Abstract: An air conditioner provided which has: a main refrigerant circuit including a compressor, a heat source side heat exchanger, a first expansion valve, and a utilization side heat exchanger and configured such that refrigerant flows in the main refrigerant circuit; a sub refrigerant circuit including a cooling member configured such that refrigerant branched from the main refrigerant circuit flows in the cooling member and configured such that refrigerant branched from the main refrigerant circuit flows in the sub refrigerant circuit; and a heat generator to be cooled by the cooling member, wherein a pipe in which part of refrigerant discharged from the compressor flows is connected to the cooling member of the sub refrigerant circuit.

Abstract: An air conditioner provided which has: a main refrigerant circuit including a compressor, a heat source side heat exchanger, a first expansion valve, and a utilization side heat exchanger and configured such that refrigerant flows in the main refrigerant circuit; a sub refrigerant circuit including a cooling member configured such that refrigerant branched from the main refrigerant circuit flows in the cooling member and configured such that refrigerant branched from the main refrigerant circuit flows in the sub refrigerant circuit; and a heat generator to be cooled by the cooling member, wherein a pipe in which part of refrigerant discharged from the compressor flows is connected to the cooling member of the sub refrigerant circuit.

Abstract: A reduction in measurement accuracy of a concentration sensor is minimized. An exhaust gas purifying device of a work machine includes a reduction catalyst that is placed in an exhaust flow passage of an exhaust gas of an engine and uses a reducing agent to reduce and purify nitrogen oxides in the exhaust gas, and a reducing agent injector to inject the reducing agent into the exhaust flow passage. The exhaust gas purifying device of a work machine includes: a storage unit that stores the reducing agent; a concentration sensor that has a sensing part placed within the storage unit to detect a concentration of the reducing agent; an air-bubble removal device that injects the reducing agent toward the sensing part; and a reducing agent pump that supplies the reducing agent in the storage unit to the air-bubble removal device.

Abstract: An air conditioner is provided, which is capable of accurately determining appropriateness of a refrigerant amount in a refrigerating cycle. A control apparatus is configured to: stop a cooling operation; set an expansion valve to a fully-closed state and, at the same time, switch the selector valve to change the direction, in which a refrigerant flows, to an opposite direction; operate a compressor to perform a refrigerant recovery operation, in which a refrigerant contained in an outdoor heat exchanger is recovered by an indoor heat exchanger; and determine the appropriateness of a refrigerant amount in a refrigerating cycle, based on at least one of a time required for recovering the refrigerant, a pressure change in a refrigerant suctioned by the compressor, and temperature of the refrigerant discharged from the compressor during the refrigerant recovery operation.

Abstract: A reduction in measurement accuracy of a concentration sensor is minimized. An exhaust gas purifying device of a work machine includes a reduction catalyst that is placed in an exhaust flow passage of an exhaust gas of an engine and uses a reducing agent to reduce and purify nitrogen oxides in the exhaust gas, and a reducing agent injector to inject the reducing agent into the exhaust flow passage. The exhaust gas purifying device of a work machine includes: a storage unit that stores the reducing agent; a concentration sensor that has a sensing part placed within the storage unit to detect a concentration of the reducing agent; an air-bubble removal device that injects the reducing agent toward the sensing part; and a reducing agent pump that supplies the reducing agent in the storage unit to the air-bubble removal device.

Abstract: A cooling/heating switching unit includes first to third fittings, expansion valves and expansion-valve driving sections, a housing, a heat insulating material, and a refrigerant leak detection sensor. The first and second fittings respectively connect with a high/low-pressure-gas main pipe and a low-pressure-gas main pipe, which are linked to an outdoor unit. The third fitting connects with an indoor-unit connection pipe, which is linked to indoor units. The expansion valve for high/low-pressure-gas pipe, the expansion valve for low-pressure-gas pipe, and expansion-valve driving sections selectively connect the first or second fitting with the third fitting via a refrigerant pipe to control a flow direction of refrigerant. The housing houses the refrigerant pipe. The heat insulating material fills inside of the housing to insulate the refrigerant pipe arranged inside of the housing from heat. The refrigerant leak detection sensor is installed outside of the housing to detect leaked refrigerant.

