摘要:
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.
摘要:
A hydraulic control valve apparatus including a flow control valve having a pair of variable throttles, a feeder passage, a pair of load passages, directional control valve devices comprise a seat valve having a seat valve body movably disposed in a housing to form an auxiliary variable throttle in the feeder passage, and a control variable throttle (33) formed in the seat valve body for changing an opening area in accordance with an amount of movement of the seat valve body; (b) a pilot line (24, 29-31, 35-37) for communicating a portion (7C) of the feeder passage upstream of the auxiliary variable throttle with a downstream portion (7A, 7B) of the feeder passage through the control variable throttle to determine the amount of movement of the seat valve body in accordance with a flow rate of the hydraulic fluid passing through the pilot line; and (c) pilot flow control (400; 401; 403; 405; 406; 407; 408) having a pilot variable throttle (45) disposed in the pilot line and input (800; 52-59; 159, 54-59; 231A, 231B, 251, 252) for receiving a flow restricting signal whereby an opening area of the pilot variable throttle is changed in accordance with the received flow restricting signal to control a flow rate of the hydraulic fluid passing through the pilot line.
摘要:
A flow control valve apparatus includes a housing including a main fluid passage having an inlet port and an outlet port; a main valve disposed between the inlet port and the outlet port for allowing or shutting off communication between the inlet port and the outlet port; a backpressure chamber formed between an inner wall of the housing and a rear portion of a valve member of the main valve, the backpressure chamber communicating with the inlet port through an orifice; an auxiliary passage for placing the backpressure chamber in communication with the outlet port; and a pivot valve for actuating the main valve by controlling the opening and closing of the auxiliary passage and varying the fluid pressure in the backpressure chamber. A differential pressure generating means is disposed in the main fluid passage for generating differential pressures that correspond to the flow rate in the main fluid passage. The differential generating means includes a displacement member disposed for movement in the direction in which a fluid flows in the main fluid passage and spring means for urging the displacement member in the direction opposite to the direction in which the fluid flows, and the displacement member cooperates with a wall surface of the main fluid passage to define a fluid passage having an opening area which increases in accordance with an increase in the stroke of travel of the displacement member.
摘要:
A flow control system is arranged in a hydraulic circuit provided with a variable displacement hydraulic pump, plural actuators and a pump controller. The pump controller controls the displacement of the pump so that a delivery pressure becomes higher by a predetermined value than a maximum load pressure of the plural actuators, whereby the flow rate of pressure oil to the actuators is controlled. The system includes plural valve units connected between the pump and the actuators. Each valve unit has an operating and correcting variable restrictors. The system also includes pressure compensation valves, which are each arranged on an upstream side of a restrictor group consisting of the operating and correcting variable restrictors. The opening of the pressure compensation valve is independently set by an opening drive force set based on a downstream pressure of the restrictor group, an opening drive force set by a pressure-difference setting device and a closing drive force set based on an upstream pressure of the restrictor group so that the upstream pressure becomes higher by a predetermined pressure than the downstream pressure of the restrictor group.
摘要:
Pressure adjusting valves (9A, 9B) control outlet pressures of variable throttle portions (8a) of directional control valves (8A, 8B) of closed center type to be kept substantially equal to a maximum load pressure detected by a detecting line (13). A variable throttle valve (40) and a pressure adjusting valve (41) are disposed in a bypass line (5) branched from a pump supply line (3) for controlling an outlet pressure of the variable throttle valve (40) to be also kept substantially equal to the maximum load pressure. The variable throttle valve (40) has an opening area controlled to be reduced with an increase in the input amount by which a control lever unit is operated, and a pump delivery rate is controlled by a tilting control device (2n) to become a flow rate corresponding to the input amount of the control lever unit.
