Pump noise attenuator and method thereof

A pump assembly includes a pump with a pump body having a discharge passage, a motor operable to drive the pump to discharge compressed air through the discharge passage, a casing at least partially surrounding the pump and the motor, and a motor mount at least partially supporting the motor within the casing. The motor mount includes an outer axial wall, an inner axial wall, a radial wall extending between the outer axial wall and the inner axial wall, a first plurality of projections extending from the radial wall toward the motor, and a second plurality of projections extending from the radial wall away from the motor.

BACKGROUND

The present disclosure relates to a pump noise attenuator and method for commercial and residential use, and more specifically for use within vehicular seating systems (aircraft, automobiles, etc.).

SUMMARY

The present disclosure provides a configuration for a pump and a method of pumping air from a pump and into a pneumatic line that provides for improved reduction and/or optimization of pump noise. As described in greater detail below, an end cap and/or seal and motor mount configuration may reduce noise generated by air flowing through a pump assembly during operation of a pneumatic bladder system. The resulting pump assembly may be advantageously used in applications of the pneumatic bladder system (e.g., in vehicle seats, massage chairs, etc.) where quieter operation is desirable.

For example, the present disclosure provides, in one aspect, a pump assembly including a pump with a pump body having a discharge passage, a motor operable to drive the pump to discharge compressed air through the discharge passage, a casing at least partially surrounding the pump and the motor, and a motor mount at least partially supporting the motor within the casing. The motor mount includes an outer axial wall, an inner axial wall, a radial wall extending between the outer axial wall and the inner axial wall, a first plurality of projections extending from the radial wall toward the motor, and a second plurality of projections extending from the radial wall away from the motor.

The present disclosure provides, in another aspect, a pump assembly including a diaphragm with a wall defining an interior volume, a plunger coupled to the wall, the plunger including a circumferential rib, and a drive mechanism configured to reciprocate the plunger to perform cycles of compressing and expanding the interior volume. The circumferential rib is engageable with the wall of the diaphragm as the interior volume is compressed to support the wall.

Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of supporting other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. In addition, as used herein, the terms “upper”, “lower”, and other directional terms are not intended to require any particular orientation but are instead used for purposes of description only.

DETAILED DESCRIPTION

It may be desirable to reduce noise created by a pump during operation. For example, when configuring a pump for a specific application it may be desirable to reduce, change, or remove a frequency of vibration created by a pump, which can manifest as noise heard by a user of an application for the pump. In general, two types of noise may be produced by a pump: motor noise and pumping noise. In some pumps, for example pneumatic pumps that are connected to an air bladder, the air bladder may act as a speaker that amplifies periodic bursts of air produced by the pump when the pump is operating. To reduce such noise, pumps according to the present disclosure may be located in a plastic housing filled with foam, suspended on rubber mounts, and/or include a muffler placed along an output line from the pump.

For example,FIG.1illustrates a pump assembly100including a first or upper casing101and a second or lower casing102. In an embodiment, the pump assembly100is configured for providing air for use in an application, for example in an automotive application. Such air may be provided from the pump assembly100through an upper casing outlet103. The pump assembly100may include a pump configured to run (i.e., pump air through the upper casing outlet103) using an electrical connection105, which may supply electric power to the pump assembly100. The electrical connection105may, through the use of a connector104, be connected to a power source.

FIG.2illustrates an embodiment of a pneumatic system200including the pump assembly100. The pneumatic system200may be a portion of an automobile. For example, in the illustrated embodiment, the pneumatic system200is part of an automobile seating assembly. Other applications of the pneumatic system200are contemplated, however, such as aerospace applications, office/desk chair applications, or the like.

In the illustrated embodiment, the pneumatic system200includes a power source201, which may be part of an electrical power system of an automobile. The connector104is configured to connect to the power source201. As such, the power source201may supply power202(e.g., at 12 Volts or 24 Volts in some embodiments) through the electrical connection105and to the pump assembly100via the connector104.

When the pump assembly100is powered, the pump assembly100may operate to pump air through the upper casing outlet103. Air may flow from the upper casing outlet103through a pneumatic line206. The pneumatic line206may include valves203along or at either end of the pneumatic line206. The valves203may be a single valve and/or may be multiple valves, and in either case may serve to: (i) direct air along the pneumatic line206from the pump assembly100, (ii) stop a flow of air along the pneumatic line206directed from the pump assembly100, (iii) regulate pressure of a flow of air through the pneumatic line206, and/or (iv) regulate flow rate of a flow of air through the pneumatic line206. Additionally or alternatively, the valves203may include a release valve, which may allow air to vent from the pneumatic line206to the atmosphere or into another, connected pneumatic line.

