CN113614388A

CN113614388A - Noise attenuator for a fluid switching module of a pneumatic system

Info

Publication number: CN113614388A
Application number: CN202080022117.3A
Authority: CN
Inventors: 吉列尔梅·哈尔滕伯格·沃森; 韦德·欧摩尔; 霍里亚·布兰迪尔; 雷纳托·科利亚; 罗伯特·J·麦克米伦
Original assignee: Leggett and Platt Canada Co
Current assignee: Leggett and Platt Canada Co
Priority date: 2019-03-20
Filing date: 2020-03-16
Publication date: 2021-11-05
Also published as: KR20210141940A; JP2023055938A; EP3942188A1; JP7271707B2; JP7440676B2; WO2020186330A1; EP3942188A4; JP2022526125A

Abstract

A pneumatic system includes a fluid switching module having an air channel and a vent in fluid communication with the air channel. The pneumatic system also includes a sound attenuator coupled to the fluid switching module, the sound attenuator having a first chamber in fluid communication with the vent, a first aperture in fluid communication with the vent via the first chamber, a second chamber in fluid communication with the first chamber via the first aperture, and a second aperture in fluid communication with the first aperture via the second chamber.

Description

Noise attenuator for a fluid switching module of a pneumatic system

Cross Reference to Related Applications

This application is a partially continuous application of co-pending U.S. patent application No.16/116, 433 filed 2018, 8, 29, which is incorporated herein by reference in its entirety.

Background

The present disclosure relates to a pneumatic massage system for commercial and residential use (e.g., office and home furniture), and more particularly for use within vehicle seating systems (aircraft, automobiles, etc.).

Disclosure of Invention

In one embodiment, the present disclosure provides a pneumatic system including a fluid switching module having an air channel and a vent in fluid communication with the air channel. The pneumatic system also includes a sound attenuator coupled to the fluid switching module, the sound attenuator having a first chamber in fluid communication with the vent, a first aperture in fluid communication with the vent via the first chamber, a second chamber in fluid communication with the first chamber via the first aperture, and a second aperture in fluid communication with the first aperture via the second chamber.

In another embodiment, the present disclosure provides a noise attenuator for a fluid switching module that includes a body having a first wall, a first plurality of exterior sidewalls, a plurality of interior sidewalls extending from the first wall, and a floor extending between the plurality of interior sidewalls. The noise attenuator also includes a cover coupled to the body, the cover having a second wall opposite the first wall and a second plurality of exterior sidewalls. A first aperture extends through one of the plurality of inner side walls and is in fluid communication with a chamber extending between the floor and the second wall. A second aperture extends through one of the first plurality of outer side walls or one of the second plurality of outer side walls.

In another embodiment, the present disclosure provides a pneumatic system comprising a fluid switching module having an air channel and a vent in fluid communication with the air channel and a sound attenuator coupled to the fluid switching module, the sound attenuator configured to attenuate noise generated by air flowing through the fluid switching module to less than 40dB across an audible range.

Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of a pneumatic system including a fluid switching module.

Fig. 2 is a front perspective view of the fluid switching module of fig. 1.

Fig. 3 is a rear perspective view of the fluid switching module of fig. 1.

Fig. 4 is an exploded view of the fluid switching module of fig. 1.

Fig. 5 is a front view of the fluid switching module of fig. 1 with the cover removed.

Fig. 6 is an enlarged view of the portion of the fluid switching module of fig. 5 identified by line 6-6.

Fig. 7 is an enlarged view of the portion of the fluid switching module of fig. 5 identified by line 7-7.

Fig. 8 is an enlarged view of the portion of the fluid switching module of fig. 5 identified by line 8-8.

Fig. 9 is a schematic view of an air channel of the fluid switching module of fig. 5.

Fig. 10A-10E are schematic illustrations of gas flow operation through the fluid switching module of fig. 5.

FIG. 11 is a perspective view of an assembly including the fluid switching module of FIG. 1 coupled to a sound attenuator.

Fig. 12 is an exploded view of the assembly of fig. 11.

FIG. 13 is a perspective view of the sound attenuator of FIG. 11.

FIG. 14 is another perspective view of the sound attenuator of FIG. 11.

FIG. 15 is a cross-sectional view of the assembly of FIG. 11 taken along line 15-15.

FIG. 16 is the cross-sectional view of FIG. 15 further illustrating the airflow path from the fluid switching module through the sound attenuator.

Fig. 17A is a graph illustrating an operational noise profile of the fluid switching module of fig. 1.

Fig. 17B is a graph illustrating an operational noise profile of the assembly of fig. 11.

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 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. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. And as used herein and in the appended claims, the terms "upper," "lower," "top," "bottom," "front," "back," and other directional terms are not intended to require any particular orientation, but are used for descriptive purposes only.

Detailed Description

Referring to fig. 1, a pneumatic system 10 (i.e., a pneumatic massage system, a vibrating pneumatic system, etc.) is shown. The pneumatic system 10 includes a pneumatic source 14 (e.g., an air pump, air compressor, etc.), a first air bladder 18, a second air bladder 22, a third air bladder 26, and a fourth air bladder 30. The pneumatic system 10 further includes a fluid switching module 34, the fluid switching module 34 being fluidly connected to the pneumatic source 14 and the

air bags

18, 22, 26, 30. In some embodiments, the pneumatic source 10 is driven by an electric motor. In other words, the pneumatic pressure is generated by a dedicated electric motor. In alternate embodiments, pneumatic source 10 is any suitable source of compressed air, including a pneumatic module or any pneumatic source within an existing vehicle pneumatic system.

