Integrated air supply unit and air pump

Abstract

An integrated air supply unit and air pump is provided. The integrated air supply unit includes a compressor housing, a pressure control unit (PCU) body, and a desiccant housing extending between the compressor housing and the PCU body. The desiccant housing defines a desiccant chamber holding a desiccant container to remove moisture from air passing through the desiccant container. A piston is slidably disposed within a piston bore of the compressor housing. The PCU body defines a plurality of fluid passages with solenoid valves selectively controlling air flow through the plurality of fluid passages. The integrated air supply unit can also include a manifold, a discharge control valve, a compressor supplying pressurized air in a first pressurized air passage, a desiccant configured to remove moisture from the pressurized air in the first pressurized air passage and supply dry pressurized air in a second pressurized air passage, a supply control valve controlling air flow between the second pressurized air passage and the manifold, and a pilot exhaust valve.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to air supply units for vehicles, such as automobiles. More particularly, the present disclosure relates to an integrated air supply unit for operating an air-lift suspension in a vehicle. BACKGROUND

[0002] Air suspension assemblies are known in the art for use in various vehicles, including automobiles. Air suspension assemblies generally include a plurality of air springs, each air spring for interconnecting a vehicle body and one of the vehicle wheels of a motor vehicle, for damping relative forces between the vehicle body and the vehicle wheels, and for adjusting the height of the motor vehicle. One example of such an air suspension assembly is disclosed in U.S. Patent No. 5,465,209 to Sammut et al. The air suspension assembly includes a compressor for filling the air springs and a plurality of valves disposed between the compressor and the air springs and controlled by a controller for regulating airflow from the compressor to the air springs.

[0003] The air suspension assembly can include an air supply unit (ASU) that combines the compressor and dryer with the exhaust control valve. A separate integrated air management module (IAMM) can include the control valve, manifold pressure sensor, and ECU in a single unit. The IAMM can communicate with the ASU through a pressure port, a boost port, and through one or more electrical connections.

[0004] Known air supply and management systems can be relatively expensive, bulky, and complex in design. Accordingly, there remains a need for low-cost improvements to such air supply and management. SUMMARY

[0005] The present disclosure also provides an integrated air supply unit. The integrated air supply unit includes a compressor housing including a piston slidably disposed within a piston bore. The integrated air supply unit also includes a pressure control unit (PCU) body defining a plurality of fluid passages and a plurality of solenoid valves configured to selectively control airflow through a corresponding fluid passage of the plurality of fluid passages. The integrated air supply unit also includes a desiccant housing extending between the compressor housing and the PCU body and defining a desiccant chamber configured to hold a desiccant container to remove moisture from air passing through the desiccant container.

[0006] The present disclosure provides an integrated air supply unit including a manifold including at least one fluid passageway; a discharge control valve configured to selectively control airflow from the manifold to a supply port to supply pressurized air to an external device; a compressor configured to supply pressurized air in a first pressurized air passageway; a desiccant configured to remove moisture from the pressurized air in the first pressurized air passageway and supply dry pressurized air in a second pressurized air passageway; and a supply control valve configured to selectively control airflow between the second pressurized air passageway and the manifold. The integrated air supply unit further includes a piloted exhaust valve. The piloted exhaust valve includes an inlet passageway and a discharge passageway and is configured to control airflow between the inlet passageway and the discharge passageway. The piloted exhaust valve includes an exhaust valve bore having a semi-closed end, a tubular portion extending from the semi-closed end and into the exhaust valve bore, and a stepped piston slidably movable within the exhaust valve bore. The stepped piston divides the exhaust valve bore between a first chamber and a second chamber. The stepped piston includes a control surface defining an end of the first chamber and an underside surface opposite the control surface. The stepped piston further includes a piston extension extending into the tubular portion. The piston extension includes a sealing face configured to selectively seal against a valve seat to block fluid communication between the inlet passageway and the discharge passageway. The integrated air supply unit further includes a first exhaust control valve configured to selectively control flow of pressurized air from the second pressurized air passageway to the first chamber of the piloted exhaust valve. The integrated air supply unit further includes a second exhaust control valve configured to selectively control flow of pressurized air between the first chamber and the second chamber of the piloted exhaust valve. The inlet passageway of the piloted exhaust valve is in direct fluid communication with the first pressurized air passageway.

[0007] The present disclosure also provides an integrated air supply unit including a manifold including at least one fluid passageway; a discharge control valve configured to selectively control airflow from the manifold to a supply port to supply pressurized air to an external device; a compressor configured to supply pressurized air in a first pressurized air passageway; a desiccant configured to remove moisture from the pressurized air in the first pressurized air passageway and supply dry pressurized air in a second pressurized air passageway; and a supply control valve configured to selectively control airflow between the second pressurized air passageway and the manifold. The integrated air supply unit also includes a pilot exhaust valve. The pilot exhaust valve includes an inlet passageway and a discharge passageway and is configured to control airflow between the inlet passageway and the discharge passageway. The pilot exhaust valve includes an exhaust valve bore having a semi-closed end, a tubular portion extending from the semi-closed end and into the exhaust valve bore, and a stepped piston slidably movable within the exhaust valve bore. The stepped piston divides the exhaust valve bore between a first chamber and a second chamber. The stepped piston includes a control surface defining an end of the first chamber and an underside surface opposite the control surface. The stepped piston includes a piston extension extending into the tubular portion. The piston extension includes a sealing face configured to selectively seal against a valve seat to block fluid communication between the inlet passageway and the discharge passageway. The integrated air supply unit also includes an exhaust control valve configured to selectively control air flow between the first chamber and the second chamber of the pilot exhaust valve. The first chamber of the pilot exhaust valve is in direct fluid communication with the second pressurized air passageway. The second chamber of the pilot exhaust valve is in direct fluid communication with an exhaust passageway open to atmosphere. The inlet passageway of the pilot exhaust valve is in direct fluid communication with the first pressurized air passageway.

[0008] The present disclosure also provides an air pump. The air pump includes a compressor housing and a sliding member. The compressor housing defines a stepped bore including a low pressure bore having a first cross-sectional area and a high pressure bore coaxial with the low pressure bore and having a second cross-sectional area less than the first cross-sectional area. The sliding member includes a low pressure piston slidably disposed in the low pressure bore and a high pressure piston slidably disposed in the high pressure bore. The sliding member defines a hollow chamber between the low pressure piston and the high pressure piston. The air pump also includes a hinged member disposed within the hollow chamber of the sliding member and pivotably coupled to the sliding member by a wrist pin. BRIEF DESCRIPTION OF DRAWINGS

[0009] Further details, features and advantages of the design of the present invention result from the following description of embodiments examples with reference to the associated drawings.