Abstract: Provided is a air conditioner including high-and-low-pressure gas pipe expansion valves each of which is provided to a corresponding one of the cooling-heating switching units and adjusts feeding of high-temperature and high-pressure gas refrigerant to the corresponding indoor unit; and a refrigeration cycle controller which adjusts a valve opening degree of the high-and-low-pressure gas pipe expansion valve of the cooling-heating switching unit connected to one of the indoor units which is not in heating operation, in accordance with a determination result on excess or deficiency of refrigerant in a refrigeration cycle.

Abstract: An air conditioner provided which has: a main refrigerant circuit including a compressor, a heat source side heat exchanger, a first expansion valve, and a utilization side heat exchanger and configured such that refrigerant flows in the main refrigerant circuit; a sub refrigerant circuit including a cooling member configured such that refrigerant branched from the main refrigerant circuit flows in the cooling member and configured such that refrigerant branched from the main refrigerant circuit flows in the sub refrigerant circuit; and a heat generator to be cooled by the cooling member, wherein a pipe in which part of refrigerant discharged from the compressor flows is connected to the cooling member of the sub refrigerant circuit.

Abstract: An air conditioner is provided, which is capable of accurately determining appropriateness of a refrigerant amount in a refrigerating cycle. A control apparatus is configured to: stop a cooling operation; set an expansion valve to a fully-closed state and, at the same time, switch the selector valve to change the direction, in which a refrigerant flows, to an opposite direction; operate a compressor to perform a refrigerant recovery operation, in which a refrigerant contained in an outdoor heat exchanger is recovered by an indoor heat exchanger; and determine the appropriateness of a refrigerant amount in a refrigerating cycle, based on at least one of a time required for recovering the refrigerant, a pressure change in a refrigerant suctioned by the compressor, and temperature of the refrigerant discharged from the compressor during the refrigerant recovery operation.

Abstract: Provided is a air conditioner including high-and-low-pressure gas pipe expansion valves each of which is provided to a corresponding one of the cooling-heating switching units and adjusts feeding of high-temperature and high-pressure gas refrigerant to the corresponding indoor unit; and a refrigeration cycle controller which adjusts a valve opening degree of the high-and-low-pressure gas pipe expansion valve of the cooling-heating switching unit connected to one of the indoor units which is not in heating operation, in accordance with a determination result on excess or deficiency of refrigerant in a refrigeration cycle.

Abstract: A cooling/heating switching unit is provided that is capable of simply and reliably detecting leak of refrigerant. The switching unit includes: first and second fittings having a high/low-pressure-gas main pipe and a low-pressure-gas main pipe connected thereto, respectively, wherein the main pipes are linked to an outdoor unit; a third fitting having an indoor-unit connection pipe connected thereto, wherein the connection pipe is linked to indoor units; an expansion valve for high/low-pressure-gas pipe, an expansion valve for low-pressure-gas pipe, and expansion-valve driving sections that selectively connect the first or second fitting with the third fitting via a refrigerant pipe to control a flow direction of refrigerant; a housing that houses the refrigerant pipe; a heat insulating material that fills inside of the housing to insulate the refrigerant pipe arranged inside of the housing from heat; and a refrigerant leak detection sensor installed outside of the housing to detect leaked refrigerant.

Abstract: A pump control apparatus for a hydraulic work machine includes: a rotation speed setting device that sets a target rotation speed for an engine; a rotation speed control device that controls an engine rotation speed so as to adjust the engine rotation speed to the target rotation speed; a first variable hydraulic pump used to drive a work hydraulic actuator, driven by the engine; a second variable hydraulic pump used to drive a cooling fan, driven by the engine; and a pump control device that controls an output flow rate of the first variable hydraulic pump and an output flow rate of the second variable hydraulic pump so as to ensure that a sum of an intake torque of the first variable hydraulic pump and an intake torque of the second variable hydraulic pump does not exceed an engine output torque determined in advance based upon the target rotation speed.

Abstract: To permit a precise and easy adjustment of a pump absorption torque of a main pump in accordance with environmental conditions when a sub-pump different in characteristics from the main pump is connected to a prime mover. A main controller 12 includes a processor means for setting the level of an absorption torque of a cooling fan pump 20 at a maximum absorption torque in use, a processor means for incrementing an adjustment target absorption torque for a main pump 13 at a slow rate from a sufficiently small pump absorption torque, and a processor means for repeating loading of a load factor signal and the increment of the adjustment target absorption torque as long as “NO” is determined by a fourth determination means, and a processor means for storing the adjustment target absorption torque as an adjustment value when “YES” has been determined by the fourth determination means.

