Patent Publication Number: US-2021188021-A1

Title: Inflation/deflation system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 62/621,731, filed Jan. 25, 2018, the disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates, in general, to an inflation/deflation system for tire in tire systems such as those having an inner bladder and an outer ground engaging tire, and more particularly, to an inflation/deflation system which can inflate/deflate a tire, inflate a bladder, and inflate a tire utilizing pressurized air from the bladder. 
     BACKGROUND 
     Central Tire Inflation Systems (CTIS) are a widely recognized technology applied to on/off highway and military wheeled vehicles to facilitate tire pressure adjustment in order to provide enhanced mobility, increased traction and improved fuel economy when adapting to varying load and terrain conditions. Application of CTIS to agricultural vehicles is an emerging market opportunity, which provides unique challenges to current CTIS implementations. 
     A primary limitation of CTIS applied to agricultural vehicles is the limited output flow capacity of the on-board vehicle air compressor required to quickly re-inflate the large volumetric tires typical of agricultural applications. An additional limitation is conventional axle air sealing systems may not be cable of flowing the increased air volume should high capacity air supply systems be incorporated. 
     Another challenge to incorporating tire in tire technology into CTIS strategy is that it requires a means of managing pressure in both inner and outer tire cavities. This also applies to external auxiliary reservoirs mounted on a wheel end incorporating conventional tires. In one prior art system, two air conduits are incorporated into the rotary union located at each wheel end. This approach is costly and requires additional real estate within the wheel end. 
     Alternatively, CTIS associated controls, valves and measurement devices can reside on the wheel end to accommodate a single passage rotary air seal implementation. These components are thus susceptible to the extreme operating environment of the rotating wheel given the operating profile of an agricultural vehicle. These components also demand considerable electrical power consumption at the wheel, requiring a means to charge its power source. Many such strategies require this remote power source to be available for all CTIS operations. When the power source is depleted, the CTIS is completely inoperable with no fall back to conventional inflate and deflate control. The wheel mounted components such as the atmospheric vent may be susceptible to failures due to contamination ingestion at the wheel. These and other problems in the prior art show a need for an improved inflation system for tire in tire applications. 
     SUMMARY 
     At least one embodiment of the invention provides an inflation/deflation system for a vehicle having a tire/wheel assembly including a first pressure chamber and a second pressure chamber, the vehicle having a source of pressurized fluid separate from the tire/wheel assembly and a connection to atmosphere separate from the tire/wheel assembly, the inflation/deflation system comprising: a valve and fluid passageway arrangement attached to a rim of the tire/wheel assembly; a first single fluid passageway extending from the vehicle to the valve and fluid passageway arrangement through a rotary union, the first fluid passageway selectively (1) closed to fluid flow, (2) coupled to the source of pressurized fluid, and (3) coupled to the connection to atmosphere; the valve and fluid passageway arrangement having a first state coupling the first fluid passageway to the first pressure chamber; a second state coupling the first fluid passageway to the second pressure chamber; and a third state coupling the second pressure chamber to the first pressure chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of this invention will now be described in further detail with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic of an embodiment of the inflation/deflation system of the present invention; 
         FIG. 2  is a schematic of a second embodiment of the inflation/deflation system of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWING 
     The principles of this invention have particular application to an inflation/deflation system for allowing inflation and deflation of vehicle tire in tire system, and thus will be described below chiefly in this context. It will be appreciated that principles of this invention may be applicable to other fluid systems where it is desirable to reduce or increase pressure of a fluid in a reservoir using a local pressure source such as a bladder or accumulator. 
     An embodiment of the inflation/deflation system  10  of the present invention is shown schematically in  FIG. 1  with box  20  representing a vehicle, box  30  representing a tire/wheel assembly mounted on the vehicle  20 , and a rotary union  40  therebetween. The tire/wheel assembly  30  includes a tire  31  mounted on a rim  32  and forming a first pressure chamber  34  and a bladder  35  mounted on the rim  32  and forming a second pressure chamber  36 , which are shown in partial cross-section on the schematic of  FIG. 1 . It is noted that the invention is applicable to other configurations, i.e.—where the bladder and/or valves are mounted to the axle hub or wheel end, and that the invention is not limited to the configuration shown in the figures. 
