EP4045368A1

EP4045368A1 - Trailer control valve with a leakage protection function for a brake system of a vehicle

Info

Publication number: EP4045368A1
Application number: EP19790830.4A
Authority: EP
Inventors: Stephan Eisfelder; Thooyavan JANAKIRAMAN; Rengasamy KABILAN; Lingeswaramurthy PALANISAMY; Karl-Heinz Riediger-Janisch; Satheshkumar RUDHRAMURTHY
Original assignee: Wabco India Ltd
Current assignee: ZF Commercial Vehicle Control Systems India Ltd
Priority date: 2019-10-14
Filing date: 2019-10-14
Publication date: 2022-08-24
Also published as: WO2021074663A1; CN114401875A

Abstract

The invention relates to a valve (100) for controlling flow pressurized fluid to a trailer (200) attached to a vehicle comprising a housing (110) including a lateral extension (120) and a guide (124) with a sliding surface (126), a first port (P11) for receiving pressurized fluid from a first source of pressurized fluid, a second port (P22) selectively connected to the first port (P11), wherein the second port (P11) is configured to provide control pressure to brakes provided at the trailer (200). A third port (P12) is provided in the valve (100) that is operably and selectively connected to the first port (P11) and is configured to provide supply pressure to the brakes provided at the trailer (200). Finally, said valve (100) an intermediary valve unit (118) configured to directly facilitate the connection between at least the first port (P11) and particularly, the third port (P12).

Description

TRAILER CONTROL VALVE WITH A LEAKAGE PROTECTION FUNCTION FOR A

BRAKE SYSTEM OF A VEHICLE

TECHNICAL FIELD OF THE INVENTION

The invention relates to a valve for a brake system associated with a trailer portion of a vehicle that comprises a vehicle portion and said trailer portion attached to the vehicle portion. Alternatively, such valves may be referred as “trailer control valves”. In particular, the present invention relates to the trailer control valve that operates as a part of a pneu- matic braking system for applying brakes to the trailer.

BACKGROUND OF THE INVENTION

The general working principle of trailer control valves and their various operating states can be found in e.g., PCT application no. PCT/IB2018/054101 of the applicant.

However, during the functioning of the trailer control valves at their varying operating states, a controlled release of pressurized fluid may become necessary. In the present context, the controlled release may refer to turning 'ON' or OFF' or providing the pres- surized fluid with varying flow rate, quantity, and/or velocity during different operating states of the trailer control valve selectively to one or more output ports.

OBJECTIVE OF THE INVENTION

It is one of the objectives of the invention to achieve said controlled release of the pres- surized fluid, wherein the flow paths of pressurized fluid have to be controlled and re- leased at different points within the trailer control valve, preferably based on the braking situations and/or based on safety regulations associated with the pneumatic braking sys- tems. While the conventional trailer control valves may allegedly achieve said controlled release of the pressurized fluid, there is nevertheless a need to improve certain construc- tional features of the trailer control valves to provide optimal and controlled flow path for the pressurized fluid within the valve. In particular, despite the possibility of leakage due to failures in, e.g., the connection lines originating from the trailer control valve, the brake pressure supply to e.g., trailer brakes has to be ensured.

It is also one of the objectives of the invention to provide a device with an optimized metered flow of the pressurized fluid for the trailer brakes by designing an actuation mech- anism within the trailer control valve. This actuation mechanism ensures a metered and/or controlled flow of the pressurized fluid from a supply port (e.g., P11 - suitable for receiving the pressurized fluid from a brake fluid source) to a control port (e.g., P22 - suitable for supplying a control pressure to the trailer brake) and a trailer brake supply port (e.g., P12 - suitable for supplying a supply pressure to the trailer brakes). For the sake of complete- ness, it is noted that, for instance, the wheels associated with the trailer include a brake actuator that receives the pressurized fluid from the above-mentioned valve. On supplying the pressurized fluid to the brake actuator, the trailer brakes apply brake on the respective wheels via, e.g., wheel-end brake assemblies.

SUMMARY OF THE PRESENT INVENTION

In accordance with an embodiment of the present invention, a valve for controlling flow of pressurized fluid to a trailer attached to a vehicle or simply, a trailer control valve is pro- vided. Said valve comprises a housing including a lateral extension and a guide with a sliding surface, a first port (P11) for receiving pressurized fluid from a first source of pres- surized fluid (e.g., a fluid reservoir or an air reservoir storing pressurized air), a second port (P22) being selectively connected to the first port (P11), wherein the second port (P22) is configured to provide control pressure to one or more brakes at a trailer or alter- natively, e.g., a trailer portion of the vehicle-trailer combination, and for instance, wherein the second port (P22) may be denoted with yellow color, a third port (P12) operably con- nected to the first port (P11), wherein the third port (P12) is configured to provide supply pressure to the brakes provided at the trailer, and for instance, wherein the third port (P12) may be denoted with red color; and an intermediary valve unit configured to directly facilitate the connection between at least the first port (P11), and the second port (P22) of the valve. In accordance with this embodiment, the intermediary valve unit comprises a spring, a first valve seat being supported by the spring, the valve seat experiencing an upward force due to the spring, and engaging with the lateral extension of the housing, wherein the first valve seat is configured to move in a downward direction on experiencing a downward force that is greater than the elastic force of the spring thereby disengaging from the lateral extension of the housing, and characterized in that, the intermediary valve unit additionally comprises sealing means that is attached to the first valve seat, wherein the sealing means includes at least one elastically deformable structure that forms a fluid tight sealing in association with the sliding surface of the guide of the housing.