[0010] FIG. 1A A perspective view of an integrated air supply unit of the present disclosure is shown;

[0011] FIG. 1B A top view of an integrated air supply unit of the present disclosure is shown; FIG. 1A

[0012] FIG. 1C A side view of an integrated air supply unit of the present disclosure is shown; FIG. 1A

[0013] FIG. 2 An exploded view of an integrated air supply unit of the present disclosure is shown; FIG. 1A

[0014] FIG. 3A A perspective view of a compressor housing of an integrated air supply unit of the present disclosure is shown; FIG. 3B

[0015] A perspective view of a desiccant housing of an integrated air supply unit of the present disclosure is shown; FIG. 4A

[0016] A partial cutaway view of a desiccant housing of the present disclosure is shown; FIG. 4B FIG. 4A A perspective view of a desiccant housing of the present disclosure is shown, partially transparent to show internal components;

[0017] FIG. 4C FIG. 4A A perspective view of a desiccant housing of the present disclosure is shown, partially transparent to show internal components;

[0018] FIG. 5 A perspective view of a pressure control unit (PCU) body is shown, partially transparent to show internal components;

[0019] FIG. 6A A perspective view of a dual piston assembly of an integrated air supply unit of the present disclosure is shown;

[0020] FIG. 6B A top view of a dual piston assembly of the present disclosure is shown; FIG. 6A

[0021] A perspective view of a dual piston assembly of the present disclosure is shown, with additional components attached to the dual piston assembly; FIG. 6C FIG. 6A A partial view of a reed valve including a dual piston assembly of the present disclosure is shown;

[0022] FIG. 6D FIG. 6A A partial view of a reed valve including a dual piston assembly of the present disclosure is shown;

[0023] FIG. 7A ​​​​​​​A first cross-sectional view of a compressor assembly of an integrated air supply unit of the present disclosure is shown;

[0024] FIG. 7B A second cross-sectional view of the compressor assembly is shown through a plane that is perpendicular to the plane of the first cross-sectional view; FIG. 7A

[0025] FIG. 8A to FIG. 8C Each shows a cross-sectional view of a dryer assembly of an integrated air supply unit of the present disclosure;

[0026] FIG. 9 A schematic view of a first arrangement of an integrated air supply unit of the present disclosure is shown; and

[0027] FIG. 10 A schematic view of a second arrangement of an integrated air supply unit of the present disclosure is shown. DETAILED DESCRIPTION

[0028] The present application will be described in detail with reference to the following embodiments in conjunction with the accompanying drawings.

[0029] FIG. 1A to FIG. 1C Various views of an integrated air supply unit (IASU) 20 are shown that can be installed in a vehicle for operating an air lift suspension in the vehicle. The IASU 20 of the present disclosure can combine a compressor, a dryer, an exhaust control valve, and an integrated air management module (IAMM) in an integrated assembly. The IASU 20 of the present disclosure can be more compact and have a lighter weight than conventional air supply units.

[0030] The IASU 20 includes a mounting bracket 22 to which the remaining components are attached. The mounting bracket 22 can include a base such as a floor panel and mounting structures such as tabs, flanges, holes, etc. for attaching to one or more vehicle structures. The mounting bracket 22 can be customized for a particular vehicle application, while the other components of the IASU 20 can be standardized. The IASU 20 also includes a compressor housing 24, a pressure control unit (PCU) body 26, a desiccant housing 28, a motor assembly 30, an electronic control unit (ECU) 32, an exhaust muffler 38, and an intake hose 46.

[0031] FIG. 2 ​An exploded view of the IASU 20 is shown, including tie rod bolts 34 that join the compressor housing 24, the desiccant housing 28, the motor assembly 30, and the PCU body 26. Three isolation mounts 36 are attached to the mounting bracket 22 for holding corresponding compressor housings 24 and PCU bodies 26 while preventing vibration from the compressor housing 24 from being transmitted to the mounting bracket 22. It should be understood that this is merely an example configuration, and the mounting bracket 22 can have a different size or shape, and the IASU 20 can include any number of any configuration of isolation mounts 36.

[0032] FIG. 2 Also shown is an exhaust muffler 38 attached to the compressor housing 24, and a dual piston assembly 40 that fits within a stepped bore 42 of the compressor housing 24. The stepped bore 42 is surrounded by a low pressure chamber cover 44 that overlies and is attached to the compressor housing 24 with screws on a corresponding face of the compressor housing 24. An intake hose barb 48 is threaded into the compressor housing 24 for fluidly coupling to an intake hose 46. A service cover 50 is threaded into a corresponding port (not shown in FIG. 2

[0033] The PCU body 26 can include a block of material, such as machined aluminum, that defines a plurality of fluid passages (not shown in FIG. 2 The PCU body 26 can include a plurality of solenoid bores 25, each solenoid bore 25 housing a corresponding spool 27. The spools 27 can each cooperate with a corresponding fluid passage to form a solenoid valve configured to selectively control airflow through the corresponding fluid passage. The PCU body 26 also defines a plurality of air ports 29 that provide fluid communication to transmit air to / from external devices, such as air springs and / or external air reservoirs.

[0034] A pilot exhaust valve 52 is coupled to the PCU body 26 and fits within a corresponding exhaust valve bore 54 of the desiccant housing 28. The compressor housing 24 defines a motor bore 56 for housing the motor assembly 30. The compressor housing 24 also defines a desiccant bore 58 for housing the desiccant housing 28. Each of the motor bore 56 and the desiccant bore 58 are defined in a common face of the compressor housing 24, adjacent to one another, and each extend perpendicular to the stepped bore 42.

[0035] The motor assembly 30 includes a motor shaft 60 having a main shaft bearing 62 disposed about the motor shaft 60 and an eccentric bearing 64 on an end of the motor shaft 60. A power connector 66 extends from an end of the motor assembly 30 opposite the eccentric bearing 64 and through a corresponding bore in the PCU body 26 for insertion into the ECU 32. ​

[0036] FIG. 3A and FIG. 3B Additional details of the compressor housing 24 are shown, including various integrally formed cooling fins, and illustrating the attachment of the air intake hose barb 48 and service cover 50 . FIG. 3B The compressor housing 24 is shown partially transparent to illustrate internal components including the low-pressure outlet check valve LOCV and the high-pressure outlet check valve HOCV integrated therein.