The pneumatic line206may be connected to one or more bladders205. The bladder205may be configured to expand or contact as air from the pneumatic line206flows into or is removed from the bladder205. In an embodiment, the bladder205may be supported in a bladder supporting device204. In some embodiments, the bladder supporting device204is a seat configured to be positioned within an automobile. In an embodiment, the bladder205may be positioned within the bladder supporting device204to provide lumbar support when a user sits against the bladder supporting device204. In such an embodiment, the user may provide a request for increasing or decreasing lumbar support (e.g., the user may press a button) which may activate the pump assembly100to provide air from the pump assembly100, through the pneumatic line206, and into the bladder205positioned within the bladder supporting device204, thereby inflating the bladder205and providing the requested lumber support.

FIG.3illustrates an assembly view of an embodiment of the pump assembly100along a longitudinal axis or central axis408. The pump assembly100may include the upper casing101and a lower casing102. The upper casing may include the upper casing outlet103. The lower casing102may be configured to engage the upper casing101. For example, the lower casing may include a locking device300configured to engage the upper casing101. In an embodiment, the locking device300includes four lock members301,302,303, and304positioned equidistantly around a circumference of the upper casing101. Each of the lock members301,302,303, and304may be configured to engage a corresponding receiving portion, for example receiving portions602and603shown inFIG.3. As such, to connect the upper casing101with the lower casing102, the lock members302and303may engage (e.g., by clipping into) the receiving portions602and603.

In an embodiment, a seal310may be positioned between the upper casing101and the lower casing102to provide a substantially air-tight seal between the upper casing101and the lower casing102. In an embodiment, the seal310comprises rubber or another suitable resilient elastomeric material. Greater detail regarding the seal310is provided in reference toFIG.4.

With continued reference toFIG.3, the connector104and the electrical connection105may pass through a motor mount309and into a lower pump assembly305. The lower pump assembly305may be connected to an upper pump assembly306. The seal310may be located at the connection between the lower pump assembly305and the upper pump assembly306, and may engage both the lower pump assembly305and the upper pump assembly306. Accordingly, when the upper casing101is connected to the lower casing102, the seal310may retain the lower pump assembly305and the upper pump assembly306because the seal310at the same time may also engage the upper casing101and the lower casing102. The motor mount309may be configured to engage the lower pump assembly305and the lower casing102when the lower casing102is locked to the upper casing101.

The upper pump assembly306may be connected to an outlet plate307, which may be positioned on an opposite side of the upper pump assembly306from the seal310. An end cap308may be positioned on/adjacent the outlet plate307and positioned on the opposite side of the outlet plate307from the upper pump assembly306. In some embodiments, the cap308may be integrally formed with the outlet plate307and/or other portions of the upper pump assembly306. In other embodiments, the cap308may be formed separately and coupled to the outlet plate307by a snap-fit, one or more fasteners, adhesive(s), or any other suitable means.

FIG.4illustrates a cross-section view along the central axis408of a portion of the pump assembly100. InFIG.4, the lower pump assembly305is shown connected to the upper pump assembly306. A drive interface406may extend between the lower pump assembly305and the upper pump assembly306and may provide electrical and/or mechanical communication between the lower pump assembly305and the upper pump assembly306. For example, the lower pump assembly305may include an electric motor315, and the upper pump assembly306may include a pneumatic pump410. In such an embodiment, the drive interface406may communicate rotational energy (for example, via a driveshaft) to the upper pump assembly306to drive the pneumatic pump410contained therein.

The pneumatic pump410may pump air through an upper assembly outlet407in the outlet plate307and into a first volume (i.e., a first chamber)401. The upper assembly outlet407may be positioned along and parallel to the central axis408. The outlet plate307may be secured to the upper pump assembly306via a plurality of pins404or in any other suitable manner. In other embodiments, the outlet plate307may be integrally formed with one or more portions of the upper pump assembly306. The first volume401in the illustrated embodiment is defined by the outlet plate307and the end cap308. The first volume401is in communication with the upper assembly outlet407such that air discharged by the pneumatic pump410enters the first volume401.