One of the technical advantages of said intermediary valve unit is to facilitate the above- mentioned throttled and/or controlled flow of the pressurized fluid due to the usage of elastically deformable structure within the intermediary valve unit in association with, inter alia, the sliding surface of the guide. The sealing so formed between the elastically de- formable structure and the guiding surface can facilitate variable flow, e.g., due to the upward and/or downward movement of the valve seat. In a particular embodiment, the guide is disclosed, for instance, to have a plurality of vertically defined grooves and the elastically deformable structure is provided that reciprocates in combination with the first valve seat along a longitudinal axis. In this embodiment, the elastomeric deformable structure, after a certain limited movement along the axis, may either at least partially close and/or open the flow passage via said grooves for the pressurized fluid to flow through.

In accordance with another embodiment, said at least one elastically deformable structure includes an elastomeric lip seal or an elastomeric sealing element with at least one seal- ing lip. In accordance with yet another embodiment, the elastomeric lip seal is either di- rectly or indirectly attached to the first valve seat. In accordance with still another embod- iment, wherein the elastomeric lip seal or the elastomeric sealing element has at least one protrusion making contact with the sliding surface of the guide. While the term 'lip seal’ may not be part of the technical parlance of a skilled person in the field of pneumatic brake systems, the explanation is provided herewith while explaining the technical effect of said feature. The elastomeric lip seal, according to the present embodiment, extends above or protrudes from, e.g., an outer surface of the first valve seat. In this regard, the term lip seal may represents its orientation taking the cross-sectional view. This extending and/or protruding lip seal or the elastomeric lip seal facilitates formation of the fluid tight sealing when a contact is made with the sliding surface of the guide. Further, usage of elastomeric material enables varying tightness through elastically deformable sealing means. In accordance with an exemplary embodiment, the elastomeric lip seal can have more than one protrusion so that e.g., suitable and optimally designed sealing structure can be designed that complements the sliding surface of the guide.

In a further illustrative embodiment, the sealing means includes a metal sheet at least partially covering the first valve seat. In certain exemplary embodiments, the first valve seat may be at least partially made of the metal sheet. In a yet further illustrative embod- iment, the metal sheet includes a provision for receiving the elastomeric lip seal or the elastomeric sealing element. For instance, since the metal sheet is associated with the valve seat, it is configured to contact the lateral extension for opening and closing a cir- cular orifice that is created due to the lateral extension. For instance, the lateral extension, as can also be derived from the accompanying figures, is circumferentially arranged and is symmetric about axis (e.g., '108’ labeled in figures) within the valve. Further, by using the sheet made of metal to enclose at least partially the first valve seat, the life of the valve is relatively extended in comparison to e.g., any plastic material.

In accordance with at least one of the above-mentioned embodiments, preferably the elastomeric lip seal or an elastomeric sealing element includes an O-ring. O-rings can, for example, be easily assembled to the first valve seat and reduce the assembly effort. Moreover, O-rings are relatively easier to manufacture and are sometimes, readily avail- able in the market.

In accordance with one or more of the above mentioned embodiments, the sliding surface of the guide forms a complementary sealing means to the at least one elastically deform- able structure, wherein a portion of the sliding surface has a curvilinear profile or surface. In the same embodiment, preferably wherein the curvilinear surface and the at least one elastically deformable structure form the sealing means and wherein the valve is config- ured such that linear movement of the first valve seat along a longitudinal axis enable a variable flow of pressurized fluid. In the present embodiment, as the valve seat moves along said longitudinal axis, the variable fallow of the pressurized fluid is enabled due to the design of the curvilinear surface of the guide and the sealing means. The curvilinear surface, for instance, in combination with the guide, may enable varying tightness.

In accordance with one of the above mentioned embodiments, the guide includes a plu- rality of vertically defined grooves which are opened and/or closed based on the linear movement of the first valve seat along the sliding surface. In accordance with this em- bodiment, the presence of the vertically defined grooves assists in releasing the pressur- ized fluid in a variably controlled manner. As the valve seat, for instance, moves in an upward direction (U), the grooves allow the pressurized fluid to flow through them in a streamlined manner. Furthermore, in an exemplary embodiment, as the guide may in- clude one or more slots for letting the pressurized fluid to an outlet port that is connected, for instance, said second and third ports.

Pursuant to a preferred embodiment of the present invention, the intermediary valve unit of one of the above embodiments is configured such that it provides a throttled flow of pressurized fluid to the third port (P12) and more preferably, the port P22 even when there is a_, leakage detected in second port P22. This is enabled, for instance, to facilitate supply of the pressurized fluid when there is a leakage detected in second port P22. In accordance with an embodiment, despite the present of the leakage in second port P22 or the failure of the second port P22, which e.g., supplies control pressure to the trailer brakes, the supply of controlled flow of pressurized fluid to the supply port P12 at least should be ensured as a linear extension of the valve is actuated. This ensures at least supply of the supply pressure to the trailer brakes under failure conditions at e.g., port P22.

In a further exemplary embodiment, use of the valve in accordance with any one of the above embodiments in tractor- trailer combination type of vehicle is claimed. In this em- bodiment, in tractor-trailer combination, for instance, the towing vehicle portion which is the tractor, for instance, may have braking system actuated by hydraulic fluid; however, the trailer brakes may be controlled using the pressurized air. The valve for controlling trailer brakes as per the current invention can also be used in such hybrid i.e., hydraulic- pneumatic brakes for the tractor-trailer combination type of vehicles.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig. 1a shows a cross-sectional view of a valve for controlling flow pressurized fluid to a trailer (schematically shown), in particular its brakes that is attached to a vehicle e.g., tractor in accordance with an embodiment of the present invention;

Figs. 1b to 1j illustrates various operating states of the valve for controlling flow of the pressurized fluid to a trailer (schematically shown) with attached to a vehicle e.g., tractor in accordance with an embodiment of the present invention;