[0037] FIG. 4A to FIG. 4C Various views of the desiccant housing 28 are shown, which includes radial O-ring seals 55, 149, 151, 163 for sealing the exhaust valve hole 54 and passageways 148, 150, 162 on the common face of the PCU body 26, respectively. A desiccant container 68 containing desiccant material and a filter is disposed within the desiccant housing 28. The desiccant housing 28 defines a through-bore 150 that extends between and fluidly connects the compressor housing 24 and the PCU body 26. The through-bore 150 may also be referred to as a boost passage. The desiccant housing 28 also defines an exhaust passage 37 for conveying exhaust air to the exhaust muffler 38. In FIG. 4B A compressor-side radial O-ring seal 152 is shown for sealing the through hole 150 of the desiccant housing 28 to the compressor housing 24 .

[0038] FIG. 5 Details of a pressure control unit (PCU) body 26 are shown, including a solenoid bore 25 and a plurality of air ports 29 all disposed on a common face of the PCU body 26 .

[0039] FIG. 6A to FIG. 6D Various views are shown of a dual piston assembly 40 including a sliding member 70. The sliding member 70 includes a low pressure piston 74 and a high pressure piston 76 on opposite ends thereof.

[0040] The sliding member 70 also includes a central portion extending between the low pressure piston 74 and the high pressure piston 76 and defines a central chamber 72 between the low pressure piston 74 and the high pressure piston 76. The sliding member 70 can be made of cast aluminum and / or machined aluminum, although other materials can be used. The low pressure piston 74 includes two reed-type valves 78 on its surface and the two reed-type valves 78 are held thereon by rivets 79. The reed-type valves can allow air to flow through the low pressure piston 74 in one direction while blocking air flow in the opposite direction. The high pressure piston 76 can also include one or more reed-type valves 78 and the reed-type valves 78 can be held on the low pressure piston 74 and / or the high pressure piston 76 by other fastening means, such as using one or more fasteners, adhesives, and / or by welding.

[0041] Still referring to FIG. 6A to FIG. 6D The dual piston assembly 40 also includes a hinge member 80 disposed in the central chamber 72. The hinge member 80 defines a large bore 82 that holds a steel wear sleeve 84. The steel wear sleeve 84 can be secured within the large bore 82, for example, by a press fit. It should be appreciated that the steel wear sleeve 84 is not necessarily made of steel and can include one or more other materials suitable for this application.

[0042] The hinge member 80 can be made of cast aluminum, although other materials can be used. The steel wear sleeve 84 defines a cylindrical inner surface 86 for press-fitting the eccentric bearing 64. The hinge member 80 is pinned for axial movement with the sliding member 70 by a wrist pin 90 and a pin bushing 92. The wrist pin 90 passes through the sliding member 70 and allows the sliding member 70 to hinge through a defined arc length. The eccentric bearing 64, the wrist pin 90, and the hinge member 80 together convert the rotational motion of the motor shaft 60 to the reciprocating linear motion of the sliding member 70.

[0043] FIG. 7A And FIG. 7B A cross-section of the compressor assembly within the compressor housing 24 of the IASU 20 is shown. As FIG. 7AAs shown, the stepped bore 42 includes a low pressure bore 42l and a high pressure bore 42h that are coaxial with one another. The low pressure bore 42l has a first cross-sectional area, and the high pressure bore 42h has a second cross-sectional area that is smaller than the first cross-sectional area. In some embodiments, and as shown, the low pressure bore 42l and the high pressure bore 42h each have a circular cross-section, and the first cross-sectional area of the low pressure bore can be represented by a circle having a diameter that is larger than a diameter of the high pressure bore 42h. A low pressure piston 74 is slidably disposed in the low pressure bore 42l, and a high pressure piston 76 is slidably disposed in the high pressure bore 42h. The compressor assembly of the IASU 20 of the present disclosure provides a two-stage air pump (compressor) having a one-piece sliding member 70. The sliding member 70 includes the low pressure piston 74 and the high pressure piston 76 that are coupled together and configured to slide along a common axis through the stepped bore 42.

[0044] The low pressure piston 74 includes a first sealing member 75 incorporated therein for providing an air-tight seal with the low pressure bore 42l, and the high pressure piston 76 includes a second sealing member 77 incorporated therein for providing an air-tight seal with the high pressure bore 42h. The sealing members 75, 77 can be disposed circumferentially around the corresponding one of the pistons 74, 76, as shown. Either or both of the sealing members 75, 77 can provide an air-tight seal for pressures in the range of 0-50 bar. FIG. 7A The low pressure piston 74 includes a first sealing member 75 incorporated therein for providing an air-tight seal with the low pressure bore 42l, and the high pressure piston 76 includes a second sealing member 77 incorporated therein for providing an air-tight seal with the high pressure bore 42h. The sealing members 75, 77 can be disposed circumferentially around the corresponding one of the pistons 74, 76, as shown. Either or both of the sealing members 75, 77 can provide an air-tight seal for pressures in the range of 0-50 bar.

[0045] FIG. 7A A motor shaft 60 is also shown that includes an eccentric shaft extension 94 about which the eccentric bearing 64 is disposed. The eccentric bearing 64 can be fixed to the eccentric shaft extension 94, for example, by a press fit. The eccentric shaft extension 94 is offset a distance from the axis of rotation of the motor shaft 60. For example, the eccentric shaft extension 94 can be offset 2-6 millimeters from the axis of rotation of the motor shaft 60. FIG. 7A A compressor housing 24 is also shown that defines a motor bore 56 that is transverse to the stepped bore 42. A main bearing 62 is disposed in and supports in the motor bore 56 for supporting the motor shaft 60 while allowing the motor shaft 60 to rotate. The compressor housing 24 also includes a boss 96 that is transverse to the stepped bore 42 and co-linear with the motor bore 56. The boss 96 is configured to house and retain the motor housing 31 of the motor assembly 30. A sealing member 97, such as an O-ring, extends around the boss 96 and seals against the motor housing to provide a seal therebetween.

[0046] FIG. 7AAlso shown is an interface between the compressor housing 24 and the desiccant housing 28, including an outlet check valve 100 comprising an elastomeric member 101 configured to selectively seal against a seating surface 102 of the compressor housing 24 and selectively block airflow through a fluid passage 104 in fluid communication with the end of the high-pressure bore 42h. A coil spring 106 biases the elastomeric member 101 against the seating surface 102 of the compressor housing 24. The outlet check valve 100 can allow air to flow out of the compressor housing 24 and into the desiccant housing 28 while blocking airflow in the opposite direction.

