Abstract: In a hydraulic excavator, a hydraulic cylinder drives a boom via a hydraulic fluid discharged from a first hydraulic pump. A first hydraulic circuit connects the first hydraulic pump and the hydraulic cylinder and forms a closed circuit therebetween. A hydraulic motor rotates a revolving upper unit with hydraulic fluid discharged from a second hydraulic pump. A second hydraulic circuit independent from the first hydraulic circuit connects the second hydraulic pump and the hydraulic motor. A motor hydraulic pressure reduction unit reduces the driving hydraulic pressure of the hydraulic motor when a predetermined condition is satisfied. The predetermined condition is a condition in which an operation of the boom operating member to raise the boom and an operation of the rotation operating member to rotate the revolving upper unit are conducted together and an operation amount of the boom operating member is equal to or greater than a predetermined threshold.

Abstract: In a rotary compressor of a vane rotary type, an outer peripheral surface of an eccentric portion of a shaft on a side adjacent to a center of the shaft is located radially inwardly of an outer peripheral surface of a main shaft inserted in a main bearing and that of an auxiliary shaft inserted in an auxiliary bearing. Also, a back clearance means used in mounting a piston on the shaft is provided in each of an inner peripheral surface of the piston and the eccentric portion of the shaft. Such configurations can reduce a diameter of the eccentric portion.

Abstract: A hydraulic fluid flowpath includes a first flowpath and a second flowpath. The first flowpath connects a first pump port and a first chamber in a hydraulic cylinder. The second flowpath connects a second pump port and a second chamber in the hydraulic cylinder. The hydraulic fluid flowpath forms a closed circuit between a hydraulic pump and the hydraulic cylinder. A bleed-off flowpath bleeds off a portion of the hydraulic fluid from the second flowpath. A control valve connects the second flowpath to the bleed-off flowpath via a throttle when an operation amount of an operating member for lowering a work implement is less than a predetermined operation amount so that a hydraulic pressure in second flowpath is maintained at less than a relief pressure. The predetermined operation amount is less than or equal to the maximum operation amount for lowering the work implement.

Abstract: A hermetic compressor includes: a main bearing (126) which supports a main shaft (120) of a shaft (119); and a thrust ball bearing at an upper end portion of the main bearing (126). A rotor (116) is fixed to the main shaft (120) via a flange. A rotor core (117) has a magnetic center displaced upward relative to the magnetic center of a stator core (115) so that a downward magnetic attractive force is applied between the rotor (116) and the stator (114). Accordingly, a contact load between steel balls and upper and lower races in the thrust ball bearing is appropriately maintained.

Abstract: A scroll compressor employs therein a refrigerant having a small global warming potential and a small ozone depletion potential and mainly comprising hydrofluoroolefin having a carbon-carbon double bond. A stationary scroll has and end plate and a discharge port defined in the end plate at a central portion thereof so as to open into a discharge chamber. The stationary scroll also has a bypass hole defined in the end plate to allow a plurality of compression chambers to communicate with the discharge chamber before the compression chambers communicate with the discharge port. A check valve is provided on the bypass hole to allow the refrigerant to flow from the compression chambers to the discharge chamber. This construction can restrain a baneful influence on the global environment, reduce a temperature increase caused by excessive compression, and restrain decomposition of the refrigerant even in long-term use.

Abstract: A compressor, characterized in that a steel is used as the base material for the other sliding material vane 10 and nitrided, a CrN or DLC film is formed on the surface by PVD treatment, and a Ni—Cr—Mo cast iron is used for the other corresponding sliding material piston 9. It is possible in such a configuration to suppress the temperature rise by sliding friction of the sliding materials, such as the vane tip region 10a and the peripheral region of piston 9 that are vigorously slid, relax decomposition of the refrigerant, and suppress corrosion by hydrogen fluoride generated in reaction with water and oxygen, and thus to provide a compressor higher in reliability.

Abstract: A hydraulic cylinder causes a work implement to be lowered due to the exhaust of hydraulic fluid from a first chamber and the supply of hydraulic fluid to a second chamber. A hydraulic fluid flowpath has a first flowpath and a second flowpath. The first flowpath connects a first pump port and the first chamber. The second flowpath connects a second pump port and the second chamber. The hydraulic fluid flowpath configures a closed circuit between a hydraulic pump and the hydraulic cylinder. A bleed-off flowpath branches off from the first flowpath. A portion of hydraulic fluid exhausted from the first chamber when lowering the work implement flows into the bleed-off flowpath.

