A brake modulator (1) for a compressed air braking system (80) of a vehicle is disclosed. The brake modulator (1) has a main housing (8) and two relay valves (2, 3) Each relay valve is configured with a delivery valve seat (31, 131) and a vent valve seat (30, 130) and a vent position, wherein compressed air inlets (2d, 3d) are connected via a transverse bore (27) to a common compressed air inlet port (25, 26), and a delivery duct (12a, 112a) extends in the axial direction (A) in each relay valve (2, 3) The relay valves (2, 3) have guide body inserts (12, 112) which are inserted into a longitudinal bore (29) of the main housing (8), which longitudinal bore (29) extends in the axial direction (A), and the relay valves (2, 3) in each case have the delivery duct (12a, 112a).

A brake modulator (1) for a compressed air braking system (80) of a vehicle is disclosed. The brake modulator (1) has a main housing (8) and two relay valves (2, 3) Each relay valve is configured with a delivery valve seat (31, 131) and a vent valve seat (30, 130) and a vent position, wherein compressed air inlets (2d, 3d) are connected via a transverse bore (27) to a common compressed air inlet port (25, 26), and a delivery duct (12a, 112a) extends in the axial direction (A) in each relay valve (2, 3) The relay valves (2, 3) have guide body inserts (12, 112) which are inserted into a longitudinal bore (29) of the main housing (8), which longitudinal bore (29) extends in the axial direction (A), and the relay valves (2, 3) in each case have the delivery duct (12a, 112a).

A brake pedal unit includes a housing defining a bore formed therein. An input piston is slidably disposed in the bore. The input piston is connected to a brake pedal such that engagement of the brake pedal causes movement of the input piston within the bore of the housing of the brake pedal unit. The brake pedal unit is defined to be in an at rest position when the brake pedal in not engaged causing movement of the input piston. A primary piston is slidably disposed in the bore for pressurizing a primary chamber. A primary passageway permits fluid communication between the primary chamber and the reservoir, wherein fluid flow through the primary passageway is blocked when the brake pedal unit is in the rest position. A secondary piston is slidably disposed in the bore for pressurizing a secondary chamber. A secondary passageway permits fluid communication between the secondary chamber and the reservoir, wherein fluid flow through the secondary passageway is blocked when the brake pedal unit is in the rest position.

A retrofit pneumatic circuit complements an existing factory braking system to preserve the original function of the driver's foot pedal while also adding the ability for a computer to actuate the brakes separately and independently. In the event where both the primary and secondary drivers are actuating the brakes at any time, the braking force applied is the maximum of the two. In the preferred approach, a shuttle valve is connected between a primary proportional valve and a copy of that proportional valve. Directional control valves are also included to isolate both the input and the output portions of the secondary circuit in order to enforce positive shutdown of computer control. One directional valve blocks a supply pressure to prevent bleeding of the system in any situation where pressure is requested when computer control is supposed to be disabled. A second directional valve vents any built-up pressure to the atmosphere, so that any residual pressure does not actuate the brakes after computer control is disabled.

A retrofit pneumatic circuit complements an existing factory braking system to preserve the original function of the driver's foot pedal while also adding the ability for a computer to actuate the brakes separately and independently. In the event where both the primary and secondary drivers are actuating the brakes at any time, the braking force applied is the maximum of the two. In the preferred approach, a shuttle valve is connected between a primary proportional valve and a copy of that proportional valve. Directional control valves are also included to isolate both the input and the output portions of the secondary circuit in order to enforce positive shutdown of computer control. One directional valve blocks a supply pressure to prevent bleeding of the system in any situation where pressure is requested when computer control is supposed to be disabled. A second directional valve vents any built-up pressure to the atmosphere, so that any residual pressure does not actuate the brakes after computer control is disabled.