[0047] FIG. 7B Shows the cross section perpendicular to FIG. 7A A second cross-sectional view of the compressor assembly is provided in the plane of the first cross-sectional view. FIG. 7B As shown, the low pressure piston 74 includes two passages 98 extending therethrough. Each passage 98 can be connected to a corresponding reed valve 78 ( FIG. 7B not shown) covered.

[0048] FIG. 8A to FIG. 8C A cross section of the desiccant housing 28 of the IASU 20 is shown. The desiccant housing 28 includes a desiccant-type dryer assembly to remove moisture from the incoming air and replenish the desiccant from the outgoing air. The desiccant housing 28 may be constructed of injection molded plastic, although other materials may also be used. FIG. 8A As shown, a desiccant housing 28 extends between the compressor housing 24 and the PCU body 26 .

[0049] Desiccant housing 28 defines a desiccant chamber 110 that holds desiccant container 68 therein. Desiccant container 68 has a cup-like cylindrical shape, and desiccant chamber 110 has a cylindrical shape that is large enough to create an airflow gap between desiccant container 68 and its inner surface. Desiccant container 68 includes at least one perforated holder 112 having a thin cylindrical shape and at least one filter 113 having a thin cylindrical shape for holding desiccant material therein.

[0050] A desiccant spring 116 is located at one end of the desiccant container 68 and presses against the end of the desiccant hole 58 in the compressor housing 24. The desiccant spring 116 can be configured to exert a force on the desiccant material in the desiccant container 68 sufficient to keep the desiccant material firmly compacted during periods of high flow. A desiccant retainer 118 having a cup shape is located between the compressor housing 24 and the desiccant spring 116. The desiccant retainer 118 includes an annular flange 120 with an O-ring seal 122 located between the annular flange 120 and the compressor housing 24 to provide an airtight seal therebetween. FIG. 4BAs best shown, the desiccant retainer 118 includes an end surface defining a plurality of air intake holes 119 for transmitting air from the compressor housing 24 into the desiccant container 68.

[0051] Referring back to FIG. 8A , the desiccant housing 28 defines a deflection hole 130 to provide an exhaust air flow out of the desiccant chamber 110. The deflection hole 130 can extend parallel to and offset from a central axis of the desiccant chamber 110. A pilot exhaust valve 52 controls the exhaust air flow out of the desiccant chamber 110 via the deflection hole 130. The desiccant housing 28 defines an exhaust valve bore 54 having a cup shape including a semi-closed end 53. A tubular portion 139 extends from the semi-closed end 53 and into the exhaust valve bore 54.

[0052] The pilot exhaust valve 52 includes an inlet passage 131 and a discharge passage 132. In some embodiments, and as FIG. 8A shown, the deflection hole 130 of the desiccant housing 28 defines the inlet passage 131 of the pilot exhaust valve 52. However, the pilot exhaust valve 52 can have another configuration or arrangement, which can be in different portions of the desiccant housing 28 or spaced apart from the desiccant housing 28.

[0053] The pilot exhaust valve 52 includes a stepped piston 134 disposed within and slidably movable within the exhaust valve bore 54. The stepped piston 134 includes a large diameter portion 135 that spans the exhaust valve bore 54 and divides the exhaust valve bore 54 into a first chamber 146 and a second chamber 147, the first chamber 146 extending between the large diameter portion 135 and the semi-closed end 53. The large diameter portion 135 of the stepped piston 134 includes a control surface 136 defining an end of the first chamber 146. The large diameter portion 135 of the stepped piston 134 also includes an undersurface 137 opposite the control surface 136. The stepped piston 134 further includes a piston extension 138 extending from the control surface 136 and into the tubular portion 139. The piston extension 138 includes a sealing face 140 configured to selectively seal against a valve seat 141, thereby blocking fluid communication between the inlet passage 131 and the discharge passage 132. The large diameter portion 135 of the stepped piston 134 includes a first groove 144 holding a respective O-ring configured to seal against the exhaust valve bore 54. The piston extension 138 of the stepped piston 134 includes a second groove 145 holding a respective O-ring configured to seal against an inner surface of the tubular portion 139.

[0054] In some embodiments, and as FIG. 8AAs shown, an elastomeric seal 142 is disposed over the sealing face 140 to provide an air-tight seal with the valve seat 141. A valve spring 143 is disposed within the second chamber 147 and is configured to bias the sealing face 140 of the stepped piston 134 against the valve seat 141. This can make the pilot exhaust valve 52 a normally closed valve. The valve spring 143 can act on a surface of the PCU body 26, such as FIG. 8A As shown, although other physical configurations are possible.

[0055] In operation, the stepped piston 134 is configured to move away from the semi-closed end 53 in response to the force of the air pressure in the first chamber 146 acting on the control surface 136 overcoming the force of the first air pressure in the second chamber 147 acting on the lower surface 137 and the biasing force of the valve spring 143, thereby causing the sealing face 140 to be pulled away from the valve seat 141 and providing fluid communication between the inlet passage 131 and the exhaust passage 132.

[0056] In some embodiments and as shown, for example, in FIG. 10 the second chamber 147 of the pilot exhaust valve 52 is in fluid communication with the exhaust passage 37 to atmosphere.

[0057] In some embodiments, the stepped piston 134 can have an area ratio between the lower surface 137 and the sealing face 140 that can be in the range of 8 to 11. In other words, the area of the lower surface 137 can be 8 to 11 times the area of the sealing face 140.

[0058] The desiccant housing 28 also defines a control passage 148 configured to provide fluid communication between the PCU body 26 and the first chamber 146 for the transfer of air to control the operation of the pilot exhaust valve 52.

[0059] As also shown, for example, in FIG. 8A The desiccant housing 28 also defines a through-hole 150 configured to provide direct fluid communication between the compressor housing and the PCU body 26. The through-hole 150 is sealed at one end by a first radial O-ring seal 151 against the PCU body 26. The opposite end of the through-hole 150 is sealed by a second radial O-ring seal 152 against the compressor housing 24. The through-hole 150 can provide pneumatic connections between a boost solenoid in the PCU body 26 and a low pressure outlet check valve, LOC V, and a high pressure inlet check valve, HICV, in the compressor housing 24.

[0060] FIG. 8B A cross-section of the desiccant assembly of the IASU 20 is shown through a plane parallel to and spaced apart from the cross-section shown in FIG. 8A As shown, for example, in FIG. 8BAs shown in FIG, the desiccant housing 28 includes a protrusion 160 defining a through-hole 162. The through-hole 162 may extend parallel to and offset from the central axis of the desiccant chamber 110. A radial O-ring seal 163 is disposed on the protrusion 160 of the desiccant housing 28 around the through-hole 162 and is configured to fit within a corresponding recess 169 in the surface of the PCU body 26 to seal therewith.