With reference toFIG.5, the end cap308may be substantially sealed to the outlet plate307via a plurality of inter-engaging features or snaps403. Air that is pumped into the first volume401may be forced out and into a second volume (i.e., a second chamber)402by the pneumatic pump410via a plurality of outlets501arranged about the periphery of the end cap308. While the end cap308is shown with the plurality of spaced outlets501spaced by the equidistantly spaced snaps403, either and/or both of the outlets501and the snaps403may be provided singularly or non-uniformly about the end cap308. The plurality of outlets501from the end cap308may be positioned offset and equidistant from the central axis408and may additionally or alternatively be positioned perpendicular to the central axis408.

Referring again toFIG.4, the second volume402may be defined by the end cap308, the outlet plate307, the upper pump assembly306, the seal310and the upper casing101. In the illustrated embodiment, the second volume402surrounds the first volume401, and the second volume402may extend cylindrically along the central axis408to the seal310, which serves to terminate the second volume402(i.e., the second volume402extends around the entire head of the pump410). Air may then be forced from the second volume402and out of the upper casing outlet103to be used in a downstream application. In an embodiment, the upper casing outlet103may be positioned parallel to the central axis408.

In the illustrated embodiment, the first volume401is smaller than the second volume402. As such, the first volume401may act as a first resonant cavity for higher frequency vibrations (e.g., greater than 500 Hz) emitted from the pneumatic pump410. The second volume402may act as a resonant chamber for lower frequency vibrations (e.g.,500Hz or less) emitted by the pneumatic pump410. The relative volumes of the first volume401and the second volume402may be tuned to remove specific frequency vibrations emitted from the pneumatic pump410. In such an embodiment, the combination of the end cap308, the first volume401and the second volume402may serve to muffle or diminish sound created by the operation of the pneumatic pump410.

For example, the first volume401may be configured to resonate at a relatively high, first resonant frequency (e.g., above 500 Hertz (Hz) in some embodiments) and the second volume402may be configured to resonate at a lower, second resonant frequency (e.g., below 500 Hz). In some embodiments, the first resonant frequency is at least 10% higher than the second resonant frequency. In some embodiments, the first resonant frequency is at least 25% higher than the second resonant frequency. As airflow passes through the volumes401,402during operation, the differing resonances of the volumes401,402may produce destructive interference that attenuates the sound produced by air flowing through the pump assembly100. This is accomplished without any active noise cancelling or absorbent materials (e.g., foam, baffles, etc.) lining the airflow path, which would tend to increase flow resistance and decrease flow rate.

Furthermore, the configurations described and illustrated herein may be desirable to limit sound from vibrations and air pulses created by the pneumatic pump410. The upper casing outlet103is not in direct communication with the upper assembly outlet407in the illustrated embodiment, because the first volume401and the second volume402are disposed fluidly between the upper assembly outlet407and the upper casing outlet103. That is, air discharged from the pneumatic pump410through the upper assembly outlet407must pass through both the first volume401and the second volume402before being discharged from the pump assembly100through the upper casing outlet103. In addition, the orientations of the outlets501in the end cap308(e.g., perpendicular to the central axis408) and the orientation of the upper casing outlet103(e.g., parallel to the central axis408) may also force the pumped air to change directions and thereby form a tortuous pathway for the pumped air. These features may advantageously reduce downstream noise amplification effects that may be produced by the bladder(s)205or other components of the pneumatic system200.

Referring toFIG.4, the seal310may be configured to reduce vibration of the pneumatic pump410and/or motor315and thereby further reduce noise generated by the pump assembly100. For example, the seal310may extend along the central axis408and toward the end cap308, between the upper pump assembly306and a support flange405fixed to a lower end of the upper pump assembly306. Then, the seal310may wrap around the support flange405and extend away from the end cap308and along the central axis408to an upper casing extension409while positioned between the support flange405and the upper casing101. Then, the seal310may wrap around the upper casing extension409and extend back toward the end cap308along the central axis408while positioned between the upper casing101and the lower casing102. Finally, the seal310may extend radially away from the central axis408and between the upper casing101and the lower casing102. In such an embodiment, the upper casing101may be held tightly against the lower casing102via the locking device300, thereby compressing the seal310and forming an air-tight seal to enclose the second volume402everywhere except at the upper casing outlet103. In such an embodiment, the seal310may serve as a vibration damper to dampen vibration created by the pneumatic pump410and/or motor315.

