Noise Attenuators for Fluid Switching Modules in Pneumatic Systems

Abstract

A pneumatic system includes a fluid switching module having an air passage and a vent in fluid communication with the air passage. 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 orifice 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.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Patent Application No. 16 / 359,709, filed on March 20, 2019, the entire contents of which are incorporated herein by reference. Background Art

[0003] The present disclosure relates to a pneumatic massage system for commercial and residential applications (eg, office and home furniture), and more particularly for use within vehicle seating systems (aircraft, automobiles, etc.). Summary of the invention

[0004] In one embodiment, the present disclosure provides a pneumatic system comprising a fluid switching module having an air passage and a vent in fluid communication with the air passage. The pneumatic system further comprises a sound attenuator coupled to the fluid switching module, the sound attenuator having a first chamber in fluid communication with the vent, a first orifice 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.

[0005] In another embodiment, the present disclosure provides a noise attenuator for a fluid switching module, comprising a body having a first wall, a first plurality of outer side walls, a plurality of inner side walls extending from the first wall, and a bottom plate extending between the plurality of inner side walls. 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 outer side walls. A first orifice extends through one of the plurality of inner side walls, and the first orifice is in fluid communication with a chamber extending between the bottom plate and the second wall. A second orifice extends through one of the first plurality of outer side walls or one of the second plurality of outer side walls.

[0006] In another embodiment, the present disclosure provides a pneumatic system comprising a fluid switching module and a sound attenuator connected to the fluid switching module, the fluid switching module having an air channel and a vent fluidly connected to the air channel, the sound attenuator being configured to attenuate noise generated by air flowing through the fluid switching module to less than 40 dB over the entire audible range.

[0007] Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of a pneumatic system including a fluid switching module.

[0009] Figure 2 yes Figure 1 Front perspective view of a fluid switching module.

[0010] Figure 3 yes Figure 1 Rear perspective view of the fluid switching module.

[0011] Figure 4 yes Figure 1 Exploded view of the fluid switching module.

[0012] Figure 5 yes Figure 1 Front view of the fluid switching module with the cover removed.

[0013] Figure 6 yes Figure 5 An enlarged view of the portion of the fluid switching module identified by line 6-6.

[0014] Figure 7 yes Figure 5 An enlarged view of the portion of the fluid switching module identified by line 7-7.

[0015] Figure 8 yes Figure 5 An enlarged view of the portion of the fluid switching module identified by line 8-8.

[0016] Fig. 9 yes Figure 5 Schematic diagram of the air channel of the fluid switching module.

[0017] Figures 10A-10E is through Figure 5 Schematic diagram of the fluid switching module performing airflow operation.

[0018] Fig.11 Includes connection to sound attenuator Figure 1 A perspective view of the components of a fluid switching module.

[0019] Fig.12 yes Fig.11 Exploded view of the components.

[0020] Fig.13 yes Fig.11 Perspective view of a sound attenuator.

[0021] Fig.14 yes Fig.11 Another perspective view of the sound attenuator.

[0022] Fig.15 It was taken along line 15-15 Fig.11 A cross-sectional view of an assembly.

[0023] Fig.16 is a diagram further illustrating the airflow path from the fluid switching module through the sound attenuator Fig.15 sectional view of .

[0024] Fig.17A It is shown Figure 1 Graph of the operating noise profile of a fluid switching module.

[0025] Fig. 17B It is shown Fig.11 A diagram of the operating noise profile of a component.

[0026] Before explaining any embodiment of the present disclosure in detail, it should be understood that the application of the present disclosure is not limited to the construction details and component arrangements set forth in the following description or shown in the subsequent drawings. The present disclosure can support other embodiments and can be practiced or implemented in various ways. Moreover, it should be understood that the words and terms used herein are for descriptive purposes and should not be considered restrictive. "Including," "comprising," or "having" and their variations used herein are intended to cover the items listed thereafter and their equivalents and 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 only used for descriptive purposes. DETAILED DESCRIPTION

[0027] Reference Figure 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, an air compressor, etc.), a first air bag 18, a second air bag 22, a third air bag 26, and a fourth air bag 30. The pneumatic system 10 further includes a fluid switching module 34, which is fluidically 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 alternative embodiments, the pneumatic source 10 is any suitable compressed air source, including a pneumatic module or any pneumatic source within an existing vehicle pneumatic system.

[0028] As explained in more detail below, the pneumatic system 10 is used to produce a massage effect by cyclically inflating and deflating the air bags 18, 22, 26, 30 without using any electric or mechanical valves. Specifically, the pneumatic source 14 provides a source of pressurized air to the fluid switching module 34, which controls the flow of air to the air bags 18, 22, 26, 30 in a predetermined sequence without moving any part of the fluid switching module 34. Specifically, the flow of air is controlled by the fluid switching module 34 so that the air bags 18, 22, 26, 30 are repeatedly inflated and deflated in a staggered manner (i.e., inconsistent inflation), thereby producing a massage effect. In some embodiments, the pneumatic system 10 is integrated into a seat, which for the purposes of the following description can be any vehicle seat in the passenger compartment of a vehicle, but the seat is not necessarily limited to vehicle applications.