     The vehicle  20  includes a pressure source  21 , a fluid passageway  22  and supply valve  23  in the fluid passageway  22  to selectively open and close the fluid passageway  22 . A pressure sensor  27  is positioned in fluid passageway  22  between the pressure source  21  and supply valve  23 . A second pressure sensor  28  is positioned in fluid passageway  22  on the opposite side of supply valve  23  from pressure sensor  27 . The vehicle  20  may include a fluid passageway  24  connecting fluid passageway  22  to a source of atmosphere  25 . A vent valve  26  is in the fluid passageway  24  to selectively open and close the fluid passageway  24 . The supply valve  23  and vent valve  26  are typically on off solenoid valves that are controlled by a controller (not shown) based on information it receives from the pressure sensor  28  as to whether inflation or deflation is needed at either the first pressure chamber  34  or the second pressure chamber  36 . The pressure source  21 , also referred to herein as a source of pressurized fluid, is typically a source of compressed air or nitrogen. The pressure source  21  is positioned on the vehicle  20  separate from the tire/wheel assembly  30 . The access point to the source of atmosphere  25  may also be positioned separate from the tire/wheel assembly  30 . 
     The inflation/deflation system  10  comprises a valve and fluid passageway arrangement  50  attached to the rim  32  of the tire/wheel assembly  30  or attached to the axle hub or wheel end (not shown). The valve and fluid passageway arrangement  50  includes a plurality of valves and fluid passageways including valve  51 . Valve  51  has a first inlet/outlet port  52  and a second inlet/outlet port  53 . The Valve  51  has a closed position (as shown in  FIG. 1 ) preventing flow from the first inlet/outlet port  52  to the second inlet/outlet port  53  and an open position allowing flow from the first inlet/outlet port  52  to the second inlet/outlet port  53 . 
     Valve  51  is shown as a timer wheel valve of the type and operation as disclosed in U.S. Pat. No. 10,131,192, filed on Sep. 28, 2015, issued on Dec. 20, 2018, and entitled Central Tire Inflation/Deflation System with a Timed Function CTIS Wheel Valve which is hereby incorporated by reference. In addition to the open and closed positions, the valve  51 , referred to hereafter as timer wheel valve  51 , has a reset or initialization position in which the valve is closed. For example, when the pressure at the first inlet/outlet  52  of the timer wheel valve  51  reaches a reset pressure threshold (“the reset pressure or initialization pressure”) above a corresponding pressure at the second inlet/outlet port  53 , timer wheel valve  51  transitions from the closed position to the reset position. The reset timer wheel valve  51  is still in a closed condition, however, when the pressure at first inlet/outlet port  52  is lowered to or below an opening threshold pressure with respect to the pressure at the second inlet/outlet port  53 , the timer wheel valve  51  will transition from the reset position to an open position. The timer wheel valve  51  may be configured to transition from the reset position to the open position in a prescribed period of time reset. For example, the valve  51  may be configured to transition from the reset position to the open position in 0.5 seconds or less once the opening pressure threshold is achieved as the pressure at the first inlet/outlet port  52  and approaches the pressure at the second inlet/outlet port  53 . Once the tire wheel valve  51  is in the open position, it will stay in the open position for a prescribed period of time after which the valve  51  will transition to the closed position. The valve  51  may be configured to transition from the open position to the closed position in a prescribed period of time open, i.e. thirty seconds (as example only and not limited to a particular time). The timer wheel valve  51  operates by changes in pressure on the valve and does not require electric power to operate. However, it is contemplated that a typical solenoid on/off valve could be used in a system having electrical power at the tire/wheel assembly and the invention is not limited to a particular valve except as claimed. 
