BRAKE PRESSURE MODULATOR AND USE OF A BRAKE PRESSURE MODULATOR

Abstract

A brake pressure modulator (110; 106) includes a relay valve (202) for controlling a supply of pressurized air from a primary source (II) to at least one brake actuator (112a, 112b), a first valve sub-unit (204) configured to be electronically actuated and configured to receive a primary control pressure from the primary source (II) intended for operating the relay valve (202), and a second valve unit (206) configured to receive a secondary control pressure from a secondary source (‘BST’) and at least part of the primary control pressure from the primary source (II) and to transmit either the primary control pressure or the secondary control pressure to the relay valve (202). When the secondary control pressure is transmitted to the relay valve (202), the primary control pressure from the primary source (II) is disconnected.

Claims

1. A brake pressure modulator (110; 106), comprising: a relay valve (202) for controlling a supply of pressurized air from a primary source (II) to at least one brake actuator (112a, 112b); a first valve sub-unit (204) configured to be electronically actuated, wherein the first valve sub-unit (204) is configured to receive a primary control pressure from the primary source (II) intended for operating the relay valve (202); and a second valve unit (206) configured to at least receive a secondary control pressure from a secondary source (‘BST’) and at least part of the primary control pressure from the primary source (II) and to transmit either the primary control pressure or the secondary control pressure to the relay valve (202), and wherein, when the secondary control pressure is transmitted to the relay valve (202) from the second valve unit (206), the primary control pressure from the primary source (II) is disconnected, and when the primary control pressure is transmitted to the relay valve (202) from the second valve unit (206), the secondary control pressure from the secondary source is disconnected, and wherein the second valve unit (206) is a mechanically operable valve, wherein said mechanically operable valve is a double-sided check valve (206) that selectively transmits the pressure of a higher magnitude among the primary control pressure and secondary control pressure received from the primary source (II) and the secondary source (BST), respectively, to the relay valve (202) and wherein the first valve sub-unit (204) includes at least two solenoid controlled valves (208, 210), wherein an outlet (208.2) of a first one (208) of the at least two solenoid controlled valves (208, 210) leads to an inlet (206.1) of said double-sided check valve (206) and also to an inlet (210.1) of a second one (210) of the at least two solenoid controlled valves (208, 210).

2. The brake pressure modulator (110; 106) of claim 1, wherein the double-sided check valve (206) includes a spool (302) having two opposite sides (302a; 302b), wherein a first one of the two opposite sides receives the pressurized air from the primary source (II) and a second one of the two opposite sides receives the pressurized air from the secondary source (BST).

3. The brake pressure modulator (110; 106) of claim 2, wherein the double-sided check valve (206) includes a casing (304) that covers the spool (302), wherein the spool (302) linearly translates within the casing (304), and wherein the direction of movement of the spool (302) within the casing (304) is directly dependent on a difference in the magnitude of the pressure received from primary source (II) and the secondary source (BST).

4. The brake pressure modulator (110; 106) in accordance with claim 3, wherein the casing (304) includes a shoulder portion (304.1) that limits the linearly translating movement of the spool (302) in at least one of the two directions (‘L’ or ‘R’).

5. The brake pressure modulator (110; 106) of claim 2, wherein each of the two opposite sides (302a and 302b) of the spool (302) includes a conical depression (302c, 302d).

6. The brake pressure modulator (110; 106) of claim 3, wherein the double check valve (206) further includes an external sleeve (310) within which the casing (304) is disposed, and wherein at least one sealing ring (310.3) is provided between the external sleeve (310) and the casing (304) so as to establish an air-tight assembly between them.

7. The brake pressure modulator (110; 106) of claim 1, wherein the first valve sub-unit (204) includes first and second solenoid controlled 2/2 direction control valves (208, 210) and wherein, based on an actuation state of each of the first and second solenoid controlled 2/2 direction control valves, the brake pressure modulator (110; 106) performs at least one of the following functions: enabling the supply of the primary control pressure from the primary source (II) to actuate the relay valve (202); disabling or blocking the supply of the primary control pressure from the primary source (II) to the relay valve (202); and/or releasing the primary control pressure from the primary source (II) to the atmosphere, wherein the primary control pressure is intended for operating the relay valve (202).

