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1. 发明授权

US5152143A Hydraulic drive system 失效
标题翻译：液压驱动系统
公开(公告)号：US5152143A
公开(公告)日：1992-10-06
申请号：US449848
申请日：1989-12-21
申请人： Yusuke Kajita , Toichi Hirata , Genroku Sugiyama
发明人： Yusuke Kajita , Toichi Hirata , Genroku Sugiyama
IPC分类号： E02F9/22 , F15B11/00 , F15B11/05
CPC分类号： E02F9/2246 , E02F9/2228 , E02F9/2235 , E02F9/2292 , E02F9/2296
摘要： A hydraulic drive system comprising a prime mover (21), a hydraulic pump (22) driven by the prime mover, a plurality of hydraulic actuators (23-28) driven by hydraulic fluid supplied from the hydraulic pump, a plurality of flow control valves (29-34) for controlling flow of the hydraulic fluid supplied to the actuators, and a plurality of pressure compensating valve (35-40) for controlling respective differential pressures across the respective flow control valves, in which each of the pressure compensating valves applies a control force (f-F.sub.c) in a valve opening direction for setting a target value of the differential pressure across the flow control valve. There are provided a first detector (60) for detecting the target rotational speed (N.sub.0) of the prime mover (21), and controllers (61, 62, 63) for controlling the control force on the basis of the target rotational speed detected by at least the first detector such that the control force (f-F.sub.c) decreases in accordance with a decrease in the target rotational speed.
摘要翻译： PCT No.PCT / JP89 / 00893 Sec。 371日期1989年12月21日第 102（e）1989年12月21日PCT PCT 1989年8月31日PCT公布。出版物WO90 / 02268 日本1990年8月3日。一种液压驱动系统，包括原动机（21），由原动机驱动的液压泵（22），多个液压致动器（23-28），由液压泵，用于控制供应到致动器的液压流体的流动的多个流量控制阀（29-34）和用于控制横跨各个流量控制阀的相应差压的多个压力补偿阀（35-40），其中每个压力补偿阀在阀打开方向上施加控制力（f-Fc），以设定跨过流量控制阀的差压的目标值。提供了用于检测原动机（21）的目标转速（N0）的第一检测器（60）和用于根据由原动机（21）检测到的目标转速控制控制力的控制器（61,62,63）至少第一检测器，使得控制力（f-Fc）根据目标转速的降低而减小。

2. 发明授权

US5152140A Pressure compensating valve spool positioned by difference in pressure receiving areas for load and inlet pressures 失效
标题翻译：压力补偿阀由压力接收区域负载和入口压力的差异定位
公开(公告)号：US5152140A
公开(公告)日：1992-10-06
申请号：US640440
申请日：1991-02-06
申请人： Toichi Hirata , Hideaki Tanaka , Genroku Sugiyama , Yusuke Kajita , Kazunori Nakamura
发明人： Toichi Hirata , Hideaki Tanaka , Genroku Sugiyama , Yusuke Kajita , Kazunori Nakamura
IPC分类号： E02F9/22 , F15B13/04
CPC分类号： F15B13/0417 , E02F9/2232 , E02F9/2296 , Y10T137/7858
摘要： A hydraulic drive system has a hydraulic pump (1), an actuator (2), a flow control valve (5) disposed between the hydraulic pump and the actuator, a pressure compensating valve (8; 8A; 8B) having a valve spool (23; 23A; 23B) that controls the differential pressure (Pz-PLS) across the flow control valve, and a pump delivery rate control device (9) 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 first control chamber (30; 30A) subjected to the load pressure (PLS) of the actuator such that the load pressure acts on a first pressure receiving section (28; 28A) of the valve spool to urge the valve spool in the valve-opening direction, a second control chamber (29; 29A) subjected to the inlet pressure (Pz) of the flow control valve such that the inlet pressure acts on a second pressure receiving section (27; 27A) of the valve spool to urge the valve spool in the valve-closing direction, and a target differential pressure setting arrangement (31, 50, 51; 31B, 51) for urging the valve spool in the valve-opening direction. A damping capability to the actuator (2) is provided by setting pressure receiving area (Az) of the second pressure receiving section (27; 27A) to be greater than a pressure receiving area (ALS) of the first pressure receiving section (28; 28A).
摘要翻译： PCT No.PCT / JP90 / 01310 Sec。 371日期1991年2月6日 102（e）日期1991年2月6日PCT 1990年10月11日PCT PCT。出版物WO91 / 05958 日期：1991年5月2日。液压驱动系统具有液压泵（1），致动器（2），设置在液压泵和致动器之间的流量控制阀（5），压力补偿阀（8; 8A; 8B ）具有控制跨过流量控制阀的差压（Pz-PLS）的阀芯（23; 23A; 23B）和用于控制从所述流量控制阀输送的液压流体的流量的泵输送速率控制装置（9）液压泵取决于泵压力和执行器的负载压力之间的压差（Pd-PLS）。压力补偿阀具有受到致动器的负载压力（PLS）的第一控制室（30; 30A），使得负载压力作用在阀芯的第一压力接收部分（28; 28A）上，以推动阀阀门处于阀打开方向，第二控制室（29; 29A）经受流量控制阀的入口压力（Pz），使得入口压力作用在阀的第二压力接收部分（27; 27A）上阀芯沿阀关闭方向推压阀芯，以及用于沿阀打开方向推压阀芯的目标压差设定装置（31,50,51; 31B，51）。通过将第二受压部分（27; 27A）的压力接收面积（Az）设定为大于第一压力接收部分（28; 27）的受压面积（ALS）来提供致动器（2）的阻尼能力。 28A）。