     The fluid passageway  22  extends from the vehicle  20  through the rotary union  40  and is fluidly connected to the first inlet/outlet  52  of the timer wheel valve  51 . In one embodiment the fluid passageway  22  is a single passageway. The fluid passageway  22  is selectively: (1) closed to fluid flow when the supply valve  23  and the vent valve  26  are closed; (2) coupled to the source of pressurized fluid  21  when the supply valve  23  is open and the vent valve  26  is closed; and (3) coupled to a source of atmosphere  25  when the supply valve  23  is closed and the vent valve  26  is open. 
     A fluid passageway  54  fluidly connects the second inlet/outlet port  53  of the timer wheel valve  51  to the first pressure chamber  34 . Fluid passageway  54  allows the inflation of the tire  31  when the fluid passageway  22  is coupled to the source of pressurized fluid  21  and the timer wheel valve  51  is in the open position. Fluid passageway  54  allows the deflation of the tire  31  when the fluid passageway  22  is coupled to the source of atmosphere  25  and the timer wheel valve  51  is in the open position. 
     A fluid passageway  55  fluidly connects the fluid passageway  22  to the second pressure chamber  36 . Fluid passageway  55  is shown connected to fluid passageway  22  at the first inlet/outlet port  51  of the timer wheel valve  51 . A one-way valve  56 , typically either a spring loaded check valve as shown in  FIG. 1  or a pressure relief valve  56 ′ as shown in  FIG. 2  is positioned in the fluid passageway  55  preventing flow through the valve  56  unless the fluid pressure entering the fluid passageway  55  from the fluid passageway  22  is above a predetermined pressure threshold (“check valve threshold pressure”). In a typical agricultural application, this check valve threshold pressure may be set higher than any anticipated tire pressure and higher than the timer wheel valve  51  initialization pressure applicable to the anticipated tire pressure, as an example, 85 psi is a typical check valve threshold pressure in such applications. The high check valve threshold pressure allows the system  10  to perform all desired lower pressure actions such as tire inflate, deflate, and pressure measure routines without any interaction with the second pressure chamber  36  (when the pressure chamber  36  is at a pressure above the pressure of the supply pressure). The valve  56  prevents fluid flow through the fluid passageway  55  in the direction from the second pressure chamber to the fluid passageway  22 . Fluid passageway  55  allows the inflation of the bladder  35  when the fluid passageway  22  is coupled to the source of pressurized fluid  21 , the pressurized fluid is above a predetermined valve pressure threshold of valve  56 , and the wheel valve  51  is in the initialized closed position. 
     A fluid passageway  57  connects fluid passageway  54  to fluid passageway  55 . A second check valve  58  is positioned in the fluid passageway  57  preventing flow through fluid passageway  57  in the direction from the fluid passageway  55  to fluid passageway  54 . Check valve  58  ensures that the pressure within the tire  31  cannot exceed the pressure within bladder  35 . 
     A fluid passageway  59  connects fluid passageway  54  to fluid passageway  55 . A valve  60 , referred to as a transfer valve, is positioned in fluid passageway  59 , the transfer valve  60  having a first position preventing flow through the transfer valve  60  and a second position allowing flow through the transfer valve  60 . A fluid passageway  61  connects the fluid passageway  55  to the transfer valve  60 . Transfer valve  60  is a normally closed pneumatically piloted on/off valve having a predetermined actuation pressure to move the transfer valve  60  from the first position to the second position. Fluid passageway  61  is connected to fluid passageway  55  on an upstream side of pressure relief or check valve  56  while fluid passageways  57  and  59  are connected to fluid passageway  55  on a downstream side of pressure relief or check valve  56 . 
     A valve  62  is positioned in the fluid passageway  61  having a first position preventing flow through the valve  62  and a second position allowing flow through the valve  62 . Valve  62  is a normally closed, low power solenoid operated 3,2 valve. The valve  62  may be a wireless piezo valve, which are commonly use in applications where low power consumption due to its momentary power requirement to transition positions and remote actuation is desired. The valve  62  is operated by a switch  63  which is a piezo-electric element suitable for the application, which is activated and deactivated by a remotely controlled signal. The signal may be an RF signal or other appropriate signal that is detected by the receiver  64 . The signal may be encoded so that only a particular valve  62  operates in response to a signal received by receiver  64 . The receiver  64  and the valve  63  may be powered by a power source  65 . Power source  65  may be a battery or any other suitable power source. The power source  65  may be recharged if needed as known in the art such as those disclosed in European Patent 2 196 336 (B1) granted on Oct. 3, 2012 and entitled Tyre inflation pressure control system. 
