AU2006249296B2 - Pressure-controlled three-way valve device, transport vehicle having tire inflation pressure control and method for remote pressure-controlling the valve device - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant(s): COL-VEN S.A.

Invention Title: PRESSURE-CONTROLLED THREE-WAY VALVE DEVICE, TRANSPORT VEHICLE HAVING TIRE INFLATION PRESSURE CONTROL AND METHOD FOR REMOTE PRESSURE- CONTROLLING THE VALVE DEVICE The following statement is a full description of this invention, including the best method for performing it known to me/us: 2 00 0 PRESSURE-CONTROLLED THREE-WAY VALVE DEVICE, TRANSPORT VEHICLE HAVING TIRE INFLATION PRESSURE CONTROL AND METHOD FOR REMOTE PRESSURE-CONTROLLING THE VALVE DEVICE FIELD OF THE INVENTION: 0D The present invention relates to a valve device for CI installation in a pressurized air or gas pipe, which 0device may be controlled either by the gas relative 0D pressure applied to one of the ways of the valve device or by the pressure differential between two of its ways.

Thus, the condition of the valve device is remotecontrollable through a pipe connected to said one of its ways, without any auxiliary control lines, by varying the air pressure applied in the other end of the pipe. The present invention relates in particular to a three-state valve device capable of operatively being in: a closed or locking position, (ii) an open position between a pair of ways, or (iii) an open position between another pair of ways, according to the state of pressure in one of those ways, which becomes a controller for the valve device.

The invention also relates to a method of controlling the positions of the valve device through the state of pressure of the pressurized gas conveyed by the installation pipework.

The valve device of the present invention is applicable to inflating and deflating pressurized loads, in particular as a chamber valve, as a component for a tire inflation pressure control system in a motor vehicle. Such systems are used in transport vehicles, in particular trucks and buses, since they allow for corrective actions to be taken with regard to the state of inflation of each particular N:Melboume\Cases\Patent\4I10-41999 P41640.AU 2\SpeMs\P41640.AU.2 Specdication 2008-&26.doc 27/0608 3 00 0 tire and/or tire axle, either automatically or by hand Soperation by the driver, without the need for stopping the vehicle, thus resulting in an important element for transport safety.

ND In the aforesaid application, the valve device is Ci interposed between one end of one installation pipe and 0the air inlet in the tire, replacing or applied onto the ID tire's conventional tire valve, and allows performing three operations essential to the abovementioned application, namely: to close the air flow when the installation is depressurized, in order to prevent the vehicle tires from going down, (ii) to allow a flow of air sufficient for inflating a tire or for keeping it inflated, for instance in case of a flat, so as to avoid stopping the car anywhere, and (iii) to allow for deflating the tires, for example when the road and/or load conditions require to reduce the inflation pressure.

In this application, the aforesaid controller way, which is provided on one side of the valve device plunger, is connected to the pipework which, in addition to providing the state control pressure, simultaneously provides the inflating air (gas); while a second way, provided on the other side of the plunger, is coupled to the tire inner tube, and the third way may be arranged for venting air from the second way.

BACKGROUND ART In the abovementioned application, in addition to being able to inflate transport vehicle tires in a controlled way and during motion, it is also desirable to have the possibility of reducing the tire pressure, under the N:\Melboume\CasesPatent\41000-41999\P41640 AU 2\Specis\P41640.AU.2 Specification 2008-6-26.doc 27/06/08 00 O control of a remote device, such as described in Argentine Spatent application No P96.01.04.874 published on September 1998 (AR 004.085). For such purpose, it is not desirable to use, as the component designated with reference numeral 39 in said document, conventional three- ND way valves having independent controls, for example C1 solenoid valves, since this would require laying control lines to the wheel location, which would complicate the ND installation and cannot be easily protected against mechanical accidents.

This problem was initially solved by the two-way valve device described in Argentine patent application N°P97.01.01607, published on 29th September 1999 (AR 006772), which conventionally comprises a valve body within which a passage extends between two air inlet/outlet ports provided in opposite longitudinal ends of the valve body, a plunger housed in the passage and a spring stress means which stresses the plunger towards a valve seat in the passage for normally closing the passage, that is in the absence of a greater pressure in the installation pipe. Said valve is provided with an opening adjuster which makes it selectively bidirectional to take, under pipe pressure control, the following positions: locked when the installation is depressurized), maximum opening for air flow in the positive direction (inflation), which is reached when the inlet pressure or resultant force on the plunger is sufficient to overcome the stressing spring restoring force, and N:Vvelboume\CasesIPatent41000-41999\P41640 AU.2\SpedsP41 640.AU.2 Specificadon 2008-6-26.doc 27/06108 00 S0 minimum opening for air return in the opposite Sdirection (deflation). In the latter minimum opening position, the valve device allows a controlled air C, flow to return through the installation pipework.

