摘要:
The present invention is applied to a system comprised of large number of hydraulic excavators 1 deployed at construction sites and a base station 16. Each hydraulic excavator 1 is provided with a storage unit (memory 402), a control unit (CPU 401) for executing the work operation and receiving as input a quantitative machine status relating to the work operation, and a communications device 42. The base station 16 is provided with a communications device 16a, a management server 17 for identifying the serial number of the hydraulic excavator 1 and transferring information, and a database 18 for storing various information. The control unit of the hydraulic excavator 1 and the management server 17 of the base station 16 transfer information. With this system configuration, the control unit measures the duration during which the quantitative machine status satisfies a predetermined condition and stores it in the storage unit and transmits the measurement data of the duration to the management server 17 of the base station 16 conditional on the power input key being in the off position, while the management server 17 receives the measurement data of the duration and calculates the cumulative operating time. Further, the quantitative machine status and various event data stored in the storage unit of the hydraulic excavator 1 are sent to the base station 1, while the management server of the base station 16 stores the quantitative machine status and various event data in the database 18 by a predetermined format.
摘要:
A construction machine comprises a location detector for detecting location information for the construction machine, a determination device for determining whether or not location information is to be transmitted and outputting a transmission signal if it is determined that information is to be transmitted, and a transmitter for transmitting the detected location information to a base station in response to the transmission signal.
摘要:
A hydraulic excavator 1 working in fields includes a controller 2 for measuring a working time for each of an engine 32, a front 15, a swing body 13, and a travel body 12, storing measured data in a memory of the controller 2, and then transferring it to a base station computer 3 via satellite communication, an FD, etc. The transferred data is stored as a database 100 in the base station computer 3. The base station computer 3 reads the data stored in the database 100 for each hydraulic excavator, calculates a working time of a part belonging to each section on the basis of the working time of that section, and compares the calculated working time with a preset target replacement time interval of the relevant part, thereby calculating a remaining time up to next replacement of the relevant part and managing the scheduled replacement timing thereof. Thus, the appropriate scheduled replacement timing of parts can be determined even in a construction machine having a plurality of sections that differ in working time from each other.
摘要:
A hydraulic control system is intended to easily hydraulically back up a trouble caused in an electric system, while employing a control unit (13) to utilize the advantage of electric control, when the displacement of a hydraulic pump (1) is controlled in accordance with a status variable of a hydraulic driving system. To this end, a pump regulator (16) is constructed so as to increase the tilting amount .theta. of a swash plate (1a) with a reduction in pressure of a second hydraulic signal Pc. A characteristic of the pump regulator is set such that a negative control pressure Pco can be employed to operate the pump regulator in place of the second hydraulic signal, and characteristics of a fixed throttle (10) and a spring (18d) in the pump regulator are set such that the pump regulator can be operated in the working range of the negative control pressure. The control unit (13) sets a modified negative control pressure Pc1 as a target value of the second hydraulic signal and determines a second electric signal E corresponding to the target value in a block (102), so that the working range of the second hydraulic signal generated by the solenoid proportional valve (15) is substantially at the same level as the working range of the negative control pressure.
摘要:
A controller 24 includes function generators 151, 152. The function generator 151 is set to have such a characteristic that as the detected value P.sub.N of a negative control pressure from a pressure sensor 21 is reduced, a first target tilting amount .theta..sub.N increases from a minimum value to a maximum value, and the function generator 152 is set to have such a characteristic that as the detected value P.sub.B of a control input (pilot pressure) for driving a boom cylinder 6 is increased, a second target tilting amount .theta..sub.B increases from a predetermined minimum value to the same maximum value as the above maximum value. Minimum one of the two target tilting amounts from both the function generators is selected, and a proportional solenoid valve 25 is driven based on the selected minimum tilting amount. This makes it possible to surely suppress an unwanted speed increase of a specific hydraulic actuator other than a boom cylinder, such as a swing motor 9, that would be caused when the tilting amount is controlled based on only the negative control pressure.
