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公开(公告)号：JPH07173811A
公开(公告)日：1995-07-11
申请号：JP32036493
申请日：1993-12-20
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： OSHINA MORIO , KANAI TAKASHI , TAMAI HIROSHI , KOBAYASHI TORU , SANAO KOJI
Abstract: PURPOSE:To drive an operating hydraulic motor and a traveling hydraulic motor with one prime mover and to make it possible to increase a car speed by stepping on the accelerator even if the operating hydraulic motor is operated within a high speed range. CONSTITUTION:An operation car is equipped with a variable capacity traveling hydraulic pump 2 driven by a prime mover 1 and an HST closed circuit of a traveling hydraulic motor 5. An operating hydraulic motor 14 is driven with discharge oil from an operating hydraulic pump 12 driven by the prime mover 1. The bigger the differential pressure occurs in accordance with number of revolutions of the prime mover 1, the greater the discharge capacity of the traveling hydraulic pump 2. In such a state as an accelerator 22 is not operated, the differential pressure is reduced to zero, a tilting and rolling amount reaches approximate zero, and the car is stopped. The greater a manipulated variable of the accelerator 22, the bigger the differential pressure, and a tilting and rolling amount of the hydraulic pump 2 is also increased to speed up a car speed.
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公开(公告)号：JPH05106732A
公开(公告)日：1993-04-27
申请号：JP29636791
申请日：1991-10-15
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： OKUI HISAO , KANAI TAKASHI , KAMATA HIROSHIGE , TSURUMI GENICHI
IPC: E02F9/22 , F16H59/18 , F16H61/02 , F16H61/40 , F16H61/4043
Abstract: PURPOSE:To raise lubrication oil temperature at an early time by releasing temporarily brake effect that is by means of an HST at the time of coldness in the winter season, increasing the operation frequency of a mechanical type brake. CONSTITUTION:The closed circuit connection of a variable displacement type hydraulic pump 2 driven by means of a motor 1 and a hydraulic motor 5 that drives drive wheels 11, is made by means of a pair of main pipe passages 3, 4. A bypass pipe passage 17 is provided between main pipe passages 3,4 and made openable/closable by means of an opening/closing valve 18. An oil temperature sensing switch 22 is provided at a circuit that extends to the solenoid coil 18a of the onening/closing valve 18 from a power source 20 through a main switch 21, and when the detection temperature of an oil temperature sensor 25 to detect the lubrication oil temperature of a motive power transmission mechanism 10 has arrived at more than a fixed value, the solenoid coil 18a is magnetized. An acceleration switch 23 that falls into a non- electrification state in a state in which an acceleration pedal is not stepped on, its provided, and when the acceleration pedal is stepped on in connection with a relay 24, the magnetization of the solenoid coil 18a is stopped.
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公开(公告)号：JPH0565903A
公开(公告)日：1993-03-19
申请号：JP22434391
申请日：1991-09-04
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： KANAI TAKASHI , TATEKAWA NOBORU , OKAJIMA SUSUMU , ARITAKE TAKESHI
Abstract: PURPOSE:To provide an attachment hydraulic circuit enabling the gentle start of a working device so as to attain the safety of work and prolong the life span of the whole device. CONSTITUTION:There are provided a direction switching valve 12 for operating the start and stop of a working device 1, and a flow control valve 31 for controlling the flow of pressure oil supplied to the working device 1. There is also provided an escape valve 32 operated in response to differential pressure between load pressure at the inlet of the working device 1 and the delivery pressure of pressure oil from a hydraulic source 21 so as to let pressure oil from a hydraulic pump 21 escape to a return circuit 3B in order to maintain the differential pressure to the specified value. There are further provided a pressure transmission delay means 37a, installed at pilot circuits 33, 34, 35 for leading load pressure at the inlet of the working device 1, for limiting the transmission of this load pressure so as to delay the response of the escape valve 32; and a pressure control valve for regulating the maximum pressure of the pilot circuits 33, 34.
