CN113819273A - Novel proportional reversing valve - Google Patents
Novel proportional reversing valve Download PDFInfo
- Publication number
- CN113819273A CN113819273A CN202111155103.1A CN202111155103A CN113819273A CN 113819273 A CN113819273 A CN 113819273A CN 202111155103 A CN202111155103 A CN 202111155103A CN 113819273 A CN113819273 A CN 113819273A
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- stepper motor
- valve
- valve core
- stepping motor
- displacement
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- 238000006073 displacement reaction Methods 0.000 claims abstract description 68
- 230000033001 locomotion Effects 0.000 claims abstract description 12
- 230000003068 static effect Effects 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 4
- 230000008859 change Effects 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims 1
- 230000007935 neutral effect Effects 0.000 claims 1
- 230000004044 response Effects 0.000 description 4
- 239000007788 liquid Substances 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 239000012636 effector Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011295 pitch Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K11/00—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves
- F16K11/10—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with two or more closure members not moving as a unit
- F16K11/20—Multiple-way valves, e.g. mixing valves; Pipe fittings incorporating such valves with two or more closure members not moving as a unit operated by separate actuating members
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/04—Actuating devices; Operating means; Releasing devices electric; magnetic using a motor
- F16K31/041—Actuating devices; Operating means; Releasing devices electric; magnetic using a motor for rotating valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/04—Actuating devices; Operating means; Releasing devices electric; magnetic using a motor
- F16K31/046—Actuating devices; Operating means; Releasing devices electric; magnetic using a motor with electric means, e.g. electric switches, to control the motor or to control a clutch between the valve and the motor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/12—Actuating devices; Operating means; Releasing devices actuated by fluid
- F16K31/36—Actuating devices; Operating means; Releasing devices actuated by fluid in which fluid from the circuit is constantly supplied to the fluid motor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/44—Mechanical actuating means
- F16K31/50—Mechanical actuating means with screw-spindle or internally threaded actuating means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/44—Mechanical actuating means
- F16K31/53—Mechanical actuating means with toothed gearing
- F16K31/535—Mechanical actuating means with toothed gearing for rotating valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K37/00—Special means in or on valves or other cut-off apparatus for indicating or recording operation thereof, or for enabling an alarm to be given
- F16K37/0075—For recording or indicating the functioning of a valve in combination with test equipment
- F16K37/0083—For recording or indicating the functioning of a valve in combination with test equipment by measuring valve parameters
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electrically Driven Valve-Operating Means (AREA)
- Control Of Fluid Pressure (AREA)
Abstract
一种新型比例换向阀，属于机械领域，它包括第一步进电机、滚珠丝杠螺母、左位位移传感器、变刚度弹簧、阀芯、阀体、阀套、齿轮副、第三步进电机、右位位移传感器和第二步进电机；所述第一步进电机和第二步进电机与阀体通过连接件刚性连接，且第一步进电机和第二步进电机的旋转轴线与阀芯轴线重合；所述第三步进电机输出轴安装于齿轮副主动齿轮位置；所述左位位移传感器和右位位移传感器均安装与阀芯伸出端，检测阀芯的位移；所述阀套安装于阀体内。本发明可以实现小开度下的开环控制，减小滞缓对与阀芯运动控制的影响。
A novel proportional reversing valve, belonging to the field of machinery, comprises a first stepping motor, a ball screw nut, a left position displacement sensor, a variable stiffness spring, a valve core, a valve body, a valve sleeve, a gear pair, and a third stepping a motor, a right position displacement sensor and a second stepping motor; the first stepping motor and the second stepping motor are rigidly connected with the valve body through the connecting piece, and the rotation axes of the first stepping motor and the second stepping motor are coincides with the axis of the valve core; the output shaft of the third stepping motor is installed at the position of the driving gear of the gear pair; the left position displacement sensor and the right position displacement sensor are both installed at the extension end of the valve core to detect the displacement of the valve core; The valve sleeve is installed in the valve body. The invention can realize the open-loop control under small opening degree, and reduce the influence of sluggishness on the movement control of the valve core.
Description
Technical Field
The invention relates to a valve port opening control method of a proportional reversing valve under different working conditions, in particular to a novel proportional reversing valve structure.