As explained in more detail below, the pneumatic system 10 is used to produce a massage effect by cyclically inflating and deflating the

bladders

18, 22, 26, 30 without using any electrical or mechanical valves. Specifically, pneumatic source 14 provides a source of pressurized air to fluid switching module 34, and fluid switching module 34 controls the flow of air to

bladders

18, 22, 26, 30 in a predetermined sequence without moving any portion of fluid switching module 34. Specifically, the flow of air is controlled by the fluid switching module 34 such that the

air cells

18, 22, 26, 30 repeatedly inflate and deflate in a staggered manner (i.e., inconsistent inflation) to produce a massage effect. In some embodiments, the pneumatic system 10 is integrated within a seat, which may be any vehicle seat within the passenger compartment of a vehicle for the purposes described below, but the seat is not necessarily limited to vehicle applications.

Referring to fig. 1-2, fluid switching module 34 includes a base 38 and a cover 42. The module 34 further includes five air connections 46A-46E formed on one side 50 of the base 38. Specifically, the base 38 includes a pneumatic source connector 46A, a first airbag connector 46B, a second airbag connector 46C, a third airbag connector 46D, and a fourth airbag connector 46E.

Referring to fig. 4, an air passage 54 is formed in the base 38. Specifically, the air channel 54 is defined in part by a passageway 58 having a floor 62 and a cover 42. In other words, the air channel 54 is at least partially defined by the floor 62, the cover 42, and the side walls extending between the floor 62 and the cover 42. Referring to FIG. 5, air connections 46A-46E are fluidly connected to air channels 54 via respective holes 66A-66E through base plate 62. Additionally,

vents

70, 74, 78, 82 (fig. 3) to atmosphere are formed in the base 38 (more specifically, in the floor 62) to place the air channels 54 in fluid communication with the atmosphere. The operation of the air channel 54 and

vents

70, 74, 78, 82 is described in more detail below. Generally, the air passageway 54 and

vents

70, 74, 78, 82 passively control (i.e., without additional mechanical or electrical valves) the flow of air from the pneumatic source 14 to the

bladders

18, 22, 26, 30 in a predetermined sequence.

Referring to FIG. 9, the air channels 54 define a plurality of "zones" and "subsystems". Specifically, the air channel 54 includes a first subsystem 86 (shaded in fig. 9), a second subsystem 90 fluidly connected to the first subsystem 86, and a third subsystem 94 fluidly connected to the first subsystem 86. The first subsystem 86 includes an intake zone 98 at a first upstream location and including the air source connection 46A and a first flow-splitting zone 102 downstream of the intake zone 98. The first subsystem 86 further includes a first transfer zone 106 and a second transfer zone 110. The first flow splitting region 102 is fluidly connected to a first transport region 106 and a second transport region 110. The first transfer zone 106 is in fluid communication with an intake zone 114 of the second subsystem 90. Likewise, the second transfer zone 110 is in fluid communication with the intake zone 118 of the third subsystem 94.

With continued reference to fig. 9, second subsystem 90 includes an intake area 114 at a second upstream location and a second air splitter 122 fluidly connected to intake area 114. The second subsystem 90 further includes a first bladder area 126 and a second bladder area 130 fluidly connected to the second flow splitting area 122. The first bladder connector 46B is located within the first bladder area 126 and the second bladder connector 46C is located within the second bladder area 130. In addition, the second subsystem 90 includes a first vent region 134 fluidly connected to the first airbag section 126 and a second vent region 138 fluidly connected to the second airbag section 130. The first vent 70 is positioned within the first vent region 134 and the second vent 74 is positioned within the second vent region 138. Further, the second subsystem 90 includes a feedback zone 142 fluidly connected to the second vent zone 138 and the first transfer zone 106 of the first subsystem 86.

With continued reference to fig. 9, the third subsystem 94 is similar to the second subsystem 90. Third subsystem 94 includes an intake area 114 at a third upstream location and a third air splitter area 146 fluidly connected to intake area 114. The third subsystem 94 further includes a third bladder area 150 and a fourth bladder area 154 fluidly connected to the third shunt area 146. The third balloon connector 46D is located in the third balloon region 150 and the fourth balloon connector 46E is located in the fourth balloon region 154. Additionally, third subsystem 94 includes a third vent region 158 fluidly connected to third airbag section 150 and a fourth vent region 162 fluidly connected to fourth airbag section 154. The third vent opening 78 is located within the third vent region 158 and the fourth vent opening 82 is located within the fourth vent region 162. Further, the third subsystem 94 includes a feedback zone 166 fluidly connected to the fourth ventilation zone 162 and the second conveyance zone 110 of the first subsystem 86.

Referring to fig. 5-8, the air channels 54 further define a plurality of "channels," "walls," "dimensions," etc. The first air intake region 98 includes an air intake passage 170 in fluid communication with the air source connector 46A and defines an intake air flow axis 174 (FIG. 6). Bore 66A of air source connector 46A defines a diameter 178 in the range of about 1.0mm to about 3.0 mm. The intake passage 170 narrows downstream of the nozzle 182. Specifically, the intake passage 170 includes an intake opening width dimension 186 and the nozzle 182 defines a nozzle width dimension 190 that is less than the intake opening width dimension 186. In the illustrated embodiment, the inlet width dimension 186 is equal to the diameter 178. The inlet width dimension 186 is about 1.25 to about 5.5 times greater than the nozzle width dimension 190.