[0029] Reference Figure 1-2 , the fluid switching module 34 includes a base 38 and a cover 42. The module 34 further includes five air connections 46A-46E formed on a 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.

[0030] Reference Figure 4 , an air passage 54 is formed in the base 38. Specifically, the air passage 54 is partially defined by a passage 58 having a bottom plate 62 and a cover 42. In other words, the air passage 54 is at least partially defined by the bottom plate 62, the cover 42, and the sidewalls extending between the bottom plate 62 and the cover 42. Figure 5 The air connections 46A-46E are fluidly connected to the air passage 54 via corresponding holes 66A-66E through the bottom plate 62. In addition, vents 70, 74, 78, 82 (open to the atmosphere) are formed in the base 38 (more specifically, in the bottom plate 62). Figure 3 ) to place the air passage 54 in fluid communication with the atmosphere. The operation of the air passage 54 and the vents 70, 74, 78, 82 is described in more detail below. Generally, the air passage 54 and the vents 70, 74, 78, 82 passively control (i.e., without additional mechanical or electric valves) the flow of air from the pneumatic source 14 to the airbags 18, 22, 26, 30 in a predetermined sequence.

[0031] Reference Fig. 9 , the air passage 54 defines a plurality of "zones" and "subsystems". Specifically, the air passage 54 includes a first subsystem 86 ( 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 air intake region 98 at a first upstream position and including an air source connection 46A, and a first flow diversion region 102 located downstream of the air intake region 98. The first subsystem 86 further includes a first transfer region 106 and a second transfer region 110. The first flow diversion region 102 is fluidly connected to the first transfer region 106 and the second transfer region 110. The first transfer region 106 is in fluid communication with the air intake region 114 of the second subsystem 90. Similarly, the second transfer region 110 is in fluid communication with the air intake region 118 of the third subsystem 94.

[0032] Continue to refer to Fig. 9, the second subsystem 90 includes an air intake area 114 at a second upstream position and a second air diversion area 122 fluidly connected to the air intake area 114. The second subsystem 90 further includes a first airbag area 126 and a second airbag area 130 fluidly connected to the second diversion area 122. The first airbag connector 46B is located in the first airbag area 126 and the second airbag connector 46C is located in the second airbag area 130. In addition, the second subsystem 90 includes a first ventilation area 134 fluidly connected to the first airbag area 126 and a second ventilation area 138 fluidly connected to the second airbag area 130. The first vent 70 is positioned in the first ventilation area 134 and the second vent 74 is positioned in the second ventilation area 138. Moreover, the second subsystem 90 includes a feedback area 142 fluidly connected to the second ventilation area 138 and the first transmission area 106 of the first subsystem 86.

[0033] Continue to refer to Fig. 9 , the third subsystem 94 is similar to the second subsystem 90. The third subsystem 94 includes an air intake zone 114 at a third upstream position and a third air diversion zone 146 fluidly connected to the air intake zone 114. The third subsystem 94 further includes a third airbag zone 150 and a fourth airbag zone 154 fluidly connected to the third diversion zone 146. The third airbag connector 46D is located in the third airbag zone 150 and the fourth airbag connector 46E is located in the fourth airbag zone 154. In addition, the third subsystem 94 includes a third ventilation zone 158 fluidly connected to the third airbag zone 150 and a fourth ventilation zone 162 fluidly connected to the fourth airbag zone 154. The third vent 78 is located in the third ventilation zone 158 and the fourth vent 82 is located in the fourth ventilation zone 162. Moreover, the third subsystem 94 includes a feedback zone 166 fluidly connected to the fourth ventilation zone 162 and the second transfer zone 110 of the first subsystem 86.

[0034] Reference Figure 5-8 , the air passage 54 further defines a plurality of "passages", "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 air intake flow axis 174 ( Figure 6 ). The hole 66A of the air source connector 46A defines a diameter 178 in the range of about 1.0 mm to about 3.0 mm. The inlet passage 170 narrows downstream of the nozzle 182. Specifically, the inlet passage 170 includes an inlet width dimension 186 and the nozzle 182 defines a nozzle width dimension 190 that is smaller than the inlet 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 larger than the nozzle width dimension 190.

[0035] Reference Figure 6, downstream of the nozzle 182 is the first flow splitter 102. The first flow splitter 102 includes an air splitter 194, a first exhaust passage 198, a second exhaust passage 202, and a notch 206 (i.e., an airflow biasing feature). The air splitter 194 is positioned at a distance 208 of about 2.0 mm to about 3.0 mm from the nozzle 182. In some embodiments, the distance 208 is approximately equal to four times the 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 can be concave or convex. Specifically, the air splitter 194 includes a center point 214 aligned with the intake air flow axis 174. The first exhaust passage 198 includes a first wall 218 and the second exhaust passage 202 includes a second wall 222 positioned opposite the first wall 218. The first wall 218 is oriented relative to the intake air flow axis 174 to define a first angle 226. Likewise, second wall 222 is oriented relative to intake airflow axis 174 to define a second angle 230. First angle 226 and second angle 230 are both within a range of about 15 degrees to about 25 degrees. In some embodiments, first angle 226 is equal to second angle 230.