Background
The reversing valve is a valve which changes the on-off relationship between oil ports on the valve body by using the difference of the relative positions between the valve core and the valve body, thereby realizing the communication and the cutting-off of each oil path or changing the flow direction. The reversing valve is also the valve with the largest usage amount and the most complicated variety and name in a hydraulic system.
After the valve port of the reversing valve is opened, the liquid flow can generate acting force on the valve core due to the change of the liquid flow momentum, and the acting force is called as hydraulic power. When the opening degree of the valve port is fixed, the size and the direction of the hydraulic force can be influenced by the change of factors such as load, flow and the like. The fundamental reason for the generation of hydraulic force is that the momentum of fluid flowing through the valve port changes, and the generation of hydraulic force is inevitable, so that the influence of hydraulic force on the displacement control of the valve core cannot be completely avoided. The end effector of a hydraulic system usually has two control requirements, one is a precise position control requirement with low speed and small flow, and the second is a speed control requirement with high speed and large flow.
Disclosure of Invention
The invention provides a novel proportional reversing valve, aiming at the problems of hysteresis with small opening degree and slow dynamic response time in large opening degree of the existing reversing valve.
A novel proportional reversing valve comprises a first stepping motor (1), a ball screw nut (2), a left displacement sensor (3), a variable stiffness spring (4), a valve core (5), a valve body (6), a valve sleeve (7), a gear pair (8), a third stepping motor (9), a right displacement sensor (10) and a second stepping motor (11); the first stepping motor (1) and the second stepping motor (11) are rigidly connected with the valve body through a connecting piece, and the rotating axes of the first stepping motor (1) and the second stepping motor (11) are superposed with the axis of the valve core (5); an output shaft of the third stepping motor (9) is arranged at the position of a driving gear of the gear pair; the two ends of the valve core (5) are cut with transmission threads, the length of the threads is 3 times of the working stroke of the valve core, and the transmission threads of the valve core (5) and the ball screw nut (2) form a thread pair; the left displacement sensor (3) and the right displacement sensor (10) are both arranged at the ends extending out of the valve core (5) to detect the displacement of the valve core; the valve sleeve (7) is arranged in the valve body (6) and has a single degree of freedom rotating around the axis after being arranged; the valve sleeve (7) is rigidly connected with a driven gear in the gear pair, and the output shaft of the third stepping motor (9) and the valve sleeve (7) are two rotating parts connected with the gear pair respectively; and the variable stiffness spring (4) is arranged in the pilot pressure oil cavity and is in direct contact with the valve body.
The angular displacement output by the first stepping motor (1) and the second stepping motor (11) is in direct proportion to the input pulse number, after the stepping motors finish the specified angular displacement, a static locking state is kept, the first stepping motor (1) and the second stepping motor (11) can output holding torque, namely the valve core is kept static at the moment, the stepping motors finish open-loop control, and meanwhile, the first stepping motor (1) and the second stepping motor (11) obtain electric signals which are always the same in pulse number and different in direction level.
When the valve core (5) of the novel proportional reversing valve is subjected to self-zero unidirectional displacement less than 6mm, the valve core is driven by a stepping motor to generate displacement.
When the pilot pressure oil enters a pilot pressure oil cavity of the novel proportional reversing valve to push a valve core to move, the first stepping motor (1) and the second stepping motor (11) output angular displacement at the same time.
The lead angle of the cut thread of the valve core (5) is larger than the friction angle, and the ball screw and the screw nut in the screw pair can be used as driving parts. When the first stepping motor (1) and the second stepping motor (11) output angular displacement, the ball screw nut (2) is a driving part, and the valve core (5) moves linearly and in a driven manner. When the valve core is subjected to micro-motion displacement of less than 0.5mm under the action of pilot pressure oil, the first stepping motor (1) and the second stepping motor (11) are in an open circuit state, the valve core (5) is in driving linear motion, and the ball screw nut (2) is in driven rotary motion.
The valve sleeve (7) is provided with a throttling window, and when the third stepping motor (9) drives the gear pair (8) to rotate, the size of the area of the through-flow window on the valve sleeve (7) can be changed.