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公开(公告)号：JPH0560237A
公开(公告)日：1993-03-09
申请号：JP24505791
申请日：1991-08-30
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： KATO HIDEYO , KANAI TAKASHI , OCHIAI MASAMI , OSHINA MORIO , SONODA MITSUO
IPC: F16H59/42 , F16H61/42 , F16H61/431 , F16H61/448 , F16H61/46 , F16H61/465
Abstract: PURPOSE:To prevent lowering of the engine speed in a HST hydraulic driving device for controlling a discharge capacity of a variable capacity hydraulic pump with a differential pressure, of which pressure loss against a passing flow quantity is primarily proportioned in outline, even in the case, for example, a load except for a HST circuit is input to an engine. CONSTITUTION:The pushing force corresponding to the operation quantity of an accelerator pedal 21 is given to a switching valve 20. A differential pressure generating unit 8 generates the differential pressure to be primarily proportioned to the engine speed in outline. The pressure receiving force corresponding to this differential pressure is given to the switching valve 20 so as to resist the described pushing force. In the case that the pushing force is smaller than the pressure receiving force, the switching valve 20 increases a discharge capacity of a hydraulic pump 2, and in the case that the pushing force is larger than the pressure receiving force, the switching valve 20 reduces the discharge capacity. When a load of a hydraulic pump 14 driven by the same engine is applied, an engine load is increased, but discharge capacity of the hydraulic pump 2 is reduced by the increased quantity of the torque absorbed by the pump 14 by working of the switching valve 20 to prevent lowering of the engine speed.
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公开(公告)号：JPH0516989B2
公开(公告)日：1993-03-05
申请号：JP565584
申请日：1984-01-18
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： KANAI TAKASHI , OCHIAI MASAMI , OOSHINA MORIO
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Patent Agency Ranking
公开(公告)号：JPH04250226A
公开(公告)日：1992-09-07
申请号：JP2379491
申请日：1991-01-25
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： OCHIAI MASAMI , KANAI TAKASHI
Abstract: PURPOSE:To improve fine operability by making the operator perform the intended action even when a hydraulic actuator with high inertia is driven. CONSTITUTION:Detectors 11a-12b for detecting the manipulated variable of manipulating devices 11, 12 and a setting means for setting the relation between the manipulated variable of manipulating devices 11, 12 and the discharge pressure of a pump 2 and the load pressure of hydraulic actuators 4, 5 in advance are installed. The relation is set so that as the manipulated variable increases, the differential pressure increases gradually, and it becomes constant after the manipulated variable reaches the specified value. An arithmetic unit 22 is installed to perform arithmetic operation for determining differential, pressure corresponding to the signal value from the relation set by the setting means by taking signals from the detectors 11a-12b. In addition a control unit 24 is installed to output control signals in accordance with the arithmetic operation result of the arithmetic unit 22. Thus, a variable unload valve 26 is driven in accordance with the control signal outputted by the control unit 24, by which the flow rate of pressure oil flowing from the hydraulic pump 2 to a tank is controlled.
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公开(公告)号：JPH04238740A
公开(公告)日：1992-08-26
申请号：JP1821991
申请日：1991-01-08
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： OSHINA MORIO , SONODA MITSUO , KANAI TAKASHI
IPC: B60K28/00 , E02F9/22 , F15B20/00 , F16H61/40 , F16H61/4192
Abstract: PURPOSE:To hold adequate running performance even when a trouble is generated in an electric system for controlling a tilt rotary amount of an oil hydraulic pump and motor. CONSTITUTION:In the case of a hydraulic running driving gear having a variable displacement oil hydraulic pump 1 driven by a prime mover 2, oil hydraulic motor 3 connected by a closed circuit to this oil hydraulic pump 1 through a pair of main pipe lines 4, 5 and a displacement volume control means 15 for electrically adjusting the displacement volume of the variable displacement oil hydraulic pump 1 in accordance with a rotational speed of the prime mover, a detecting means 15i for detecting abnormality of the displacement volume control means 15 and a free means for freeing rotation of the oil hydraulic motor 3 at the time of detecting the abnormality are provided. Accordingly, an inertia running condition is provided at the time of abnormality.