ND SUMMARY OF THE INVENTION C' According to one aspect of the present invention there is provided a pressure-controlled three-way valve device ND including: a valve body having an inlet port, a second port, an outlet port, an inlet passage extending through said valve body between said inlet port and said second port, and an outlet passage extending between said outlet portand said second port; a plunger housed in said passage and moveable within said inlet passage between a pair of stroke limit positions; recovery means for urging said plunger in the direction of the inlet port and an outlet valve in said outlet passage, said outlet valve remaining closed when the plunger is in one of said stroke limit positions, such that said outlet passage is opened by means of said outlet valve when the position of said plunger is in a range intermediate said stroke limit positions; wherein said stroke limit positions of said plunger comprise a pair of opposite seats said outlet valve comprises a pair of seals located in said outlet passage and which alternatively abut against said pair of seats such that said outlet passage is opened by means of respective gaps formed between said seals and the seats corresponding thereto when the position of said plunger is in said intermediate range; and N \Melboume\Cases\PatentW1000-41999P41640.AU.2\Specs\P41640AU 2 Specification 2008-6-26 doc 27/06/08 6 00 said pair of seats comprises a pair of Scircumferential steps formed on the plunger outer wall h-c surface; characterized in that: said device includes an o-ring located between said steps, and IND said pair of seals comprises two inner CI circumferential lips formed on said o-ring in respective correspondence with said circumferential steps, whereby, IND in a stoke limit position of said plunger a predetermined O 10 one of said steps abuts against the corresponding lip, thus closing said outlet passage which is otherwise open when said o-ring is in a position intermediate said steps.

According to a preferred embodiment, the outlet valve comprises a pair of circumferential steps formed on the plunger outer wall surface, between which is a seal ring made up of two inner circumferential lips respectively in correspondence with the steps, such that in both plunger travel limit positions a predetermined one of those steps abuts against the corresponding lip, thus closing the outlet way, which lip remains in the open position only by means of respective gaps formed between the seals and their corresponding seats in the plunger's intermediate position. The inlet passage crosses the plunger longitudinally, passing through an inlet valve normally closed by the elastic restoring means.

The above features are essentially provided as a result of the plunger actually involving a mobile seat for the inlet valve, thus inserting an intermediate pressure range within which the plunger longitudinal movement is used as a control for the outlet valve.

N:\Melboume\Cases\Patent\41 000-41999\P41 640.AU 2\Specs\P41640AU 2 Specification 2008-6-26.doc 27/06/08 -7 00 0 The present invention also provides a novel method for Sremotely controlling the state of the valve device without ;Z any additional control lines, to correct or maintain a desired pressure in the tire, by varying the gas pressure in the conduit coupled to the inlet way. The method IND comprises the steps of: depressurizing the pipework, Ci to shut the valve device; (ii) pressurizing the pipework 0at a positive pressure differential greater than the ND air pressure in the chamber) range, to open the inlet passage for inflating; and (iii) applying gas to the inlet way at a pressure within a second range, substantially lower than the pressure present in the second way, that is a "negative' differential relative to the second way (for example, initially depressurizing and bringing the inlet way to the desired pressure), to open the venting way and deflate the tire. In the first case, the valve device will operate to protect the pressure existing in the controlled side, while in the two other cases it will act to restore or correct the pressure of the tire being controlled, bringing it to the value present in the pipework.

The present invention is applicable to transport vehicles provided with tires which inflation pressure is controlled by a pressurized air pipework, for connecting each tire being controlled as a pipework load, through a respective valve device according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the invention as well as the way it may be developed, implemented and practiced will be more apparent upon consideration of the following detailed description of an N:\Melboume\Cases\Patent\41000-41999\P41640 AU.2\Specis\P41640AU 2 Specification 2008-6-26 doc 27/06f08 00 -8 00 0 exemplary embodiment, taken in conjunction with the Saccompanying drawings, in which: Figures 1, 2 and 3 are longitudinal cross-sectional views of the valve device according to a preferred embodiment of the present invention wherein Figure 1 shows ND the valve device in the closed position Figure 2 Ci shows the valve device in the inflation position and t Figure 3 shows the valve device in the deflated position IND (iii).

