摘要:
Electromagnetic actuators having a coil and an armature are used in a number of applications in which it is useful to have an indication of the position of the armature with respect to the coil without the use of external sensors. Accordingly, an actuator control system is provided for determining the position of the armature with respect to the coil in response to the magnitude and rate of change of current flowing in the coil.
摘要:
An apparatus for determining the position of an armature of an electromagnetic actuator having a coil, the armature being movable to and between first and second positions in response to a current flowing in the coil. The apparatus includes circuitry for measuring the magnitude of current in the coil and producing a magnitude signal, measuring the rate of change of current in the coil and producing a rate of change signal, and measuring the derivative of flux linkage versus current in the coil in response to the rate of change signal and producing a flux linkage signal. The apparatus additionally includes circuitry for determining the position of the armature with respect to the coil in response to the magnitude and flux linkage signals.
摘要:
In machines that are articulated in response to a steer input mechanism, it is many times necessary for the operator to make a steer input and then to make corrective adjustments in order to obtain the desired steer angle of the machine. In the subject invention, an electro-hydraulic steering system is provided which senses the desired steer input by the operator, senses the degree of articulation of the machine and a microprocessor delivers an electrical control signal (P) to an electro-hydraulic valve mechanism which effectively controls articulation of the machine. Once the machine has reached the degree of articulation desired by the operator, the microprocessor signals the electro-hydraulic valve mechanism to stop articulation of the machine. Consequently, the operator does not have to provide any adjustments thereto. Additionally, the ground speed of the machine is sensed and the rate of articulation is controlled in response thereto. In the subject arrangement, in the event of an electrical system failure, a back-up steering control circuit is automatically functional to control steering of the machine in a conventional manner. This arrangement provides an electro-hydraulic steering system that eases the operators fatigue by eliminating the need for corrective steer adjustments and is simple in construction and reliable in operation.
摘要:
A fluid control system including a control valve providing a simple, easy to use regeneration capability in association with a pump, a tank, and a double acting actuator having a first actuating chamber and a second actuating chamber. The control valve has a first actuating chamber port connected to the first actuating chamber, a second actuating chamber port connected to the second actuating chamber, a tank port connected to the tank, a first pump port and a second pump port. The control valve includes a connecting passage connecting the first pump port and the second pump port to the pump, and is operable in a first position to allow fluid flow from the pump through the first pump port and the first actuating chamber port to the first actuating chamber and fluid flow from the second actuating chamber through the second actuating chamber port and the tank port to the tank. For regeneration, the control valve member is movable from the first position to a second position to allow the fluid flow from the second actuating chamber port to be diverted to the second pump port such that the fluid flow can pass through the connecting passage to the first pump port and through the first actuating chamber port to the first actuating chamber of the actuator.
摘要:
An electrohydraulic pressure regulating valve comprises a variable orifice disposed between a supply port and a control port and has a fixed size vent orifice disposed downstream of the variable orifice and in parallel with the control port to reduce the flow forces acting on the spool so that the valve is less sensitive to solenoid and spool quality and has improved pressure control capability.
摘要:
A vehicle such as an earthmoving wheel loader has an engine, a torque converter having an impeller element, a reactor element and a turbine element, and an input clutch connected between the engine and the impeller element. An electrohydraulic control device is provided to controllably engage the input clutch and that includes a microprocessor-based electronic control module, an actuator mechanism having a control member that is progressively movable between first, second and third positions to deliver a first electrical signal to the electronic control module, and a valve for directing fluid to the input clutch at a decreasing pressure level when the control member is moved from the first to the second positions in response to another signal from the electronic control module. The electronic control module is programmed to maintain at least a minimal pressure level to the actuating piston of the input clutch when the control member is between the second and third positions. Moreover, a service brake is increasingly engaged by a service brake mechanism in response to the control member moving between the second and third positions. Other logic functions are included to control the input clutch and a lockup clutch connected between the engine and the turbine element.
摘要:
A system for providing hydraulic power in a machine transmission includes a first hydraulic variator and a second hydraulic variator, each variator having a mechanical input to a hydraulic pump, and a hydraulic motor linked to the hydraulic pump via a hydraulic circuit, and a mechanical output from the hydraulic motor. In an embodiment, the first hydraulic circuit side of one variator is hydraulically connected to the first hydraulic side of the other variator, and the second hydraulic circuit sides are likewise linked together. A common input is geared to the inputs of the variators and a common output is geared to the outputs of the variators, tying the pump and motor of each variator to rotate at the same speed as the counterpart components of the other variator.
摘要:
An apparatus is adapted to detect an end-of-fill condition of an actuator having a varying control volume, C. The apparatus includes a solenoid having a coil and an armature. The armature is movable relative to the coil in response to energization of the coil. A control valve delivers a flow of fluid to the actuator. The rate of the fluid flow is responsive to the movement of the armature. An electrical circuit detects a voltage spike across the coil and responsively produces an end-of-fill signal. The voltage spike is generated by an electromotive force produced by the armature in response to the control volume achieving a predetermined end-of-fill pressure.
摘要:
A system for providing hydraulic power in a machine transmission includes a first hydraulic variator and a second hydraulic variator, each variator having a mechanical input to a hydraulic pump, and a hydraulic motor linked to the hydraulic pump via a hydraulic circuit, and a mechanical output from the hydraulic motor. In an embodiment, the first hydraulic circuit side of one variator is hydraulically connected to the first hydraulic side of the other variator, and the second hydraulic circuit sides are likewise linked together. A common input is geared to the inputs of the variators and a common output is geared to the outputs of the variators, tying the pump and motor of each variator to rotate at the same speed as the counterpart components of the other variator.
摘要:
A split torque transmission for a work machine is provided. The split torque transmission includes a transmission housing. A variator pump is mounted to an exterior surface of the transmission housing. A variator motor is operably coupled to the variator pump and mounted to the exterior surface of the transmission housing.