[0036] The notch 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 notch 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 through the first exhaust passage 198 first before flowing through the second exhaust passage 202. The notch 206 is defined by a size 234 in the range of about 0.025 mm to about 0.50 mm. The larger the notch size, the greater the biasing effect on the corresponding exhaust passage 198. However, a notch size that is too large can cause airflow instability. In an alternative embodiment, the notch 206 can be a groove, a slot, or other suitable geometric feature in the wall 218 to create a low pressure area.

[0037] Continue to refer to Figure 6 , downstream of the first diversion zone 102 are both the first transfer zone 106 and the second transfer zone 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 transfer zone 106 includes a transfer passage 238 having two curved walls 242, and the second transfer zone 110 similarly includes a transfer passage 246 having two curved walls 250.

[0038] Downstream of the first delivery zone 106 is the intake zone 114 of the second subsystem 90. Figure 7, the transfer passage 238 is in fluid communication with an inlet passage 254 defining an air flow axis 258. The inlet passage 254 narrows to a nozzle 262 that is narrower than the nozzle 182. Specifically, the nozzle 262 defines a nozzle width dimension 266 that is smaller than the nozzle width 190. The nozzle width dimension 266 is equal to the nozzle width 190 or is approximately 100% to approximately 50% smaller than the nozzle width 190.

[0039] Downstream of the nozzle 262 is the second flow splitter 122. The second flow splitter 122 includes an air splitter 270, a first exhaust passage 274, a second exhaust passage 278, and a notch 282. The air splitter 270 is positioned at a distance 284 of about 2.0 mm to about 3.0 mm from the nozzle 262. In some embodiments, the distance 284 is approximately equal to four times the nozzle width 266. The air splitter 270 is curved and defines at least one radius 286. As with the air splitter 194, the air splitter 270 can be concave or convex. Specifically, the air splitter 270 includes a center point 290 aligned with the intake air 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 intake air flow axis 258 to define a first angle 302. Likewise, second wall 298 is oriented relative to intake air flow axis 258 to define second angle 306. First angle 302 and second angle 306 are both within a range of about 15 degrees to about 25 degrees. In some embodiments, first angle 302 is equal to second angle 306.

[0040] The notch 282 is positioned upstream of the first exhaust passage 274. More specifically, the notch 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 0.025 mm to about 0.5 mm. As explained in further detail below, the notch 282 biases the airflow from the nozzle 262 to flow through the first exhaust passage 274 first before flowing through the second exhaust passage 278.

[0041] Downstream of the second flow splitter region 122 are the first airbag region 126, the second airbag region 130, the first ventilation region 134, and the second ventilation region 138. Specifically, the first exhaust passage 274 is in fluid communication with the first airbag region 126 and the first ventilation region 134. Likewise, the second exhaust passage 278 is in fluid communication with the second airbag region 130 and the second ventilation region 138. The first airbag region 126 includes a passage 314 having two opposing walls 318 and a first airbag connector 46B. Similarly, the second airbag region 130 includes a passage 322 having two opposing walls 326 and a second airbag connector 46C. The first ventilation region 134 includes a passage 330 having two curved walls 334 and a first vent 70. Similarly, the second ventilation region 138 includes a passage 338 having two curved walls 342 and a second vent 74. The first vent 70 defines a first vent diameter 346 and the second vent 74 defines a second vent diameter 350.

[0042] Reference Figure 6 , Figure 7 and Fig. 9 , the feedback zone 142 includes a feedback channel 351, which includes two curved walls 352. The feedback channel 254 is in fluid communication with the channel 338 of the second ventilation zone 138 and is in fluid communication with the delivery channel 238 of the first delivery zone 106. As explained in more detail below, the feedback zone 142 provides a passive way to switch airflow from the second subsystem 90 to the third subsystem 94.

[0043] The third subsystem 94 is similar to the second subsystem 90. In some embodiments, the third subsystem 94 is identical to (i.e., identical to) the second subsystem 90. Downstream of the second transfer zone 110 is an intake zone 118 of the third subsystem 94. Figure 8 , the transfer passage 246 is in fluid communication with an inlet passage 354 defining an air flow axis 358. The inlet passage 354 narrows to a nozzle 362 that is narrower than the nozzle 182. Specifically, the nozzle 362 defines a nozzle width dimension 366 that is smaller than the nozzle width 190. The nozzle width dimension 366 is equal to the nozzle width 190 or is approximately 100% to approximately 50% smaller than the nozzle width 190.