A master brake cylinder for a brake system of a vehicle having a master brake cylinder housing, a primary piston component, a secondary piston component, a primary spring device which is preloaded with a first preload force between the primary piston component and the secondary piston component, and a secondary spring device, which is preloaded with a second preload force between the secondary piston component and a wall component (of the master brake cylinder housing, with the second preload force of the secondary spring device being greater than the first preload force of the primary spring device. A brake device for a vehicle, a brake system for a vehicle, and a production method for a mater brake cylinder for a brake system of a vehicle are also described.

According to the embodiment of the present disclosure, it provides an inspection valve installed at a flow path connecting a reservoir to a chamber of a master cylinder, comprising: a housing at which a bore is formed and having one side at which an inlet hole is formed; a plunger provided to be movable along the bore of the housing; a seat member configured to close one side of the bore and through which an outlet hole passes; and an elastic member having one side supported by the plunger and the other side supported by the seat member, wherein the plunger is provided to block the outlet hole when a hydraulic pressure flowing in through the inlet hole is greater than an elastic force of the elastic member.

Also, according to the embodiment of the present disclosure, it provides an inspection valve installed at a bypass flow path connecting a front side of a check valve to a rear side thereof at a reservoir flow path connecting a reservoir to a master cylinder, comprising: a housing at which a bore is formed and having one side at which an inlet hole communicating with the master cylinder is formed; a plunger provided to be movable along the bore of the housing; a seat member configured to close one side of the bore and through which an outlet hole communicating with the reservoir passes; and an elastic member having one side supported by the plunger and the other side supported by the seat member, wherein the check valve is provided at the reservoir flow path and enables fluid to flow in a direction from the reservoir to the master cylinder, and the plunger is provided to block the outlet hole when a hydraulic pressure flowing in through the inlet hole is greater than an elastic force of the elastic member.

A method for determining a likely internal pressure for a master brake cylinder including: estimating/measuring a displacement path(s) of a brake input element configured on a master cylinder from initial position thereof; estimating/measuring a first hydraulic fluid volumetric flow rate of a hydraulic fluid of the braking system out of or into a first pressure chamber of the master cylinder, and of a second hydraulic fluid volumetric flow rate of the hydraulic fluid out of or into a second pressure chamber of the master cylinder; and determining the likely internal pressure for a master cylinder considering the estimated/measured displacement path(s), the estimated and/or measured first hydraulic fluid volumetric flow rate, and the estimated and/or measured second hydraulic fluid volumetric flow rate. Also described is a device for determining a likely internal pressure for a master brake cylinder, and an electromechanical brake booster, ESP control, and vehicle braking system.

In a system including a reservoir tank RSV integral with a master cylinder M/C, an inlet fluid passage 16 for connecting an inlet portion 22 of a pump P to the reservoir tank RSV, a pressure reducing fluid passage 32 that connects the inlet fluid passage 16 to wheel cylinders W/C and a normally closed pressure reducing vale 30 that is connected to the pressure reducing fluid passage 32 and opened when it is intended to depressurize a brake fluid to in the wheel cylinders thereby to return the brake fluid to the reservoir tank through the inlet fluid passage 16, there is employed a normally closed reservoir shutting valve 31 that is connected to the pressure reducing valve 30 in series with respect to the wheel cylinders W/C and the reservoir tank RSV.

In a system including a reservoir tank RSV integral with a master cylinder M/C, an inlet fluid passage 16 for connecting an inlet portion 22 of a pump P to the reservoir tank RSV, a pressure reducing fluid passage 32 that connects the inlet fluid passage 16 to wheel cylinders W/C and a normally closed pressure reducing vale 30 that is connected to the pressure reducing fluid passage 32 and opened when it is intended to depressurize a brake fluid to in the wheel cylinders thereby to return the brake fluid to the reservoir tank through the inlet fluid passage 16, there is employed a normally closed reservoir shutting valve 31 that is connected to the pressure reducing valve 30 in series with respect to the wheel cylinders W/C and the reservoir tank RSV.