A nozzle with changeable press fit and a method for calibrating a nozzle is described. The nozzle may be used in a nozzle/flapper type servovalve. The method comprises the steps of providing a nozzle within a cylindrical body defining a cylindrical bore, the nozzle having a tubular shape with an outer cylindrical surface and an inner radial surface, the method further comprises the steps of positioning a first, tubular locking member within the nozzle, and axially moving the first, tubular locking member within the nozzle. The first tubular locking member is configured to cause the nozzle to become positionally fixed at a selected position within the bore in response to the first, tubular locking member being axially moved relative to the nozzle. A nozzle positioning system is also described herein.

A method of calibrating a solenoid actuated valve includes: providing a brake system including a fluid pressure source: providing a valve having a solenoid, and wherein the valve is in fluid communication with the fluid pressure source; operating the fluid pressure source to provide a constant flow of fluid to the valve; energizing the solenoid of the valve with a constant current such that fluid flows through the valve; measuring the pressure of the fluid flowing at the valve; adjusting the current sent to the solenoid until a predetermined pressure has been obtained; storing a nominal current value of the current required to obtain the predetermined pressure; and calibrating the valve by adding a correction offset factor to the nominal current value for future actuation of the solenoid of the valve.

The present invention includes a stroke sensor which is arranged on a hydraulic cylinder and measures a stroke length of the hydraulic cylinder; a rotary encoder and a magnetic force sensor which measure a reset reference point to reset a value of the stroke length measured by the stroke sensor; a stroke end detection processing unit which detects a stroke end position of the hydraulic cylinder; a calibration processing unit which calibrates the measured value of the stroke length when the reset reference point and/or the stroke end position is detected; an HMI monitor which displays an entire work machine mounted with the hydraulic cylinder when an initial calibration work for the hydraulic cylinder is carried out; and a highlight display processing unit that highlights a moving portion to drive a hydraulic cylinder to be calibrated along with an indication of a driving direction.

A malfunction diagnosing device that includes pistons arranged in a circumferential direction and discharges oil with rotation in the circumferential direction is provided, including: a pressure sensor for detecting a pressure value of oil discharged from a hydraulic pump in rotation; a speed sensor for detecting a rotation phase of the hydraulic pump at a time when a pressure value of oil is detected by the pressure sensor; a phase calculation part; and a rendering part for rendering a model of a relationship between pressure values of oil detected by the pressure sensor and rotation phases of the hydraulic pump detected by the speed sensor and the phase calculation part to thereby obtain pulsating waveform data. This makes it possible to diagnose a malfunction of the hydraulic pump without influence of a change in a rotation speed of the hydraulic pump.

An inspection device for hydraulic equipment includes a hydraulic circuit having a branch valve, an optical detection section, a pump configured to supply oil to the hydraulic circuit, and a controller. The optical detection section includes an inspection oil passage connected to the branch valve. The inspection oil passage includes a filter arranged to collect foreign matter. The controller operates the branch valve to supply oil to the inspection oil passage. The optical detection section includes first and second foreign matter detection sections arranged on upstream and downstream sides of the filter to detect foreign matter. A work vehicle includes the inspection device. An inspection system includes the inspection device. An inspection method includes supplying oil to an inspection oil passage by operating a branch valve of a hydraulic circuit, and detecting foreign matter on upstream and downstream sides of a filter arranged on the inspection oil passage.

An inspection device for hydraulic equipment includes a hydraulic circuit having a branch valve, an optical detection section, a pump configured to supply oil to the hydraulic circuit, and a controller. The optical detection section includes an inspection oil passage connected to the branch valve. The inspection oil passage includes a filter arranged to collect foreign matter. The controller operates the branch valve to supply oil to the inspection oil passage. The optical detection section includes first and second foreign matter detection sections arranged on upstream and downstream sides of the filter to detect foreign matter. A work vehicle includes the inspection device. An inspection system includes the inspection device. An inspection method includes supplying oil to an inspection oil passage by operating a branch valve of a hydraulic circuit, and detecting foreign matter on upstream and downstream sides of a filter arranged on the inspection oil passage.

This invention provides to set plural test patterns in which two or more control valves are picked up from the plural control valves as diagnosis target, and there being installed a malfunction diagnosis means (47) in which the diagnosis of malfunctioned valve is applied to the test patterns as unit, and malfunction valve identification means (48) in which the malfunctioned valves are identified by checking the control valves one another, that control valves are included in the test patterns having been diagnosed whether malfunction exists or not by the malfunction diagnosis means (47).

A diagnostic apparatus for a fluidic actuator, in particular a fluidic valve drive, which has an actuator element displaceable into different positions (x1, x2, xp1, xp2), wherein the diagnostic apparatus is configured to provide a first break-away pressure measured value (pi1) for a first position of the actuator element. The diagnostic apparatus is further configured to determine, based on the first break-away pressure measured value (pi1) and break-away pressure reference information (pri) stored in the diagnostic apparatus, a first break-away pressure prediction value (pp1) for a first prediction position (xp1) of the actuator element, the first prediction position being different from the first position (x1).

A monitoring device and a method for determining operating health of a pressure medium operated device. The monitoring device is configured for processing input measuring data relating to operation of the pressure medium operated device. An operating condition value is determined in the monitoring device, where after the operating condition value is compared to an input reference data in order to determine current operating health. The reference data is determined by utilizing strength analysis, which is executed for a design model of the associated pressure medium operated device.

A method for controlling a cylinder includes providing a cylinder having a piston, a servo valve and a measuring device having at least one first position sensor and one second position sensor, measurements are taken of the position of the piston in the cylinder body simultaneously with the first position sensor and the second position sensor, at least one first displacement speed of the piston is determined on the basis of the piston position measurements obtained with the first position sensor, at least one second displacement speed of the piston is determined on the basis of the piston position measurements obtained with the second position sensor, and each of the first and second determined displacement speeds of the piston are compared with a modelled or predetermined displacement speed of the piston, in such a way as to identify the most reliable position sensor.