[0044] Downstream of the nozzle 362 is the third flow splitter 146. The third flow splitter 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 at a distance 384 of about 2.0 mm to about 3.0 mm from the nozzle 362. In some embodiments, the distance 384 is approximately equal to four times the nozzle width 366. The air splitter 370 is curved and defines at least one radius 386. As with the air splitter 270, the air splitter 370 can be concave or convex. Specifically, the air splitter 370 includes a center point 390 aligned with the intake air flow axis 358. The first exhaust passage 374 includes a first wall 394 and the second exhaust passage 378 includes a second wall 398 positioned opposite the first wall 394. The first wall 394 is oriented relative to the intake air flow axis 358 to define a first angle 402. Likewise, the second wall 398 is oriented relative to the intake air flow axis 358 to define a second angle 406. Both the first angle 402 and the second angle 406 are within a range of about 15 degrees to about 25 degrees. In some embodiments, the first angle 402 is equal to the second angle 406.

[0045] The notch 382 is positioned upstream of the first exhaust passage 374. More specifically, the notch 382 is positioned between the nozzle 362 and the first wall 394. In other words, the notch 382 replaces a portion of the first wall 394. The notch 382 defines a dimension 410 in the range of about 0.025 mm to about 0.5 mm. As explained in further detail below, the notch 382 biases the airflow from the nozzle 362 to flow through the first exhaust passage 374 first before flowing through the second exhaust passage 378.

[0046] Downstream of the third flow splitter region 146 are the third airbag region 150, the fourth airbag region 154, the third ventilation region 158, and the fourth ventilation region 162. Specifically, the first exhaust passage 374 is in fluid communication with the third airbag region 150 and the third ventilation region 158. Likewise, the second exhaust passage 378 is in fluid communication with the fourth airbag region 154 and the fourth ventilation region 162. The third airbag region 150 includes a passage 414 having two opposing walls 418 and a third airbag connector 46D. Similarly, the fourth airbag region 154 includes a passage 422 having two opposing walls 426 and a fourth airbag connector 46E. The third ventilation region 158 includes a passage 430 having two curved walls 434 and a third vent 78. Similarly, the fourth ventilation region 162 includes a passage 438 having two curved walls 442 and a fourth vent 82. The third vent 78 defines a third vent diameter 446 and the fourth vent 82 defines a fourth vent diameter 450.

[0047] The feedback zone 166 includes a 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 in fluid communication 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 airflow from the third subsystem 94 to the second subsystem 90.

[0048] In operation, the pump 14 provides a source of pressurized air at the air connector 46A. The air passage 54 passively controls the source of pressurized air to cyclically and sequentially inflate and deflate the air bags 18, 22, 26, 30. In other words, the air passage 54 inflates and deflates each of the air bags 18, 22, 26, 30 in a predetermined sequence without additional electric or mechanical valves, switches, or other external controls. In the illustrated embodiment, the predetermined sequence includes inconsistent inflation of each of the air bags 18, 22, 26, 30 (i.e., inflating the first air bag first, then the second air bag, then the third air bag, etc.).

[0049] Reference Fig. 10A , pressurized air from the pump 14 is received by the fluid switching module 34 and enters the inlet passage 170 of the air passage 54. The pressure in the inlet passage 170 (i.e., the inlet pressure) determines the maximum output pressure and output flow that may be affected by the airbags 18, 22, 26, 30. As the inlet passage 170 narrows to form the nozzle 182, the air flow accelerates. Too fast air speed will produce excessive turbulence, which will degrade the operation and stability of the module 34.

[0050] When the pressurized air leaves the nozzle 182, the airflow contacts the first air splitter 194. The first splitter 194 distributes the airflow between one of the two exhaust channels 198, 202. Initially, a low pressure field is formed along the two adjacent angled walls 218, 222 due to the entrainment of the surrounding air. However, due to the notch 206 in the first wall 218, the low pressure field formed along the adjacent angled walls 218, 222 is different. Specifically, the low pressure field along the first wall 218 is stronger than the low pressure field along the second wall 222. The difference in low pressure field deflects the airflow toward the first wall 218 by offsetting the notch 206 and the corresponding first exhaust channel 198. The physical phenomenon that causes the airflow to attach to one of the two walls 218, 222 is called the Coanda effect. The Coanda effect is the tendency of a fluid jet ejected from an orifice (e.g., nozzle 182) to follow an adjacent flat or curved surface (e.g., wall 218) and entrain fluid from the surroundings. Therefore, the air flow first flows from the first air splitter 194 to the second subsystem 90. Figure 6) The angles 226, 230 relative to the airflow centerline 174 are designed to control the strength of the low pressure field and the point at which the airflow attaches to the downstream walls 218, 222.