     In operation, the inflation/deflation system  10  has a first state coupling the source of pressurized fluid  21  or the source of atmosphere  25  to the first pressure chamber  34 ; a second state coupling the source of pressurized fluid  21  to the second pressure chamber  36 ; and a third state coupling the second pressure chamber  36  to the first pressure chamber  31 . The first state is achieved when the timer wheel valve  51  is in the open position and either the supply valve  23  or the vent valve  26  is in an open position. The second state is achieved when the timer wheel valve  51  is in a closed initialized position, the supply valve  23  is in an open position, and the pressurized fluid from the pressure source  21  is above the predetermined valve pressure threshold of valve  56 . The third state is achieved when the timer wheel valve  51  is in a closed initialized position, the supply valve  23  is in an open position, valve  62  is in an open position, the pressure of the pressurized fluid from the pressure source  21  is above the predetermined actuation pressure of the transfer valve  60  such that transfer valve  60  is in an open position. 
     The operation of the inflation/deflation system  10  to fill the first pressure chamber  34  is now described. The supply valve  23  is opened with pressure source  21  above the initialization pressure such that the timer wheel valve  51  changes from the closed position to initialized position. The pressure from the pressure source is lowered to a pressure at or below the opening threshold of the timer wheel valve  51  allowing the timer wheel valve to transition from the initialized position to the open position. The timer wheel valve  51  will return to a closed position after a predetermined time, typically around 30 seconds. When the timer wheel valve  51  is open, the vehicle tire  31  can be inflated or deflated as directed by the controller based on information from the pressure sensor  28  by opening or closing the supply valve  23  and the vent valve  26  as needed. 
     The operation of the inflation/deflation system  10  to fill the second pressure chamber  36  is now described. The timer wheel valve  51  is in a normally closed position as depicted in  FIG. 1 . Pressurized fluid is provided at a pressure above the initialization pressure of the timer wheel valve  51  and above the valve threshold pressure of valve  56 . The controller opens the supply valve  23  to provide the pressurized fluid to first inlet/outlet port  52  causing the timer wheel valve  51  to move to and stay in an initialization position where the timer wheel valve  51  is closed. The pressurized fluid bypasses the timer wheel valve  51  through fluid passageway  55  where it opens the valve  56  and inflates the second pressure chamber  36 . The pressure in the second pressure chamber  36  is determined by the controller based on pressure sensor  28 . The controller can periodically de-energize the solenoid of the supply valve  23  to allow the pressure sensor  28  to measure the current pressure of second pressure chamber  36 . Once the second pressure chamber  36  has achieved the desired inflation pressure, the controller will de-energize the supply valve  23 , and the solenoid of the vent valve  26  will be momentarily energized causing the pressure at the first inlet/outlet  52  to fall below a predetermined timer wheel valve  51  open pressure and causing the timer wheel valve  51  to open. The one-way valve  56  will prevent deflation of the second pressure chamber  36  through the vent valve  26 . After the vent valve  26  is de-energized and vent valve  26  is closed, the timer wheel valve  51  will remain open until timed out, but there is no fluid flow through the timer wheel valve  51  as both the supply valve  23  and vent valve  26  are closed. After the timer wheel valve  51  has timed out and returns to the closed position, the fluid passageways  22 ,  24  can be vented by again momentarily energizing vent valve  26  as usual. 
     The inflation of the bladder  35  can be accomplished when the inflation/deflation system  10  is not being used to inflate or deflate the tire  31 . The inflation/deflation system  10  will take advantage of this idle time to use the conventionally sized fluid supply compressor (not shown) provided on the vehicle  20  to fill the second pressure chamber  36  to a pressure substantially higher than then the maximum anticipated tire inflation pressure required. This high pressure charged volume in the second pressure chamber  36  would be available for extremely fast re-inflation of the ground tire  31 , with approximately 30% less overall volume of the ground tire  31  due to the resulting displacement of the inner tire or bladder  35  in the tire  31 . 