Referring to fig. 6, downstream of the nozzle 182 is the first splitter region 102. The first flow splitting zone 102 includes an air splitter 194, a first exhaust passage 198, a second exhaust passage 202, and a notch 206 (i.e., an air flow biasing feature). The air splitter 194 is positioned at a distance 208 of about 2.0mm to about 3.0mm from the nozzle 182. In some embodiments, distance 208 is approximately equal to four times nozzle width 190. The air splitter 194 is curved and defines at least one radius 210. In an alternative embodiment, the air splitter is pointed. In other words, the air splitter 194 may be concave or convex. Specifically, the air splitter 194 includes a center point 214 aligned with the intake flow axis 174. First exhaust passage 198 includes a first wall 218 and second exhaust passage 202 includes a second wall 222 positioned opposite first wall 218. The first wall 218 is oriented relative to the intake flow axis 174 to define a first angle 226. Likewise, the second wall 222 is oriented relative to the inlet flow axis 174 to define a second angle 230. Both the first angle 226 and the second angle 230 are in the range of about 15 degrees to about 25 degrees. In some embodiments, the first angle 226 is equal to the second angle 230.

The recess 206 is positioned upstream of the first exhaust passage 198 and downstream of the nozzle 182. More specifically, the notch 206 is positioned between the nozzle 182 and the first wall 218. In other words, the recess 206 replaces a portion of the first wall 218. As explained in further detail below, the notch 206 biases the airflow from the nozzle 182 to flow first through the first exhaust passage 198 before flowing through the second exhaust passage 202. The notch 206 defines a dimension 234 in the range of about 0.025mm to about 0.50 mm. The larger the notch size, the greater the biasing effect on the corresponding vent passage 198. However, too large a notch size can cause airflow instability. In alternative embodiments, the recess 206 may be a groove, slot, or other suitable geometric feature in the wall 218 to create a low pressure region.

With continued reference to fig. 6, downstream of the first splitter region 102 are both the first transport region 106 and the second transport region 110. Specifically, the first exhaust passage 198 is in fluid communication with the first transfer zone 106. Likewise, the second exhaust passage 202 is in fluid communication with the second transfer zone 110. The first conveying section 106 includes a conveying passage 238 having two curved walls 242, and the second conveying section 110 similarly includes a conveying passage 246 having two curved walls 250.

Downstream of the first transfer section 106 is an intake section 114 of the second subsystem 90. Referring to FIG. 7, the transfer passage 238 is in fluid communication with an intake passage 254 that defines an airflow axis 258. Intake passage 254 narrows to a nozzle 262 that is narrower than nozzle 182. Specifically, nozzle 262 defines a nozzle width dimension 266 that is less than nozzle width 190. Nozzle width dimension 266 is equal to nozzle width 190 or about 100% to about 50% less than nozzle width 190.

Downstream of the nozzle 262 is the second split zone 122. The second splitter region 122 includes the air splitter 270, the first exhaust passage 274, the second exhaust passage 278, and the notch 282. The air splitter 270 is positioned a distance 284 of about 2.0mm to about 3.0mm from the nozzle 262. In some embodiments, distance 284 is approximately equal to four times nozzle width 266. The air splitter 270 is curved and defines at least one radius 286. Like the air splitter 194, the air splitter 270 may be concave or convex. Specifically, the air splitter 270 includes a center point 290 aligned with the intake flow axis 258. The first exhaust passage 274 includes a first wall 294 and the second exhaust passage 278 includes a second wall 298 positioned opposite the first wall 294. The first wall 294 is oriented relative to the inlet flow axis 258 to define a first angle 302. Likewise, the second wall 298 is oriented relative to the inlet flow axis 258 to define a second angle 306. Both the first angle 302 and the second angle 306 are in the range of about 15 degrees to about 25 degrees. In some embodiments, first angle 302 is equal to second angle 306.

The notch 282 is positioned upstream of the first exhaust passage 274. More specifically, the recess 282 is positioned between the nozzle 262 and the first wall 294. In other words, the notch 282 replaces a portion of the first wall 294. The notch 282 defines a dimension 310 in the range of about 0.025mm to about 0.5 mm. As explained in further detail below, the notch 282 biases the airflow from the nozzle 262 to flow first through the first exhaust passage 274 before flowing through the second exhaust passage 278.

Downstream of the second flow splitting region 122 are a first bladder area 126, a second bladder area 130, a first vent area 134, and a second vent area 138. Specifically, first exhaust passage 274 is in fluid communication with first airbag zone 126 and first vented zone 134. Likewise, the second vent passage 278 is in fluid communication with the second bladder zone 130 and the second vent zone 138. First bladder area 126 includes a channel 314 having two opposing walls 318 and a first bladder connector 46B. Similarly, the second balloon region 130 includes a channel 322 having two opposing walls 326 and a second balloon connector 46C. The first vented zone 134 includes a channel 330 having two curved walls 334 and the first vent 70. Similarly, the second venting area 138 includes a channel 338 having two curved walls 342 and the second venting opening 74. The first vent 70 defines a first vent diameter 346 and the second vent 74 defines a second vent diameter 350.

Referring to fig. 6, 7 and 9, the feedback region 142 includes a feedback channel 351, the feedback channel 351 including two curved walls 352. The feedback passage 254 is in fluid communication with the passage 338 of the second venting zone 138 and with the transfer passage 238 of the first transfer zone 106. As explained in more detail below, the feedback zone 142 provides a passive way to switch the airflow from the second subsystem 90 to the third subsystem 94.