[0051] Continue to refer to Fig. 10A As the airflow moves through the transfer passage 238, due to the Venturi effect, the airflow first draws in additional air inflow through the feedback passage 351. Specifically, additional airflow is drawn into the transfer passage 238 from the vent 74. However, when the transfer passage 238 reaches approximately 15% to approximately 25% of the input pressure at the nozzle 182, the airflow through the feedback passage 351 reverses direction, thereby flowing toward the vent 74. In other words, the airflow through the transfer passage 238 first creates a Venturi effect, thereby drawing in additional airflow through the feedback passage 351, until the pressure in the transfer passage 238 reaches a threshold value (e.g., approximately 28% of the intake pressure). Therefore, this variable direction airflow is Fig. 10A The transfer passage 238 reaches and temporarily stabilizes at about 40% to about 60% of the input pressure and provides a temporarily stable intake pressure to the second subsystem 90.

[0052] Continue to refer 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 the two adjacent angled walls 294, 298 due to the entrainment of ambient air. The difference between the low pressure fields is formed due to the offset notch 282, and the airflow from the nozzle 262 is deflected toward the angled wall 294 and the first exhaust passage 274. In other words, a stronger low pressure area 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 wall effect, and the airflow is directed to the first airbag exhaust passage 314, thereby inflating the first airbag 18.

[0053] When the first airbag 18 begins to inflate, additional air is drawn from the first ventilation passage 330 into the first airbag passage 314 due to the Venturi effect. The additional airflow from the vent 70 due to the Venturi effect increases the airflow in the passage 314 by about 1.0 to about 1.1 times. When the first airbag 18 reaches about 50% of the maximum pressure, the airflow in the first ventilation passage 330 is reversed. Therefore, the airflow through the first ventilation passage 330 is Fig. 10AThe first airbag 18 reaches a maximum pressure of about one third of the input pressure. When the first airbag 18 reaches the maximum pressure, the airflow at the second air splitter 270 is deflected, and the airflow is switched to the second exhaust channel 278 and the second airbag channel 322 corresponding to the second airbag 22.

[0054] Reference Fig. 10B , the back pressure from the inflated first air bag 18 causes the airflow at the second air splitter 270 to switch and deflect toward the second exhaust passage 278. Fig. 10B In the state shown, the first airbag 18 now begins to deflate through the first ventilation channel 330 and the first vent 70, and the second airbag 22 begins to inflate. As the second airbag 22 inflates, feedback to the first subsystem 86 occurs through the pressure increase in the feedback channel 351 connected between the second ventilation channel 338 and the first transfer channel 238. When the second airbag 22 reaches a pressure of about 35% to about 50% of the input pressure, the pressure in the feedback channel 351 is high enough to cause the airflow at the first air diverter 194 to switch and deflect toward the second exhaust channel 202. In other words, when the pressure in the second airbag 22 reaches a threshold, the pressure feedback through the feedback channel 351 causes the airflow at the first air diverter 194 to deflect and switch to the second exhaust channel 202 corresponding to the third subsystem 94.

[0055] Reference Fig. 10C , with both the first airbag 18 and the second airbag 22 deflated (shown by 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 the air moves through the transfer channel 110, the airflow first draws in additional air inflow through the feedback channel 451 due to the Venturi effect. However, when the transfer channel 246 reaches approximately 15% to approximately 25% of the input pressure, the airflow through the feedback channel 451 reverses, thereby flowing toward the vent 82. In other words, the airflow through the transfer channel 246 first creates a Venturi effect, thereby drawing in additional airflow through the feedback channel 451 until the pressure in the transfer channel 246 reaches a threshold. Therefore, this variable airflow is Fig. 10C The transfer passage 246 reaches and temporarily stabilizes at about 40% to about 60% of the input pressure and provides a temporarily stable intake pressure to the third subsystem 94.

[0056] Continue to refer 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 two adjacent angled walls 394, 398 due to the entrainment of ambient air. The difference between the low pressure fields is formed due to the offset notch 382, ​​and the airflow from the nozzle 362 is deflected toward the angled wall 394 and the first exhaust passage 374. In other words, a stronger low pressure area 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 wall effect, and the airflow is directed to the third airbag exhaust passage 414, thereby inflating the third airbag 26.

[0057] When the third air bag 26 begins to inflate, additional air is drawn from the third ventilation passage 430 into the third air bag passage 414 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 about 1.0 to about 1.1 times. When the third air bag 26 reaches about 50% of the maximum pressure, the airflow in the third ventilation passage 430 is reversed. Therefore, the airflow through the third ventilation passage 430 is Fig. 10C The third airbag 26 reaches a maximum pressure of about one third of the input pressure. When the third airbag 26 reaches the maximum pressure, the airflow at the third air splitter 370 is deflected, and the airflow is switched to the second exhaust channel 378 corresponding to the fourth airbag 30 and the fourth airbag channel 422.