Fig. 2 shows a cross-sectional view of a portion of said trailer control valve, in particular an intermediary valve unit in accordance with an embodiment of the present invention;

Fig. 3 illustrates an isometric view of a guide of said portion of said trailer control valve (e.g., an intermediary valve unit) in accordance with an embodiment of the present inven- tion;

Fig. 4 is a schematic view of said valve in accordance with an embodiment of the present invention;

Fig. 5 is a schematic view of said valve in accordance with another embodiment of the present invention; and

Fig. 6 is a schematic view of said valve in accordance with yet another embodiment of the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1a shows a cross-sectional view of a valve 100 for controlling flow of the pressurized fluid to a trailer 200 (schematically shown), in particular its brakes, that is attached to a vehicle e.g., tractor in accordance with an embodiment of the present invention. In one or more embodiments, such valves for the sake of simplicity may be referred to as trailer brake control valves.

Said valve 100 comprises a housing 110 that is shown, for instance, to include a plurality of pistons and ports (more on this below), and covering 106 to cover a top portion of valve 100. All of said ports and said pistons are however not necessary or essential to define the present invention. In this regard, appended claims include the features that are actu- ally necessary for defining the present invention. Further, references will be made while following the course of the description to said pistons and ports nevertheless so that a skilled person able to understand the underlying invention sufficiently and clearly.

For the sake of illustration, port P41 is to receive pressurized fluid from a primary control pressure source e.g., a foot brake valve for controlling the trailer brakes. Port P42 is pro- vided to receive secondary control pressure from e.g., the foot brake valve for controlling the trailer brakes. P43 is provided to receive control pressure from a hand brake valve for controlling the trailer brakes. Port P11 receives pressurized fluid from a supply source such as a reservoir. Port P12 is to provide supply pressure for applying the trailer brakes. P22 is to provide ‘control’ pressure or to provide pressurized fluid for controlling the trailer brakes.

In accordance with the present embodiment, housing 110 includes lateral extension 120 and a guide 124 with a sliding surface 126. Valve 100 further includes a first port P11 for receiving pressurized fluid from a first source of pressurized fluid, a second port P22 being selectively connected to the first port P11, wherein the second port P22 is config- ured to provide control pressure to brakes provided at trailer 200, and wherein the second port P22 is provided with yellow color. The coloration is merely provided to determine which port is provided for what purpose. Valve 100 also in includes a third port P12 oper- ably connected to the first port P11, wherein the third port P12 is configured to provide supply pressure to the brakes provided at trailer 200, and wherein third port P12 is pro- vided with red color.

Valve 100 further comprises an intermediary valve unit 118 (explained in detail in refer- ence to Fig. 2) configured to facilitate the connection between at least the first port P11 , second port P22 of valve 100. Intermediary valve unit 118 comprises a spring 128, a first valve seat 130 that is being supported by spring 128.

First valve seat 130 experiences an upward force due to spring 128 as can be derived from Fig. 1a, and said valve seat 130 engages with lateral extension 120 of housing 110 e.g., under the influence of spring 128. First valve seat 130 is configured to move in a downward direction (D) on experiencing a downward force that is greater than the elastic force of spring 128 thereby disengaging from lateral extension 120 of housing 110. It is hereby noted that in order to understand the meaning of the upward and downward di- rections throughout the present application is denoted, for instance, in Figs. 4, 5 and 6 with arrow marks ‘U’ and ‘D’ in relation to axis 108.

Furthermore, intermediary valve unit 118 additionally comprises sealing means attached directly or indirectly to first valve seat 130. The sealing means includes at least one elas- tically deformable structure 132 that forms a fluid tight sealing with sliding surface 126 of guide 124 of housing 110. For the sake of completeness, the details of intermediary valve unit 118 can be found, for instance, in the description associated with Fig. 2 of the present application.

The general working principle of valve 100 as illustrated in fig. 1a will be explained below. However, detailed operating states of valve 100 is illustrated and explained in association with Figs. 1b to 1j.

Housing 110 generally also includes a first piston 102 with a top surface 102s. When a driver situated in a tractor driver cabin presses a brake pedal, pressurized fluid enters port P41 shown in fig. 1a. Said pressurized fluid impinges on top surface 102s of said first piston 102 as illustrated with tiny arrow marks ‘AM’ in fig. 1a. This causes first piston 102 to move linearly downwards along longitudinal axis 108. First piston 102 is, for instance, functionally connected to plurality of relay pistons 102p (collectively labeled) in fig. 1a. Said plurality of relay pistons 102p are configured to transfer the force on a linear exten- sion member 114 so that the work can be transferred from the impinging pressurized fluid on top surface 102s to subsequent components aligned along axis 108 in e.g., the down- ward direction (see e.g., Figs. 4 to 6 for ascertaining what is meant with the downward direction with arrow marked ‘D’ in said figures).

Linear extension member 114 further contacts and displaces components of intermediary valve unit 118 within housing 110 to facilitate connection between at least ports e.g., P11 and P22, Intermediary valve unit 118 is generally labelled with a dotted line in fig. 1a. However, the detailed view of said valve unit is shown in fig. 2 of the present application. Following the impact of linear extension member 114, first valve seat 130 is moved or displaced from its initial position. It should be noted however that before any such impact i.e., in its initial position of the linear extension member 114, first valve seat 130 is in contact with lateral extension 120 due to the upward force exerted by spring 128 on a bottom side (not labeled but derivable from fig. 1a) of first valve seat 130. When first valve seat 130 is in contact with lateral extension 120, no fluid connection between e.g., ports P11 , and P22 is possible. However, following the impact of linear extension member 114 due its downward movement along axis 108, it removes the established contact between first valve seat 130 and lateral extension 120. This enables flow of pressurized fluid from port P11 to (follow arrow mark with arrow head at port P11) port P22. However, on the other hand, a skilled person would appreciate that portions P11 and P12 may always be operatively connected.