     The operation of the inflation/deflation system  10  to inflate the tire  31  by using pressurized fluid from the bladder  35  is now described. The timer wheel valve  51  is in a normally closed position as depicted in  FIG. 1 . When supply pressure measured at sensor  27  is determined to be above the pilot pressure required to operate transfer valve  60  and the initialization pressure required for timer wheel valve  51 , the controller opens the supply valve  23  to provide the pressurized fluid to first inlet/outlet port  52  causing the timer wheel valve  51  to move to an initialization position. The controller also sends a signal to the receiver  64  to open the electrically actuated valve  62 . The pressurized fluid bypasses the timer wheel valve  51  through fluid passageway  55 . The one-way valve  56  prevents flow through the relief valve or check valve  56 . The pressurized fluid flows through fluid passageway  61  and valve  62  to open the pneumatically piloted valve  60  in fluid passageway  59  which fluidly connects the second pressure chamber  36  to the first pressure chamber  34  allowing the high pressure fluid in the bladder  35  to inflate the tire  31 . The amount of pressurized air volume required to inflate the tire from the bladder to the desired pressure and therefore the appropriate time to energize the transfer valve shall be estimated by means of a predictive adapting algorithm. This algorithm estimates the vehicle tire size and therefore applicable volumes of the tire and its associated bladder. Once this transfer time is complete, the system shall measure tire pressure and adjust accordingly using the previously described control methods. In order to measure tire pressure, timer wheel valve  51  must again be opened as previously described by de-energizing supply valve  23  and momentarily energizing vent valve  26 . Note that this will also reduce pressure in fluid passageway  55  such that valve  60  will close. When inflating the tire  31  from the bladder  35  is assumed to be complete, the controller will turn off valve  62 , thus removing pilot pressure supplied to valve  60  and valve  60  will close. At this point, the bladder  35  should have been sufficiently utilized for fast inflation of the tire  31 , and normal inflate, deflate, and measure control will remain available for additional tire pressure adjustment in the same manner as the prior art inflation/deflation system. 
     A second embodiment of the invention is shown in  FIG. 2  as inflation/deflation system  10 ′ which is identical to the system  10  except that 1) the valve  56 ′ is depicted as a relief valve instead of a spring loaded check valve; 2) fluid passageway  61  and valve  62  are removed; and 3) pressure operated transfer valve  60  has been replaced by valve  60 ′ which operates like former valve  62  to remotely open and close fluid passageway  59  to transfer pressurized fluid from the second pressure chamber  36  to the first pressure chamber  34 . In the inflation/deflation system  10 ′, the third state is achieved when timer wheel valve  51  is in a first closed position and the transfer valve  60 ′ is activated to move from a closed first position to an open second position. This allows pressurized fluid in the second pressure chamber  36  to flow into the first pressure chamber  34 . During the third state the supply valve  23  and vent valve  26  are typically in the closed first position, however, it may be desirable to open the supply valve  23  such that the pressure source  21  is also utilized to inflate the first pressure chamber  34 . This feature may be utilized to speed up the inflation process which is important with large agricultural tire volumes. 
     As in the prior art, the inflation/deflation system  10  is utilized in a system having a controller having communication lines to operably connect the controller to the pressure source and the control system to allow operation of each timer wheel valve  51  as more than one tire in tire is contemplated such that any number of tire in tires may be utilized. 
     Also, wireless control of electrically actuated valves mounted to a wheel for the purpose of tire inflation are known, and obvious to those skilled in the art. Examples of wireless communication methods include either radio frequency or inductive coupled. An embodiment of the wheel end electrical power source if RF communication is implemented would be to incorporate a charging method for the power source located at the wheel. The methodology of generating electrical power, including a centrifugal or mechanical generator on a rotating device are well known and contemplated herein. 