3. 发明授权

US5056312A Hydraulic drive system for construction machines 失效
标题翻译：液压驱动系统
公开(公告)号：US5056312A
公开(公告)日：1991-10-15
申请号：US449845
申请日：1989-11-22
申请人： Toichi Hirata , Genroku Sugiyama , Yusuke Kajita , Yukio Aoyagi , Tomohiko Yasudi , Gen Yasuda , Hiroshi Watanabe , Eiki Izumi , Yasuo Tanaka , Hiroshi Onoue , Shigetaka Nakamura
发明人： Toichi Hirata , Genroku Sugiyama , Yusuke Kajita , Yukio Aoyagi , Tomohiko Yasudi , Gen Yasuda , Hiroshi Watanabe , Eiki Izumi , Yasuo Tanaka , Hiroshi Onoue , Shigetaka Nakamura
IPC分类号： E02F9/22 , F15B11/16 , F15B21/08
CPC分类号： F15B21/087 , E02F9/2228 , E02F9/2235 , E02F9/2285 , E02F9/2292 , E02F9/2296 , F15B11/163 , F04B2205/05 , F04B2207/01 , F15B2211/20553 , F15B2211/25 , F15B2211/30535 , F15B2211/3111 , F15B2211/40515 , F15B2211/40569 , F15B2211/428 , F15B2211/455 , F15B2211/6052 , F15B2211/6309 , F15B2211/6313 , F15B2211/6355 , F15B2211/65 , F15B2211/6653 , F15B2211/6654 , F15B2211/71 , F15B2211/78
摘要： A hydraulic system for a construction machine comprising plural hydraulic actuators (23-28) driven by fluid supplied from a pump (22), first and second flow control valves (29-34) for controlling flows of fluid supplied to the first and second actuators, and first and second distribution compensating valves (35-40) for controlling first differential pressure (.DELTA.P v1-.DELTA.P v6) produced between inlets and outlets of the first and second flow control valves. The first and second distribution compensating valves have respective drives (45-50, 35c-40c) for applying control forces (Fc1-Fc2) in accordance with the second differential pressure to the associated distribution compensating valves, to thereby set target values of the first differential pressures. The hydraulic system includes first means (59) for detecting the second differential pressure (.DELTA.P LS) from the discharge pressure (P s) of the pump (22) and the maximum load pressure (P amax) out of the first and second actuators; second means (61) for calculating individual values (Fc1-Fc6), as values of the control forces applied from the drives (45-50, 35C-40C) of the first and second distribution compensating valves (35-40), in accordance with at least the second differential pressure detected by the first means; and first and second control pressure generators (62a-62f) provided in association with the first and second distribution compensating valves. The first and second control pressure generators (62a-62f) produce control pressures (P c1-P c6) dependent on the individual values obtained by the second means and output the control pressures to the drives (35c-40c) of the first and second distribution compensating valves.