It follows from the above, in the current operating state displayed in fig. 1a, the control pressure for operating valve 100 arrives at port P41. And the working principle of valve 100 when such control pressure arrives at port P41 has been described in the above paragraphs. This is however not inclusive of all the working possibilities of valve 100. For instance, control pressure may arrive at one of ports P42 and P43, too (see, e.g., figs. 1c and 1f). For instance, when control pressure arrives at port P42, which is a port configured to receive secondary control pressure from unlabeled foot brake valve, the impact of the control pressure is received on a second piston 104 and/or directly or indirectly on a por- tion of linear extension member 114. For another instance, when control pressure arrives at port P43, which is a port configured to receive control pressure due to an activation of an unlabeled hand brake valve, the resulting impact is felt on a portion of linear extension member 114. The control pressure fluid flow path is however not shown for such cases in fig. 1a of the present application. More information on this is provided below.

Figs. 1b to 1j illustrates various operating states of valve 100 for controlling flow pressur- ized fluid to trailer 200 with attached to a vehicle e.g., tractor in accordance with an em- bodiment of the present invention. Each of the figures is explained as provided below.

Fig. 1b shows an operating state of valve 100 where, for instance, the action performed by valve 100 as shown in Fig. 1 a is at least partially reversed. In the operating state shown in Fig. 1b, first piston 102 moves up as a consequence of e.g., when the driver releases applying pressure on the brake pedal provided in the driver's cabin. As can be derived from the figure, due to first piston 102’s upward movement, valve seat 130 reengages and/or establishes contact with lateral extension 120, under the influence of spring 128. This effectively disconnects the connection between, inter alia, ports P11 and P22. What- ever remaining pressurized fluid is left in port P22 is released to the atmosphere as dis- played in Fig. 1b (follow line 116b in Fig. 1b). The pressurized fluid from port P11 is how- ever supplied to port P12 as shown in the figure (see arrow mark labeled 116a in Fig. 1b).

In accordance with Fig. 1b, a flow path 134 provided through housing 110, guide 124 and other components of valve 100. This provides the connection between port P11 to a space defined by sliding surface 126 of guide 124. The pressurized fluid in the defined space within guide 124 flows through a plurality of vertically defined grooves (not shown in Fig. 1b, but clearly derivable from Fig. 3, see ‘308’) and then to port P12, as can be followed form flow line of the pressurized fluid. It can be also noted that such a flow of air from the internal space defined by guide 124 to port P12 is possible because said at least one elastically deformable structure 132 is above a level where said plurality of vertically defined grooves start so that the pressurized fluid can flow through said grooves. This also enables a throttled flow or reduced flow of pressurized fluid to port P12 from P11. Such an arrangement of intermediary valve unit 118, in particular guide 124 with grooves, is one of the technical advantages of the present invention. Further details of intermediary valve unit 118 will be explained in conjunction with Figs. 2 and 3.

Fig. 1c illustrates another operating state of valve 100 of the present invention. In accord- ance with the present operating state of valve 100, pressurized fluid is received through port P42. The impact of the pressurized fluid is realized on at least partially a top surface 104s of second piston 104 of valve 100, and part of a wing member 114a of extension member 114 as can be followed from arrow marks ‘AM’ in Fig. 1c. Due to this downward movement of extension member 114, the contact between lateral extension 120 and valve seat 130 is removed. The flow of pressurized fluid from port P11 to ports P12 and P22 is similar to the follow realized in Fig. 1a. Therefore, such an explanation is not repeated here.

Fig. 1d illustrates yet another operating state of valve 100 when the pressurized fluid source from port P42 as explained in reference to Fig. 1c is removed. In other words, steps explained in reference to Fig. 1c are at least partially reversed. As can be seen from the arrow marks ‘AM’ marked in Fig. 1 d, the movement of piston 104 is upward and op- posite to the direction of Fig. 1c. Owing to this upward movement of piston 104 along axis 108 and of other components, valve seat 130 and lateral extension 120 are in contact again. As the contact is established between valve seat 130 and lateral extension 120, the flow of pressurized fluid from port P11 to, inter alia, P22 is prevented. This can be derived from Fig. 1d. The flow of pressurized fluid within intermediary valve unit 118 or in general valve 100 and exhaust of fluid from port P22 to the atmosphere (can be followed from arrow mark 116b) is similar to the flow of pressurized fluid as displayed in Fig. 1b of the present application.

Fig. 1e illustrates an operating state of valve 100 when a Hand Bake Valve (HBV) is engaged by the driver of the vehicle and this braking force also has to be applied to the brakes of trailer 200 to activate e.g., parking brakes associated with trailer 200. As can be seen with reference sign Ί40’ at port P43, the pressurized fluid from port P43 is ex- hausted or released to the atmosphere. As can also be derived from fig. 1e, this also results in upward movement of plurality of relay pistons e.g., 104 and 102. However, at the same time, the pressurized fluid from port P11 to ports P12 and P22 is enabled so that control pressure and supply pressure for the brakes of trailer 200 are transmitted, albeit in a controlled manner. This enables application of e.g., parking brake in trailer 200 when the HBV is activated by the driver. Contrary to the disclosure provided in Figs. 1a and 1c, the pressurized fluid from port P43 is actually released to the atmosphere as the brake pressure supply is applied to the trailer brakes via port P12 and control pressure is applied via port P22.