摘要:
A valve apparatus has a casing (11; 41) formed therein with at least one pair of spool bores (12a, 13c, etc.; 42a, 43a), a single common pump port (19), at least one tank port (16t) and a plurality of actuator ports (22a, 23a, etc.) including a pair of actuator ports communicating with each of the spool bores, and a plurality of spools (14a, 15a, etc.; 44a, 45a) slidably inserted respectively in the spool bores in the casing. Each of the spools control communication between the common pump port and tank port and the corresponding pair of the actuator ports. The common pump port is arranged to communicate with a common pump line (18) which is formed between the pair of spool bores and spools arranged in juxtaposed relation to each other so as to intersect a plane in which the axes of the pairs of spool bores extend.
摘要:
A hydraulic drive system comprises a controller (12) and several condition sensors. A boom-up target flow rate setting section determines a boom-up target flow rate based on signals from a pressure sensor (11) and a rotational speed meter (16), a pump delivery rate detecting section determines a pump delivery rate based on signals from a tilt angle sensor (15) and the rotational speed meter (16), a differential pressure detecting section and a center bypass flow rate calculating section determine a center bypass flow rate based on signals from pressure sensors (9, 10), a boom cylinder calculating section determines a boom cylinder flow rate from the pump delivery rate and the center bypass flow rate, and a first pump target displacement volume calculating section calculates a first pump target tilt angle .theta..sub.1 in accordance with the difference between the boom-up target flow rate and the boom cylinder flow rate. In this case, .theta..sub.1 is larger than a second pump target tilt angle .theta..sub.2 for negative control and is selected by a maximum value selecting section. Then, a minimum value selecting section selects the smaller one of .theta..sub.1 and a maximum tilt angle .theta..sub.max determined with horsepower control, and drive signal generating section outputs a corresponding target current to a solenoid proportional valve (13) for driving a piston (6a) of a regulator (6) to the right in FIG. 4.
摘要:
A valve apparatus has a flow control valve having a supply passage communicating with a hydraulic fluid supply source, a load passage communicating with an actuator, and a first meter-in variable restrictor disposed between the supply passage and the load passage and opened dependent on an operation amount there; a first signal passage located downstream of the first variable restrictor and having a passage section for detecting load pressure of the actuator; a tank passage communicating with a reservoir tank; a discharge passage for communicating the first signal passage with the tank passage; and a second variable restrictor provided in the discharge passage and having its opening variable dependent on the operation amount of the flow control valve to produce in the first signal passage a control pressure different from the load pressure, the control pressure in the first signal passage being led to the hydraulic fluid supply source though a second signal passage. An auxiliary restrictor is disposed in the first signal passage to reduce the load pressure detected in the passage section of the first signal passage so that a pressure lower than the detected load pressure is produced in the first signal passage as the control pressure.
摘要:
There is disclosed a direction selector valve having function of detecting load. The valve is used in a hydraulic system. A spool has two passage holes extending axially partially through the spool from both side ends. These two passage holes have their respective high-pressure holes. When the spool is in its neutral position, the high-pressure holes are closed off by spool hole walls between bridge ports and actuator ports. The two passage holes further include low-pressure holes which are in communication with tank ports via load check valves mounted in the passage holes, respectively. Guide holes are formed near the front end of one passage hole and in communication with a load-sensing port. A restriction portion is formed on the outer surface of the spool adjacently to the guide holes to control the flow from the load-sensing port to the tank ports. First guide holes and second guide holes which are close to each other are formed near the front end of the other passage hole. The first guide holes are in communication with the load-sensing port even when the spool is in its neutral position. The second guide holes are placed in communication with the load-sensing port after the spool has shifted from its neutral position, connecting the high-pressure holes with the bridge ports. This structure smoothly responds to the load pressure in the actuator.
摘要:
A hydraulic drive system for a construction machine has a flow control valve (5) disposed between a hydraulic pump and an acutator, a pressure compensating valve for controlling a differential pressure across the flow control valve, and a pump delivery rate regulator for controlling a flow rate of the hydraulic fluid delivered from the hydraulic pump dependent on a differential pressure (Pd-PLS) between a pump pressure and a load pressure of the actuator. The pressure compensating valve has a valve body subjected to control forces. A first control force based on the differential pressure across the flow control valve to the valve body urges the valve body in the valve-closing direction. A second predetermined control force urges the valve body in the valve-operating direction; and a third control force based on the differential pressure (Pd-PLS) between the pump pressure and the load pressure of the actuator urges the valve body in the valve-opening direction.