When no control pulse signal exists and the pilot pressure is zero, the valve core (5) is positioned at the middle position, and the working port A, the working port B, the oil inlet P and the oil return port T are all in a closed state; when the actuator needs small flow and accurately controls the displacement of the valve core, the position of the valve core (5) is controlled to be an open-loop control system at the moment, the control unit outputs pulse signals to the first stepping motor (1) and the second stepping motor (11), and the accurate angular displacement of the stepping motor can be converted into accurate axial movement of the valve core (5) to complete open-loop control; when the executing element needs large flow, the control unit outputs an electric signal to control pilot pressure oil to enter one side of the reversing valve to push the valve core (5) to move, meanwhile, the control unit (15) can also output pulse signals to the first stepping motor (1) and the second stepping motor (11), the moving speed of the valve core (5) is improved, the valve core (5) reaches a preset position, the first stepping motor (1) and the second stepping motor (2) are converted into torque control, the left displacement sensor (3) and the right displacement sensor (10) can detect the displacement of the valve core, the pilot pressure oil controlled by the control unit (15) and the novel proportional reversing valve middle displacement sensor form an electro-hydraulic closed-loop control system, and the displacement of the valve core is controlled by controlling the pilot pressure.
The novel proportional reversing valve has a pilot pressure control mode and a stepping motor control mode.
In order to meet the control requirements of the actuating element under different working conditions, the invention adopts a mode of directly driving the stepping motor to control the displacement of the valve core under the condition of small flow, eliminates the influence of steady-state hydrodynamic force and system hysteresis on the position control accuracy of the valve core, utilizes the characteristic of keeping torque by electrifying the stepping motor, keeps the lead screw nut static by utilizing the characteristic when the valve core reaches specified displacement, ensures that the screw pair between the lead screw nut and the valve core does not rotate, ensures the position of the valve core to be static, and can balance spring force, damping force, friction force, steady-state hydrodynamic force and the like under small opening degree by utilizing the static torque. When the actuator needs a large flow, the large-displacement hydraulic actuator is characterized in that the valve core has a large displacement, and the large compression amount of the spring generates a large spring force, and meanwhile, the value of the hydraulic force is also increased due to the change of the flow. The stepper motor holding torque is relatively limited and may fail in the above-described situation. Therefore, a pilot oil-liquid driven valve is needed to drive the valve core, the control unit (15) outputs certain electric signals to the first stepping motor (1), the second stepping motor (11) and the three-way proportional pressure reducing valve, the valve core can rapidly open the valve port under the driving of pressure oil and the two stepping motors, and the closed-loop control of the novel proportional reversing valve under the condition of large opening degree is completed. When the flow of the actuator needs to be further increased, the flow area in the flow passage can be increased by rotating the valve sleeve (7), and the actuator needs the maximum flow.
The invention adds mechanical elements to the structure of the prior conventional valve body to directly drive the valve core, simultaneously utilizes a displacement sensor to detect the displacement of the valve core when the valve core is in large opening degree, utilizes a stepping motor to reduce the influence of hysteresis on the valve core under small opening degree, utilizes pilot pressure oil and the stepping motor to improve the overall dynamic response of the novel proportional reversing valve, and reduces the response time of the displacement movement of the valve core under large opening degree.
The invention adopts the mechanical open-loop control and pilot oil closed-loop control to control the displacement of the valve core, can realize accurate control of the displacement of the valve core under different working condition openings of the reversing valve, and realizes the control requirement of the reversing valve on continuous proportion to the displacement of the valve core.
Compared with the prior proportional reversing valve, the proportional reversing valve has the following advantages:
(1) the stepping motors arranged on two sides can realize open-loop control under small opening degree, and influence of hysteresis on motion control of the valve core is reduced.
(2) The rotatable valve sleeve (7) can improve the maximum flow value of the novel proportional directional valve.
(3) When the valve core is in a large opening degree, the valve core displacement control is still an electro-hydraulic closed-loop control system, and the speed of the valve core movement can be increased when the installed stepping motor moves, so that the specified displacement can be quickly reached, and the response time is reduced.
Drawings
Fig. 1 is a detailed structural view of the present invention.
Fig. 2 is a structural diagram of the valve sleeve (7) driven by the gear pair (8) of the present invention. When the gear pair (9) rotates, the flow area between the valve core (6) and the oil inlet P of the valve body can be increased or reduced.