[0061] Desiccant container 68 includes a tubular protrusion 164 configured to fit into through-hole 162 with a sealing fit to provide fluid communication between its interior space and a corresponding recess 169 in PCU body 26 via through-hole 162. An O-ring 168 is disposed around tubular protrusion 164 and is configured to seal with a corresponding step 166 in protrusion 160 of desiccant housing 28.

[0062] FIG. 8C The dryer assembly of the IASU 20 is shown passing through the FIG. 8A and FIG. 8B The cross sections are parallel and spaced apart from each other. FIG. 8C As shown, the desiccant housing 28 defines a guide hole 170 that is large enough to serve as a guide for one of the tie bolts 34 that physically hold the compressor housing 24 to the PCU body 26. More specifically, the guide hole 170 in the desiccant housing 28 is aligned with a first bolt hole 172 in the compressor housing 24 and a threaded hole 174 in the PCU body 26 to provide a sufficiently strong holding force between the compressor housing 24 and the PCU body 26.

[0063] FIG. 9 A schematic diagram of a first arrangement 320 of the IASU 20 is shown. FIG. 9 As shown, the first arrangement 320 includes four supply ports 322, 324, 326, and 328, including a left front supply port 322, a right front supply port 324, a left rear supply port 326, and a right rear supply port 328. Each of the supply ports 322, 324, 326, and 328 is fluidly coupled to supply air to a corresponding air spring 323, 325, 327, and 329, including a left front air spring 323, a right front air spring 325, a left rear air spring 327, and a right rear air spring 329. Each of the air springs 323, 325, 327, and 329 can be connected to a corresponding wheel of the vehicle. In some embodiments, an auxiliary pressure relief valve (APR) can be connected to the air line of one or more of the air springs 323, 325, 327, and 329.

[0064] The first arrangement 320 also includes a bleed control valve 330, 332, 334, 336 corresponding to each of the air springs 323, 325, 327, 329. Each of the bleed control valves 330, 332, 334, 336 is configured to selectively control airflow from a manifold 338 to a corresponding supply port 322, 324, 326, 328 for supplying pressurized air to an external device, such as a corresponding one of the air springs 323, 325, 327, 329. The manifold 338 includes at least one fluid passageway. In some embodiments, the manifold 338 can include multiple passageways in fluid communication with one another, such as holes in the PCU body 26.

[0065] Each of the bleed control valves 330, 332, 334, 336 can be a normally closed solenoid valve. The bleed control valves 330, 332, 334, 336 can include a left front control valve 330 that controls airflow to and from the left front air spring 323 via the left front supply port 322, a right front control valve 332 that controls airflow to and from the right front air spring 325 via the right front supply port 324, a left rear control valve 334 that controls airflow to and from the left rear air spring 327 via the left rear supply port 326, and a right rear control valve 336 that controls airflow to and from the right rear air spring 329 via the right rear supply port 328. The left front control valve 330 and the right front control valve 332 are each fluidly connected to a front side air passageway 340, and the left rear control valve 334 and the right rear control valve 336 are each fluidly connected to a rear side air passageway 341.

[0066] The front side air passageway 340 is fluidly connected to the manifold 338 via a front side check valve 342 that provides airflow from the manifold 338 to the front side air passageway 340 while blocking airflow in the opposite direction. The front side air passageway 340 is also fluidly connected to the manifold 338 via a front side orifice 344 that provides a limited amount of airflow between the manifold 338 and the front side air passageway 340 in either direction. The rear side air passageway 341 is fluidly connected to the manifold 338 via a rear side check valve 346 that provides airflow from the manifold 338 to the rear side air passageway 341 while blocking airflow in the opposite direction. The rear side air passageway 341 is also fluidly connected to the manifold 338 via a rear side orifice 348 that provides a limited amount of airflow between the manifold 338 and the rear side air passageway 341 in either direction.

[0067] The reservoir 310 is fluidly connected to FIG. 9The reservoir port 312 in the first arrangement 320 of the IASU 20 is shown in FIG. The reservoir 310 may be external to the IASU 20, such as FIG. 9 Alternatively, the reservoir 310 may be integrally constructed with the IASU 20. At least one reservoir valve 350, 352 is configured to selectively provide fluid communication between the reservoir port 312 and the manifold 338. In some embodiments, and as FIG. 9 As shown, at least one reservoir valve 350, 352 includes a first reservoir valve 350 and a second reservoir valve 352 arranged in parallel, wherein the reservoir valves 350, 352 each have different flow characteristics. For example, the first reservoir valve 350 can be relatively small to allow it to open at a high delta pressure between the reservoir 310 and the manifold 338 to balance the pressure therebetween, and the second reservoir valve 352 can be substantially larger than the first reservoir valve 350 to allow a relatively high gas flow rate therethrough.

[0068] The first arrangement 320 of the IASU 20 also includes a manifold pressure sensor 354 that measures the pressure in the manifold 338. The first arrangement 320 of the IASU 20 also includes an electronic control unit (ECU) 32 that is configured to control several electrical devices, such as the control valves 330, 332, 334, 336, 350, 352, 376, 380, 394, 396 and the electric motor 362, via corresponding electrical conductors 356. The ECU 32 may also monitor one or more sensors, such as the manifold pressure sensor 354 and position sensors on one or more of the air springs 323, 325, 327, 329. The ECU 32 may exhaust to atmosphere via an external exhaust port 314.

[0069] The first arrangement 320 of the IASU 20 also includes a compressor 360 that includes an electric motor 362, a low-pressure air pump 364, and a high-pressure air pump 366. The compressor 360 is configured to supply pressurized air in a first pressurized air passage 370. One or both of the air pumps 364, 366 may include a piston driven by the electric motor 362 and configured to supply pressurized air in the first pressurized air passage 370. The compressor 360 may include the dual-piston assembly 40 of the present disclosure. In some embodiments, and as FIG. 9As shown, intermediate air passage 368 connects low-pressure air pump 364 and high-pressure air pump 366. Low-pressure air pump 364 draws air from air inlet 316 and discharges it at a higher pressure into intermediate air passage 368. Low-pressure air pump 364 includes a low-pressure inlet check valve LICV and a low-pressure outlet check valve LOCV. High-pressure air pump 366 draws air from intermediate air passage 368 and discharges it at a higher pressure into first pressurized air passage 370. High-pressure air pump 366 includes a high-pressure inlet check valve HICV and a high-pressure outlet check valve 100.

