Abstract:
A hydraulic excavator includes a base body portion, a movable portion, a hydraulic cylinder, a position sensor, a rotary encoder, and a control unit. The rotary encoder includes a light emitting unit, a light receiving unit, and a disk unit having a plurality of transmission portions. The control unit measures the stroke length of the hydraulic cylinder by correcting deviation of the stroke length, which is measured by the position sensor, based on the pulse signal output from the rotary encoder. In this way, there can be obtained a hydraulic excavator capable of precisely measuring a stroke length of a hydraulic cylinder driving a work implement, as well as a method for measuring the stroke of the hydraulic cylinder of the hydraulic excavator.
Abstract:
A hydraulic cylinder spool valve device, which extends and retracts a cylinder rod of a hydraulic cylinder, includes: a first spool valve having a first dead band and a first opening characteristic; a second spool valve having a second dead band and a second opening characteristic; and a controller performing communication with the hydraulic cylinder by using the first spool valve and positioning the second spool of the second spool valve within the second dead band and performing communication with the hydraulic cylinder by using the second spool valve and positioning the first spool of the first spool valve within the first dead band, and adjusting a characteristic of a switching dead band between the first opening characteristic and the second opening characteristic.
Abstract:
A filter state estimation system is configured to estimate a state of a filter provided in a hydraulic circuit. The hydraulic circuit includes: the filter; a bypass channel circumventing the filter and through which an oil flows; and a valve provided in the bypass channel and configured to be opened and closed based on a differential pressure. The filter state estimation system includes: a sensor to detect that the valve is in an open state or in a closed state; a temperature sensor to detect a temperature of the oil; and a state estimating unit to estimate a state of the filter based on detection results detected by the sensor and the temperature sensor. The state estimating unit estimates the state of the filter based on the temperature of the oil which is detected by the temperature sensor when the sensor detects that the valve is in the open state.
Abstract:
An operation lever includes: a pair of rods disposed at point-symmetrical positions with respect to an operation axis; magnets disposed on the respective rods; and a pair of magnetic sensors disposed at line-symmetrical positions with respect to a second straight line perpendicular to a first straight line connecting centers of one of the rods and the other rod, on a plane perpendicular to the operation axis.
Abstract:
A hydraulic excavator includes a base body portion, a movable portion, a hydraulic cylinder, a position sensor, a rotary encoder, and a control unit. The rotary encoder includes a light emitting unit, a light receiving unit, and a disk unit having a plurality of transmission portions. The control unit measures the stroke length of the hydraulic cylinder by correcting deviation of the stroke length, which is measured by the position sensor, based on the pulse signal output from the rotary encoder. In this way, there can be obtained a hydraulic excavator capable of precisely measuring a stroke length of a hydraulic cylinder driving a work implement, as well as a method for measuring the stroke of the hydraulic cylinder of the hydraulic excavator.
Abstract:
A hydraulic cylinder spool valve device, which extends and retracts a cylinder rod of a hydraulic cylinder, includes: a first spool valve having a first dead band and a first opening characteristic; a second spool valve having a second dead band and a second opening characteristic; and a controller performing communication with the hydraulic cylinder by using the first spool valve and positioning the second spool of the second spool valve within the second dead band and performing communication with the hydraulic cylinder by using the second spool valve and positioning the first spool of the first spool valve within the first dead band, and adjusting a characteristic of a switching dead band between the first opening characteristic and the second opening characteristic.
Abstract:
A filter state estimation system is configured to estimate a state of a filter provided in a hydraulic circuit. The hydraulic circuit includes: the filter; a bypass channel circumventing the filter and through which an oil flows; and a valve provided in the bypass channel and configured to be opened and closed based on a differential pressure. The filter state estimation system includes: a sensor to detect that the valve is in an open state or in a closed state; a temperature sensor to detect a temperature of the oil; and a state estimating unit to estimate a state of the filter based on detection results detected by the sensor and the temperature sensor. The state estimating unit estimates the state of the filter based on the temperature of the oil which is detected by the temperature sensor when the sensor detects that the valve is in the open state.
Abstract:
The hydraulic excavator comprises a revolving frame, a boom, a rotary encoder, and a link member. The revolving frame has a base plate and a first vertical plate and second vertical plate that are opposite each other and rise from the base plate. The boom is rotatably supported by the first vertical plate and the second vertical plate. The rotary encoder is provided at a position that is different from a position of the rotational axis of the boom, and senses the rotational angle of the boom according to the rotation of the boom. The link member transmits displacement of the boom to the rotary encoder.
Abstract:
A stroke detection device includes: four rods provided, moveably along respective axial directions, side by side on a same circumference of a device body, the stroke detection device detecting a change in relative positions of the four rods at a time the rods perform a stroke with respect to the device body; a magnet disposed to each of the rods such that a magnetic field is generated between rods adjacent to each other on the circumference and that the magnetic field varies at a time the rods adjacent to each other on the circumference perform a stroke relatively; and magnetic field detection units disposed on at least three positions between the magnets adjacent to each other in the device body, each of the magnetic field detection unit detecting the magnetic field between the magnets and outputting an electric signal in accordance with the detected magnetic field.
Abstract:
An operation lever includes: a pair of rods disposed at point-symmetrical positions with respect to an operation axis; magnets disposed on the respective rods; and a pair of magnetic sensors disposed at line-symmetrical positions with respect to a second straight line perpendicular to a first straight line connecting centers of one of the rods and the other rod, on a plane perpendicular to the operation axis.