As can also be noted in Fig. 1 e, a tiny gap may be formed between valve seat 130 and lateral extension 120. This gap enables flow of pressurized fluid from ports P11 to, inter alia, port 22. The flow of pressurized fluid within intermediary valve unit 118 is similar to the one showed in Figs.1a and 1c therefore further explanation in this regard is not re- peated. In any case, the flow of pressurized fluid is already shown with flow lines e.g., reference sign ‘116’ and a skilled person would readily be able to understand any such information.

Fig. 1f illustrates an operating state of valve 100 when said HBV is disengaged by the driver of the vehicle and respective brake has to be released. As can be noticed, pressure form the control line is exhausted or released into the atmosphere. In other words, no control pressure is supplied via port P22 to the brakes of trailer 200.

Fig. 1g illustrates an operating sate of valve 100 when there is failure or leakage or rupture in control line connected to port P22 of valve 100. As a result when the driver of the vehicle presses the brake pedal, the pressurized fluid enters port P41 from the first pres- surized fluid source and impacts top surface 102s of first piston 102. In accordance with exemplary embodiment, when the driver applies force on the brake pedal and activates a foot brake valve (not shown in figures), the delivery air from a primary circuit of said foot brake valve will be routed to port P41 i.e. primary control port of valve 100 (as shown in Fig. 1g). As a consequence, extension member 114 moves linearly downward along axis 108, and disengages the contact between valve seat 130 and lateral extension 120. The ports P11 and P12 and P22 are now connected. While the flow of the pressurized fluid is similar to what has been illustrated in association with Fig. 1a, it has to be noted that due to leakage in line connected to port P22, the control pressure does not however fully reach the brakes of trailer 200 due to said failure or leakage in connection to port P22. In the present state of valve 100, as can also be derived from fig. 1b, the supply line P12 is also vented or exhausted via port P22 due to the leakage. The function of valve 100 when such a failure in the line connected to port P22 is experienced is commonly referred to as a dump function.

It can be further seen in Fig. 1g that the supply via port P11 (from a primary pressurized fluid source) will be blocked by at least one elastically deformable structure 132. More particularly, due to the downward movement of valve seat 130 against the force of spring 128, at least one elastically deformable structure 132 is at a level within guide 124 where plurality of vertically defined grooves (not shown in Fig. 1g, but see ‘308’ of Fig. 3) cannot be reached by the flow of pressurized fluid. As already mentioned in the explanation of other figures, for instance, the resulting combination of at least one elastically deformable structure 132 and sliding surface 126 of guide 124 forms a fluid tight seal. The pressur- ized fluid flow path can be followed via said path 134 labeled in Fig . 1g.

In any case, intermediary valve unit 118 is configured such that it still maintains throttled minor pressurized fluid flow to port P12 even during the presence of the leakage in port P22. For instance, this is enabled by providing an additional flow path 134a (alternatively see also path labeled within a first slot ‘202’ in Fig. 2) within guide 124 which flow path maintains throttled minor pressurized fluid flow and consequently, providing supply to port P12. This throttled minor pressurized fluid flow is provided to port P12 and P22, particu- larly when the leakage in the line connected to e.g., port P22 is present, could be envis- aged as one of the technical effects of the feature in question. Further, the throttled supply to port P12 is exhausted through the rupture in the line connected therein.

Fig. 1h is an operating state of valve 100 that is subsequent to the state of valve 100, when the driver removes the force applied on the brake pedal. This operating state of Fig. 1h is also part of dump function enabled by overall structure of valve 100 of the present invention. When the driver does not press the pedal, the pressure form the primary circuit characteristically provided for the towing portion of the vehicle is closed. As a conse- quence, the pressurized fluid applied to port P41 is also at least temporarily stopped. Arrow marks 'AM' in fig. 1h shows upward movement of first piston 102 along axis 108.

It follows from the above that, the gap between valve seat 130 and lateral extension 120 is removed as extension member 114 moves up. Consequently, fluid connection between port P11 and port P22 is interrupted. However, the fluid connection between ports P11 and P12 is established. In contrast to Fig. 1g , as can be noticed, the pressure from the line connected to port P12 is not released to atmosphere because of the non-existence of the gap between valve seat 130 and lateral extension 120.

Figs. 1i and 1j represent operating states similar to the ones explained in Figs. 1g and 1h. However, the difference is the source of pressurized fluid to control the operating state of valve 100 arrives through port P42. In fig. 1i, the inflow of pressurized fluid via port P42 results in vertically downward movement of second piston 104 as the impact of the pres- surized fluid is received on top surface 104s and on wing member 114a of extension member 114. Except for this difference, the operation of valve 100 is similar to the oper- ation illustrated in reference to Figs. 1g and 1h. For instance, the fluid flow in relation to ports P11 , P12 and P22 of Fig. 1i is similar to the fluid flow illustrated in Fig. 1g and the fluid flow illustrated in relation to ports P11 , P12 and P22 of Fig. 1j is similar to the fluid flow illustrated in Fig. 1h. Therefore, the explanation of function of functioning of valve 100 is not repeated herewith. It is however, maybe worth to note that in Fig. 1j, the oper- ating state is achieved due to upward movement of second piston 104 (see arrow marks ‘AM’ labeled in Fig. 1j). The dump function including throttled fluid flow achieved interme- diary valve unit 118 illustrated in reference to Figs. 1g and 1 h is also applicable to Figs. 1i and 1j.

It is noted that the working of valve 100 explained in relation to Figs. 1a to 1j is merely provided for understanding of general working of said valve while technical references provided in relation intermediary valve unit 118 are to read in relation to the detailed ex- planation that will be provided below.

Fig. 2 shows a cross-sectional view of a portion of valve 100 (i.e., trailer control valve) in accordance with an embodiment of the present invention. In particular, the portion re- ferred to is intermediary valve unit 118 of valve 100.