[0058] Reference Fig. 10D , the back pressure from the third air bag 26 causes the airflow at the third air splitter 370 to be deflected toward the second exhaust passage 378. Fig. 10D In the state shown, the third air bag 26 is deflated through the third vent 78, and the fourth air bag 30 is being inflated. When the fourth air bag 30 is inflated, feedback to the first subsystem 86 occurs through the pressure increase in the feedback channel 451 connected between the fourth ventilation channel 438 and the second transfer channel 246. When the fourth air bag 30 reaches a pressure of about 35% to about 50% of the input pressure, the pressure in the feedback channel 451 is high enough to cause the air flow at the first air diverter 194 to switch back to the first exhaust channel 198. In other words, when the pressure in the fourth air bag 30 reaches a threshold, the feedback through the feedback channel 451 causes the air flow at the first air diverter 194 to deflect and switch to the first exhaust channel 198 corresponding to the second subsystem 90.

[0059] Reference Fig.10E , the operation of the fluid module 34 begins another cycle of inflating and deflating the airbags 18, 22, 26, 30. Specifically, Fig.10E The status shown in Fig. 10AThe state shown in FIG. 1 is similar in that the airflow is biased to inflate the first airbag 18. However, Fig.10E The difference is that while the first airbag 18 is being inflated, the remaining airbags 22, 26, 30 are being deflated. The inflation and deflation of the airbags 18, 22, 26, 30 continues as long as the inlet pressure is provided at the air connector 46A. In other words, the cyclic inflation and deflation of the airbags 18, 22, 26, 30 is repeated indefinitely in a predetermined sequence until the pressurized air source 14 is turned off. Therefore, when pressurized air is supplied to the inlet connector 46A, the fluid module 34 provides a continuous massage effect in a defined sequence via the inflation and deflation of the airbags 18, 22, 26, 30.

[0060] In contrast, conventional pneumatic massage systems in automotive seats use a pneumatic pump that supplies pressurized air to an electromechanical valve module, which controls the massage sequence and cycle time according to a predefined massage program. Each independent airbag requires a separate electromechanical valve within the module to control inflation and deflation. Basic massage systems typically have three airbags, while high-end massage systems can have up to twenty airbags. The cost of 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, the prior art designs include modules that are very complex and need to communicate with the vehicle's electronic systems, which increases development and production costs.

[0061] In contrast, the fluid module 34 does not rely on the use of electronics or moving mechanical parts for operation or control. This makes the module 34 reliable, repeatable, and cost-effective. A defined massage sequence (i.e., cyclic inflation / deflation of the airbags 18, 22, 26, 30) is achieved by using cascaded vented fluid amplifiers (i.e., subsystems 86, 90, 94) that are biased to follow a defined order or sequence. The sequence is further defined by using feedback zones 146, 166 that force switching of airflow at a predefined static pressure. The vented fluid amplifiers are selected to eliminate sensitivity to false switching under load and also provide the additional benefit of providing a channel for automatic deflation when operation of the pneumatic system 10 is completed.

[0062] Fig.11 and Fig.12 An assembly 500 including a fluid module 34 and a sound attenuator 504 is shown according to one embodiment. As described in more detail below, the sound attenuator 504 can reduce noise generated by air flowing through the fluid module 34 during operation of the pneumatic system 10. The assembly 500 can be advantageously used in applications of the pneumatic system 10 where quieter operation is desired (e.g., in vehicle seats, massage chairs, etc.).

[0063] The illustrated sound attenuator 504 includes a body 508 and a cover 512 movably coupled to the body 508. The cover 512 is pivotally coupled to the body 508 by a hinge 516 such that the cover 512 can be moved relative to the body 508 in an open position ( Fig.12 ) and closed position ( Fig.11 ). The body 508 and the cover 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). Therefore, the body 508, the cover 512, and the hinge 516 can be molded together in a single process. This advantageously reduces the cost of manufacturing and assembling the sound attenuator 504.

[0064] In other embodiments, the body 508 and the lid 512 may be separate components coupled together by the hinge 516, or the lid 512 may be removably coupled to the body 508. In some embodiments, the lid 512 may be secured to the body 508 in the closed position by adhesive, welding (e.g., ultrasonic or hot air welding), mechanical structure, etc., such that the lid 512 cannot be reopened. In still other embodiments, the lid 512 may be integrally formed with the body 508 in the closed position.

[0065] The body 508 of the sound attenuator 504 includes a first wall or top wall 520, and the cover 512 includes a second wall or bottom wall 524 opposite the top wall 520 when the cover 512 is in the closed position, such as Fig.11 The body 508 has first, second, third and fourth side walls or outer side walls 528A, 528B, 528C, 528D extending from the top wall 520, and the cover 512 also has a bottom wall 524 ( Figure 13-14 ) extends from the first, second, third and fourth side walls or outer side walls 532A, 532B, 532C, 532D. The first side wall 528A, 532A (or front side wall) is positioned opposite the second side wall 528B, 532B (or rear side wall). The third side wall 528C, 532C is positioned opposite the fourth side wall 528D, 532D. When the lid 512 is in the closed position ( Fig.11 ), the first side walls 528A, 532A, the second side walls 528B, 532B, the third side walls 528C, 532C and the fourth side walls 528D, 532D are generally aligned (ie, the outer surfaces of each pair of side walls are generally flush).