8. The brake pressure modulator (110; 106) of claim 1, wherein the relay valve (202), the first valve sub-unit (204), and the second valve unit (206) in the form of the double-sided check valve are encompassed within a single cast body of the brake pressure modulator (110; 106).

9. The brake pressure modulator (110; 106) of claim 1, wherein the brake pressure modulator (110; 106) controls supply of the pressurized air to brake actuators (112a, 112b) of the at least one brake actuator that are associated with a front axle (FA) of a vehicle.

10. The brake pressure modulator (110; 106) of claim 7, wherein a spatial arrangement or spatial requirement of each of the two solenoid controlled 2/2 direction control valves (208, 210) within the brake pressure modulator (110; 106) is the same as a spatial arrangement or spatial requirement of the double-sided check valve (206).

11. The brake pressure modulator (110; 106) of claim 1, further comprising a pressure sensor (212), wherein said pressure sensor (212) is a Pulse-Width-Modulation (PWM) based pressure sensor.

12. The brake pressure modulator (106; 110) of claim 1, wherein the brake pressure modulator (106; 110) is installed in a pneumatic brake system (100) comprising: a centralized pressure modulator (102) connected to the brake pressure modulator (106; 110), and a centralized electronic control unit operatively connected with the centralized pressure modulator (102), wherein the centralized electronic control unit transmits control signals to at least the first valve sub-unit (204).

13. The brake pressure modulator (106; 110) of claim 1, wherein the brake pressure modulator (106; 110) and the pneumatic brake system (100) are installed in a vehicle.

14. The brake pressure modulator (106; 110) of claim 1, wherein the brake pressure modulator is used as a trailer control valve (106).

15. The brake pressure modulator (106; 110) of claim 1, wherein the brake pressure modulator is used as a rear axle brake pressure modulator (104).

16. The brake pressure modulator (106; 110) of claim 7, wherein, when the first solenoid controlled 2/2 direction control valve (208) is in an open state, supply of at least part of the primary control pressure form the primary source is provided via an outlet port (208.2) to the double-sided check valve (206), when the first solenoid controlled 2/2 direction control valve (208) is in a closed sate, the supply of the primary control pressure to the double-sided check valve is blocked, and

17. The brake pressure modulator (110; 106) of claim 16, wherein when the second solenoid controlled 2/2 direction control valve (210) is in an open state, the primary control pressure provided via the outlet port (208.2) of the first solenoid controlled 2/2 direction control valve (208) is exhausted via an outlet port (210.2) to an exhaust port (202.4), and when the second solenoid controlled 2/2 direction control valve (210) is in a closed state, primary control pressure provided via the outlet port (208.2) of the first solenoid controlled 2/2 direction control valve (208) is directed to an inlet port (206.1) of the double-sided check valve (206).

18. The brake pressure modulator (110; 106) of claim 1, wherein the first valve sub-unit (204) and the relay valve (202) are each connected to the primary source via a bifurcated connection, wherein a connection from the primary source splits such that one connection leads directly a first port (208.1) of the first valve sub-unit (204) and another connection leads directly to the relay valve (202).

19. The brake pressure modulator (110; 106) of claim 5, wherein each of the conical depressions has the same cross-sectional profile such that a minute difference in pressure experienced at the opposite sides of the spool (302) causes linear translation of the spool (302), and supply of control pressure to the relay valve (202) is provided from the side of the spool (302) having the greater magnitude pressure.

20. The brake pressure modulator (110; 106) of claim 6, wherein the casing (304) defines a first inlet (304a) and the external sleeve (310) defines a second inlet (306), and the casing includes a first shoulder stop (304b) and the external sleeve defines a second shoulder stop (310.2), wherein the casing is slidably received in the external sleeve in a tube portion (310.1) of the external sleeve in an interference fit in an airtight manner, and the spool (302) linearly reciprocates between the first and second shoulder stops (304b; 310.2) in response to differences in pressure present at the first inlet (304a) and the second inlet (306).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 illustrates a pneumatic brake system of a vehicle in accordance with an embodiment of the present disclosure;

[0044] FIG. 2 illustrates a brake pressure modulator in accordance with an embodiment of the present disclosure;

[0045] FIG. 3a illustrates a cut-section of a double-sided check valve in accordance with an embodiment of the present disclosure;

[0046] FIG. 3b illustrates a perspective view of a double-sided check valve in accordance with an embodiment of the present disclosure;

[0047] FIG. 3c illustrates a cross-sectional view of a brake pressure modulator in accordance with an embodiment of the present disclosure;

[0048] FIG. 4 illustrates a conventional brake pressure modulator; and

[0049] FIG. 5 illustrates a cross-sectional view of the conventional brake pressure modulator.