Reference is also made to the dump function that is particularly explained in relation to Figs. 1g to 1j where the role of intermediary valve unit 118 is further exemplified in achiev- ing said dump function and the throttled flow of pressurized fluid within valve 100. While said dump function and the role of said valve unit 118 have been sufficiently explained in association with figures 1g to 1j, emphasis is made that the term “dump” function is merely a technical parlance known to skilled person in the art of the valves used in electro-pneu- matic brake circuits for a vehicle-trailer combination.

In accordance with the present embodiment, as illustrated in Fig. 2 at least one elastically deformable structure 132 includes an elastomeric lip seal or the elastomeric sealing ele- ment with at least two sealing lips 132a and 132b. Together, sealing lips 132a and 132b may provide better fluid tight seal when valve seat 130 moves downward along axis 108, In any case, two sealing lips 132a and 132b may provide improved sealing properties as it contacts a flat surface e.g., sliding surface 126 of guide 124. More information on this is provided below.

In accordance with an embodiment, it is derivable that the elastomeric lip seal or elasto- meric sealing element (132a or 132b) is attached to first valve seat 130. For instance, from Fig. 2, it may be derivable that elastomeric lip seal 132 is continuous like a sheet that covers first valve seat 130, This may however not be necessary. While such an ar- rangement of elastomeric lip seal 132 covering valve seat 130 is preferred, it is foreseen that only the bottom portion of elastomeric lip seal 132 is made of elastic material and an outer cover provided over valve seat 130 could for instance be made of metal or plastic. In accordance with an embodiment, sealing means (including at least one elastically de- formable structure 132) includes a metal sheet covering at least partially first valve seat 130, e.g., on its outer side. Just for the frame of reference, inner side or inner surface of first valve seat 130 receives spring 128 (see e.g,, Figs. 1 a to 1j and Fig. 2) and the side or surface opposite to the inner surface or inner side is outer side or outer surface. In accordance with another embodiment, said metal sheet (covering valve seat 130) in- cludes a provision for receiving said elastomeric lip seal e.g., 132.

In accordance with yet another embodiment, the elastomeric lip seal 132 has at least one protrusion e.g., 132a makes contact with sliding surface 126 of guide 124.

On a different note, from Fig. 2, it should be noted that sliding surface 126 is provided as a curvilinear surface at its top portion or it should be noted that at least a portion of sliding surface 126 is a curvilinear surface (see ‘212’ of Figs 2 and 3). For instance, guide 124 may include plurality of protrusions such as the one labeled as '210’ in fig. 2. Between protrusions 210 there could be a plurality of vertically defined grooves (not shown in Fig. 2, but see e.g., ‘308’ of Fig. 3). Sliding surface 126 includes an including surface 212, at the region where at least partially protrusions 210are located. The technical effect of this curvilinear surface 212 is to provide fluid tight seal in combination with elastomeric lip seal or elastomeric sealing element 132 with e.g., varying tightness. For instance, tightness of fluid tight seal is between seal 132 and surface 212 at a bottom portion is tighter compared to its top portion. While this may not be the only technical reason behind providing such fluid tight seal, it nevertheless plays certain role in defining throttling fluid flow as de- scribed in reference also to Figs. 1g to 1j (see above). As valve seat 130 moves down due to impact of extension member 114, elastomeric lip seal or elastomeric sealing ele- ment 132 forms the fluid tight seal or the increasingly tighter sealing with sliding surface 126, which is also contributed due to curvilinear surface 212 at the top portion. In certain embodiments, sliding surface 126 of guide 124 forms a complementary sealing means to at least one elastically deformable structure 132, wherein sliding surface 126 has said curvilinear surface 212. In other embodiments, it could be other components within hous- ing 110 of valve 100.

In certain implementations of the present invention, it is envisaged that the at least one elastically deformable structure 132 such as elastomeric lip seal (see, e.g., Figs. 4 and/or 5 and their corresponding description) or elastomeric sealing element includes an O-ring (see, e.g., Fig. 6 and its corresponding description).

It is one of the most preferred features of the present invention, wherein curvilinear sur- face 212 and at least one elastically deformable structure 132 form the sealing means and wherein valve 100 is configured such that the linear movement of first valve seat 130 along a longitudinal axis (e.g., 108) enable variable flow of the pressurized fluid e.g., within said valve 100 in general or said intermediary valve unit 118. This flow is mentioned in certain above embodiments as 'throttled flow or reduced flow of pressurized fluid’. As an alternative, it is denoted that the movement of first valve seat 130 along axis 108 en- ables opening and closing of plurality of grooves (see e.g., '308' of Fig. 3) in guide 124. In particular, this is enabled due to the design of guide 124 (more on this in reference to Fig. 3). As shown in Fig. 2, flow path 134 shows the direction or path of pressurized fluid entering port P11 (not shown in Fig. 2). This flow path 134 while traveling within guide 124 is split at a second slot 204 of guide 124 into two paths, namely ‘204a’ and ‘204b’.

Due to the impact of extension member 114 on valve seat 130, valve seat 130 moves against the resistant force of spring 128. Consequent to the movement of valve seat 130, elastically deformable structure 132 is now at a level where it forms fluid tight seal with sliding surface 126 of guide 124. At this said level, the plurality of grooves (see ‘308’ of Fig. 3), the does not or cannot receive pressurized fluid flow following path 204a and hence, the fluid flow is blocked. However, on the other hand, an additional path 204b created due to a first slot 202 provided in guide 124. This slot 202 enables flow of throttled amount of pressurized fluid and connects port P11 with at least one of ports P12 and P22 following path 204b. For instance, connection between port P11 with P22 is enabled also because there is gap between first valve seat 130 and lateral extension 120. Orientation of ports P11 , P12 and P22 in relation to valve 100 is provided in Fig. 2 for the sake of convenience of understanding.