FIG.6illustrates a cross-section view along the central axis408of an embodiment of the pump assembly100. InFIG.6, the upper casing101and the lower casing102are locked via the locking device300, specifically the lock member301and upper assembly receiving portion601are shown engaged inFIG.6. Accordingly, the seal310is compressed between the upper casing101, the lower casing102, and the support flange405. In such a configuration, the upper pump assembly306is likewise held in place axially in the direction away from the lower pump assembly305and along the central axis408by the engagement of the support flange405and the seal310.

The lower pump assembly305is supported at its end opposite the upper pump assembly306by the motor mount309, which may be compressible. In some embodiments, the motor mount309may be retained in a compressed position by the support flange405engaging the seal310. Such a configuration may retain the upper pump assembly306, which may contact the lower pump assembly305and may compress the motor mount309between the lower pump assembly305and the lower casing102. In an embodiment, the motor mount309may include rubber or another suitable resilient elastomeric material. In such a configuration, the motor mount309may further act to dampen vibrations created by the pneumatic pump410and/or the motor315. Further, in such a configuration, the only contact points between the pneumatic pump410and the upper casing101, and between the motor315and the lower casing102are resilient contact points (via the seal310and the motor mount309), thereby further damping the vibration. Stated otherwise, the pneumatic pump410and the motor315may be fully supported on resilient rubber/elastomeric mounts.

As shown inFIG.6, the motor mount309still allows for access for the electrical connection105to connect to the lower pump assembly305to power the pneumatic pump. For example, the motor mount309includes an inlet opening650that provides a passage for the electrical connection105. In some embodiments, the inlet opening650also serves as an air inlet to the pump assembly100to provide an air supply for the pneumatic pump410.

FIG.7illustrates an assembly view of an embodiment of the pump assembly100.FIG.7is provided without the lower casing102for illustration purposes. As shown, the motor mount309may be configured with a motor mount recess702. As such, the illustrated motor mount309has an annular shape. The motor mount recess702may be configured to engage a lower pump assembly engagement portion701positioned on the lower pump assembly305. As shown, the lower pump assembly engagement portion701may be generally cylindrical and configured to engage the correspondingly cylindrical motor mount recess702. While not required to be cylindrical, providing both the lower pump assembly engagement portion701and the motor mount recess702in a cylindrical configuration may provide the additional advantage of damping in a radial direction perpendicular to the central axis408. In such an embodiment damping of the pneumatic pump410and motor315is improved because the seal310(not shown inFIG.7) and the motor mount309together provide for radial damping along the central axis408at two different locations along the central axis408, which removes or limits another degree of freedom of vibration, namely, vibration rotationally along the central axis408.

Referring toFIG.6, the illustrated motor mount309includes an outer axial wall704, an inner axial wall705, and a radial wall706extending between and interconnecting the outer axial wall704and the inner axial wall705. The illustrated motor mount309further includes a first plurality of compressible tubular elements707aextending upward from the radial wall706(i.e. toward the motor315), and a second plurality of compressible tubular elements707bextending downward from the radial wall706(i.e. away from the motor315). The first plurality of tubular elements707aabuts a lower end wall of the motor315to define a generally cup-shaped volumes708atherebetween. Similarly, the second plurality of tubular elements707babuts a lower end wall of the lower casing102to define generally cup-shaped volumes708btherebetween.

With reference toFIG.7, the tubular elements707a,707bare arranged in an annular array, in a circumferential direction of the radial wall706. The tubular elements707a,707bare positioned adjacent each other in the circumferential direction, with a spacing between consecutive tubular elements707a,707bbeing less than a width of one of the tubular elements707a,707b. In addition, as shown inFIG.6, each of the first plurality of tubular elements707ais axially aligned with a corresponding one of the second plurality of tubular elements707b.

Referring toFIGS.7A-7B, in another embodiment, the tubular elements707a,707bmay be spaced further apart in the circumferential direction. For example, in the illustrated embodiment, a spacing between consecutive tubular elements707a,707bin the circumferential direction is greater than a width of one of the tubular elements707a,707b. In such embodiments, the tubular elements707a,707binclude greater space to flex, thereby reducing the stiffness of the motor mount309. Furthermore, in the illustrated embodiment, the first tubular elements707aare axially misaligned with the second tubular elements707b(FIG.7B). The axial misalignment of the tubular elements707a,707bdecreases the stiffness of the motor mount309in the axial direction. Finally, in the illustrated embodiment the outer axial wall704includes a plurality of gaps709, which may be aligned in a radial direction with each of the tubular elements707a,707b. The gaps709in the outer axial wall704may permit additional expansion of the tubular elements707a,707b(e.g., into the gaps709) and thereby further increase dampening performance. In yet other embodiments, the motor mount309may include other configurations, such as a honeycomb pattern.