[0066] The body 508 includes a recess 536 in the top wall 520 that is opened by the front wall 528A. The fluid module 34 is received in the recess 536 and is 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 ways (e.g., a friction fit, one or more fasteners, an adhesive, etc.). In the illustrated embodiment, the size and shape of the recess 536 are designed so 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 connectors 46A-46E protrude beyond the front wall 528A to facilitate and ease connection (e.g., connection to Figure 1 The pneumatic source 14 and air bags 18, 22, 26, 30 shown in FIG.

[0067] Reference Fig.15 , the base 38 of the fluid module 34 and the recess 536 together define a first chamber 540. The length and width of the first chamber 540 are substantially 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. Therefore, air from the first chamber 540 can be drawn in through any one of the vents 70, 74, 78, 82 during operation of the fluid module 34, and air can also be discharged from any one of the vents 70, 74, 78, 82 into the first chamber 540 during operation of the fluid module 34. Therefore, 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.

[0068] The recess 536 is defined by inner side walls 544C, 544D extending generally from the front wall 528A toward the rear wall 528B of the body 508 and a floor 546 extending between the inner side walls 544C-D. The base 38 of the fluid module 34 includes corresponding side walls 548C, 548D extending from the lower side 552 of the base 38 and abutting the inner side walls 544C-D ( Fig.15 ). 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 surrounds the first chamber 540 and also extends between the bottom plate 546 and the bottom wall 524. In other embodiments, the second chamber 556 can completely surround the first chamber 540 on all sides.

[0069] Continue to refer to Fig.15, the second chamber 556 is in fluid communication with the first chamber 540 via a first orifice 560 extending through the side walls 544D, 548D. That is, air can flow between the first chamber 540 and the second chamber 556 through the first orifice 560. The second orifice 564 extends through the third side walls 528C, 532C. In the illustrated embodiment, the second orifice 564 is partially defined by each of the body 508 and the cover 512. In other embodiments, the second orifice 564 can be entirely disposed on the body 508 or entirely disposed on the cover 512. The second orifice 564 is in fluid communication with the surrounding environment surrounding the assembly 500. That is, air can flow between the surrounding environment and the second chamber 556 through the second orifice 564.

[0070] In operation, the pneumatic source 14 provides pressurized air to the fluid switching module 34, which operates in a manner generally described above ( Figure 1 ) in a predetermined order to inflate and deflate each of the air bags 18, 22, 26, 30. When the air bags 18, 22, 26, 30 are inflated and deflated, air can be drawn in or exhausted through the vents 70, 74, 78, 82. Fig.16 As shown, when 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 orifice 560 and enters the first portion 568 of the second chamber 556 between the inner sidewall 544D and the outer sidewalls 528D, 532D.

[0071] Continue to refer to Fig.16 , the first orifice 560 is oriented vertically relative to each of the vents 70, 74, 78, 82, which causes the airflow to change direction by about 90 degrees when flowing from the vents 70, 74, 78, 82 to the first orifice 560. The air then flows from the first portion 568 of the second chamber 556 into the second portion 572 of the second chamber 556 extending below the first chamber 540. This again causes the airflow to change direction by about 90 degrees. When entering the third portion 576 of the second chamber 556 located between the inner side wall 544C and the side walls 532C, 528C, the airflow changes direction by about 90 degrees for the third time. Finally, the air is discharged into the surrounding environment through the second orifice 564.

[0072] The chambers 540, 556 and the 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 in through one or more of the vents 70, 74, 78, 82, then as described above and Fig.16 The flow paths shown in FIG.

[0073] 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 of a plastic material having a flexural modulus of between about 1.0 megapascals (MPa) and about 3.0 MPa under ASTM D790. In some embodiments, the plastic material may have a flexural modulus of between about 1.0 MPa and about 2.0 MPa under ASTM D790. This corresponds to a relatively high flexibility, which advantageously provides the sound attenuator 504 with desirable resonant characteristics.

[0074] For example, in the illustrated embodiment, the first chamber 540 has a first volume and the second chamber 564 has a second volume greater than the first volume. Thus, 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. When airflow passes through the orifices 560, 564 and chambers 540, 556 during operation, the different resonances of the chambers 540, 556 produce destructive interference that attenuates the sound generated by the air flowing along the airflow path 54 of the fluid switching module 34. This is achieved without any active noise reduction or sound absorbing materials (e.g., foam, baffles, etc.) lining the airflow path, which tend to increase flow resistance and reduce flow velocity.