D Figures 4A and 4B are two state of pressure versus time graphs depicting the operation of the valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The following detailed description of the preferred embodiment of the valve device of the invention has been developed such that those skilled in the art can reproduce, with the relevant authorization or license, a chamber valve device to control a vehicle tire inflation and deflation which may be used, for example, with the device as defined in the abovementioned Argentine patent application No P96.01.04874, as the component therein designated by reference numeral 39.

Construction Figures 1, 2 and 3 show a cross-sectional view of a two-valve device 11 according to the present invention, in full length. The two-valve device 11 comprises a valve body 13 within which is an inlet circuit 15A extending longitudinally between two air ways 17A, 17C, implemented in respective longitudinally-opposing ends 19 of the valve body 13. Way 17A is for the inflow of inflating air; accordingly, it is coupled to the pressurizing N:\Melboume\Cases\Patent\41000-41999\P41640.AU 2\Specs\P41640.AU.2 Specification 2008-6-26.doc 27/06/08 9 00 0 installation pipework (not shown), from which it receives Sboth the inflating air flow and pressure signals for controlling the valve device 11. In contrast, the way 17C is coupled to the tire chamber (also not shown), such that it behaves as an inflating air inlet/deflating air outlet sD conduit. A port 17B is provided on one side of the valve CA body 13 to define a deflating air outlet way in tcommunication with way 17C through an outlet circuit (\i The inside of the valve body houses a longitudinallytravelling plunger 21, spring- stressed in the direction of the end corresponding to the inlet way 17A. Plunger 21 is internally crossed by an axial passage 25 normally closed by an inlet valve comprised of a piston 27 axially slidable within the valve body 13 and stressed by spring 23 against a plunger end, wherein the piston has an axial projection 29 which is introduced into the inner passage of the plunger in order to keep the piston axially centered with respect to the plunger, and a circumferential lip closing against end 33 of plunger 21, thus normally closing the outlet of the said passage Piston 27 does not seal against the side wall of the valve body 13 but has longitudinal slots allowing for the gas flow.

A circumferential recess 35 is provided on the outer surface of the plunger 21 in which a seal ring 37, arranged against the surface of the valve body 13 inner wall, extends laterally and inwards. This seal ring 37 also has a pair of circumferential lips 39A, 39B in respective correspondence with the pair of steps 41A, 41B defined by the recess 35. Thus, the travel of plunger 21 is limited by the steps 41 (for generalization, suffixes N:\Melboume\Cases\Patent\41000-41999\P41640.AU.2\Specis\P41640.AU.2 Specification 2008-6-26.doc 27/06/08 00 10 00 0 etc. are omitted in the reference numerals) Salternatively abutting against lips 39.

Operation To inflate the tire, pressurized air is applied to the IND inlet way 17A, at a pressure sufficiently exceeding the Cl tire pressure present in way 17C to push plunger 21 t against the spring, until step 41A abuts against lip 39B IND of seal 37, thus keeping closed the air passage to the S 10 venting way 17A. Plunger 21 stops at this travel limit, but the air pressure in inlet way 17A acts on piston 27 breaking the strength of spring 23 to open passage thus allowing for the tires to be inflated.

Thus, a possible pressure drop in the chamber, for example as a result of a flat, causes a positive pressure differential generating a net resultant on plunger 21 in the direction of way 17C, sufficient to break the strength of spring 23 and to fully open the inlet circuit 15A, as shown in Figure 1.

The device of the invention is designed to foresee any possible breakage or failure in the installation, in which case the valve device 11 automatically closes during any depressurization of the pipework. Therefore, in the absence of air pressure in the inlet way 17A, spring 23 stresses the valve piston 27 against plunger 21, thus closing passage 25, as well as plunger to its limit position in the direction of inlet way 17A, wherein the other step 41 B abuts against the other lip 39B of seal 37, thus closing the air flow through the deflation circuit 15B, that is isolating the venting way 17B from N:AMelboume\Cases\Patent\41000-41999\P41640 AU 2\Speds\P41640 AU.2 Specification 2008-6-26.doc 27/06/08 11 00 0 way 17C coupled to the tire, the three ways of the valve Sthus remaining locked, as shown in Figure 2.