[0050] Further details and advantages of different components are explained in the detailed description provided below. The labeling of the elements of different drawings is not to be construed as limiting. The scope of the present disclosure is defined by one or more claims listed under ‘claims’ section.

[0051] For identical or equivalent items or items of identical or equivalent function in the following the some reference marks are used. For corresponding features thus it is referred to the above description.

DETAILED DESCRIPTION

[0052] FIG. 1 illustrates a pneumatic brake system 100 of a vehicle (not labeled) in accordance with an embodiment of the present disclosure. Alternatively, the vehicle (not labeled) includes pneumatic brake system 100.

[0053] Pneumatic brake system 100 in general includes a centralized (brake) pressure modulator 102, which is configured, inter alia, to receive a brake control input in the form of control pressure from a brake signal transmitter (labeled as ‘BST’ in FIG. 1) and in a preferred embodiment, to receive electronic signals from Electronic Stability Controller Module (ESCM) 102a connected to it via e.g., CAN (Controller Area Network) bus. In a further preferred embodiment, centralized pressure modulator 102 is also connected to a Power Line Carrier (PLC) 108 that is, for example, connected to a trailer (not shown in FIG. 1). It is noted that the driver of the vehicle actuates a brake pedal or BST to supply brake pressure to wheel end actuators 112a, 112b, 112c, 112d associated with different wheels (not shown in the figure).

[0054] In modern pneumatic brake systems such as the one shown in FIG. 1, the BST simply transmits an electronic signal using a stroke sensor (not shown in FIG. 1) to read a control output from a brake pedal (not shown in FIG. 1) to a central brake pressure modulator unit provided in combination with centralized pressure modulator 102. Said stroke sensor (not shown in FIG. 1) is configured to read or determine the movement of a plunger as a result of the driver applying pressure on the brake pedal.

[0055] On receiving the control inputs from the BST, centralized pressure modulator 102 transmits control pressure to the brake pressure modulators, in particular to the ones located at front axle ‘FA’ as well as to the brake pressure modulator assigned for trailer brakes. In FIG. 1, the brake pressure modulator assigned for the front axle brakes is labeled as “110” and the brake pressure modulator assigned for the trailer brakes is labeled as “106”. From the respective brake pressure modulators, the control pressure is transferred to respective wheel end actuators 112a, 112b, 112c and 112d through which the vehicle brakes are applied.

[0056] Furthermore, there different accumulators or reservoirs displayed in FIG. 1 are for supplying pressurized air to different receivers present within pneumatic brake system 100. For instance, reservoir ‘I’ is configured to supply pressurized air to wheel end actuators 112c and 112d present at the rear axle of the vehicle whereas reservoir ‘III’ is predominantly for applying parking brakes and supplying pressurized air to trailer brake pressure modulator 106. Reservoir ‘II’ is for supplying pressurized air to front axle brake control modulator 110.

[0057] Pneumatic brake system 100 of the present embodiment also additionally discloses wheel speed sensors WSS1, WSS2, WSS3 and WSS4 located at each of the wheels to determine their rotational speeds, a CAN network unit 114 (refers to a networking unit operating via CAN protocol), an on-board battery 116, and a steering angle sensor 118. The functioning of these components is not part of the present invention and therefore, no further explanation is provided in this regard.

[0058] Additionally, pneumatic brake system 100 includes also park brake control unit denoted as—PB—in FIG. 1. For instance, PB is connected to brake pressure modulator 104, which in accordance with an embodiment used for modulating parking brakes, and which is also associated with the spring brakes (or e.g., the actuators 112c and 112d) of a rear axle, (denoted as—‘RA’—in FIG. 1).

