Abstract: A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

Abstract: A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.

Abstract: A method of detecting a leak in a hydraulic trailer brake circuit of a trailer includes providing a controller, a base valve, a first sensor, a second sensor, a control valve having a solenoid, a reduction valve, a hydraulic fluid supply, a first brake output, and a second brake output. The method also includes supplying a first pressure to an inlet of the base valve and outputting a second pressure from an outlet of the base valve to the first brake output. The first pressure is detected by the first sensor and the second pressure is detected by the second sensor, and the detected first and second pressures are communicated to the controller. The difference between the first and second pressures are compared to a threshold, and a leak is detected in the hydraulic trailer brake circuit if the difference satisfies the threshold.

Abstract: A dual pressure margin priority circuit and method for controlling flow from a pump to steering valve and low priority inlets. A steering pressure valve controls flow from pump to steering valve inlets, and provides a steering valve load sense pressure. A priority valve controls flow from pump to low priority inlets. A load sense cutoff valve has a first inlet receiving the steering valve load sense pressure. The load sense cutoff valve controls flow through the priority valve based on steering valve load sense pressure at the first cutoff valve inlet. The cutoff valve can include a second inlet coupled to tank, and a load sense input coupled to the steering valve load sense pressure. The cutoff valve can be a pressure limiter valve. The priority and steering pressure valves can be 2-way proportional flow spool valves with bias springs, and contributing and opposing load sense inputs.

Abstract: A braking system of a trailer and work machine includes a pressurized fluid supply, a hydraulic base valve fluidly coupled to the supply, and a pneumatic base valve fluidly coupled to the supply. A proportional control valve is also fluidly coupled to the supply, and it includes an outlet disposed in fluid communication with the inlets of the hydraulic base valve and the pneumatic base valve. The system further includes a hydraulic output configured to be fluidly coupled to a hydraulic braking system of a trailer, and a pneumatic output configured to be fluidly coupled to a pneumatic braking system of a trailer. The hydraulic output is fluidly coupled to the outlet of the hydraulic base valve, and the pneumatic output is fluidly coupled to the outlet of the pneumatic base valve.

Abstract: A method of detecting a leak in a hydraulic trailer brake circuit of a trailer includes providing a controller, a base valve, a first sensor, a second sensor, a control valve having a solenoid, a reduction valve, a hydraulic fluid supply, a first brake output, and a second brake output. The method also includes supplying a first pressure to an inlet of the base valve and outputting a second pressure from an outlet of the base valve to the first brake output. The first pressure is detected by the first sensor and the second pressure is detected by the second sensor, and the detected first and second pressures are communicated to the controller. The difference between the first and second pressures are compared to a threshold, and a leak is detected in the hydraulic trailer brake circuit if the difference satisfies the threshold.

Abstract: A braking system of a trailer and work machine includes a pressurized fluid supply, a hydraulic base valve fluidly coupled to the supply, and a pneumatic base valve fluidly coupled to the supply. A proportional control valve is also fluidly coupled to the supply, and it includes an outlet disposed in fluid communication with the inlets of the hydraulic base valve and the pneumatic base valve. The system further includes a hydraulic output configured to be fluidly coupled to a hydraulic braking system of a trailer, and a pneumatic output configured to be fluidly coupled to a pneumatic braking system of a trailer. The hydraulic output is fluidly coupled to the outlet of the hydraulic base valve, and the pneumatic output is fluidly coupled to the outlet of the pneumatic base valve.

Abstract: A braking system of a work machine includes a pressurized fluid supply, a base valve fluidly coupled to the supply, a proportional control valve fluidly coupled to the supply, and a fluid output configured to be fluidly coupled to a braking system of a trailer. A first fluid path is selectively fluidly coupling the supply to the fluid output via the base valve, and a second fluid path is selectively fluidly coupling the supply to the fluid output via the proportional control valve. The base valve includes a predefined fixed gain and the proportional control valve includes an adjustable ratio.