With reference toFIGS.6-7B, the tubular elements707a,707breduce the weight and amount of material required to form the motor mount309(as compared to a motor mount that is solid through its entire thickness), while providing a desired amount of compressibility. In addition, the tubular elements707a,707battenuate vibration of the motor315along multiple axes via a dampening effect. For example, in some embodiments, vibration of the motor315causes compression of the tubular elements707a,707b, which reduces the size of the cup-shaped volumes708a,708b(FIG.6). This forces air out of the cup-shaped volumes708a,708b. Because the tubular elements707a,707babut the motor315and the lower casing102(but without forming an air-tight seal), air flow into and out of the volumes708a,708bis restricted. Each of the tubular elements707a,707bmay thus act as a dashpot to attenuate vibration along multiple axes.

In the illustrated embodiment, the motor mount309also includes a radial projection703. The inlet opening650extends through the radial projection703to allow the electrical connection105to pass from the connector104, through the motor mount309, and into the lower pump assembly305such the electricity may be supplied to the pneumatic pump410. In the illustrated embodiment, the entire motor mount309, including the radial projection703, the walls704,705,706, and the tubular elements707a,707b, is integrally formed as a single piece of resilient material via a suitable molding process. In other embodiments, however, the motor mount309may be formed in other ways.

The embodiments described and illustrated herein thus provide a method of reducing vibration of the pump assembly100that may include supporting the lower pump assembly305and/or the upper pump assembly306within the upper casing101and the lower casing102with the seal310and/or the motor mount309. The seal310and/or the motor mount309may be configured to dampen vibration in the axial direction (i.e., along the central axis408) and/or the radial direction (i.e., radially in a plane perpendicular to the central axis408).

The embodiments described and illustrated herein further provide a method of directing air from a pump to an application that may include providing compressed air from the pneumatic pump, directing the air through the upper assembly outlet407positioned on the outlet plate307and into the first volume401, with the first volume401defined at least by the outlet plate307and the end cap308. The method may additionally or alternatively include directing the air from the first volume401, through the outlets501positioned on the end cap308and into the second volume402, the second volume402defined by at least the end cap308and the upper casing101. The method may additionally or alternatively include directing the air from the second volume402and through the upper casing outlet103. In an embodiment, the upper casing outlet103is connected to a pneumatic line or other structure where compressed air may be desired.

FIGS.8and9illustrate a portion of a pump assembly1100according to another embodiment. The pump assembly1100is similar to the pump assembly100described above with reference toFIGS.1-7, and features and elements of the pump assembly1100corresponding with features and elements of the pump assembly100are given identical reference numbers plus1000. In addition, the following description focuses primarily on differences between the pump assembly1100and the pump assembly100.

With reference toFIGS.8-9, the illustrated pump assembly1100includes a pneumatic pump1410having an outlet plate1307. The pneumatic pump1410may pump air through an upper assembly outlet1407in the outlet plate1307. In the illustrated embodiment, the upper assembly outlet1407includes a first portion1407a, which may extend along or parallel to a longitudinal axis or central axis1408of the pump assembly1100, and a second portion1407bdownstream of the first portion1407a(FIG.9). The second portion1407bmay extend radially outward from the central axis1408and along a second axis1409oriented at an angle with respect to the central axis1408. In the illustrated embodiment, the second axis1409is oriented perpendicular to the central axis1408; however, the second axis1409may be oriented at other angles relative to the central axis1408. As such, air that is pumped by the pneumatic pump1410may change direction at the transition between the first portion1407aand the second portion1407b, and may then be discharged from the second portion1407b(e.g., in a direction generally perpendicular to the central axis1408).

The second portion1407bof the upper assembly outlet1407may be in fluid communication with a volume or chamber1402surrounding the upper pump assembly1306(FIG.9). The volume1402may be defined, for example, between the upper pump assembly1306and the upper casing1101. In other words, the upper casing1101may be spaced from the outside of the upper pump assembly1306to define the volume1402therebetween. The air that is discharged from the second portion1407bof the upper assembly outlet1407may enter the volume1402before being discharged from the upper casing1101via the upper casing outlet1103.

