Abstract: A spool for a hydraulic valve includes a cylindrical body having a first end, a second end disposed opposite the first end, and an annular wall defined by an internal surface of the cylindrical body and an external surface of the cylindrical body. The annular wall defines a plurality of holes therethrough. The internal surface defines a first chamber, a second chamber, and a slot chamber within the cylindrical body, the second chamber being in fluid communication with the plurality of holes via the first chamber, the slot chamber being located between the second chamber and the second end of the cylindrical body. The annular wall defines a slot therethrough, the slot extending from the second end of the cylindrical body toward the first end of the cylindrical body along the longitudinal direction, the slot being open at the second end of the cylindrical body along the longitudinal direction.

Abstract: A spool assembly is disclosed for use in a valve. The spool assembly may have a cylindrical body that is hollow and has a least one radially oriented orifice that passes through a wall of the cylindrical body. The spool assembly may also have an insert slidably disposed inside the cylindrical body. The insert may have a land that axially divides a space inside the cylindrical body.

Abstract: A system for controlling operation of a hydraulic valve is provided. The system includes a solenoid coupled to a spool assembly of the hydraulic valve. The system further includes a sensor disposed on the hydraulic valve. The sensor generates signals indicative of operational parameter of the hydraulic valve. The system also includes a controller in communication with the solenoid and the sensor. The controller receives signals generated by the sensor. The controller includes a booster circuit connected to the solenoid. The booster circuit boosts an actuating current generated in response to the signals received from the sensor. The controller further includes a switching circuit connected across the solenoid. The switching circuit controls a direction of the actuating current flowing through the solenoid. The solenoid actuates the spool assembly of the hydraulic valve to control the operation of the hydraulic valve based on the actuating current.

Abstract: The present disclosure describes a spool for a hydraulic valve. The spool includes a cylindrical body having at least one slot configured to engage with a valve body of the hydraulic valve. The spool also includes a first chamber and a second chamber located downstream of the first chamber and in fluid communication with the first chamber. The first chamber is defined within the cylindrical body and configured to receive fluid through a plurality of holes defined in the cylindrical body. An inner diameter of the second chamber is less than an inner diameter of the first chamber. The first chamber is configured to elongate along a longitudinal axis thereof based on a pressure of the fluid received within the first chamber. Further, an outer surface of the first chamber is configured to contract based on the elongation of the first chamber.

Abstract: A spool assembly is disclosed for use in a valve. The spool assembly may have a cylindrical body with a first end, a second end, and a bore passing from the first end through the second end. The spool assembly may also have a first insert with a first land slidably disposed inside the bore at the first end, and a second insert separate from the first insert. The second insert may have a second land slidably disposed inside the bore at the second end.

Abstract: A valve is disclosed for use with a hydraulic circuit including a valve block, a central bore and an actuator passage formed in the valve block, and at least one of a supply and a drain passage. The valve also includes a control spool movable to selectively connect the actuator passage and at least one of the supply passage and the drain passage. The control spool includes a base end, and a tip end with a tapered outer surface. The valve also includes a first actuator configured to selectively direct pilot fluid to the tip end of the control spool, and a second actuator configured to selectively direct pilot fluid to the base end of the control spool. The first and second actuators each include a primary axis oriented generally orthogonal to an axis of the control spool, and are located at opposing sides of the control spool.

Abstract: A control system for a machine is disclosed. The control system may have a bypass passage situated to allow fluid to bypass an actuator, and a warmup valve disposed within the bypass passage that is movable between flow-passing and-blocking positions. A controller is configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, compare the pressure of the fluid of the actuator with a threshold, and move the warmup valve to the flow-blocking position and reduce a pump outlet pressure when the pressure of the fluid is greater than the threshold. The controller may be configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, and adjust an input speed of the pump in response to the signal.

Abstract: A hydraulic system is disclosed for use with. a machine. The hydraulic system may have an actuator, a valve associated with the actuator, at least one sensor configured to generate signals indicative of performance parameters of the hydraulic system, and a controller. The controller may be configured to determine at least one of a diagnostic movement and position of at least one of the fluid actuator and valve required to perform a health cheek, and to correlate the signals generated only during completion of the diagnostic movement or only when the at least one of the fluid actuator and valve are in the diagnostic position to values of the performance parameters. The controller may also be configured to make a comparison of the values of the performance parameters to expected values, and to determine a health of the hydraulic system based on the comparison.

Abstract: A system can include one or more valve arrangements with a working chamber to receive a working fluid at a first pressure, and a control chamber to receive fluid at a second pressure. A dynamic seal can be disposed on a land of a valve element. The valve arrangement may include a sleeve against which the dynamic seal is slidably engaged. The valve element may include a check stem. A pressure compensating system may be in communication with bores formed in with the valve element. A pressure system to monitor dynamic seal wear may be in communication with the control chamber of the valve arrangement.