     A portion of the inflation/deflation system  10 ,  10 ′ can be used as an add-on to prior art CTIS systems or customized as a system optimized for the additional capabilities of the inflation/deflation system  10 ,  10 ′. The inflation/deflation system  10 ,  10 ′ removes the need of incorporating large and costly auxiliary driven air compressors in conjunction with high flow air sealing systems at the tire/wheel assembly  30 . The high capacity reservoir of the second pressure chamber  36  located on the tire/wheel assembly  30  allows quick inflation of the tire  31 . 
     At least one embodiment of the invention provides an inflation/deflation system comprising: a tire/wheel assembly including a first pressure chamber and a second pressure chamber; a source of pressurized fluid located separate from the tire/wheel assembly; a first fluid passageway fluidly connecting the tire/wheel assembly to the source of pressurized fluid; a first valve positioned in the first fluid passageway to selectively open and close the first fluid passageway; a second fluid passageway connecting the first fluid passageway to a source of atmosphere; a second valve positioned in the second fluid passageway to selectively open and close the second fluid passageway; the tire wheel assembly further comprising: a third valve mounted on a wheel rim of the tire/wheel assembly, the third valve having a first inlet/outlet port and a second inlet/outlet port, the first inlet/outlet port fluidly connected to the first fluid passageway, the third valve having a closed position preventing flow from the first inlet/outlet port to the second inlet/outlet port, the third valve having an open position allowing flow from the first inlet/outlet port to the second inlet/outlet port; a third fluid passageway connecting the second inlet/outlet port to the first pressure chamber; a fourth fluid passageway connecting first fluid passageway to the second pressure chamber; a relief or check valve in the fourth fluid passageway preventing flow through the relief or check valve unless the fluid pressure entering the fourth fluid passageway is above a predetermined valve pressure threshold; a fifth fluid passageway connecting the third fluid passageway to the fourth fluid passageway; a check valve in the fifth fluid passageway preventing flow from the fourth fluid passageway to the third fluid passageway; a sixth fluid passageway connecting the fourth fluid passageway to the third fluid passageway; a fourth valve in the sixth fluid passageway having a first position preventing flow through the fourth valve and a second position allowing flow through the fourth valve; a seventh fluid passageway connecting the fourth fluid passageway to the fourth valve, the fourth valve being a pressure operated valve having a predetermined actuation pressure to move the fourth valve from the first position to the second position; a fifth valve in the seventh fluid passageway having a first position preventing flow through the fifth valve and a second position allowing flow through the fifth valve; the fourth fluid passageway is connected to the first fluid passageway at the first inlet/outlet of the third valve. 
     At least one embodiment of the invention provides a vehicle comprising: a tire mounted on a rim to define a first pressure chamber and a bladder mounted on the rim to define a second pressure chamber; a source of pressurized fluid mounted on the vehicle separate from the rim; a rotary union having a single fluid passageway therethrough; an inflation/deflation system mounted on the rim; the single fluid passageway through the rotary union being fluidly coupled to the inflation/deflation system and selectively (1) closed, (2) coupled to the source of pressurized fluid on the vehicle, and (3) coupled to atmosphere; the inflation/deflation system having a first state coupling the single fluid passageway through the rotary union to the first pressure chamber; a second state coupling the single fluid passageway through the rotary union to the second pressure chamber; and a third state coupling the second pressure chamber to the first pressure chamber. 
     Although the principles, embodiments and operation of the present invention have been described in detail herein, this is not to be construed as being limited to the particular illustrative forms disclosed. They will thus become apparent to those skilled in the art that various modifications of the embodiments herein can be made without departing from the spirit or scope of the invention. For example, as previously discussed, instead of a tire in tire application, the reservoir may be an accumulator mounted at the wheel end and used in the same manner as the bladder reservoir to inflate the tire in accordance with the present invention. Also, it is noted that in the claims, the check valves and/or pressure relief valves are claimed specifically as check valves and/or pressure relief valves and not generally referred to as a “valve” alone such a numbered valve.