The upper casing outlet1103may extend along a third axis1411that is parallel to the central axis1408. The second portion1407bof the upper assembly outlet1407may extend generally away from the upper casing outlet1103. For example, referring toFIG.8, the second axis1409may be oriented at an angle1413relative to a line1415extending between the central axis1408and the third axis1411. The angle1413may be between about 45 degrees and about 180 degrees in some embodiments, between about 90 degrees and about 180 degrees in some embodiments, or between about 120 degrees and about 180 degrees in some embodiments.

Because the volume1402is disposed fluidly between the upper assembly outlet1407and the upper casing outlet1103, air discharged from the pneumatic pump1410through the upper assembly outlet1407must pass through the volume1402before being discharged from the pump assembly1100through the upper casing outlet1103. In addition, the orientation of the second portion1407bof the upper assembly outlet1407(e.g., perpendicular to the central axis1408and oriented generally away from the upper casing outlet1103) and the orientation of the upper casing outlet1103(e.g., parallel to the central axis1408) may also force the pumped air to change directions and thereby form a tortuous pathway for the pumped air. These features may advantageously reduce downstream noise amplification effects and provide for quieter operation of the pump assembly1100(e.g., in a pneumatic system such as the pneumatic system200).

FIG.10illustrates a pump assembly2100according to another embodiment. The pump assembly2100is similar to the pump assembly100described above with reference toFIGS.1-7, and features and elements of the pump assembly2100corresponding with features and elements of the pump assembly100are given identical reference numbers plus2000. In addition, the following description focuses primarily on differences between the pump assembly2100and the pump assembly100.

With reference toFIG.10, the illustrated pump assembly2100includes a first or upper casing2101connected to a second or lower casing2102. An electric motor2315is disposed at least partially within the lower casing2102. An upper pump assembly2306, which includes a pneumatic pump2410(e.g., a diaphragm pump) in the illustrated embodiment, is disposed at least partially within the upper casing2101. As such, the upper casing2101and lower casing2102cooperate to enclose the motor2315and the upper pump assembly2306.

A seal2310, which may be similar to the seal310described above with reference toFIG.4, is positioned between the upper casing2101and the lower casing2102. The seal2310extends between a support flange2405fixed to a lower end of the upper pump assembly2306and an inner wall of the upper casing2101. The seal2310is made of a flexible material, such as rubber, silicone, other resilient elastomeric materials, or the like. As such, the seal2310provides a vibration-isolating or dampening connection between upper pump assembly2306and the upper casing2101.

With continued reference toFIG.10, in the illustrated embodiment, the lower end of the motor2315is supported by a motor mount2309, which may be similar to the motor mount309described above with reference toFIGS.6-8. The motor mount2309is made of a flexible material, such as rubber, silicone, other resilient elastomeric materials, or the like. As such, the motor mount2309provides a vibration-isolating or dampening connection between the motor2315and the lower casing2102.

The upper pump assembly2306includes an outlet plate2307and an outlet plate fitting2323that extends from the outlet plate2307along a central axis2408of the pump assembly2100. In the illustrated embodiment, the outlet plate fitting2323is configured as a barb fitting; however, the outlet plate fitting2323may be configured differently in other embodiments. The outlet plate fitting2323is integrally formed with the outlet plate2307in the illustrated embodiment (e.g., as a molded part). Alternatively, the outlet plate fitting2323may be formed separately and coupled to the outlet plate2307via any suitable connection (and preferably an air-tight connection, such as a threaded connection). An outlet plate discharge passage2120extends through the outlet plate2307and the outlet plate fitting2323and provides an outlet for air to exit the upper pump assembly2306.

The upper casing2101includes an upper casing outlet2103positioned at an end of the upper casing2101. The illustrated upper casing outlet2103includes an inner fitting2325extending from an interior side of the upper casing2101and an outer fitting2327extending from an exterior side of the upper casing2101. The inner fitting2325and the outer fitting2327are each configured as barb fittings integrally formed with the upper casing2101(e.g., as a molded part) in the illustrated embodiment. In other embodiments, the inner fitting2325and/or the outer fitting2327may have other configurations and may be formed separately and coupled to the upper casing2101via any suitable connection (and preferably an air-tight connection, such as a threaded connection). An upper casing outlet passage2329extends through the fittings2325,2327and provides an outlet for air to exit the upper casing2101.

In the illustrated embodiment, the outlet plate discharge passage2120and the upper casing outlet passage2329are each coaxially aligned with the central axis2408of the pump assembly2100. In other embodiments, the upper casing outlet passage2329or a portion thereof may be parallel to the central axis2408or oriented at an angle (e.g., a 90-degree angle) relative to the central axis2408. In yet other embodiments, the outlet plate discharge passage2120or a portion thereof may be parallel to the central axis2408or oriented at an angle (e.g., a 90-degree angle) relative to the central axis2408.

