Brake pressure modulator, pneumatic brake system and vehicle

A brake pressure modulator (110, 110a, 110b, 110c, 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 opening 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), wherein,
• when the secondary control pressure is transmitted to the relay valve (202), the primary control pressure from the primary source (II) is disconnected, and when the primary control pressure is transmitted to the relay valve (202), the secondary control pressure from the secondary source (BST) is disconnected,
• wherein the second valve unit (206) is a mechanically operable valve, in form of a pneumatically controlled valve (206D, 206A, 206B, 206C) having a valve casing (304), the valve casing (304) comprising:
• a pressurized guiding sleeve (304.4) defining a valve chamber (305) that axially guides a pressure pickup piston or spool (320) adapted for pneumatic actuation thereof, and
• a coil casing (304.5) defining a coil chamber (306) adjacent to the pressurized guiding sleeve (304.4), wherein the coil casing includes an open space that is radially adjacent and outside of the guiding sleeve, wherein the open space is sized and configured to extend around the guiding sleeve,
• wherein the valve chamber (305) is free of a spring (321) and the open space of the coil chamber (306) is free of a coil and free of a solenoid (311), such that the spool (320) is actuable pneumatically only, wherein the spool (320) is subject to a pneumatic force only due to pneumatic pressure in the valve chamber (305);
• wherein the pneumatically controlled valve (206A, 206B, 206C) is a 3/2-directional valve, wherein the 3/2-directional valve switches between a first and a second state when receiving a first and/or second switch-control pressure (P1, P2) derived from the primary and/or secondary control pressure (Pc1, Pc2), wherein the 3/2-directional valve, in the second state transmits the secondary control pressure to the relay valve (202) and in the first state transmits the primary control pressure to the relay valve (202).

A brake pressure modulator (110, 110a, 110b, 110c, 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 opening 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), wherein,
• when the secondary control pressure is transmitted to the relay valve (202), the primary control pressure from the primary source (II) is disconnected, and when the primary control pressure is transmitted to the relay valve (202), the secondary control pressure from the secondary source (BST) is disconnected,
• wherein the second valve unit (206) is a mechanically operable valve, in form of a pneumatically controlled valve (206D, 206A, 206B, 206C) having a valve casing (304), the valve casing (304) comprising:
• a pressurized guiding sleeve (304.4) having a guiding sleeve wall defining a valve chamber (305) that axially guides a pressure pickup piston or spool (320) adapted for pneumatic actuation thereof, and
• a coil casing (304.5) defining a coil chamber (306) adjacent to the pressurized guiding sleeve (304.4), wherein the coil chamber includes an open space that is radially adjacent and outside of the guiding sleeve wall, wherein the open space the coil casing is sized and configured to extend around the guiding sleeve wall,
• wherein the valve chamber (305) is free of a spring (321) and the open space of the coil chamber (306) is free of a coil and free of a solenoid (311), such that the spool (320) is actuable pneumatically only, wherein the spool (320) is subject to a pneumatic force only due to pneumatic pressure in the valve chamber (305);
• wherein the relay valve (202), the first valve sub-unit (204), and the second valve unit (206) are encompassed within a single cast body of the brake pressure modulator (110,106);
• wherein the guiding sleeve (304.4) and the guiding sleeve wall are axially fixed relative to each other, wherein the pressure pickup piston or spool (320) slidably moves within the guiding sleeve wall.