Fig. 3 is a block diagram of the present invention installed in a hydraulic system.
In the figure, 1-a first stepping motor, 2-a ball screw nut, 3-a left position displacement sensor, 4-a variable stiffness spring, 5-a valve core, 6-a valve body, 7-a valve sleeve, 8-a gear pair, 9-a third stepping motor, 10-a right position displacement sensor, 11-a third stepping motor, a P-oil inlet, an A-working port 1, a B-working port 2, a T-oil return port, 12-a right position three-way proportional reversing, 13-a novel proportional reversing valve, 14-a left position three-way proportional reducing valve and 15-a control unit.
Detailed Description
The invention relates to a novel proportional reversing valve, which is characterized in that a first stepping motor (1) and a stepping motor (11) are added to directly drive a valve core in the axial direction of the valve core on the basis of the existing proportional reversing valve. And a rotatable valve sleeve (7) is designed, a third stepping motor (9) can control the valve sleeve (7) to rotate, wherein the cross section of a flow channel at a pressure oil P opening of the valve sleeve (7) and the valve body is variable, the rotation angle of the valve sleeve (7) is changed, and the flow area of the flow channel can be controlled.
And increasing variable stiffness springs (4) are arranged at two ends of the valve core, the springs (4) are helical cylindrical springs with unequal pitches, and the stiffness of the springs is increased along with the increase of the compression amount.
As shown in figure 1, the novel proportional reversing valve adopting mechanical open-loop control and pilot oil closed-loop control comprises a first stepping motor (1), a ball screw nut (2), a left displacement sensor (3), a variable stiffness spring (4), a valve core (5), a valve body (6), a valve sleeve (7), a gear pair (8), a third stepping motor (9), a right displacement sensor (10) and a second stepping motor (11).
The valve core is required to move leftwards, and the pressure oil inlet P is communicated with the left working port A.
When the actuator requires low speed and small flow and accurate position control, the control unit (15) sends specified electric signals to the first stepping motor (1) and the second stepping motor (11), the first stepping motor (1) and the second stepping motor (11) start to make angular displacement with opposite rotation directions, and the angular displacement is converted into linear displacement of the valve core (5) through a screw pair consisting of a ball screw and a screw nut. When the first stepping motor (1) and the second stepping motor (11) reach specified angular displacement, the control unit (15) has no pulse signal, the windings of the motor phases of the first stepping motor (1) and the second stepping motor (11) are electrified with rated current and are in a static locking state, the stepping motors are static in order to keep torque, the valve core can keep the position unchanged at the moment, open-loop control is completed, and because the steady-state hydrodynamic force under small opening degree and the spring force of the variable stiffness spring (3) are small values, the moment can be balanced with the forces, and the valve core keeps steady state and reaches a stable working state.
When the working condition is high speed and large flow, and the valve port is opened greatly, the control unit (15) outputs an electric signal to the right three-way proportional pressure reducing valve to increase the pressure of the pilot pressure oil entering the right pilot oil cavity. According to the electric signal of the control unit (15) to the three-way proportional pressure reducing valve, the first stepping motor (1) and the second stepping motor (11) can obtain an electric pulse with a similar position, and at the moment, the valve core (5) starts to generate displacement under the combined action of the pressure oil and the two stepping motors. When the valve core reaches the designated position and still needs to be subjected to micro-motion displacement adjustment, the first stepping motor (1) and the second stepping motor (11) are in an open circuit state, the left displacement sensor (4) detects the displacement of the valve core, the pilot pressure is changed, and the novel proportional reversing valve control mode is electro-hydraulic closed-loop control at the moment.
When the execution element needs to further improve the flow passing through the novel proportional reversing valve, the control unit (15) inputs pulses to the third stepping motor (9) to drive the valve sleeve (7) to rotate, the flow area of the valve core (5) and the oil inlet P is increased, and the working mechanism needs the novel proportional reversing valve to provide the maximum flow.
When the novel proportional reversing valve is required to return to the middle position, each stepping motor has no pulse signal, no pilot oil enters the valve body, and the valve core (5) returns to the middle position under the action of the variable stiffness spring (3).