The third subsystem 94 is similar to the second subsystem 90. In some embodiments, the third subsystem 94 is identical (i.e., one-piece) to the second subsystem 90. Downstream of the second transfer section 110 is an air intake section 118 of the third subsystem 94. Referring to FIG. 8, the transfer passage 246 is in fluid communication with an intake passage 354 that defines an airflow axis 358. The inlet channel 354 narrows to a nozzle 362 that is narrower than the nozzle 182. Specifically, nozzle 362 defines a nozzle width dimension 366 that is smaller than nozzle width 190. Nozzle width dimension 366 is equal to nozzle width 190 or about 100% to about 50% less than nozzle width 190.

Downstream of the nozzle 362 is the third splitter region 146. The third flow splitting region 146 includes an air splitter 370, a first exhaust passage 374, a second exhaust passage 378, and a notch 382. The air splitter 370 is positioned a distance 384 of about 2.0mm to about 3.0mm from the nozzle 362. In some embodiments, distance 384 is approximately equal to four times nozzle width 366. The air splitter 370 is curved and defines at least one radius 386. Like the air splitter 270, the air splitter 370 may be concave or convex. Specifically, the air splitter 370 includes a center point 390 aligned with the intake flow axis 358. First exhaust passage 374 includes a first wall 394 and second exhaust passage 378 includes a second wall 398 positioned opposite first wall 394. The first wall 394 is oriented relative to the intake flow axis 358 to define a first angle 402. Likewise, the second wall 398 is oriented relative to the intake flow axis 358 to define a second angle 406. Both the first angle 402 and the second angle 406 are in the range of about 15 degrees to about 25 degrees. In some embodiments, the first angle 402 is equal to the second angle 406.

Notch 382 is positioned upstream of first exhaust passage 374. More specifically, notch 382 is positioned between nozzle 362 and first wall 394. In other words, the notch 382 replaces a portion of the first wall 394. Notch 382 defines a dimension 410 in the range of about 0.025mm to about 0.5 mm. As explained in further detail below, the notch 382 biases the airflow from the nozzle 362 to flow first through the first exhaust passage 374 before flowing through the second exhaust passage 378.

Downstream of third splitter 146 are third bladder zone 150, fourth bladder zone 154, third vent zone 158, and fourth vent zone 162. Specifically, first exhaust passage 374 is in fluid communication with third bladder zone 150 and third vent zone 158. Likewise, second exhaust passage 378 is in fluid communication with fourth airbag section 154 and fourth vent section 162. The third balloon region 150 includes a channel 414 having two opposing walls 418 and a third balloon connector 46D. Similarly, fourth balloon region 154 includes a channel 422 having two opposing walls 426 and a fourth balloon connector 46E. The third vent region 158 includes a passageway 430 having two curved walls 434 and a third vent opening 78. Similarly, the fourth ventilation zone 162 includes a channel 438 having two curved walls 442 and the fourth ventilation opening 82. The third vent 78 defines a third vent diameter 446 and the fourth vent 82 defines a fourth vent diameter 450.

The feedback zone 166 includes a feedback channel 451, the feedback channel 451 including two curved walls 452. The feedback channel 451 is in fluid communication with the channel 438 of the fourth ventilation zone 162 and with the transfer channel 246 of the second transfer zone 110. As explained in more detail below, the feedback zone 166 provides a passive way to switch the airflow from the third subsystem 94 to the second subsystem 90.

In operation, pump 14 provides a source of pressurized air at air connector 46A. The air passage 54 passively controls the source of pressurized air to cyclically and sequentially inflate and deflate the

bladders

18, 22, 26, 30. In other words, the air passage 54 inflates and deflates each of the

air cells

18, 22, 26, 30 in a predetermined sequence without additional electrical or mechanical valves, switches, or other external controls. In the illustrated embodiment, the predetermined sequence includes inflating each of the

bladders

18, 22, 26, 30 non-uniformly (i.e., first inflating a first bladder, then inflating a second bladder, then inflating a third bladder, etc.).

Referring to fig. 10A, pressurized air from the pump 14 is received by the fluid switching module 34 and enters the intake passage 170 of the air passage 54. The pressure in the intake passage 170 (i.e., the intake pressure) determines the maximum output pressure and output flow that may affect the

airbags

18, 22, 26, 30. As the air intake passage 170 narrows to form the nozzle 182, the air flow accelerates. Too fast an air speed may create excessive turbulence, which may degrade the operation and stability of the module 34.

As the pressurized air exits the nozzle 182, the airflow contacts the first air splitter 194. The first flow splitter 194 divides the airflow between one of the two

exhaust passages

198, 202. Initially, a low pressure field is formed along the two adjacent

angled walls

218, 222 due to entrainment of ambient air. However, the low pressure fields formed along the adjacent

angled walls

218, 222 are different due to the notches 206 in the first wall 218. Specifically, the low voltage field along the first wall 218 is stronger than the low voltage field along the second wall 222. The difference in the low pressure field deflects the airflow toward the first wall 218 via the offset recess 206 and the corresponding first exhaust passage 198. The physical phenomenon that causes the airflow to attach to one of the two

walls

218, 222 is known as the coanda effect. The coanda effect is the tendency of a fluid jet issuing from an orifice (e.g., nozzle 182) to entrain fluid along an adjacent flat or curved surface (e.g., wall 218) and from the surroundings. Thus, the airflow first flows from the first air splitter 194 to the second subsystem 90. The

angles

226, 230 of the walls 218, 222 (FIG. 6) relative to the flow centerline 174 are designed to control the strength of the low pressure field and the point at which the flow attaches to the

downstream walls

218, 222.