With continued reference toFIG.10, a tube2150fluidly connects the outlet plate discharge passage2120and the upper casing outlet passage2329such that air pumped by the pneumatic pump2410may flow from the outlet plate discharge passage2120to the upper casing outlet passage2329via the tube2150. The tube2150extends linearly along the central axis2408in the illustrated embodiment, from the outlet plate fitting2323to the inner fitting2325. In other embodiments, the tube2150may be curved.

The tube2150couples the upper pump assembly2306to the upper casing2101to partially support the upper pump assembly2306within the upper casing2101. In the illustrated embodiment, the tube2150is made of a flexible material, such as rubber, silicone, other resilient elastomeric materials, or the like. As such, the tube2150provides a vibration-isolating or dampening connection between the outlet plate2307and the upper casing2101. In other embodiments, the tube2150may be made of a more rigid material, and an elastomeric member (e.g., an o-ring; not shown) may be positioned between the tube2150and one of the outlet plate fitting2323or the inner fitting2325. In such embodiments, the tube2150and the elastomeric member define the vibration-isolating or dampening connection between the outlet plate2307and the upper casing2101, and the tube2150may optionally be integral with the outlet plate fitting2323or the inner fitting2325.

Thus, the tube2150, seal2310, and motor mount2309collectively support the upper pump assembly2306and the motor2315within the upper casing2101and the lower casing2102. In the illustrated embodiment, the tube2150, seal2310, and motor mount2309are the only contact points between the upper pump assembly2306, the motor2315, and the casings2101,2102. That is, the upper pump assembly2306and the motor2315are fully supported by the vibration-dampening/isolating mounts of the tube2550, the seal2310, and motor mount2309, which are spaced apart from one another along the central axis2408. The resilient characteristics of the tube2550, seal2310, and motor mount2309permit limited relative movement of the motor2315and the pneumatic pump2410relative to the upper and lower casings2101,2102and therefore isolate the upper casing2101and the lower casing2102from vibration produced by the motor2315and the pneumatic pump2410during operation. As such, the noise generated by the pump assembly2100during operation is advantageously reduced.

FIGS.11-12illustrate portions of a pump assembly3100according to another embodiment. The pump assembly3100is similar to the pump assembly2100described above with reference toFIG.10, and features and elements of the pump assembly3100corresponding with features and elements of the pump assembly2100are given identical reference numbers plus1000. In addition, the following description focuses primarily on differences between the pump assembly3100and the pump assembly2100.

The pump assembly3100includes a seal3310positioned between the upper casing3101and the lower casing3102(FIG.11). The illustrated embodiment of the pump assembly3100does not include a support flange engaged with the seal3310. Rather, as illustrated inFIG.12, the seal3310includes a plurality of inwardly extending projections3311that are received in corresponding recesses3312formed in the bottom end of the upper pump assembly3306to couple the inner end of the seal3310to the upper pump assembly3306. The outer end of the seal3310includes a plurality of hook-shaped projections3313. The projections3313engage an edge of the lower casing3102to couple the outer end of the seal3310to the lower casing3102.

The seal3310is made of a flexible material, such as rubber, silicone, other resilient elastomeric materials, or the like. As such, the seal3310provides a vibration-isolating or dampening connection between upper pump assembly3306and the casings3101,3102.

FIG.13illustrates a pump assembly4100according to another embodiment. The pump assembly4100is similar to the pump assemblies described above, and features and elements of the pump assembly4100are given reference numbers in the ‘4000’ series. It should be understood that features of the pump assembly4100may be incorporated into the pump assemblies described above and vice versa.

With reference toFIG.13, the illustrated pump assembly4100includes a first or upper casing4101connected to a second or lower casing4102. An electric motor4315is disposed at least partially within the lower casing4102. An upper pump assembly4306including a pneumatic pump4410is disposed at least partially within the upper casing4101. As such, the upper casing4101and lower casing4102cooperate to enclose the motor4315and the pneumatic pump4410.

A seal4310, which may be similar to the seal2310described above, is positioned between the upper casing4101and the lower casing4102. In the illustrated embodiment, an inner periphery of the seal4310is directly attached to a lower end of the upper pump assembly4306. The seal4310is made of a flexible material, such as rubber, silicone, other resilient elastomeric materials, or the like. As such, the seal4310provides a vibration-isolating or dampening connection between upper pump assembly4306and the upper casing4101.