[0070] The first arrangement 320 of the IASU 20 also includes a dryer 372 configured to remove moisture from the pressurized air in the first pressurized air passage 370 and to supply dry pressurized air in the second pressurized air passage 374. In some embodiments, the dryer 372 may include FIG. 8A to FIG. 8C For example, the desiccant housing 28 may include a desiccant housing 28 defining a desiccant chamber 110 that holds a desiccant material, wherein the desiccant material is disposed in an airflow path between the first pressurized air passage 370 and the second pressurized air passage 374 for removing moisture from air passing between the first pressurized air passage 370 and the second pressurized air passage 374.

[0071] The supply control valve 376 is configured to selectively control the air flow between the second pressurized air passage 374 and the manifold 338. The supply control valve 376 may be a normally closed solenoid valve. FIG. 9 As shown in FIG, a flow control orifice 378 is provided in the second pressurized air passage 374 to restrict air flow therethrough.

[0072] In some embodiments, and as FIG. 9 As shown, the boost valve 380 provides selective fluid communication between the storage portion port 312 and the inlet of the compressor 360. The inlet of the compressor 360 can be an intermediate air passage 368. Alternatively, the inlet of the compressor 360 can be fluidically connected to the air inlet of the low-pressure air pump 364. However, this configuration may require an additional check valve (not shown) to prevent the pressurized air from the boost valve 380 from leaking from the air inlet 316. The boost check valve 382 is provided in the boost passage 384 between the boost valve 380 and the intermediate air passage 368, and is configured to allow air flow from the storage portion 310 to the inlet of the compressor 360 while blocking air flow in the opposite direction. The boost passage 384 may include the through hole 150 described elsewhere in this disclosure.

[0073] The third pressurized air passage 388 is fluidly connected to the second pressurized air passage 374 between the flow control orifice 378 and the supply control valve 376 via an exhaust check valve 390. The exhaust check valve 390 allows air flow from the second pressurized air passage 374 into the third pressurized air passage 388 while blocking air flow in the opposite direction. The third pressurized air passage 388 can include an accumulator 392, which can be a hollow volume in the compressor housing 24.

[0074] The first arrangement 320 of the IASU 20 also includes a pilot exhaust valve 52 including an inlet passage 131 and a discharge passage 132 and configured to control air flow between the inlet passage 131 and the discharge passage 132. The pilot exhaust valve 52 can include FIG. 8A The pilot exhaust valve 52 includes an inlet passage 131 and a discharge passage 132 and is configured to control air flow between the inlet passage 131 and the discharge passage 132. The pilot exhaust valve 52 can include a stepped piston 134 disposed within an exhaust valve bore 54 having a semi-closed end 53 and a tubular portion 139 extending from the semi-closed end 53 and into the exhaust valve bore 54. The stepped piston 134 divides the exhaust valve bore 54 between a first chamber 146 and a second chamber 147. The stepped piston 134 includes a control surface 136 defining an end of the first chamber 146. The stepped piston 134 also includes an undersurface 137 opposite the control surface 136. The stepped piston 134 also includes a piston extension 138 extending from the control surface 136 and into the tubular portion 139. The piston extension 138 includes a sealing face 140 configured to selectively seal against a valve seat 141, thereby blocking fluid communication between the inlet passage 131 and the discharge passage 132. The pilot exhaust valve 52 also includes a valve spring 143 disposed within the second chamber and configured to bias the sealing face 140 of the stepped piston 134 toward the valve seat 141.

[0075] The stepped piston 134 is configured to move away from the semi-closed end 53 in response to air pressure in the first chamber 146 acting on the control surface 136 overcoming the sum of the force of the first air pressure in the second chamber 147 acting on the undersurface 137 and the biasing force of the valve spring 143, thereby causing the sealing face 140 to be pulled away from the valve seat 141 and providing fluid communication between the inlet passage 131 and the discharge passage 132.

[0076] In some embodiments, and as shown in FIG. 9 The inlet passage 131 of the pilot exhaust valve 52 can be in direct fluid communication with the first pressurized air passage 370 without an obstruction or valve therebetween. In some embodiments, and as shown inFIG. 9 As shown, the discharge passage 132 of the pilot exhaust valve 52 can be in direct fluid communication with ambient atmosphere via the exhaust passage 37 and the exhaust muffler 38, and there is no valve in between. In some embodiments, and as shown in FIG. 3, a flow restrictor such as an orifice 397 is provided in the exhaust passage 37, between the discharge passage 132 of the pilot exhaust valve 52 and the exhaust muffler 38, for restricting the flow rate therethrough. FIG. 9

[0077] The first arrangement 320 of the IASU 20 further includes a first exhaust control valve 394 configured to selectively control the flow of pressurized air from the second pressurized air passage 374 to the first chamber 146 of the pilot exhaust valve 52. The first exhaust control valve 394 can be a normally closed solenoid valve. In some embodiments, and as shown in FIG. 3, the first exhaust control valve 394 can selectively control the air flow between the third pressurized air passage 388 and a first control air passage 393 in fluid communication with the first chamber 146 of the pilot exhaust valve 52. FIG. 9

[0078] The first arrangement 320 of the IASU 20 further includes a second exhaust control valve 396 configured to selectively control the flow of pressurized air between the first chamber 146 and the second chamber 147 of the pilot exhaust valve 52. The second exhaust control valve 396 can be a normally open solenoid valve. In some embodiments, and as shown in FIG. 3, the second exhaust control valve 394 can selectively control the air flow between the first control air passage 393 and a second control air passage 395 in fluid communication with the second chamber 147 of the pilot exhaust valve 52. FIG. 9

[0079] In operation, the exhaust control valves 394, 396 can control the operation of the pilot exhaust valve 52, and thus the flow of air discharged from the first pressurized air passage 370.

[0080] FIG. 10 A schematic view showing a second arrangement 420 of the IASU 20 is shown. The second arrangement 420 for the IASU 20 can be similar or identical to the first arrangement 320 of the IASU 20 shown in FIG. 3, with some variations described herein. FIG. 9

[0081] ​​​​The second arrangement 420 of the IASU 20 includes a first check valve 430 disposed in the second pressurized air passage 374 between the dryer 372 and the supply control valve 376 and configured to allow airflow from the manifold 338 to the dryer 372 while blocking airflow in the opposite direction. A bypass passage 432 provides fluid communication between the manifold 338 and the second pressurized air passage 374 around the supply control valve 376 and the first check valve 430. A second check valve 434 is disposed in the bypass passage 432 and configured to allow airflow from the second pressurized air passage 374 to the manifold 338 while blocking airflow in the opposite direction.