With continued reference to FIG. 10A, as the airflow moves through the conveyance channel 238, the airflow first draws in additional air inflow through the feedback channel 351 due to the venturi effect. Specifically, additional airflow is drawn from the vent 74 into the transfer passage 238. However, when the transfer passage 238 reaches about 15% to about 25% of the input pressure at the nozzle 182, the flow of air through the feedback passage 351 reverses, flowing toward the vent 74. In other words, the airflow through transfer passage 238 first creates a venturi effect, drawing additional airflow through feedback passage 351 until the pressure in transfer passage 238 reaches a threshold value (e.g., approximately 28% of the intake air pressure). Thus, this variable direction airflow is shown in fig. 10A as a double-headed arrow (i.e., first flowing toward the conveyance channel 238, and then flowing toward the second ventilation channel 338). The transfer passage 238 reaches and temporarily stabilizes about 40% to about 60% of the input pressure and provides a temporarily stabilized intake pressure to the second subsystem 90.

With continued reference to FIG. 10A, the second air splitter 270 of the second subsystem 90 operates in much the same manner as the first air splitter 194 of the first subsystem 86. Specifically, a low pressure field is formed along two adjacent

angled walls

294, 298 due to entrainment of ambient air. The difference between the low pressure fields is created by the biasing recess 282 and the flow of air from the nozzle 262 is deflected toward the angled wall 294 and the first exhaust passage 274. In other words, a stronger low pressure region is formed on the wall 294 with the notch 282, thereby biasing the airflow in that direction. As previously described, wall attachment occurs due to the coanda effect and airflow is directed to first airbag inflation channel 314, thereby inflating first airbag 18.

When the first bladder 18 begins to inflate, additional air is drawn into the first bladder passageway 314 from the first vent passageway 330 due to the venturi effect. The additional airflow from the vent 70 due to the venturi effect increases the airflow in the channel 314 by a factor of about 1.0 to about 1.1. When the first bladder 18 reaches about 50% of the maximum pressure, the airflow in the first vent passage 330 reverses. Thus, the airflow through the first ventilation channel 330 is shown as a double-headed arrow in fig. 10A. The first bladder 18 reaches a maximum pressure of about one-third of the input pressure. When the first air bag 18 reaches this maximum pressure, the air flow at the second air splitter 270 is deflected and switches to the second vent passage 278 and the second air bag passage 322 corresponding to the second air bag 22.

Referring to FIG. 10B, the back pressure from the inflated first air bladder 18 causes the air flow at the second air splitter 270 to switch and deflect toward the second exhaust passage 278. In the state shown in fig. 10B, the first air bladder 18 now begins to deflate through the first vent passage 330 and the first vent 70, and the second air bladder 22 begins to inflate. When second bladder 22 is inflated, feedback to first subsystem 86 occurs via an increase in pressure in feedback passage 351, which is connected between second vent passage 338 and first transfer passage 238. When the second bladder 22 reaches a pressure of about 35% to about 50% of the input pressure, the pressure in the feedback passage 351 is high enough to switch and deflect the flow of air at the first air splitter 194 toward the second exhaust passage 202. In other words, when the pressure in the second bladder 22 reaches a threshold value, pressure feedback through the feedback passage 351 causes the airflow at the first air splitter 194 to deflect and switch to the second exhaust passage 202 corresponding to the third subsystem 94.

Referring to fig. 10C, with both the first 18 and second 22 balloons deflated (shown with dashed arrows), the airflow is deflected at the first air splitter 194 to move through the transfer channel 110 toward the third subsystem 94. As air moves through the transfer passage 110, the air flow first draws in additional air inflow through the feedback passage 451 due to the venturi effect. However, when the transfer channel 246 reaches about 15% to about 25% of the input pressure, the flow of air through the feedback channel 451 reverses, flowing toward the vent 82. In other words, the airflow through the transfer passage 246 first creates a venturi effect, drawing additional airflow through the feedback passage 451 until the pressure in the transfer passage 246 reaches a threshold value. Thus, this variable airflow is shown in fig. 10C as a double-headed arrow (i.e., first flowing to the delivery channel 246 and then to the fourth ventilation channel 438). The transfer passage 246 reaches and temporarily stabilizes at about 40% to about 60% of the input pressure and provides a temporarily stabilized intake pressure to the third subsystem 94.

With continued reference to FIG. 10C, the third air splitter 370 of the third subsystem 94 operates in much the same manner as the second air splitter 270 of the second subsystem 90. Specifically, a low pressure field is formed along the two adjacent

angled walls

394, 398 due to entrainment of ambient air. The difference between the low pressure fields is created by the offset notch 382 and the gas flow from the nozzle 362 is deflected toward the angled wall 394 and the first exhaust passage 374. In other words, a stronger low pressure region is formed on the wall 394 with the notch 382, thereby biasing the airflow in that direction. As previously described, wall attachment occurs due to the coanda effect and the flow of gas is directed to the third airbag venting passage 414, thereby inflating the third airbag 26.