Furthermore, Fig. 2 displays a holder 206 for retaining spring 128. In particular, holder 206 is shown to have concentric cylindrical structures (not labeled) and spring 128 is retained between said structures. As can also be derived from Fig. 2, in accordance with an illustrative embodiment, an enclosure 208 is shown which surrounds guide 124. In accordance with one embodiment, enclosure 208 that surrounds guide 124 includes lateral extension 120. For instance, it may be conceivable to a skilled person from fig. 2, that enclosure 208 is not shown to be integral to housing 110 and in the same instance, it may also be conceivable that it is coaxial to guide 124. Flowever, enclosure 208 may be integral with housing 110. Such work around designs may be envisaged by a person skilled in the art.

Fig. 3 illustrates an isometric view of guide 124 of said portion or intermediary valve unit 118 of said trailer control valve or valve 100 in accordance with an embodiment of the present invention.

As can be derived from Fig. 3 guide 124 includes a plurality of vertically defined grooves 308 which are opened and/or closed based on the linear movement of first valve seat 130 along sliding surface 126. As mentioned above in reference to Fig. 2, the upward move- ment of first valve seat 130 opens the possibility of pressurized fluid to flow through grooves 308 whereas the downward movement of valve seat 130 below the level of grooves 308 does not. Further, how sliding surface 126 of guide 124 is curvilinear after a level to form curvilinear surface 212 is not clearly derivable from Fig. 3 due to its view. However, this can be derived from cross-sectional view provided in Fig. 2.

Furthermore second slot 204 of guide 124 is also shown in Fig. 3. Second slot 204 ena- bles, for example, the flow of pressurized fluid from port P11.

More importantly, throughout figures 1a to 3 and their corresponding detailed description, valve 100 has been disclosed in various details from working principle to constructional features. They all belong to a single embodiment, unless and otherwise specifically claimed as a different embodiment.

Fig. 4 is a schematic view of valve 100 in accordance with an embodiment of the present invention. It is noted that not only through Fig. 4, but also through Figs. 5 and 6, that only schematic view is provided without detailed view of components as has already been explained in conjunction with Figs. 1 a to 1j and Figs. 2 and 3 of the present application. It is believed that such detailed views are not necessary for explaining the alternative embodiments described in association with Figs. 4 to 6. In particular, only components from valve 100 that is necessary for explaining the features related to the embodiments associated with Figs. 4 to 6 are provided. Further details of valve 100 remain mostly same as explained in conjunction with Figs. 1a to 1j and Figs. 2 and 3 of the present application.

As illustrated in Fig. 4, valve 100 with first valve seat 130 is shown to have two elastomeric sealing elements or elastomeric lip seal with two lips 132a and 132b. This has already been illustrated, for instance, in Fig. 2 where two lips 132a and 132b in similar form is displayed. However, in addition to what has been shown in Fig. 2, valve 100 as displayed in Fig. 4 includes complementary sealing means 126a. Complementary sealing means 126a can be made, for instance, of a polymeric or metallic material. For instance, com- plementary sealing means 126a is shown to be attached to surface 126. It is nevertheless noted that it does not have to be the case. In other words complementary sealing means 126a may be attached to any internal surface of any other component of housing 110 (see Figs. 1a to 1j) too. The primary purpose of complementary sealing means 126a is facilitate formation of fluid tight sealing in combination with elastomeric sealing elements or elastomeric lip seal with two lips 132a and 132b when the fluid, for instance, is intro- duced via port P11 thereby prevent flow of the fluid between valve seat 130 and surface 126. The orientation of ports P12 and P22 are merely shown for the sake of illustration in Fig. 4.

Valve seat 130 is configured to linearly move along axis 108 in upward and downward direction as indicated with markings ‘U’ and ‘D’ respectively in Fig. 4. The orientation of upward and downward directions ‘U’ and ‘D’ with due reference to axis ‘108’ is however applicable for all the embodiments of the present application so that a skilled person clearly derives what is actually meant by ‘upward’ and ‘downward’. The range of movement of valve seat 130 is marked with label ‘R’ in Fig. 4, which is applicable for Fig. 5 too. With the movement in said range ‘R', valve seat 130 cooperates with complementary sealing means 126a. It is nevertheless noted that fluid tight seal be- tween lips 132a and 132b and surface 126 is not for entire range of movement ‘R’ by valve seat 130. As shown, for instance, in Fig. 3, there may be grooves 308 beyond a certain level within the movement of valve seat 130 within range ‘R’ after which the fluid that is supplied via e.g., port P11escapes between grooves 308. Thus, a throttled flow of pressurized fluid supplied via port P11 may be achieved in accordance with the present embodiment.

Fig. 5 is a schematic view of said valve 100 in accordance with another embodiment of the present invention.

In accordance with embodiment associated with Fig. 5, valve 100 includes valve seat 130 with single elastomeric deformable structure 132. For instance, elastomeric deformable structure 132 may be directly attached to valve seat 130 or attached to an intermediate cover (not shown in Fig. 5) between elastomeric deformable structure 132 and valve seat 130. Elastomeric deformable structure 132 coordinates with complementary sealing means 126 provided in association with e.g., housing 110 or any component like guide 124 within housing 110.

Fig. 6 is a schematic view of valve 100 in accordance with yet another embodiment of the present invention.

In accordance with the present embodiment, additionally, a cover 130a has been provided above valve seat 130. Further, cover 130a includes a slot 132c in which an elastomeric deformable structure in the form of an O-ring 132d is provided. Said O-ring 132d in com- bination with complementary sealing means 126a forms a fluid tight contact so that the pressurized fluid entering via port P11 does not pass through between them. Reference to embodiments associated with Figs. 4 and 5 is made herewith in relation to complemen- tary sealing means 126a. Finally, it is noted that wherever the term ‘fluid’ is mentioned throughout the application, it is referred, preferably to ‘air’.

