of the swash plate, and reciprocating movement of the swash plate causing reciprocating movement of the crank rods and the pistons, the reciprocating movement of the pistons pumping a fluid through the fluid inlets to the fluid outlets.

12. The system as recited in claim 11, wherein the pistons are multi-piece constructions that each comprise a base piece, a cap piece, and a seal captured between the base piece and the cap piece.

13. The system as recited in claim 12, wherein the seal includes a cavity into which the cap piece nests.

14. The system as recited in claim 13, wherein the seal circumscribes a central opening, and the cap piece includes a pin that extends through the central opening and engages a pin hole in the base piece.

15. The system as recited in claim 14, further comprising a housing around the swash plate, and a linear guide limiting rotational movement of the swash plate.

16. The system as recited in claim 15, wherein linear guide includes guide rails and a guide rail follower slidable along the guide rails.

17. The system as recited in claim 16, wherein the guide rail follower includes a pair of spring arms that ride between the guide rails.

18. The system as recited in claim 11, wherein the seal is circular and seals against side walls of the cylinder.

19. The system as recited in claim 1, wherein each of the ball joints includes a ball on one of the crank rod or the swash plate and a socket on the other of the crank rod or swash plate.

20. The system as recited in claim 1, further comprising reed valves on the cylinders.

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