When the third bladder 26 begins to inflate, additional air is drawn into the third bladder passage 414 from the third vent passage 430 due to the venturi effect. The additional airflow from the third vent 78 due to the venturi effect increases the airflow in the passage 414 by a factor of about 1.0 to about 1.1. When the third bladder 26 reaches about 50% of the maximum pressure, the flow of air in the third ventilation passageway 430 reverses. Thus, the airflow through the third ventilation channel 430 is shown as a double-headed arrow in fig. 10C. The third bladder 26 reaches a maximum pressure of about one-third of the input pressure. When the third air bladder 26 reaches this maximum pressure, the air flow at the third air splitter 370 is deflected and switches to the second vent passage 378 and the fourth air bladder passage 422 corresponding to the fourth air bladder 30.

Referring to fig. 10D, the back pressure from the third air bladder 26 causes the flow of air at the third air splitter 370 to deflect toward the second exhaust passage 378. In the state shown in fig. 10D, the third balloon 26 is deflated through the third vent 78, and the fourth balloon 30 is being inflated. When the fourth bladder 30 is inflated, feedback to the first subsystem 86 occurs through an increase in pressure in a feedback passage 451 connected between the fourth ventilation passage 438 and the second delivery passage 246. When the fourth bladder 30 reaches a pressure of about 35% to about 50% of the input pressure, the pressure in the feedback passage 451 is high enough to switch the flow of air at the first air splitter 194 back to the first exhaust passage 198. In other words, when the pressure in the fourth bladder 30 reaches a threshold value, feedback through the feedback channel 451 causes the airflow at the first air splitter 194 to deflect and switch to the first exhaust channel 198 corresponding to the second subsystem 90.

Referring to FIG. 10E, operation of the fluid module 34 begins another cycle of inflating and deflating the

bladders

18, 22, 26, 30. Specifically, the state shown in fig. 10E is similar to the state shown in fig. 10A in that the gas flow is biased to inflate first bladder 18. However, FIG. 10E differs in that while the first balloon 18 is inflating, the remaining

balloons

22, 26, 30 are deflating. Inflation and deflation of the

bladders

18, 22, 26, 30 continues as long as the intake pressure is provided at the air connector 46A. In other words, the cyclical inflation and deflation of the

bladders

18, 22, 26, 30 is repeated indefinitely in a predetermined sequence until the pressurized air source 14 is turned off. Thus, when pressurized air is supplied to the air inlet connector 46A, the fluid module 34 provides a continuous massage effect in a defined sequence via inflation and deflation of the

air cells

18, 22, 26, 30.

In contrast, conventional pneumatic massage systems in car seats use a pneumatic pump that supplies pressurized air to an electromechanical valve module that controls the massage sequence and cycle time according to a predefined massage program. Each individual bladder requires a separate electromechanical valve within the module to control inflation and deflation. The base massage system typically has three air cells, while the high end massage system may have up to twenty air cells. The cost of the electromechanical modules is high due to the complexity and electronics required to control them. This makes it difficult to equip low cost vehicles with massage services, for example. In other words, prior art designs include modules that are very complex and require communication with the vehicle electronics system, which increases development and production costs.

In contrast, the fluidic module 34 does not rely on the use of electronics or moving mechanical components for operation or control. This makes the module 34 reliable, repeatable and cost effective. The defined massage sequence (i.e., the cyclical inflation/deflation of the

bladders

18, 22, 26, 30) is achieved by using cascaded vented fluid amplifiers (i.e.,

subsystems

86, 90, 94) that are biased to follow the defined sequence or order. The sequence is further defined by the use of

feedback zones

146, 166 that force the switching of the gas flow at a predefined static pressure. The vented fluid amplifier is selected to eliminate susceptibility to false switching under load and also provides the added benefit of providing a passage for automatic deflation at the completion of operation of the pneumatic system 10.

Fig. 11 and 12 illustrate an assembly 500 including the fluid module 34 and the sound attenuator 504, according to one embodiment. As described in greater detail below, the acoustic attenuator 504 may reduce noise generated by air flowing through the fluid module 34 during operation of the pneumatic system 10. The assembly 500 may be advantageously used in applications of the pneumatic system 10 where quieter operation is desired (e.g., in vehicle seats, massage chairs, etc.).

The illustrated sound attenuator 504 includes a body 508 and a cover 512 movably coupled to the body 508. The lid 512 is pivotably coupled to the body 508 by a hinge 516 such that the lid 512 is pivotably movable relative to the body 508 between an open position (fig. 12) and a closed position (fig. 11). The body 508 and the lid 512 are integrally formed as a single component, and the hinge 516 is a living hinge (i.e., a thin strip of elastically deformable material). Thus, body 508, lid 512, and hinge 516 may be molded together in a single process. This advantageously reduces the cost of manufacturing and assembling the sound attenuator 504.

In other embodiments, the body 508 and the lid 512 may be separate components coupled together by a hinge 516, or the lid 512 may be removably coupled to the body 508. In some embodiments, the cover 512 may be secured to the body 508 in the closed position by adhesives, welding (e.g., ultrasonic or hot air welding), mechanical structures, or the like, such that the cover 512 is not re-openable. In still other embodiments, the cover 512 may be integrally formed with the body 508 in the closed position.

The body 508 of the sound attenuator 504 includes a first wall or top wall 520, and when the cover 512 is in the closed position, the cover 512 includes a second wall or bottom wall 524 opposite the top wall 520, as shown in FIG. 11. The body 508 has first, second, third and fourth side or

outer side walls

528A, 528B, 528C, 528D extending from the top wall 520, and the lid 512 likewise has first, second, third and fourth side or

outer side walls

532A, 532B, 532C, 532D extending from the bottom wall 524 (fig. 13-14). The

first side wall

528A, 532A (or front side wall) is positioned opposite the

second side wall

528B, 532B (or rear side wall).