Abstract: The present invention includes: a displacement altering unit for generating a displacement control pressure corresponding to a displacement control signal; an input unit for inputting a target displacement; a pressure calculating unit for calculating a displacement control pressure corresponding to the target displacement based upon predetermined reference characteristics of the displacement altering unit; a pressure detecting unit for detecting a pressure corresponding to the displacement control pressure; a signal calculating unit for calculating a displacement control signal corresponding to the input target displacement; and a correcting unit for correcting the displacement control signal calculated by the signal calculating unit based upon the displacement control pressure having been calculated by the pressure calculating unit and the measured pressure detected by the pressure detecting unit.

Abstract: A pump control apparatus for a hydraulic work machine includes: a rotation speed setting device that sets a target rotation speed for an engine; a rotation speed control device that controls an engine rotation speed so as to adjust the engine rotation speed to the target rotation speed; a first variable hydraulic pump used to drive a work hydraulic actuator, driven by the engine; a second variable hydraulic pump used to drive a cooling fan, driven by the engine; and a pump control device that controls an output flow rate of the first variable hydraulic pump and an output flow rate of the second variable hydraulic pump so as to ensure that a sum of an intake torque of the first variable hydraulic pump and an intake torque of the second variable hydraulic pump does not exceed an engine output torque determined in advance based upon the target rotation speed.

Abstract: [Object] To permit an precise and easy adjustment of a pump absorption torque of a main pump in accordance with environmental conditions or the like when a sub-pump different in characteristics from the main pump is connected to a prime mover. [MEANS FOR ACHIEVING THE OBJECT] An adjustment switch 25 is arranged.

Abstract: The present invention includes: a displacement altering means 4 for generating a displacement control pressure P corresponding to a displacement control signal i; an input means 12 for inputting a target displacement ?; a pressure calculating means 10 for calculating a displacement control pressure P corresponding to the target displacement ? based upon predetermined reference characteristics of the displacement altering means 4; a pressure detecting means 5 for detecting a pressure Pa corresponding to the displacement control pressure P; a signal calculating means 10 for calculating a displacement control signal i corresponding to the input target displacement ?; and a correcting means 10 for correcting the displacement control signal calculated by the signal calculating means 10 based upon the displacement control pressure P having been calculated by the pressure calculating means 10 and the measured pressure Pa detected by the pressure detecting means 5.

Abstract: A machine body controller 70A includes a modification control unit 70Ab for computing a torque modification value based on detected signals from environment sensors 75 to 83, and modifies a maximum absorption torque of a hydraulic pump controlled by a basic control unit 70Aa. An engine controller 70B includes a modification control unit 70Bb for computing an injection modification value based on detected the signals from the environment sensors 75 to 83, and modifies a fuel injection state of a fuel injection device 14 controlled by a basic control unit 70Ba. The controllers 70A, 70B further include computation element altering units 171, 181. A communication controller 70C downloads alteration data obtained from an external terminal 150 to the computation element altering units 171, 181, whereby corresponding computation elements contained in the modification control units 70Ab, 70Bb are altered.

Abstract: A machine body controller 70A includes a modification control unit 70Ab for computing a torque modification value based on detected signals from environment sensors 75 to 83, and modifies a maximum absorption torque of a hydraulic pump controlled by a basic control unit 70Aa. An engine controller 70B includes a modification control unit 70Bb for computing an injection modification value based on detected the signals from the environment sensors 75 to 83, and modifies a fuel injection state of a fuel injection device 14 controlled by a basic control unit 70Ba. The controllers 70A, 70B further include computation element altering units 171, 181. A communication controller 70C downloads alteration data obtained from an external terminal 150 to the computation element altering units 171, 181, whereby corresponding computation elements contained in the modification control units 70Ab, 70Bb are altered.

Abstract: A hydraulic drive system for a supersized hydraulic working machine such as a hydraulic excavator includes hydraulic pumps connected to main lines through a delivery line and a supply line. Branch portions from the main line include flow control valves for allowing a hydraulic fluid to flow from the hydraulic pumps toward hydraulic cylinders. A hydraulic reservoir is connected to the main lines through a reservoir line and a drain line. Other branch portions for the drain line include flow control valves for allowing a hydraulic fluid to flow from the hydraulic cylinders toward the hydraulic reservoir. A line branched for the delivery line includes a bypass valve for supplying the hydraulic fluid delivered from the hydraulic pumps to the supply line at a desired flow rate and returning the remaining hydraulic fluid to the hydraulic reservoir.