[0082] In the second arrangement 420 of the IASU 20, and as shown in FIG. 4B, the third pressurized air passage 388 is fluidly connected to the second pressurized air passage 374 between the first check valve 430 and the supply control valve 376. The third pressurized air passage 388 is also fluidly connected directly to the first chamber 146 of the pilot exhaust valve 52, with no control valve in between. FIG. 10

[0083] In the second arrangement 420 of the IASU 20, and as shown in FIG. 4B, the inlet passage 131 of the pilot exhaust valve 52 is in fluid communication with the first pressurized air passage 370. The exhaust passage 132 of the pilot exhaust valve 52 is fluidly connected to the exhaust passage 37, as in the first arrangement 320 of the IASU 20. However, unlike the first arrangement 320 of the IASU 20, the second chamber 147 of the pilot exhaust valve 52 is also fluidly coupled to the exhaust passage 37. FIG. 10

[0084] The second arrangement 420 of the IASU 20 includes only one exhaust control valve 396. The exhaust control valve 396 is configured to selectively control the flow of pressurized air between the first chamber 146 and the second chamber 147 of the pilot exhaust valve 52. As shown in FIG. 4B, the exhaust control valve 396 is fluidly connected to the first chamber 146 of the pilot exhaust valve 52 via the third pressurized air passage 388. The exhaust control valve 396 is also fluidly connected to the second chamber 147 of the pilot exhaust valve 52 via the exhaust passage 37. The exhaust control valve 396 must be a normally open solenoid valve. FIG. 10 FIG. 10

[0085] The foregoing description is not intended to be exhaustive or to limit the disclosure to the precise embodiments disclosed. Various elements or features of a particular embodiment are generally not limited to that particular embodiment, and can be interchanged with other elements or features on that particular embodiment, and on others, even if not specifically shown or described. Various elements or features of an embodiment can also be changed in many ways. Such changes not being viewed as a departure from the disclosure, and all such modifications being intended to be included within the scope of the disclosure.​​​

Claims

1. An integrated air supply unit, comprising: a compressor housing including a piston slidably disposed within the piston bore; a pressure control unit body defining a plurality of fluid channels and a plurality of solenoid valves configured to selectively control air flow through corresponding ones of the plurality of fluid channels; as well as a desiccant housing extending between the compressor housing and the pressure control unit body and defining a desiccant chamber configured to hold a desiccant container to remove moisture from air passing through the desiccant container, Wherein, the integrated air supply unit further comprises: a manifold comprising at least one fluid channel; a discharge control valve configured to selectively control air flow from the manifold to a supply port to supply pressurized air to an external device; a compressor configured to supply pressurized air in the first pressurized air passage, wherein the compressor includes the compressor housing; a dryer configured to remove moisture from the pressurized air in the first pressurized air passage and supply dry pressurized air in a second pressurized air passage, wherein the dryer further comprises a desiccant housing; a supply control valve configured to selectively control air flow between the second pressurized air passage and the manifold; a pilot exhaust valve comprising an inlet passage and a discharge passage and configured to control airflow between the inlet passage and the discharge passage, the pilot exhaust valve comprising an exhaust valve hole having a semi-enclosed end, a tubular portion extending from the semi-enclosed end and into the exhaust valve hole, and a stepped piston slidably movable within the exhaust valve hole and dividing the exhaust valve hole between a first chamber and a second chamber, the stepped piston comprising a control surface defining an end of the first chamber and a lower surface opposite the control surface, the stepped piston comprising a piston extension extending into the tubular portion, the piston extension comprising a sealing surface configured to selectively seal against a valve seat to block fluid communication between the inlet passage and the discharge passage; and an exhaust control valve configured to selectively control air flow between the first chamber and the second chamber of the pilot exhaust valve, Wherein, the inlet passage of the pilot exhaust valve is in direct fluid communication with the first pressurized air passage.

2. The integrated air supply unit according to claim 1, wherein The desiccant housing defines a through-bore extending between the compressor housing and the pressure control unit body, the through-bore being sealed at each end thereof by a radial seal.

3. The integrated air supply unit according to claim 1, wherein: The desiccant housing further defines a guide hole configured to guide a large bolt connecting the compressor housing and the pressure control unit body.

4. The integrated air supply unit according to claim 1, wherein: The compressor housing defines a fluid passage between the piston bore and the desiccant chamber; and The integrated air supply unit further includes a check valve comprising an elastomeric member biased against the compressor housing to selectively block a fluid passage between the piston bore and the desiccant chamber and allow airflow from the piston bore into the desiccant chamber while blocking airflow in the opposite direction.

5. An integrated air supply unit, comprising: a manifold comprising at least one fluid channel; a discharge control valve configured to selectively control air flow from the manifold to a supply port to supply pressurized air to an external device; a compressor configured to supply pressurized air in the first pressurized air passage; a dryer configured to remove moisture from the pressurized air in the first pressurized air passage and supply dry pressurized air in a second pressurized air passage; a supply control valve configured to selectively control air flow between the second pressurized air passage and the manifold; a pilot exhaust valve comprising an inlet passage and a discharge passage and configured to control airflow between the inlet passage and the discharge passage, the pilot exhaust valve comprising an exhaust valve bore having a semi-enclosed end, a tubular portion extending from the semi-enclosed end and into the exhaust valve bore, and a stepped piston slidably movable within the exhaust valve bore and dividing the exhaust valve bore between a first chamber and a second chamber, the stepped piston comprising a control surface defining an end of the first chamber and a lower surface opposite the control surface, the stepped piston comprising a piston extension extending into the tubular portion, the piston extension comprising a sealing surface configured to selectively seal against a valve seat to block fluid communication between the inlet passage and the discharge passage; a first exhaust control valve configured to selectively control the flow of pressurized air from the second pressurized air passage to the first chamber of the pilot exhaust valve; and a second exhaust control valve configured to selectively control the flow of pressurized air between the first and second chambers of the pilot exhaust valve; and Wherein, the inlet passage of the pilot exhaust valve is in direct fluid communication with the first pressurized air passage.

6. The integrated air supply unit according to claim 5, wherein: The dryer further includes a desiccant housing defining a desiccant chamber for retaining a desiccant material; and wherein the desiccant material is disposed in an air flow path between the first pressurized air passage and the second pressurized air passage to remove moisture from air passing between the first pressurized air passage and the second pressurized air passage.