4. 发明授权

US5267440A Hydraulic control system for construction machine 失效
标题翻译：施工机械液压控制系统
公开(公告)号：US5267440A
公开(公告)日：1993-12-07
申请号：US854668
申请日：1992-05-04
申请人： Kazunori Nakamura , Yusuke Kajita , Toichi Hirata , Genroku Sugiyama , Hiroshi Onoue , Hideaki Tanaka , Osamu Tomikawa , Masakazu Haga , Hiroshi Watanabe
发明人： Kazunori Nakamura , Yusuke Kajita , Toichi Hirata , Genroku Sugiyama , Hiroshi Onoue , Hideaki Tanaka , Osamu Tomikawa , Masakazu Haga , Hiroshi Watanabe
IPC分类号： E02F9/22 , F16D31/02 , F15B11/08 , F15B13/00
CPC分类号： E02F9/2285 , E02F9/2232 , E02F9/2235 , E02F9/2296
摘要： In a controller (229) of a hydraulic control system for construction machines, a valve control signal calculating function (301) works such that when an operation pattern signal (A-I) for actuators (201, 202 . . . ) is outputted, it selects corresponding one of plural output patterns for an auxiliary valve control pressure stored, as a function of a differential pressure signal between a pump delivery pressure and a maximum load pressure, in relation to the operation pattern signals, followed by calculating an auxiliary valve control pressure (Pc) dependent upon the differential pressure signal based on the selected output pattern, and also selects corresponding one of plural sets of rates of change (K . . . , K . . . ) for the auxiliary valve control pressure stored in relation to the operation pattern signals, followed by combining the calculated auxiliary valve control amount with the selected set of speed changes to calculate each of valve control signals (S21-S26).

5. 发明授权

US5186000A Hydraulic drive system for construction machines 失效
标题翻译：施工机械液压驱动系统
公开(公告)号：US5186000A
公开(公告)日：1993-02-16
申请号：US861395
申请日：1992-03-31
申请人： Toichi Hirata , Genroku Sugiyama , Yusuke Kajita
发明人： Toichi Hirata , Genroku Sugiyama , Yusuke Kajita
IPC分类号： E02F9/22 , F15B11/16 , F15B13/04 , F15B21/08
CPC分类号： F15B21/087 , E02F9/2225 , E02F9/2232 , E02F9/2296 , F15B11/163 , F15B13/0417 , F15B2211/20553 , F15B2211/30535 , F15B2211/30555 , F15B2211/3057 , F15B2211/3111 , F15B2211/329 , F15B2211/351 , F15B2211/50518 , F15B2211/50527 , F15B2211/5154 , F15B2211/55 , F15B2211/6054 , F15B2211/6309 , F15B2211/6313 , F15B2211/651 , F15B2211/71
摘要： A hydraulic drive system for construction machines includes a hydraulic pump (1), a plurality of hydraulic actuators (2, 3) driven by a hydraulic fluid supplied from the hydraulic pump, a plurality of flow control valves (4, 5) for controlling flow rates of the hydraulic fluid supplied to the actuators, respectively, and a plurality of distribution compensating valves (6, 7) for controlling differential pressures across the flow control valves, respectively, the plurality of actuators including a first actuator (2) which undergoes a relatively large load pressure and a second actuator (3) which undergoes a smaller load pressure than that of the first actuator. Distribution controllers (22, 23) are provided to control the distribution compensating valve (7) associated with the second actuator (3) such that a differential pressure (Pz2-PL2) across the flow control valve (5) associated with the second actuator (3) becomes larger than a differential pressure (Pz1-PL1) across the flow control valve (4) associated with the first actuator (2), when the first and second actuators (2, 3) are driven simultaneously.
摘要翻译：一种用于施工机械的液压驱动系统，包括液压泵（1），由从液压泵供应的液压流体驱动的多个液压致动器（2,3），用于控制流量的多个流量控制阀（4,5）分别供应到致动器的液压流体的速率和用于分别控制跨越流量控制阀的压差的多个分配补偿阀（6,7），所述多个致动器包括第一致动器（2）相对较大的负载压力和经受比第一致动器的负载压力更小的第二致动器（3）。分配控制器（22,23）用于控制与第二致动器（3）相关联的分配补偿阀（7），使得与第二致动器（2）相关联的流量控制阀（5）两端的差压（Pz2-PL2）当第一和第二致动器（2,3）同时被驱动时，流过控制阀（4）的第一致动器（2）的差压（Pz1-PL1）变大。