The upper pump assembly4306includes an outlet plate4307and an outlet plate fitting4323that extends from the outlet plate4307along a central axis4408of the pump assembly4100. An outlet plate discharge passage4120extends through the outlet plate4307and the outlet plate fitting4323and provides an outlet for air to exit the upper pump assembly4306.

The upper casing4101includes an upper casing outlet4103positioned at an end of the upper casing4101. The illustrated upper casing outlet4103includes an inner fitting4325extending from an interior side of the upper casing4101. A tube4150interconnects the outlet plate fitting4323and the inner fitting4325such that air pumped by the pneumatic pump4410may flow from the outlet plate discharge passage4120to the upper casing outlet4103via the tube2150.

With reference toFIGS.13-14, the upper pump assembly4306further includes a valve plate4902, a head plate4904, a diaphragm assembly4906, a wobble plate4908, an eccentric shaft4910, and a crank4912. The illustrated diaphragm assembly4906includes a plurality of cup-shaped diaphragms4914and a plunger4916extending from the center of each respective diaphragm4914(FIG.14). Each of the plungers4916includes a stem portion4918that extends through the wobble plate4908and a bead4920formed on the stem portion4918and having a larger diameter than the remainder of the stem portion4918. During assembly, the bead4920of each plunger4916is compressed and inserted through a corresponding bore4922in the wobble plate4908. The bore4922has a smaller diameter than the bead4920so as to retain the stem portions4918of the plungers4916within the wobble plate4908. In the illustrated embodiment, the diaphragm assembly4906includes four diaphragms4914and plungers4916; however, the diaphragm assembly4906may include one, two, three, or more than four diaphragms4914and plungers4916in other embodiments.

Referring toFIG.14, the head plate4904includes an inlet opening4924and an outlet opening4926in fluid communication with an interior volume of each respective diaphragm4914. The valve plate4902overlies the head plate4904and includes a one-way inlet valve4928in fluid communication with the inlet opening4924and a one-way outlet valve4930in fluid communication with the outlet opening4926. The inlet and outlet valves4928,4930are configured as reed valves in the illustrated embodiment and are integrally formed with the valve plate4902. In other embodiments, other types of one-way valves may be used.

With reference toFIG.13, the wobble plate4908is rotatably supported on the eccentric shaft4910by bearings4932. The eccentric shaft4910is eccentrically mounted on the crank4912, which in turn is coupled for co-rotation with an output shaft4934of the electric motor4315. As such, rotation of the output shaft4934rotates the crank4912. The eccentric shaft4910is oriented and positioned so as to impart a wobbling motion to the wobble plate4908. More specifically, each corner of the wobble plate4908is sequentially moved up and down, in a direction generally parallel to the central axis4408, which imparts a reciprocating (i.e. up and down) motion to the plungers4916of the diaphragm assembly4906.

In operation, as each plunger4916is moved up, the interior volume of the associated cup-shaped diaphragm4914is compressed, as illustrated inFIG.15. This expels air from the interior volume of the diaphragm4914, out through the associated outlet opening4926in the head plate4904and outlet valve4930in the valve plate4902. The expelled air is routed into the outlet plate4307, and ultimately discharged through the upper casing outlet4103. As each plunger4916is moved back downward, the interior volume of the associated diaphragm4914expands, which draws air into the interior volume of the diaphragm4914, through the associated inlet opening4924and inlet valve4928.

With continued reference toFIG.15, each plunger4916in the illustrated embodiment includes a circumferential rib4940. The rib4940has a rounded outer profile and is engageable with a wall4942of the diaphragm4914as the diaphragm4914is moved toward its compressed position (shown inFIG.15). In the illustrated embodiment, the rib4940engages the wall4942of the diaphragm4914at a position approximately half way between an inner edge4944of the wall4942, where the wall4942connects to the plunger4916, and an outer edge4946of the wall4942, where the wall4942connects to a surrounding flange4948of the diaphragm assembly4906. The engagement between the rib4940and the wall4942supports the wall4942and prevents it from buckling. The inventors determined through testing and simulations that the rib4940on the plunger4916advantageously provides a strain reduction of at least 12% in the wall4942of the diaphragm4914, compared to other embodiments in which the rib4940is omitted, resulting in significantly improved durability and lifespan of the diaphragm assembly4906.

Various features and aspects of the present disclosure are set forth in the following claims.