[0059] Further details of brake pressure modulators 110 and/or 106 of the present disclosure are provided in the forthcoming sections. To the extent the subject-matter of the present invention relates to the brake pressure modulator 110 associated with front axle FA of the vehicle, the underlying features of the claimed invention and the technical teaching associated with the brake pressure modulators provided at other parts of pneumatic brake system 100, including centralized pressure modulator 102, trailer brake pressure modulator 106 and exceptionally, rear axle pressure modulator 104.

[0060] FIG. 2 illustrates a brake pressure modulator 110 in accordance with an embodiment of the present disclosure.

[0061] As shown in FIG. 2, brake pressure modulator 110 includes a relay valve 202 for controlling a supply of pressurized air from a primary source (II) to at least one brake actuator of 112a, 112b (see FIG. 1). For instance, actuation of relay valve 202 enables connection between supply lines 202.1 and 202.2. Supply line 202.1 is connected to reservoir ‘II’ (see FIG. 1) whereas supply line 202.2 leads to Anti-lock Braking System valves ABS-1 and ABS-2 (see FIG. 1) and consequently, to wheel end actuators 112a and 112b.

[0062] However, in order to open and/or close relay valve 202, typically, a control pressure is required. As can be derived from FIG. 2, this control pressure is received from a second valve unit 206. Second valve unit 206, in accordance with the present embodiment is a mechanically operable valve. In turn, second valve unit 206 receives control pressure inputs from either of control input lines 206.1 and 206.2. In an exemplary embodiment, control input line 206.1, for instance, is connected to a first valve sub-unit 204 whereas control input line 206.2 is connected to BST (see FIG. 1).

[0063] In accordance with the present embodiment, first valve sub-unit 204 is configured to be electronically actuated, wherein first valve sub-unit 204 is configured to receive a primary control pressure from the same primary source such as reservoir ‘II’ intended for operating relay valve 202. For instance, see e.g. reference sign 202.3 where connection to reservoir II is shown to bifurcate, wherein one leads to supply line 202.1 and another leads to port 208.1 of a first solenoid controlled 2/2 direction control valve 208 of first valve sub-unit 204.

[0064] Further, in accordance with the same embodiment, second valve unit 206 is configured to at least receive a secondary control pressure from a secondary source (such as ‘BST’ of FIG. 1) and at least part of the primary control pressure from the primary source (such as reservoir ‘II’ of FIG. 1) and to transmit either the primary control pressure or the secondary control pressure to relay valve 202, in particular for activation of relay valve 202 to e.g., open, and wherein, when the secondary control pressure is transmitted to relay valve 202, the primary control pressure from the primary source (such as reservoir ‘II’ of FIG. 1) is disconnected.

[0065] Furthermore, in a preferred embodiment, first valve sub-unit 204 includes at least two solenoid controlled valves 208, 210 (more on this below). An outlet 208.2 of a first one 208 of at least two solenoid controlled valves 208, 210 leads to an inlet 206.1 of said double check valve 206 and to an inlet of a second one 210 of the at least two solenoid controlled valves 208, 210. As mentioned also in the summary section above, the technical advantage of enabling the connection between outlet 208.2 of the first one of the at least two solenoid controlled valves 208, 210 and inlet 206.1 of said double check valve 206 while at the same time enabling the connection between outlet 208.2 and inlet 206.1 of second one 210 of the at least two solenoid controlled valves 208, 210 is that the structural connection is comparatively simplified. A skilled person would appreciate this when it is seen in comparison to e.g., DE102018122193A1. The structural connections existing within the first valve sub-unit from DE102018122193A1 is rather complicated in that it makes the overall functioning of the brake pressure modulator disclosed, before the control pressure reaching double check valve 206, rather intricate. It is one of the objectives of the present invention to simplify the design of the pre-control region (e.g., region associated with first valve sub-unit 204) of brake pressure modulator 110 before the control pressure from the primary source (II) reaches double check valve 206.

[0066] In accordance with a preferred embodiment, it should be noted that second valve unit 206 receives at least part of the primary control pressure from the primary source via first valve sub-unit 204. In accordance with the present embodiment, wherein said two solenoid control valves 208, 210 are two solenoid controlled “2/2” direction control valves 208, 210 and wherein, based on an actuation state of each of the two direction control valves 208 and 210, brake pressure modulator 110 is configured to perform one of the following functions: [0067] enabling the supply of the primary control pressure from the primary source (II) to actuate relay valve 202; [0068] disabling or blocking the supply of the primary control pressure from the primary source (II) to relay valve 202; and [0069] releasing the primary control pressure from the primary source (II) to the atmosphere, wherein the primary control pressure is intended for operating relay valve 202.