Claims (8)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111155103.1A CN113819273A (en) | 2021-09-29 | 2021-09-29 | Novel proportional reversing valve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111155103.1A CN113819273A (en) | 2021-09-29 | 2021-09-29 | Novel proportional reversing valve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113819273A true CN113819273A (en) | 2021-12-21 |
Family
ID=78915973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111155103.1A Pending CN113819273A (en) | 2021-09-29 | 2021-09-29 | Novel proportional reversing valve |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113819273A (en) |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0173914A2 (en) * | 1984-08-28 | 1986-03-12 | Ube Industries, Ltd. | Spool-type flow adjusting valve |
| CN1514218A (en) * | 2003-07-30 | 2004-07-21 | 浙江大学 | Valve sleeve movable hydraulic valve internal flow field pressure distribution measuring device |
| CN203784418U (en) * | 2013-12-20 | 2014-08-20 | 宿迁学院 | Automatic loading valve of digital hydraulic pump |
| CN106321932A (en) * | 2016-06-23 | 2017-01-11 | 南通联恒新材料有限公司 | High-flow and high-frequency digital valve with function of rotatable parallel-control control |
| CN107559456A (en) * | 2017-08-11 | 2018-01-09 | 武汉科技大学 | Reaction type numeral reversal valve is driven in a kind of |
| CN108253158A (en) * | 2016-12-28 | 2018-07-06 | 比亚迪股份有限公司 | Flow control valve and with its fork truck |
| CN109630491A (en) * | 2018-12-26 | 2019-04-16 | 太原理工大学 | A kind of automatically controlled compensation two-way proportional flow control valve |
| CN110319238A (en) * | 2019-08-05 | 2019-10-11 | 安徽理工大学 | A kind of big flow electric-hydraulic proportion commutation exciting dual-purpose valve |
| CN110657263A (en) * | 2019-11-07 | 2020-01-07 | 沙洲职业工学院 | Double-cylinder building material fluid distribution control mechanism |
| CN113323933A (en) * | 2021-05-21 | 2021-08-31 | 杭州诺祥科技有限公司 | Pressure difference matching type bidirectional large-flow hydraulic control device |
| CN113357214A (en) * | 2021-06-10 | 2021-09-07 | 涌镇液压机械（上海）有限公司 | Hydraulic proportional reversing valve |
-
2021
- 2021-09-29 CN CN202111155103.1A patent/CN113819273A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0173914A2 (en) * | 1984-08-28 | 1986-03-12 | Ube Industries, Ltd. | Spool-type flow adjusting valve |
| CN1514218A (en) * | 2003-07-30 | 2004-07-21 | 浙江大学 | Valve sleeve movable hydraulic valve internal flow field pressure distribution measuring device |
| CN203784418U (en) * | 2013-12-20 | 2014-08-20 | 宿迁学院 | Automatic loading valve of digital hydraulic pump |
| CN106321932A (en) * | 2016-06-23 | 2017-01-11 | 南通联恒新材料有限公司 | High-flow and high-frequency digital valve with function of rotatable parallel-control control |
| CN108253158A (en) * | 2016-12-28 | 2018-07-06 | 比亚迪股份有限公司 | Flow control valve and with its fork truck |
| CN107559456A (en) * | 2017-08-11 | 2018-01-09 | 武汉科技大学 | Reaction type numeral reversal valve is driven in a kind of |
| CN109630491A (en) * | 2018-12-26 | 2019-04-16 | 太原理工大学 | A kind of automatically controlled compensation two-way proportional flow control valve |
| CN110319238A (en) * | 2019-08-05 | 2019-10-11 | 安徽理工大学 | A kind of big flow electric-hydraulic proportion commutation exciting dual-purpose valve |
| CN110657263A (en) * | 2019-11-07 | 2020-01-07 | 沙洲职业工学院 | Double-cylinder building material fluid distribution control mechanism |
| CN113323933A (en) * | 2021-05-21 | 2021-08-31 | 杭州诺祥科技有限公司 | Pressure difference matching type bidirectional large-flow hydraulic control device |
| CN113357214A (en) * | 2021-06-10 | 2021-09-07 | 涌镇液压机械（上海）有限公司 | Hydraulic proportional reversing valve |
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