Third side walls

528C, 532C are positioned opposite

fourth side walls

528D, 532D. When the lid 512 is in the closed position (fig. 11), the

first side wall

528A, 532A,

second side wall

528B, 532B,

third side wall

528C, 532C and

fourth side wall

528D, 532D are generally aligned (i.e., the outer surfaces of each pair of side walls are generally flush).

The body 508 includes a recess 536 in the top wall 520, the recess 536 being open by the front wall 528A. The fluid module 34 is received in the recess 536 and secured within the recess 536 by a snap-fit. In other embodiments, the fluid module 34 may be coupled to the recess 536 in other manners (e.g., a friction fit, one or more fasteners, an adhesive, etc.). In the illustrated embodiment, the recess 536 is sized and shaped such that the cover 42 of the fluid module 34 is generally aligned with the top wall 520 of the body 508 (i.e., the outer surface of the cover 42 is generally flush with the outer surface of the top wall 520). In addition, the air connections 46A-46E protrude beyond the front wall 528A to facilitate and facilitate connection (e.g., to the pneumatic source 14 and the

bladders

18, 22, 26, 30 shown in FIG. 1).

Referring to fig. 15, the base 38 and the recess 536 of the fluid module 34 collectively define a first chamber 540. The length and width of the first chamber 540 is approximately equal to the length and width of the base 38 of the fluid module 34. The first chamber 540 is in fluid communication with each of the

vents

70, 74, 78, 82 of the fluid module 34. Thus, air from the first chamber 540 may be drawn through any of the

vents

70, 74, 78, 82 during operation of the fluid module 34, and air may likewise be vented from any of the

vents

70, 74, 78, 82 into the first chamber 540 during operation of the fluid module 34. Thus, the first chamber 540 is in fluid communication with the air passage 54 of the fluid module 34 via the

vents

70, 74, 78, 82.

The recess 536 is defined by

interior sidewalls

544C, 544D of the body 508 that extend generally from the front wall 528A toward the rear wall 528B and a floor 546 extending between the interior sidewalls 544C-D. The base 38 of the fluid module 34 includes corresponding sidewalls 548C, 548D, the sidewalls 548C, 548D extending from the underside 552 of the base 38 and abutting the inner sidewalls 544C-D (FIG. 15) within the recess 536. The side walls 528A-D of the body 508 and the side walls 532A-D of the cover 512 are spaced apart from the inner side walls 544C-D such that the side walls 528A-D, 532A-D surround the inner side walls 544C-D and define a second chamber 556 therebetween. In the illustrated embodiment, the second chamber 556 partially encloses the first chamber 540 and also extends between the floor 546 and the bottom wall 524. In other embodiments, the second chamber 556 may completely surround the first chamber 540 on all sides.

With continued reference to fig. 15, the second chamber 556 is in fluid communication with the first chamber 540 via a first aperture 560 extending through the

side walls

544D, 548D. That is, air may flow between the first chamber 540 and the second chamber 556 through the first aperture 560. The second aperture 564 extends through the

third side walls

528C, 532C. In the illustrated embodiment, the second aperture 564 is partially defined by each of the body 508 and the cover 512. In other embodiments, the second orifice 564 may be provided entirely on the body 508 or entirely on the cover 512. The second aperture 564 is in fluid communication with the ambient environment surrounding the assembly 500. That is, air may flow between the ambient environment and the second chamber 556 through the second aperture 564.

In operation, pneumatic source 14 provides pressurized air to fluid switching module 34, and fluid switching module 34 inflates and deflates each of

air bags

18, 22, 26, 30 in a predetermined sequence substantially as described above (fig. 1). When the

air cells

18, 22, 26, 30 are inflated and deflated, air may be drawn in or expelled through the

vents

70, 74, 78, 82. As shown in fig. 16, as air is exhausted through one or more of the

vents

70, 74, 78, 82, it enters the first chamber 540. When the pressure within the first chamber 540 exceeds the pressure within the second chamber 556, air from the first chamber 540 flows through the first aperture 560 and into the first portion 568 of the second chamber 556 between the inner side wall 544D and the

outer side walls

528D, 532D.

With continued reference to fig. 16, the first aperture 560 is oriented perpendicularly with respect to each of the

vents

70, 74, 78, 82, which results in the airflow changing direction by approximately 90 degrees as it flows from the

vents

70, 74, 78, 82 to the first aperture 560. The air then flows from the first portion 568 of the second chamber 556 into a second portion 572 of the second chamber 556 that extends below the first chamber 540. This again causes the airflow to change direction by about 90 degrees. Upon entering the third portion 576 of the second chamber 556 between the inner sidewall 544C and the sidewalls 532C, 528C, the airflow is redirected a third time at approximately 90 degrees. Finally, the air is discharged into the ambient environment through the second apertures 564.

The

chambers

540, 556 and

apertures

560, 564 thus define a tortuous flow path for air exhausted from the fluid switching module 34 via the

vents

70, 74, 78, 82. If air is drawn through one or more of the

vents

70, 74, 78, 82, the flow path described above and shown in FIG. 16 is reversed.

The sound attenuator 504 is made of a relatively flexible plastic material (e.g., polypropylene). For example, in some embodiments, the sound attenuator 504 is made from a plastic material having a flexural modulus of between about 1.0 megapascals (MPa) to about 3.0MPa under ASTM D790. In some embodiments, the plastic material can have a flexural modulus between about 1.0MPa to about 2.0MPa under ASTM D790. This corresponds to a relatively high flexibility, which advantageously provides the sound attenuator 504 with desired resonance characteristics.