If the driver decides to reduce the pressure in the tire, it is advisable to first depressurize the pipework, sD depriving the inlet way 17A of air pressure (ensuring the Ci momentary blocking of all the vehicle tires), and to then 0increase the pressure to the desired tire calibration 0D pressure. Plunger 21 is then brought to an intermediate position opening respective gaps between both assemblies of lips 39 and steps 41, as shown in Figure 3, thus allowing air venting through passage 15B open in the direction of the outlet way 17B. The dynamic state of plunger 21 may be summarized by equation PA.SA Pc.Sc K.X [1] where: PA: air pressure in the inlet side; SA: cross-sectional area of plunger 21 in the inlet side; Pc: air pressure in the chamber side; Sc: cross-sectional area of plunger 21 in the chamber side; K: elastic constant of spring 23; X: compression of spring 23; By way of simplification, taking into account that Sc/ 5 A a is a constant ratio (depending upon the components' geometric parameters such as the diameter of valve lip 31) and defining variable R K.X SA (also constant), the state of equilibrium of plunger 21 in its intermediate position may be characterized by the following equation: PA OPc R [2] N: MelboumelCases Paten\4 1OO-4I 999IP41640.AU.2 SpecisNP4 140.AU.2 Specification 2008-6-26.doc 27/0608 12 00 This equation defines the states of operation of the Svalve device 11 c1 According to this equation to place the plunger in ND the intermediate position the pressure signal PA in the Cl inlet way 17A should be equal to the sum defined in the

S

right-hand member of equation determined by the tire ND pressure Pc and the restoring force R of spring 23 0 10 semi-compressed a length X. In addition, for the inflation operation, the inlet pressure PA must meet condition PA C oPc RA [3] where: RA is the restoring stress of spring 23 for a compression XA of same, corresponding to butt 39A-41A.

Synthesizing, provided that: PA oPc RB, wherein RB R(XB) for the plunger abutting against lip 39B of seal 37, the seal of lip 39B is closed against step 41 B, thus bringing the two-valve device 11 to the locking condition.

(ii) PA oPc RA, the seal of lip 39A is closed against step 41A, thus allowing the two-valve device 11 to be in a position capable of inflating, the inflation condition being reached by adding an overpressure APA to force piston 27 against spring 23 and open the inflating way (iii) PA oPc for XB X XA, plunger 21 floats in an intermediate position without any N:W1elboume\CasesPatentW1OO-41 999%P41640.AU.2%SpecisIP41640.AU.2 Specification 2008-6-26.doc 27106/08 13 00 0 contact with seal 37, the deflating way 1 Sthus being opened.

In the exemplary embodiment described, 0,48 and in a first approximation we can neglect R(XB) s R(XO) 0 IND depending on how the spring 23 is selected. Assuming a Ci calibrated pressure of 7 kg/cm 2 (16,5 kPa), it appears that t the opening of outlet valve 39-41 takes place in the ND vicinity of: PA oPc 0,48 x 7 kg/cm2 (16,5kPa) 3,36 kg/cm2 (7,92kPa) This is illustrated in Figures 4A and 4B. Both figures depict the different conditions of the two-valve device 11, separated by constant pressure straight lines, such conditions being the three states as mentioned above and a fourth state for which, in practice, hysteresis is observed between the inflation and deflation states.

Therefore, to deflate the loading tire at a slightly lower pressure Pc 2 in the hysteresis region, it is advisable to initially reduce inlet pressure PA to a lower value, for example 45% of the calibration value Pcl, ensuring that the device enters the deflation region during a short time interval, and to then increase the inlet pressure PA to the desired level Pc2, as shown in Figure 4A. Figure 4A shows how the tire pressure is brought to the desired level PC2 from a depressurized inlet pipework.

The operation principles described are accomplished as a result of the plunger 21 involving as a matter of fact a mobile seat for inlet valve 27, thus generating an N:WMeIboume CssesPtentN41 000-41999 P41 640.AU.2\Specis\P41 640.AU.2 Speafication 2008-6-26.doc 27/06108 14 00 0 intermediate pressure range within which the longitudinal Smovement of plunger 21 is used as a mobile element for the ;Z outlet valve.

It will be obvious to one skilled in the art that various IND modifications and/or variations can be made to the eC invention as shown in the specific embodiment described, Swithout departing from the scope and spirit of the IND invention. For example, instead of air another gas or fluid may be used other than air or mixed with air. The valve device 11 of the invention may also be used in applications such as selectively pumping or purging a gas to and from a load. For example, as a previous step to deflating the load, rather than depressurizing the inlet way 17A, its pressure PA may be reduced to a value low enough such as 45% of pressure P in the second way 17C.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

For the purposes of this specification it will be clearly understood that the word "comprising" means "including but not limited to", and that the word "comprises" has a corresponding meaning.

N:\Melboume Cases\Paent\41000-41999\P4164O.AU 2\Specis\P4I640.AU.2 Specification 20084-26.doc 27/06108