6. 发明授权

US5134853A Hydraulic drive system for construction machines 失效
标题翻译：液压驱动系统
公开(公告)号：US5134853A
公开(公告)日：1992-08-04
申请号：US439387
申请日：1989-11-16
申请人： Toichi Hirata , Genroku Sugiyama , Yusuke Kajita
发明人： Toichi Hirata , Genroku Sugiyama , Yusuke Kajita
IPC分类号： E02F9/22 , F15B11/16 , F15B13/04 , F15B21/08
CPC分类号： F15B21/087 , E02F9/2225 , E02F9/2232 , E02F9/2296 , F15B11/163 , F15B13/0417 , F15B2211/20553 , F15B2211/25 , F15B2211/30535 , F15B2211/3057 , F15B2211/3111 , F15B2211/329 , F15B2211/50527 , F15B2211/50536 , F15B2211/5157 , F15B2211/526 , F15B2211/55 , F15B2211/6054 , F15B2211/6313 , F15B2211/6654 , F15B2211/7058 , F15B2211/71
摘要： A hydraulic drive system for construction machines includes a hydraulic pump (1), a plurality of hydraulic actuators (2, 3) driven by a hydraulic fluid supplied from the hydraulic pump, a plurality of flow control valves (4, 5) for controlling flow rates of the hydraulic fluid supplied to the actuators, respectively, and a plurality of distribution compensating valves (6, 7) for controlling differential pressures across the flow control valves, respectively, the plurality of actuators including a first actuator (2) which undergoes a relatively large load pressure and a second actuator (3) which undergoes a smaller load pressure than that of the first actuator. Distribution controllers (22, 23) are provided to control the distribution compensating valve (7) associated with the second actuator (3) such that a differential pressure (Pz2-PL2) across the flow control valve (5) associated with the second actuator (3) becomes larger than a differential pressure (Pz1-PL1) across the flow control valve (4) associated with the first actuator (2), when the first and second actuators (2, 3) are driven simultaneously.

7. 发明授权

US5062350A Hydraulic drive system for civil engineering and construction machine 失效
标题翻译：公路工程施工机械液压驱动系统
公开(公告)号：US5062350A
公开(公告)日：1991-11-05
申请号：US536545
申请日：1990-07-12
申请人： Hideaki Tanaka , Toichi Hirata , Genroku Sugiyama , Masakazu Haga , Yusuke Kajita
发明人： Hideaki Tanaka , Toichi Hirata , Genroku Sugiyama , Masakazu Haga , Yusuke Kajita
IPC分类号： E02F9/22
CPC分类号： E02F9/2235 , E02F9/2228 , E02F9/2285 , E02F9/2292 , E02F9/2296
摘要： A hydraulic drive system for a civil engineering and construction machine of the present invention comprises a hydraulic pump (11, 11A), a plurality of actuators (4-6) driven by a hydraulic fluid supplied from the hydraulic pump and including an arm cylinder (5) and a boom cylinder (4), a plurality of flow control valves (12, 14, 16) for controlling flows of the hydraulic fluid supplied to the respective actuators and including an arm directional control valve (14) and a boom directional control valve (12) and a plurality of distribution compensating valves (13, 15, 17; 13A, 15A, 17A) for controlling differential pressures across the respective flow control valves, the distribution compensating valves each having a first device (13d,15d, 17d; 13e, 13f, 15e, 15f, 17e, 17f) to set a target value of the differential pressure across the associated flow control valve. The present invention is featured in further comprising a first device (21) for detecting an arm crowding operation performed by driving of the arm cylinder (5), and a second device (24, 30, 31; 24, 30A, 31) for controlling the drive means (15d; 15f) of the distribution compensating valve (15; 15A) associated with the arm cylinder so as to reduce at least the target value of the differential pressure across the flow control valve (14) associated with the arm cylinder, when the arm crowding operation is detected.
摘要翻译： PCT No.PCT / JP90 / 00375 Sec。 371日期1990年7月12日 102（e）日期1990年7月12日PCT 1990年3月29日PCT PCT。公开号WO90 / 11413 日本1990年10月4日。本发明的土木工程机械的液压驱动系统包括液压泵（11,11A），由液压供给的液压流体驱动的多个致动器（4-6）泵和包括臂缸（5）和动臂缸（4）;多个流量控制阀（12,14,16），用于控制供应到各个致动器的液压流体的流动，并包括臂方向控制阀（ 14）和用于控制横跨各个流量控制阀的压差的多个分配补偿阀（13,15,17; 13A，15A，17A）的动臂式方向控制阀（12）和分配补偿阀，分配补偿阀各自具有第一装置（13d，15d，17d; 13e，13f，15e，15f，17e，17f），以设定跨过相关的流量控制阀的差压的目标值。本发明的特征在于还包括：第一装置（21），用于检测通过所述手臂缸（5）的驱动进行的斗臂拥挤操作;以及第二装置（24,30,31; 24,30A，31），用于控制与所述悬臂气缸相关联的所述分配补偿阀（15; 15A）的驱动装置（15d; 15f），以便至少将与所述手臂气缸相关联的所述流量控制阀（14）的差压的目标值减至最小，当检测到胳膊拥挤操作时。