For example, in the illustrated embodiment, the first chamber 540 has a first volume and the second chamber 564 has a second volume that is greater than the first volume. Accordingly, the first chamber is configured to resonate at a relatively high first resonant frequency (e.g., above 500 hertz (Hz) in some embodiments), and the second chamber 556 is 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. As the airflow passes through the

apertures

560, 564 and the

chambers

540, 556 during operation, the different resonances of the

chambers

540, 556 create destructive interference that attenuates the sound produced by the air flowing along the airflow path 54 of the fluid switching module 34. This is accomplished without any active noise reducing or sound absorbing material (e.g., foam, baffles, etc.) lining the airflow path, which tends to increase flow resistance and reduce flow velocity.

Fig. 17A and 17B show a comparison of experimentally measured noise profiles or

sound output levels

580A, 580B when operating the fluid switching module 34 without the sound attenuator 504 (fig. 17A) and when coupled to the sound attenuator 504 (fig. 17B). In both cases, pressurized air is supplied to pneumatic source connector 46A at a pressure of 60 kPa. Without the sound attenuator 504, the sound output level 580A exceeds 30 decibels (dB) at all frequencies between 500Hz and 20kHz and exceeds 35 dB at all frequencies between 1000Hz and 20kHz (fig. 17A). With the use of the sound attenuator 504, the sound output level 580B remains below 30dB at all frequencies below 2000Hz and is significantly less than the sound output level 580A at all frequencies above about 200 Hz. Furthermore, the sound output level 580B remains below 40dB at all frequencies between 20Hz and 20 kHz. The range of 20Hz to 20kHz is generally identified as the audible range ("audible range") without assisting human hearing. Thus, in the illustrated embodiment, the sound output level 580B of the assembly 500 is less than 40dB over the entire audible range.

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

Claims

1. A pneumatic system, comprising:

a fluid switching module comprising

An air passage, and

a vent in fluid communication with the air channel; and

a sound attenuator coupled to the fluid switching module, the sound attenuator including a first chamber in fluid communication with the vent,

a first aperture in fluid communication with the vent via the first chamber,

a second chamber in fluid communication with the first chamber via the first orifice, and

a second orifice in fluid communication with the first orifice via the second chamber.

2. The pneumatic system of claim 1, wherein the sound attenuator includes a body having a recess, and wherein the fluid switching module is received within the recess.

3. The pneumatic system of claim 1, wherein the body is made of polypropylene.

4. The pneumatic system of claim 1, wherein the vent is one of a plurality of vents, and wherein each vent of the plurality of vents is in fluid communication with the first chamber.

5. The pneumatic system of claim 1, wherein the second chamber at least partially surrounds the first chamber.

6. The pneumatic system of claim 1, wherein the first aperture is oriented perpendicular to the vent.

7. The pneumatic system of claim 1, wherein the second orifice is in fluid communication with an ambient environment.

8. The pneumatic system of claim 1, wherein the first chamber has a first resonant frequency, wherein the second chamber has a second resonant frequency, and wherein the first resonant frequency is at least 10% higher than the second resonant frequency.

9. The pneumatic system of claim 8, wherein the first and second resonant frequencies are configured to produce destructive interference to attenuate noise produced by air flowing through the fluid switching module.

10. A noise attenuator for a fluid switching module, the noise attenuator comprising:

a body comprising a first wall, a first plurality of outer side walls, a plurality of inner side walls extending from the first wall, and a floor extending between the plurality of inner side walls;

a lid coupled to the body, the lid including a second wall opposite the first wall and a second plurality of exterior sidewalls;

a first aperture extending through one of the plurality of inner side walls, the first aperture in fluid communication with a chamber extending between the floor and the second wall; and

a second aperture extending through one of the first plurality of outer side walls or one of the second plurality of outer side walls.

11. The noise attenuator of claim 10, wherein the plurality of interior sidewalls and the floor define a recess in the body, and wherein the recess is configured to receive the fluid switching module.

12. The noise attenuator of claim 11, wherein the cavity at least partially surrounds the recess.

13. The noise attenuator of claim 10, wherein the body and the cover are integrally formed as a single piece.

14. The noise attenuator of claim 10, wherein the second aperture is in fluid communication with the first aperture via the chamber.

15. The noise attenuator of claim 10, wherein the cover is pivotably coupled to the body.

16. A pneumatic system, comprising:

a fluid switching module comprising

An air passage, and

a vent in fluid communication with the air channel; and

a sound attenuator coupled to the fluid switching module, the sound attenuator configured to attenuate noise generated by air flowing through the fluid switching module to less than 40dB over an entire audible range.

17. The pneumatic system of claim 16, wherein the sound attenuator includes a first chamber in fluid communication with the vent and a second chamber in fluid communication with the vent via the first chamber.

18. The pneumatic system of claim 17, wherein the first chamber has a first resonant frequency, wherein the second chamber has a second resonant frequency, and wherein the first and second resonant frequencies are configured to produce destructive interference to attenuate the noise.

19. The pneumatic system of claim 17, wherein the sound attenuator includes a first aperture, and wherein the second chamber is in fluid communication with the first chamber via the first aperture.

20. The pneumatic system of claim 19, further comprising a second orifice in fluid communication with the first orifice via the second chamber.