Abstract: An operating state determining unit determines whether a hydraulic cylinder is in operation or not in operation. A discharge pressure reducing unit reduces the discharge pressure of a charge pump. A discharge pressure control unit controls the discharge pressure reducing unit when the hydraulic cylinder in not in operation to reduce the discharge pressure of the charge pump to a low pressure lower than a normal pressure. The normal pressure is the discharge pressure of the charge pump when the hydraulic cylinder is in operation. An accumulator is connected to a charge flowpath. A one-way valve is disposed between the accumulator and the charge pump. The one-way valve allows the flow of hydraulic fluid from the charge pump to the accumulator and prohibits the flow of hydraulic fluid from the accumulator to the charge pump.

Abstract: A shuttle valve connects a second flowpath and a drain flowpath when the hydraulic pressure in a first flowpath is greater than the hydraulic pressure in the second flowpath. The shuttle valve connects the first flowpath and the drain flowpath when the hydraulic pressure in a second flowpath is greater than the hydraulic pressure in the first flowpath. The ratio between the pressure receiving area of a first pressure section and the pressure receiving area of a second pressure section is the same as the ratio between the pressure receiving area of a first chamber side and the pressure receiving area of a second chamber side of a cylinder rod.

Abstract: An operation for reconnecting a mobile information terminal and a base unit, which is performed when a user returns home, is made easier, and a matter that has occurred in the base unit during his absence is displayed on the mobile information terminal. The mobile information terminal enters a sleep state when receiving no signal from the base unit. When the user performs a predetermined operation, the mobile information terminal returns from the sleep state, then searches for the base unit, and displays, on a display section, information relating to the matter that has occurred during his absence, the information being transmitted from the base unit when the terminal is reconnected to the base unit. Accordingly, the user can know, through a simple operation, the record of an incoming call received through a wired network, or an answering machine message that has occurred during his absence from the base unit.

Abstract: A hydraulic driving system includes a hydraulic pump, a driving source, a hydraulic cylinder, a closed circuit hydraulic path between the pump and cylinder, a pump-flow-rate control unit controlling a discharge flow rate of the pump, a flow rate control valve between the pump and the cylinder in the fluid path, a directional control unit, a target flow rate setting unit and a control device. The directional control unit allows a flow of fluid from the pump to the cylinder and prohibits a flow of fluid from the cylinder to the pump when fluid is supplied from the pump to the cylinder via the flow rate control valve. The control device controls fluid flow to the cylinder with the flow rate control valve when the target flow rate is within a prescribed range, and with the pump-flow-rate control unit when the target flow rate is greater than the prescribed range.

Abstract: A hydraulic driving system includes a hydraulic cylinder with a cylinder tube and a cylinder rod, a main pump, a hydraulic-fluid path, a charge pump, a stroke position detecting unit, and a pump control unit. The hydraulic-fluid path forms a closed circuit between a main pump and the hydraulic cylinder. The cylinder rod expands or contracts depending on how hydraulic fluid is supplied and exhausted to and from first and second chambers. The charge pump replenishes hydraulic-fluid in the hydraulic-fluid path. The pump control unit performs flow-rate reduction control in which the pump control unit reduces a suction flow rate so that a suction flow rate of the main pump is equal to or less than a maximum discharge flow rate of the charge pump when the stroke position becomes closer to a stroke end of the cylinder rod than a prescribed reference position during the flow rate reduction control.

Abstract: In a hydraulic excavator, a hydraulic cylinder drives a boom via a hydraulic fluid discharged from a first hydraulic pump. A first hydraulic circuit connects the first hydraulic pump and the hydraulic cylinder and forms a closed circuit therebetween. A hydraulic motor rotates a revolving upper unit with hydraulic fluid discharged from a second hydraulic pump. A second hydraulic circuit independent from the first hydraulic circuit connects the second hydraulic pump and the hydraulic motor. A motor hydraulic pressure reduction unit reduces the driving hydraulic pressure of the hydraulic motor when a predetermined condition is satisfied. The predetermined condition is a condition in which an operation of the boom operating member to raise the boom and an operation of the rotation operating member to rotate the revolving upper unit are conducted together and an operation amount of the boom operating member is equal to or greater than a predetermined threshold.