[0070] An additional function of releasing the primary control pressure towards second valve unit 206 is also provided, which will be explained below.

[0071] The functions listed above will be explained in detail as follows.

[0072] For instance, when first solenoid controlled 2/2 direction control valve 208 is in an open state, supply of at least part of the primary control pressure from the primary source such as reservoir II is allowed. When said valve 208 is in closed state, the supply of the primary control pressure from the primary source (II) to relay valve 202 is either disabled or blocked. In the same example, when valve 208 is in the open state, the primary control pressure exits valve 208 at port 208.2.

[0073] It follows from the above, when second controlled 2/2 direction control valve 210 is in an open state, the primary control pressure is exhausted at port 202.4. However, when second solenoid controlled 2/2 direction control valve 210 is closed, the primary control pressure from valve 208 is directed to port 206.1 of second valve unit 206. In accordance with this embodiment, valve 210 includes first and second connection ports 210.1 and 210.2 where first connection port 210.1 is configured to act as inlet port for valve 210 and second connection port 210.2 is configured to act as outlet port for valve 210.

[0074] Further, in the present embodiment of brake pressure modulator 110, the second valve unit 206 is a double-sided check valve 206 that is configured to selectively transmit the pressure of a higher magnitude among the primary and secondary control pressure received from the primary source (II) and the secondary source (BST), respectively. For instance, more details on double-sided check valve 206 and its functioning are explained in conjunction with FIGS. 3a and 3b below.

[0075] The primary technical advantage of the presence of double-sided check valve 206 is to, for instance, prevent additional wiring elements and associated space constraints by simply providing a mechanical solution that is workable in all pressure differential conditions. For instance, a minor difference in pressure magnitude between the pressurized air received from e.g., ports 206.1 and 206.2 causes a spool 302 (see FIG. 3a) to move. This provides the pressure with higher magnitude to be supplied for actuating relay valve 202 and makes a connection between lines 202.1 and 202.2. For a manufacturer, such as the Applicant, considering the number of products manufactured, this results in also considerable cost savings.

[0076] Still further, as mentioned before, in brake pressure modulator 110 of the present embodiment, double-sided check valve 206 includes the spool 302 (see FIG. 3a), in particular, with two opposing sides 302a and 302b (see FIG. 3a), wherein a first one among the two opposite sides receives the pressurized air from the primary source (II) e.g., via port 206.1 and a second one among the two opposite sides receives the pressurized air from the secondary source (BST) e.g., via port 206.2.

[0077] In accordance with one of the advantageous embodiments of the present application, double-sided check valve 206 includes a casing (e.g., 304 or 310 of FIG. 3a) which covers the spool 302 (see FIG. 3a), wherein the spool 302 is configured to linearly translate within the casing (e.g., 304 or 310 of FIG. 3a), and wherein the direction of movement of the spool 302 within the casing 304 or 310 is directly dependent on a difference in the magnitude of the pressure received from primary source (II) and the secondary source (BST). Further details on the type of functioning of double-sided check valve 206 and its technical characteristics are explained in reference to FIGS. 3a and 3b below.

[0078] Finally, a pressure sensor 212 is provided in supply pressure line 202.2 connecting relay valve 202 and port 202.5, which connects to actuators 112a and 112b. This pressure sensor 212 sends readings to centralized brake pressure modulator 102, for instance, to determine the presence of flow of pressurized air in line 202.2 and/or the magnitude of the pressure in said line. In accordance with a preferred embodiment, pressure sensor 212 is Pulse-Width-Modulation (PWM) based pressure sensor. As an exemplary explanation, it is mentioned herewith that the PWM based pressure senor provides a pulse-width-modulated output of pressure readings in e.g., line 202.2. For instance, when brake pressure modulators such as the one disclosed in the present invention are used in an environment with external disturbances, the usage of PWM based pressure sensor may enable providing highly accurate pressure readings. For another instance, the technical purpose of providing PWM based pressure sensor as pressure sensor 212 is for enabling compliance according to “functional safety” as per ISO standard 26262.