摘要:
Provided are a photosensitive resin composition capable of being quickly cured by light and providing an optically cured product which is excellent in a transparency in a visible light of 400 to 780 nm and a heat resistant reliability, a photosensitive resin varnish, a photosensitive resin film and a photosensitive resin cured product.The photosensitive resin composition comprises (A) a polymerizable compound, (B) a polymerization initiator and (C) a hindered phenol base antioxidant, wherein (B-1) at least one selected from α-hydroxyacetophenone base photoinitiator and a glyoxy ester base photoinitiator and (B-2) a phosphine oxide base photoinitiator are contained as the component (B); the component (C) is a hindered phenol base antioxidant having in a molecule, at least one phenol group having each one group of a methyl group and a t-butyl group on the same aromatic ring; a content of the component (B) is 0.02 to 4.0 parts by mass based on 100 parts by mass of the component (A); and a content of the component (C) is 0.01 to 1 part by mass based on 100 parts by mass of the component (A).
摘要:
[Problem]To prevent an eccentric load from occurring in a nut member of a linear actuator and ensure a longer service life of the nut member.[Solution]The nut member is coupled to a driven member by a contact force equalizing mechanism having two rotation axes which are virtually perpendicular to each other, to absorb slight inclination between the nut member and the driven member and prevent occurrence of an edge load; also the point of intersection which is obtained when the two rotation axes are projected toward a threaded shaft is set as an optimum point of application of load for the nut member to let an external force transmitted from the driven member act on the optimum point of application of load to equalize the loads applied to the contact portions between the nut member and the threaded shaft and thereby prevent an eccentric load from occurring in the nut member.
摘要:
[Problem] Provided include: a resin composition for forming an optical waveguide, the resin composition having high productivity and being capable forming a thick film with high accuracy excellent in transparency, heat resistance and toughness; a resin film for forming an optical waveguide; and an optical waveguide excellent in transparency, environmental reliability and heat resistance.[Means for Solution] A resin composition for forming an optical waveguide, containing (A) a polyhydroxy polyether having an ethylenically unsaturated group on a side chain and an aromatic ring on a main chain, (B) a polymerizable compound having an ethylenically unsaturated group, and (C) a radical polymerization initiator; a resin film for forming an optical waveguide; and an optical waveguide having a core part formed by using the resin film for forming an optical waveguide.
摘要:
To provide a semiconductor memory device having an ECC circuit whereof checker-data inspection of memory cells in the user areas and the ECC areas can be performed at once, the ECC code generation circuit generates the ECC code of six bits whereof logic of each bit has XOR logic of each of six different combinations of 15 bits of the data set of 32 bits, and addresses in every user areas of the bit-columns are arranged in an order of 1, 4, 2, 5, 3, 6, . . . , b, f. When a checkerboard pattern is written, a first data set having 32 bits of logic ‘0’ and a second data set having 32 bits of logic ‘1’ are written alternately, in addresses 4n to 4n+3 and 4(n+1) to 4(n+1)+3 of the user areas on odd-numbered word-lines, and written alternately on even-numbered word-lines in an inverse order of the odd-numbered word-lines, when checker-data inspection of the memory-cell array is performed, n being an integer not less than 0.
摘要:
This invention relates to a fault diagnosis system for hydraulic pumps in a work vehicle, which is economical and permits sure identification of one or more trouble-developed ones of the hydraulic pumps.Pressure sensors 61-64 are arranged on pressurized fluid lines 30,40, which extend to a tank T from points immediately out of center bypasses of flow control valves 21,231-234,451-454,26 communicated to hydraulic pumps 1-6. Solenoid-operated directional control valves 51-56 are interposed in input circuits of individual regulators 11-16 so that, upon excitation, a pressure of a pilot pump 7 is introduced into the regulators 11-16. When all the flow control valves are brought into neutral positions thereof and a determination is instructed through a switch 80, one of the solenoid-operated directional control valves is excited by a signal from a processor 70 so that pressurized fluid is delivered at a maximum flow rate from the corresponding hydraulic pump. A detection value of the corresponding pressure sensor at this time is translated into a flow rate, which is then stored. These procedures are performed with respect to the individual hydraulic pumps successively. Based on a flow rate obtained in every determination, a fault diagnosis of the corresponding particular hydraulic pump is performed.