Abstract: A refrigerant being low in both ODP and GWP and containing at least hydrofluoroolefin having a double bond of carbon is used. By providing a first compression-chamber oil feed path for feeding refrigerating machine oil to a compression chamber 15 after the refrigerant has been enclosed therein, effects on the global environment can be suppressed and moreover temperature increases of the refrigerant due to re-expansion heating and feeding of high-temperature refrigerating machine oil can be suppressed, i.e., decomposition of the refrigerant can be inhibited.

Abstract: In a compressor, a single refrigerant of hydrofluoroolefin having a double bond of carbon or a mixed refrigerant containing hydrofluoroolefin and hydrofluorocarbon having no double bond of carbon is used, and moreover a refrigerating machine oil containing an additive for suppressing deterioration of the refrigerating machine oil and an antiwear agent is used, the compressor including a sliding portion which is exposed to the mixed refrigerant and the refrigerating machine oil and which has a hardness of 47-55 HRC. Thus, decomposition and polymerization of the refrigerant and the refrigerating machine oil can be inhibited (i.e., occurrence of sludge can be inhibited), and antiwear property of sliding portions, e.g. vane and piston, of the compressor can be maintained. As a result, reliability of the compressor and the refrigerating cycle apparatus using the compressor can be ensured.

Abstract: A scroll compressor employs therein a refrigerant having a small global warming potential and a small ozone depletion potential and mainly comprising hydrofluoroolefin having a carbon-carbon double bond. A stationary scroll has and end plate and a discharge port defined in the end plate at a central portion thereof so as to open into a discharge chamber. The stationary scroll also has a bypass hole defined in the end plate to allow a plurality of compression chambers to communicate with the discharge chamber before the compression chambers communicate with the discharge port. A check valve is provided on the bypass hole to allow the refrigerant to flow from the compression chambers to the discharge chamber. This construction can restrain a baneful influence on the global environment, reduce a temperature increase caused by excessive compression, and restrain decomposition of the refrigerant even in long-term use.

Abstract: In a rotary compressor of a vane rotary type, an outer peripheral surface of an eccentric portion of a shaft on a side adjacent to a center of the shaft is located radially inwardly of an outer peripheral surface of a main shaft inserted in a main bearing and that of an auxiliary shaft inserted in an auxiliary bearing. Also, a back clearance means used in mounting a piston on the shaft is provided in each of an inner peripheral surface of the piston and the eccentric portion of the shaft. Such configurations can reduce a diameter of the eccentric portion.

Abstract: A hermetic compressor (100) includes a closed casing (2), a compression mechanism (4), a motor (6), a discharge pipe (8), a first balance weight (18), a swirl flow generating portion (21), and a second balance weight (19). The motor (6) has a stator (14) and a rotor (15). A communication passage (20) is formed in the rotor (15) so as to introduce, into an upper space (7), a working fluid compressed in the compression mechanism (4) and discharged to a lower space (5) of the closed casing (2). A baffle plate (122) is provided as a discharge direction deflecting portion for causing the compressed working fluid to travel from the communication passage (20) to the upper space (7), while deflecting the working fluid in a direction inclined with respect to a direction parallel to a rotational axis O. The baffle plate (122) may be constituted by a part of the swirl flow generating portion (21).

Abstract: An object of the present invention is to provide a refrigeration cycle apparatus having a compressor that is not easily heated to high temperature by sliding heat and thus higher in reliability. Provided is a refrigeration cycle apparatus having a cost-effective compressor in the configuration in which a piston 9 eccentrically revolving, as driven by a shaft 4, is placed in a cylinder 6 and the circular terminal region 10a of a vane 10 partitioning the cylinder 6 into a suction chamber 12 and a compression chamber 13 is connected slidably to the external surface of the piston 9 in surface contact, which can reduce the sliding heat and is thus resistant to deterioration in reliability by reaction of the operating refrigerant.

Abstract: It was found that a refrigerant mainly containing a carbon-carbon double bond-containing hydrofluoroolefin has a function to suppress abrasive wear, compared to conventional HFC-based refrigerants, because the hydrofluoroolefin generates iron fluoride especially on the surface of the vane and piston, where sliding force is severe, from hydrogen fluoride, even if it is generated in reaction with water and oxygen. It is possible to reduce abrasive wear, by using a refrigerant containing as the base component a hydrofluoroolefin as operating refrigerant and a refrigeration oil 3 miscible with the refrigerant and a vane 10 made of a high-speed tool steel and sintered and quenched, because hydrogen fluoride generated by decomposition of the refrigerant in the region of a vane tip region 10a and a piston 9 peripheral surface, where sliding force is severe is converted to iron fluoride.