7. The integrated air supply unit according to claim 5, wherein: The compressor further comprises: electric motors; and At least one piston is driven by the electric motor and is configured to supply pressurized air in the first pressurized air passage.

8. The integrated air supply unit according to claim 5, further comprising: a reservoir port providing a fluid connection to an external reservoir; as well as At least one reservoir valve is configured to selectively provide fluid communication between the reservoir port and the manifold.

9. The integrated air supply unit according to claim 8, wherein: The at least one reservoir valve includes two reservoir valves arranged in parallel and having different flow characteristics.

10. The integrated air supply unit according to claim 8, further comprising: A boost valve is configured to selectively provide fluid communication between the reservoir port and an inlet of the compressor.

11. An integrated air supply unit, comprising: a manifold comprising at least one fluid channel; a discharge control valve configured to selectively control air flow from the manifold to a supply port to supply pressurized air to an external device; a compressor configured to supply pressurized air in the first pressurized air passage; a dryer configured to remove moisture from the pressurized air in the first pressurized air passage and supply dry pressurized air in a second pressurized air passage; a supply control valve configured to selectively control air flow between the second pressurized air passage and the manifold; a pilot exhaust valve comprising an inlet passage and a discharge passage and configured to control airflow between the inlet passage and the discharge passage, the pilot exhaust valve comprising an exhaust valve hole having a semi-enclosed end, a tubular portion extending from the semi-enclosed end and into the exhaust valve hole, and a stepped piston slidably movable within the exhaust valve hole and dividing the exhaust valve hole between a first chamber and a second chamber, the stepped piston comprising a control surface defining an end of the first chamber and a lower surface opposite the control surface, the stepped piston comprising a piston extension extending into the tubular portion, the piston extension comprising a sealing surface configured to selectively seal against a valve seat to block fluid communication between the inlet passage and the discharge passage; an exhaust control valve configured to selectively control air flow between the first chamber and the second chamber of the pilot exhaust valve; wherein the first chamber of the pilot exhaust valve is in direct fluid communication with the second pressurized air passage; wherein the second chamber of the pilot exhaust valve is in direct fluid communication with an exhaust passage to atmosphere; and Wherein, the inlet passage of the pilot exhaust valve is in direct fluid communication with the first pressurized air passage.

12. The integrated air supply unit according to claim 11, wherein The dryer further includes a desiccant housing defining a desiccant chamber for retaining a desiccant material; and wherein the desiccant material is disposed in an air flow path between the first pressurized air passage and the second pressurized air passage to remove moisture from air passing between the first pressurized air passage and the second pressurized air passage.

13. The integrated air supply unit according to claim 11, further comprising: a first check valve disposed in the second pressurized air passage and configured to allow airflow from the manifold to the dryer while blocking airflow in the opposite direction; as well as A bypass passage provides fluid communication between the manifold and the second pressurized air passage, with a second check valve disposed in the bypass passage and configured to allow air flow from the second pressurized air passage to the manifold while blocking air flow in the opposite direction.

14. The integrated air supply unit according to claim 11, further comprising: a reservoir port providing a fluid connection to an external reservoir; as well as At least one reservoir valve is configured to selectively provide fluid communication between the reservoir port and the manifold.

15. The integrated air supply unit according to claim 14, further comprising: A boost valve is configured to selectively provide fluid communication between the reservoir port and an inlet of the compressor.

16. An integrated air supply unit, comprising: a manifold comprising at least one fluid channel; a discharge control valve configured to selectively control air flow from the manifold to a supply port to supply pressurized air to an external device; a compressor configured to supply pressurized air in a first pressurized air passage, wherein the compressor includes a compressor housing defining a stepped bore including a low-pressure bore having a first cross-sectional area and a high-pressure bore coaxial with the low-pressure bore and having a second cross-sectional area smaller than the first cross-sectional area; a sliding member comprising a low-pressure piston slidably disposed in the low-pressure hole and a high-pressure piston slidably disposed in the high-pressure hole, the sliding member defining a hollow chamber between the low-pressure piston and the high-pressure piston; a hinge member disposed within the hollow chamber of the sliding member and pivotably coupled to the sliding member via a wrist pin, a dryer configured to remove moisture from the pressurized air in the first pressurized air passage and supply dry pressurized air in a second pressurized air passage; a supply control valve configured to selectively control air flow between the second pressurized air passage and the manifold; a pilot exhaust valve comprising an inlet passage and a discharge passage and configured to control airflow between the inlet passage and the discharge passage, the pilot exhaust valve comprising an exhaust valve bore having a semi-enclosed end, a tubular portion extending from the semi-enclosed end and into the exhaust valve bore, and a stepped piston slidably movable within the exhaust valve bore and dividing the exhaust valve bore between a first chamber and a second chamber, the stepped piston comprising a control surface defining an end of the first chamber and a lower surface opposite the control surface, the stepped piston comprising a piston extension extending into the tubular portion, the piston extension comprising a sealing surface configured to selectively seal against a valve seat to block fluid communication between the inlet passage and the discharge passage; an exhaust control valve configured to selectively control air flow between the first chamber and the second chamber of the pilot exhaust valve, Wherein, the inlet passage of the pilot exhaust valve is in direct fluid communication with the first pressurized air passage.

17. The integrated air supply unit according to claim 16, further comprising: a motor assembly comprising a motor housing and a motor shaft rotatable about an axis and coupled to an eccentric shaft offset from the axis; as well as A bearing is located in the hollow cavity of the sliding member and is disposed between the hinge member and the eccentric shaft and surrounds the eccentric shaft, and causes the hinge member to transmit oscillatory linear motion through the stepped hole in response to rotation of the motor shaft about the axis.

18. The integrated air supply unit according to claim 16, further comprising: a motor assembly comprising a motor housing and a motor shaft rotatable about an axis and coupled to an eccentric shaft offset from the axis, wherein the compressor housing defines a motor bore extending transversely to the stepped bore and configured to receive the motor shaft; and The compressor housing defines a boss extending outwardly around at least a portion of a periphery of the motor aperture to engage the motor housing.

19. The integrated air supply unit of claim 16, further comprising: a passage extending through the low-pressure piston; as well as A reed-type valve covers the passage and allows airflow through the passage in one direction while blocking airflow in the opposite direction.

20. The integrated air supply unit according to claim 19, wherein The reed-type valve is secured to the surface of the low-pressure piston by one of fasteners, adhesive, or by welding.

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