[0079] In an exemplary embodiment, it should be noted that valves 208, 210 are electronically actuatable based on the pressure modulating signals received from centralized pressure modulator 102. For instance, electronically controlled braking processes such as Electronic Braking System, anti-roll braking methods, anti-skid braking methods, anti-jack-knifing methods are implemented through the controlled logic stored in centralized pressure modulator 102 which naturally may include an electronic processing unit or electronic control unit of suitable caliber.

[0080] FIG. 3a illustrates a cut-section of double-sided check valve 206 in accordance with an embodiment of the present invention.

[0081] In accordance with the present embodiment, double-sided check valve 206 includes spool 302 with two opposing sides 302a and 302b, and a casing 304 within which spool 302 is configured to linearly translate or move in a linear fashion. The direction of movement of spool 302 within casing 304 is governed by which one of the sides 302a and 302b the pressurized air hits or which one of sides 302a and 302b of spool 302 experiences a pressure of higher magnitude. Alternatively, the ‘sides’ mentioned within the context of the present embodiment may also be called ‘surfaces’ or ‘contact surfaces’ of spool 302. The pressurized air is configured to either enter via a first inlet 304a present as part of casing 304 or via a second inlet 306. In accordance with one embodiment, the pressurized air entering the first inlet 304a is from BST (see FIG. 1) whereas the pressurized air entering the second inlet 306 is from first valve sub-unit 204 (see FIG. 2).

[0082] Furthermore, as shown in FIG. 3a, each of two opposing sides 302a and 302b includes a first and second conical depressions 302c and 302d. Said conical depressions 302c and 302d enable better reception (due to its depressed profile) of pressurized air such that its impact is better received at spool 302. In accordance with an exemplary implementation, the cross-sectional profiles of first and second conical depressions 302c and 302d are the same. For instance, such conical depressions ensure the functional integrity of double check valve 206 so that when all other physical conditions are the same, only the minute difference in pressure experienced at each of first and second sides 302a and 302b should be the factor which contributes to the linear (translatory) motion of spool 302.

[0083] If the pressure entering inlet 304 is of higher magnitude and impacts side 302b, spool 302 is configured to move from ‘left’ marked as ‘L’ in FIG. 3a towards ‘right’ marked as ‘R’ in FIG. 3a. Alternatively, if the magnitude of pressure entering inlet 306 is of higher magnitude, spool 302 moves from ‘right’ (R) to ‘left’ (L). For instance, the movement of spool 302 can be triggered with a difference in the pressure entering first and second inlets 304a and 306 being approximately 0.1 Bar.

[0084] It is one of the technical advantages of the present invention that double-sided check valve 206 is configured to achieve a similar function of a 2/2 solenoid valve 406 as shown in conventional brake modulator 400 in FIG. 4, but without occupying further space for the additional wiring. This contributes to e.g., cost saving on the product i.e., the brake pressure modulator while at the same time complying with the safety requirements.

[0085] In accordance with the same embodiment, casing 304 includes a shoulder portion 304.1 to limit the linearly translating movement of the spool 302 in at least one of the two directions ‘L’ or ‘R’, as can be derived from FIG. 3a.

[0086] In accordance with an advantageous embodiment, casing 304 is further enclosed by an external sleeve 310. In one exemplary embodiment, external sleeve 310 is integral to casing 304. Furthermore, in accordance with an embodiment, external sleeve 310 is provided with second inlet 306 whereas first inlet 304a is provided at casing 304. In the same embodiment, external sleeve 310 may include a horizontal tube portion 310.1 within which casing 304 is positioned in a sliding manner with e.g. an interference fit so as to establish airtight assembly between casing 304 and external sleeve 310. Furthermore, in the present embodiment, the air-tight assembly between casing 304 and external sleeve 310 is established with the help of at least one sealing ring 310.3.

[0087] In the same or another embodiment, casing 304 may include a first shoulder stop 304b and external sleeve 310 may include a second shoulder stop 310.2, wherein spool 302 is configured to linearly reciprocate between first and second shoulder stops 304b and 310.2. In other words, said shoulder stops 304b and 310.2 are configured to function as stoppages for spool 302's movement.

[0088] FIG. 3b illustrates a perspective view of double-sided check valve 206 in accordance with an embodiment of the present invention.