LIST OF REFERENCE SIGNS (PART OF THE DESCRIPTION)

100- a valve for controlling flow pressurized fluid to a trailer attached to a vehicle or simply ‘trailer control valve’

102- a first piston

102s- a top surface of the first piston 102

102p- a plurality of relay pistons

104- a second piston

104s- a top surface of the second piston

106- covering

108- axis or longitudinal axis 110- housing

112- spring supporting a linear extension member Ί14'

114- linear extension member

114a- a wing member of linear extension member 114 116- generalized flow direction of the pressurized fluid 118- intermediary valve unit 120- lateral extension 124- guide

126- sliding surface within guide 124

126a- sealing means

128- spring 130- first valve seat

130a- a cover provided above first valve seat 130

132- elastically deformable structure

132a- a first sealing lip (first of the ‘at least two sealing lips’)

132b- a second sealing lip (second of the ‘at least two sealing lips’)

132c- a slot 132d- O-ring

134- flow path within intermediary valve unit 118 as shown in Figs. 1b to 1j

134a- an additional flow path within intermediary valve unit 118 as shown in Figs. 1b to

1j

202- a first slot within the body of guide 124 as shown in Fig. 2 204- a second slot

204a- a first of two flow paths created due to the design of e.g., slots 202, 204 within guide 124

204b- a second of two flow paths created due to the design of e.g., slots 202, 204 within guide 124

206- a holder retaining spring 128

208- enclosure

210- protrusions of guide 124

212- a curvilinear surface of guide 124

308- grooves

P11- a port for receiving pressurized fluid from a supply source such as a reservoir P12- a port for providing supply pressure for applying the trailer brakes

P22- a port for providing ‘control’ pressure or for providing pressurized fluid for controlling the trailer brakes

P41- a port for receiving pressurized fluid from a primary control pressure source e.g., a foot brake valve for controlling the trailer brakes

P42- a port for receiving secondary control pressure from e.g., the foot brake valve for controlling the trailer brakes

P43- a port for receiving control pressure from a hand brake valve for controlling the trailer brakes ‘AM’ - arrow marks denoting movement of different components such as pistons within the trailer control valve.

Claims

1. A trailer brake control valve (100), comprising: a housing (110) including a lateral extension (120) and a guide (124) with a sliding surface (126); a first port (P11) for receiving pressurized fluid from a first source of pres- surized fluid; a second port (P22) being selectively connected to the first port (P11), wherein the second port (P22) is configured to provide control pressure to one or more brakes at a trailer (200); a third port (P12) operably connected to the first port (P11), wherein the third port (P12) is configured to provide supply pressure to the brakes pro- vided at the trailer (200); and an intermediary valve unit (118) configured to directly facilitate the connec- tion between at least the first port (P11), and second port (P22), wherein the intermediary valve unit (118) comprises: a spring (128); a first valve seat (130) being supported by the spring (128), the valve seat (130) experiencing an upward force due to the spring (128), and engaging with the lateral extension (120) of the housing (110), wherein the first valve seat (130) is configured to move in a down- ward direction (D) on experiencing a downward force that is greater than the elastic force of the spring (128) thereby disengaging from the lateral extension (120) of the housing (110), and characterized in that, the intermediary valve unit (118) additionally comprises seal- ing means that is attached to the first valve seat (130), wherein the sealing means includes at least one elastically deformable structure (132) that forms a fluid tight sealing in association with the sliding surface (126) of the guide (124) of the hous- ing (110).

2. The valve (100) of claim 1 , wherein the at least one elastically deformable structure (132) includes an elastomeric lip seal or an elastomeric sealing element (132a; 132b) with at least one sealing lip (132a; 132b) and preferably, at least two sealing lips (132a, 132b).

3. The valve (100) of claim 2, wherein the elastomeric lip seal or elastomeric sealing element (132a; 132b) is either directly or indirectly attached to the first valve seat (130).

4. The valve (100) of claim 2 or 3, wherein the elastomeric lip seal or elastomeric sealing element (132a; 132b) has at least one protrusion (132) that makes contact with the sliding surface (126) of the guide (124).

5. The valve (100) of claim 1, wherein the sealing means includes a metal sheet at least partially covering the first valve seat (130).

6. The valve (100) of claim 5, wherein the metal sheet includes a provision for receiv- ing the elastomeric lip seal or elastomeric sealing element (132a or 132b).

7. The valve (100) of any one of the above claims, preferably wherein the elastomeric lip seal or elastomeric sealing element (132a or 132b) includes an O-ring.

8. The valve (100) of any one of the above claims, wherein the sliding surface (126) of the guide (124) forms a complementary sealing means to the at least one elas- tically deformable structure (132), wherein a portion of the sliding surface (126) has a curvilinear surface (212).

9. The valve (100) of claim 8, wherein the curvilinear surface (212) and the at least one elastically deformable structure (132) form the sealing means and wherein the valve (100) is configured such that linear movement of the first valve seat (130) along a longitudinal axis (108) enable a variable flow of pressurized fluid.

10. The valve (100) of claim 9, wherein the guide (124) includes a plurality of vertically defined grooves (308) which are opened and/or closed based on the linear move- ment of the first valve seat (130) along the sliding surface (126).

11. The valve (100) of any one of the above claims, wherein the intermediary valve unit (100) is configured such that it provides a throttled flow of pressurized fluid to the third port (P12) even when there is a leakage detected in second port P22.

12. Use of the valve (100) in accordance with any one of the above claims in tractor- trailer combination type of vehicle.