[0075] Fig.17A and Fig. 17B shows that when there is no sound attenuator 504 ( Fig.17A ) when operating the fluid switching module 34 and when coupled to the sound attenuator 504 ( Fig. 17B ) when the pressure attenuator 504 was used. In both cases, the pressurized air was delivered to the pneumatic source connector 46A at a pressure of 60 kPa. Without the sound attenuator 504, the sound output level 580A exceeded 30 decibels (dB) at all frequencies between 500 Hz and 20 kHz and exceeded 35 dB (dB) at all frequencies between 1000 Hz and 20 kHz. Fig.17A). With the use of sound attenuator 504, sound output level 580B remains below 30 dB at all frequencies below 2000 Hz and is significantly less than sound output level 580A at all frequencies above about 200 Hz. In addition, sound output level 580B remains below 40 dB at all frequencies between 20 Hz and 20 kHz. The range of 20 Hz to 20 kHz is generally recognized as the audible range of unaided human hearing ("audible range"). Therefore, in the illustrated embodiment, sound output level 580B of assembly 500 is less than 40 dB throughout the audible range.

[0076] Various features and advantages of the disclosure are set forth in the following claims.

Claims

1. A pneumatic system comprising: a passage operable to discharge compressed air; A sound attenuator, the sound attenuator comprising: a first chamber in fluid communication with the passage, the first chamber being defined by a first wall, a first surface of a second wall spaced apart from and opposite the first wall, and a sidewall extending between the first wall and the second wall, the passage opening into the first chamber through the first wall, wherein the first chamber has a volume and includes a first opening in the sidewall; and a second chamber in fluid communication with the first opening and at least partially surrounding the first chamber, wherein the second chamber is partially defined by a second surface of the second wall and the sidewall, the second surface of the second wall being disposed opposite the first surface of the second wall, wherein the second chamber has a volume and includes a second opening to exhaust air from the second chamber, wherein the volume of the first chamber is smaller than the volume of the second chamber, and 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. 2 . The pneumatic system of claim 1 , wherein the first opening extends along a first longitudinal axis and the second opening extends along a second longitudinal axis perpendicular to the first longitudinal axis.

3. The pneumatic system of claim 1, wherein the first opening and the second opening are oriented such that a direction of airflow from the first opening to the second opening changes by at least 90 degrees.

4. The pneumatic system of claim 1, wherein the passageway and the first opening are oriented such that airflow from the passageway to the first opening changes direction.

5. The pneumatic system of claim 1, wherein the first opening and the second opening are oriented such that airflow from the first opening to the second opening changes direction.

6. The pneumatic system of claim 1, wherein the different volumes of the first chamber and the second chamber produce destructive interference to attenuate noise generated by air flowing through the pneumatic system.

7. 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 and the second resonant frequency are configured to destructively interfere to attenuate noise generated by air flowing through the pneumatic system.

8. The pneumatic system of claim 1, wherein the sound attenuator is configured to attenuate noise generated by air flowing through the passage to less than 40 dB throughout the audible range.

9. The pneumatic system of claim 1, wherein the sound attenuator comprises a body including the second wall and the side wall, and wherein the second wall and the side wall define a recess to receive a fluid switching module including the passageway.

10. The pneumatic system of claim 9, further comprising a cover coupled to the body, the cover comprising a third wall spaced apart from and opposite the second wall, wherein The sidewall is a first sidewall, and the cover includes a second sidewall extending from the third wall, and the third wall and the second sidewall define the second chamber having the second wall and the first sidewall, and wherein the second opening is located in the second sidewall.

11. The pneumatic system of claim 10, wherein the cover is pivotally coupled to the body.

12. The pneumatic system of claim 10, wherein the body and the cover are separate components.

13. The pneumatic system of claim 1, wherein the second chamber completely surrounds the first chamber on all sides.

14. A pneumatic system comprising: A fluid switching module, the fluid switching module comprising: air passages, and a vent in fluid communication with the air passage; and a sound attenuator coupled to the fluid switching module, the sound attenuator being configured to attenuate noise generated by air flowing through the fluid switching module, the sound attenuator comprising: a recess configured to receive the fluid switching module, a first chamber within the recess and defined by a first wall of the fluid switching module, a second wall spaced apart from and opposite the first wall, and a pair of spaced-apart side walls extending between the first wall and the second wall, the first chamber being in fluid communication with the vent, wherein the first chamber includes a first opening in one of the pair of spaced-apart side walls, and a second chamber in fluid communication with the second opening and partially surrounding the first chamber, wherein the second chamber is partially defined by the second wall opposite the first wall, a third wall spaced apart from and opposite the second wall, and the pair of spaced-apart side walls, the second chamber including a second opening to exhaust air from the second chamber, wherein the first chamber has a first resonant frequency, wherein the second chamber has a second resonant frequency different from the first resonant frequency, and wherein the first resonant frequency and the second resonant frequency are configured to produce destructive interference to attenuate the noise, and Wherein, the first resonant frequency is at least 10% higher than the second resonant frequency.

15. The pneumatic system of claim 14, wherein the vent, the first opening, and the second opening are oriented such that airflow from the vent to the first opening changes direction in a first direction, and airflow from the first opening to the second opening changes direction in a second direction different from the first direction.

16. The pneumatic system of claim 14, wherein the first chamber has a first volume and the second chamber has a second volume different from the first volume, and wherein the different volumes of the first chamber and the second chamber produce destructive interference to attenuate noise generated by air flowing through the pneumatic system.

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