Abstract: A valve is disclosed for use with a hydraulic circuit. The valve may have a valve block, a central bore formed in the valve block, an actuator passage formed in the valve block and intersecting with the central bore, and at least one of a supply and a drain passage. The valve may also have a control spool movable to selectively connect the actuator passage and the at least one of the supply passage and the drain passage. The control spool may have a base end, and a tip end with a tapered outer surface. The valve may also have a first actuator configured to selectively direct pilot fluid to the tip end of the control spool, and a second actuator configured to selectively direct pilot fluid to the base end of the control spool. Each of the first and second actuators may have a primary axis oriented generally orthogonal to an axis of the control spool, and may be located at opposing sides of the control spool.

Abstract: A spool assembly is disclosed for use in a valve. The spool assembly may have a cylindrical body with a first end, a second end, and a bore passing from the first end through the second end. The spool assembly may also have a first insert with a first land slidably disposed inside the bore at the first end, and a second insert separate from the first insert. The second insert may have a second land slidably disposed inside the bore at the second end.

Abstract: A spool is disclosed for use in a valve. The spool may have an elongated cylindrical body with a first end and a second end. The spool may also have a first land formed at the first end, a second land axially spaced apart from the first land, and a check element located between the first and second lands. The check element may have an outer diameter that is about 0.5-1% greater than an outer diameter of the second land.

Abstract: A method of calibrating an electrohydraulic valve is disclosed. The method includes actuating an on-off valve to an open position. A speed of a fixed displacement pump is regulated to establish a desired flow rate at an outlet of the pump. The pump is in fluid communication within a closed loop circuit with the on-off valve and the electrohydraulic valve. A target pressure in the closed loop circuit is determined as a function of the desired flow rate. The method further includes increasing a current to the electrohydraulic valve and monitoring the target pressure in the closed loop circuit. A start of a fluid flow through the electrohydraulic valve is determined based on a drop in the target pressure within the closed loop circuit.

Abstract: A spool assembly is disclosed for use in a valve. The spool assembly may have a cylindrical body that is hollow and has a least one radially oriented orifice that passes through a wall of the cylindrical body. The spool assembly may also have an insert slidably disposed inside the cylindrical body. The insert may have a land that axially divides a space inside the cylindrical body.

Abstract: A spool is disclosed for use in a valve. The spool may have an elongated cylindrical body with a first end and a second end. The spool may also have a first land formed at the first end, a second land axially spaced apart from the first land, and a check element located between the first and second lands. The check element may have an outer diameter that is about 0.5-1% greater than an outer diameter of the second land.

Abstract: A system can include one or more valve arrangements with a working chamber to receive a working fluid at a first pressure, and a control chamber to receive fluid at a second pressure. A dynamic seal can be disposed on a land of a valve element. A supply passage can be in communication between the control chamber and a tank and can include a check valve. A relief valve can be disposed between the check valve and the control chamber. A pilot pump and another relief valve may be disposed upstream of the check valve. The relief valve downstream of the check valve can have a higher pressure limit than the downstream one. A pressure sensor may be disposed between the check valve and the control chamber and used to warn the operator of a high pressure in the control chamber.

Abstract: A method of calibrating an electrohydraulic valve is disclosed. The method includes actuating an on-off valve to an open position. A speed of a fixed displacement pump is regulated to establish a desired flow rate at an outlet of the pump. The pump is in fluid communication within a closed loop circuit with the on-off valve and the electrohydraulic valve. A target pressure in the closed loop circuit is determined as a function of the desired flow rate. The method further includes increasing a current to the electrohydraulic valve and monitoring the target pressure in the closed loop circuit. A start of a fluid flow through the electrohydraulic valve is determined based on a drop in the target pressure within the closed loop circuit.

Abstract: A void protection system for a mining shovel having an operator input device includes an independent metering valve assembly including one or more fluid source-cylinder valves for fluidly connecting the fluid source to the hydraulic cylinder. The system also includes a sensor assembly for monitoring the fluid pressure within the rod end and the head end of the hydraulic cylinder, and a control module. The control module is configured to monitor movement of the operator input device, monitor pressure within the hydraulic cylinder, increase the opening of the corresponding fluid source-cylinder valve and increase fluid flow from the fluid source to fill corresponding end of the hydraulic cylinder until pressure in the corresponding end of the hydraulic cylinder is above a first threshold pressure.

Abstract: A control system for a machine is disclosed. The control system may have a bypass passage situated to allow fluid to bypass an actuator, and a warmup valve disposed within the bypass passage that is movable between flow-passing and-blocking positions. A controller is configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, compare the pressure of the fluid of the actuator with a threshold, and move the warmup valve to the flow-blocking position and reduce a pump outlet pressure when the pressure of the fluid is greater than the threshold. The controller may be configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, and adjust an input speed of the pump in response to the signal.

Abstract: A void protection system for a mining shovel having an operator input device includes an independent metering valve assembly including one or more fluid source-cylinder valves for fluidly connecting the fluid source to the hydraulic cylinder. The system also includes a sensor assembly for monitoring the fluid pressure within the rod end and the head end of the hydraulic cylinder, and a control module. The control module is configured to monitor movement of the operator input device, monitor pressure within the hydraulic cylinder, increase the opening of the corresponding fluid source-cylinder valve and increase fluid flow from the fluid source to fill corresponding end of the hydraulic cylinder until pressure in the corresponding end of the hydraulic cylinder is above a first threshold pressure.