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公开(公告)号：JPH04205201A
公开(公告)日：1992-07-27
申请号：JP33073690
申请日：1990-11-30
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： KANAI TAKASHI , OSHINA MORIO
Abstract: PURPOSE:To evade the danger of the runaway of a controlled object by shutting off a driving output to the controlled system and holding the shutoff state when the movement quantity of an input operation means exceeds a specific movement range. CONSTITUTION:When a lever 11 as the input operation means reaches a position beyond the specific movement range, an output command value 14 from an output command value generating means 12 becomes a voltage higher than a reference voltage 16 and a comparator 17 generates an output to excite an electromagnetic coil 18, thereby breaking a contact 19 and making a contact 20. An output command value 13 which is inputted to an actuator 22 is therefore shut off and becomes zero and the actuator 22 stops its driving operation. At this time, a current continues to flow to the electromagnetic coil 18 through the contact 20 and the contact 19 is held OFF. Consequently, even if the input operation means enters a noncontrol state and the movement quantity becomes maximum, the runaway of the controlled object can be prevented.
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公开(公告)号：JPH0440244A
公开(公告)日：1992-02-10
申请号：JP14606990
申请日：1990-06-06
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： KANAI TAKASHI
Abstract: PURPOSE:To make the operational speed of a single rod cylinder high at the time of arm closing operation by installing a communicating pipeline communicated with a first main pipeline and at the same time installing a sequential valve between the communicating pipeline and a second main pipeline and providing a solenoid-controlled switching valve which is able to switch the sequential valve at a second switching position and a third switching position reciprocally. CONSTITUTION:When a direction switching valve 11 is switched to a switching position (a), a pressure oil for oil pressure source 10 is led to a second main pipeline 15 through the direction switching valve 11. At that time, pilot pressure is applied to the end part of a spool 23 of a sequential valve 21 through a pilot pipeline 29 and the spool 23 moves to the limiting position toward left and is switched to a first switching position 25. Consequently, the second main pipeline 15 part and the second main pipeline 15 part are communicated each other and the pressure oil is supplied to the rod side 14 of a single rod cylinder 9. Under these conditions, arms 2, 3 are so positioned as to pinch concrete, an object to be crushed, and when the direction switching valve 11 is switched to a switching position (b), the pressure oil of the oil pressure source 10 is supplied to the bottom side 12 of the single rod cylinder 9 through a first main pipeline 13. As a result, highly fragile concrete is crushed at high efficiency.
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公开(公告)号：JPH0427784A
公开(公告)日：1992-01-30
申请号：JP13332490
申请日：1990-05-23
Applicant: HITACHI CONSTRUCTION MACHINERY
Inventor： OKUI HISAO , KANAI TAKASHI , NAKAMURA HIROYUKI , TAKAHASHI TOMOO , TAKAGI HISAO
Abstract: PURPOSE:To effectively utilize the engine output by controlling the discharge capacity of a variable-capacity hydraulic pump so that the reduction rate of the discharge capacity is increased as the engine rotating speed is decreased by a load when the command value is constant. CONSTITUTION:A pump regulator 28 sets the discharge capacity of a variable- capacity hydraulic pump 24 based on the rotating speed detected by a throttle 29 detecting the actual rotating speed of an engine 21 and the command value of the target rotating speed by an accelerator pedal 31. The pump regulator 28 controls the discharge capacity of the variable-capacity hydraulic pump 24 so that the reduction rate of the discharge capacity is increased as the engine rotating speed is decreased by a load when the command value is constant as compared with the reduction rate of the discharge capacity as the engine rotating speed is decreased by the reduction of the command value. When the work load is made larger than the engine output torque and the engine rotating speed is made smaller than the target rotating speed, the pump capacity is decreased by the amount proportional to the rotating speed deviation, and the running torque is increased by that much.
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