[0089] In the perspective view, outlet 308 of double-sided check valve 206 is shown which is connected to a third supply line 206.3 (see FIG. 2) of double-sided check valve 206. This third supply line 206.3 leads to relay valve 202.

[0090] It is noted herewith that the underlying technical teaching of the present invention is equally applicable for the brake pressure modulator e.g., ‘110’ of FIG. 1 that is associated with the front axle (FA) of the vehicle as well as the brake pressure modulator that is associated with the trailer e.g., ‘106’ of FIG. 1.

[0091] FIG. 3c illustrates a cross-sectional view of brake pressure modulator 110 in accordance with an embodiment of the present invention.

[0092] As can be noticed in FIG. 3c, brake pressure modulator 110 of the present invention is shown to include double-sided check valve 206 in the exact same position as valve 406 provided in conventional brake pressure modulator 400 of FIG. 5, without effecting further detailed changes within a housing 312.

[0093] In the same embodiment, it is also clear that the spatial arrangement of each of the two solenoid controlled 2/2 direction control valves 208, 210 within brake pressure modulator 110 or 106 is the same as the spatial requirement of double-sided check valve 206.

[0094] It is one of the technical advantages of the present invention that double-sided check valve 206 of the present invention and solenoid operated valve 406 of conventional brake modulator 400, even though having exactly the same spatial constraints, they function similarly in allowing both pneumatic control from BST as well as electric control provided by first valve sub-unit 204 This, but as already mentioned throughout the application, the double-side check valve 206 of the present disclosure results in a considerable cost saving and has an effect on the total pricing of brake pressure modulators such as ‘110’ or ‘106’. For a volume manufacturer, such as the applicant, this results in not only simply constructed brake pressure modulator, may also reduce the assembly costs.

LIST OF REFERENCE SIGNS USED IN THE FIGURES (PART OF THE DESCRIPTION)

[0095] 100 pneumatic brake system [0096] 102 centralized pressure modulator [0097] 102a Electronic Stability Controller Module (ESCM) [0098] 104 brake pressure modulator at a rear axle (RA) [0099] 106 trailer brake pressure modulator [0100] 108 Power Line Carrier (from trailer side) [0101] 110 front axle brake control modulator [0102] 112a, 112 b brake actuators at front axle [0103] 112c, 112d brake actuators at rear axle [0104] 114 CAN network unit [0105] 116 on-board battery [0106] 118 steering angle sensor [0107] FA, RA front axle, rear axle [0108] WSS1, WSS2, WSS3, WSS4 wheel speed sensors associated with respective wheels [0109] I, II, III reservoirs [0110] PB Parking Brake [0111] BST Brake Signal Transmitter [0112] ABS1, ABS2 Anti-lock Braking System [0113] 202 relay valve [0114] 202.1, 202.2 supply lines [0115] 202.3 connection to reservoir II [0116] 202.4, 202.5 connection port [0117] 204 first valve sub-unit [0118] 206 second valve unit [0119] 206.1, 206.2 control input lines [0120] 208 first solenoid controlled 2/2 direction control valve [0121] 208.1, 208.2 connection ports of first solenoid controlled 2/2 direction control valve 208 [0122] 210 second solenoid controlled 2/2 direction control valve [0123] 210.1, 210.2 first and second connection ports for second solenoid controlled 2/2 direction control valve 210 [0124] 212, 414 pressure sensor [0125] 302 spool [0126] 302a first side of spool 302 [0127] 302b second side of spool 302 [0128] 302c first conical depression on side 302a [0129] 302d second conical depression on side 302b [0130] 304 casing [0131] 304.1 shoulder portion of casing 304 [0132] 304a first inlet of casing 304 [0133] 304b first shoulder stop (of casing 304) [0134] 306 second inlet [0135] 308 outlet [0136] 310 external sleeve [0137] 310.1 horizontal tube portion [0138] 310.2 second shoulder stop (of external sleeve 310) [0139] 310.3 sealing ring [0140] 312 housing [0141] 400 conventional brake pressure modulator [0142] 402 relay valve [0143] 404 first valve unit [0144] 404a, 404b electronically actuatable valves [0145] 406 electronically actuatable valve [0146] 408 control pressure inlet [0147] 410 inlet [0148] 412 outlet [0149] 502 housing