8. 发明授权

US5203678A Valve apparatus and hydraulic drive system 失效
标题翻译：阀门装置和液压驱动系统
公开(公告)号：US5203678A
公开(公告)日：1993-04-20
申请号：US655368
申请日：1991-02-28
申请人： Genroku Sugiyama , Toichi Hirata , Yusuke Kajita
发明人： Genroku Sugiyama , Toichi Hirata , Yusuke Kajita
IPC分类号： E02F9/22 , F15B13/04
CPC分类号： E02F9/2232 , E02F9/2296 , F15B13/0417 , Y10T137/87185
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.
摘要翻译： PCT No.PCT / JP90 / 01407 Sec。 371日期1991年2月28日 102（e）日期1991年2月28日PCT 1990年11月1日PCT PCT。公开号WO91 / 10833 日期：1991年7月25日。一种阀装置具有流量控制阀，该流量控制阀具有与液压流体供给源连通的供给通道，与致动器连通的负载通道，以及设置在供给通道和负载通道和开启取决于操作量; 第一信号通道，位于第一可变节流器的下游，并具有用于检测致动器的负载压力的通道部分; 与储罐连通的罐通道; 用于使第一信号通道与油箱通道连通的排出通道; 以及第二可变节流器，其设置在所述排出通道中，其开口变化取决于所述流量控制阀的操作量，以在所述第一信号通道中产生与所述负载压力不同的控制压力，所述第一信号通道中的控制压力为通过第二个信号通道导致液压流体供应源。辅助限制器设置在第一信号通道中以减小在第一信号通道的通道部分中检测到的负载压力，使得在第一信号通道中产生低于检测到的负载压力的压力作为控制压力。

9. 发明授权

US5161575A Direction selector valve having load-sensing function 失效
标题翻译：方向选择阀具有负载感应功能
公开(公告)号：US5161575A
公开(公告)日：1992-11-10
申请号：US717537
申请日：1991-06-19
申请人： Rindo Morikawa , Kiyoshi Oyama , Toichi Hirata , Yusuke Kajita , Genroku Sugiyama
发明人： Rindo Morikawa , Kiyoshi Oyama , Toichi Hirata , Yusuke Kajita , Genroku Sugiyama
IPC分类号： E02F9/22 , F15B11/00 , F15B11/05 , F15B11/16 , F15B13/04 , F16K11/07
CPC分类号： F15B13/0417 , Y10T137/86702 , Y10T137/87169 , Y10T137/87185
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.
摘要翻译：公开了一种具有检测负载功能的方向选择阀。阀门用于液压系统。阀芯具有从两侧端部轴向部分地穿过阀芯延伸的两个通道孔。这两个通孔具有各自的高压孔。当阀芯处于其中性位置时，高压孔由桥接口和执行器端口之间的阀芯孔封闭。两个通道孔还包括分别通过安装在通孔中的负载止回阀与罐口连通的低压孔。在一个通孔的前端附近形成导向孔，并与负载传感端口连通。限制部分形成在与引导孔相邻的卷轴的外表面上，以控制从负载感测端口到罐口的流动。在另一个通孔的前端附近形成彼此靠近的第一导向孔和第二引导孔。即使当阀芯处于其中立位置时，第一引导孔也与负载感测端口连通。在阀芯已经从其中立位置移动之后，第二引导孔与负载感测端口连通，将高压孔与桥接口连接。该结构平滑地响应致动器中的负载压力。

10. 发明授权

US5150574A Hydraulic drive system for civil engineering and construction machine 失效
标题翻译：公路工程施工机械液压驱动系统
公开(公告)号：US5150574A
公开(公告)日：1992-09-29
申请号：US573138
申请日：1990-09-24
申请人： Toichi Hirata , Hideaki Tanaka , Genroku Sugiyama , Yusuke Kajita
发明人： Toichi Hirata , Hideaki Tanaka , Genroku Sugiyama , Yusuke Kajita
IPC分类号： E02F9/22 , F15B13/04
CPC分类号： F15B13/0417 , E02F9/2232 , E02F9/2296
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.
摘要翻译： PCT No.PCT / JP90 / 00573 Sec。 371 1990年9月24日第 102（e）1990年9月24日PCT PCT 1990年5月1日PCT公布。 WO90 / 13748 PCT公开日本1990年11月15日。一种用于建筑机械的液压驱动系统具有设置在液压泵和辅助器之间的流量控制阀（5），用于控制流量控制阀两端的压差的压力补偿阀，以及泵输送速率调节器，用于根据泵压力和致动器的负载压力之间的差压（Pd-PLS）控制从液压泵输送的液压流体的流量。压力补偿阀具有经受控制力的阀体。基于流量控制阀与阀体两端的差压的第一控制力在阀关闭方向上推动阀体。第二预定控制力促使阀体处于阀操作方向; 并且基于泵压力和致动器的负载压力之间的差压（Pd-PLS）的第三控制力促使阀体沿阀打开方向。

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