CN207437914U - Pilot-operated type static-difference-free water pressure overflow valve - Google Patents

Abstract

The utility model relates to a pilot type zero-static differential hydraulic relief valve, which belongs to the field of fluid transmission and control, including a pilot valve, a main valve and a feedback control system in a valve closed loop; the pilot valve includes a pilot valve sleeve, a pilot valve core, a pilot valve body, a buffer spring and an end cover, the main valve includes a main valve body, a main valve core, a main valve sleeve, a main valve seat and a main valve return spring, the feedback control system in the valve closed loop includes a micro pressure sensor, a driver and a channel connecting the pilot valve and the main valve, the pull rod of the driver connects one end of the pilot valve core, the pilot valve core is a single-sided zero-opening two-way sliding valve, and three equalizing grooves are evenly opened on the convex cylindrical surface of the pilot valve core at both ends. The utility model adopts a pressure sensor to directly detect the change of the inlet pressure of the main valve, and directly transmits the detected signal to the driver to control the opening of the pilot valve, forming a closed-loop pressure feedback control so that the control accuracy is high, the response speed is fast, the stability is good, and zero-static differential control is realized.

Description

Pilot-operated non-static differential pressure relief valve

technical field

The utility model belongs to the field of fluid transmission and control, in particular to a pilot-operated non-static difference water pressure overflow valve.

Background technique

Hydraulic transmission has become one of the important research directions of fluid transmission and control due to its advantages of no pollution, good flame retardancy, good economy and wide sources. Among them, the hydraulic pressure control valve is one of the important components of the hydraulic transmission system. However, the traditional pressure control valves all have differential valves, the constant pressure accuracy is low, and the hydraulic transmission has defects such as large leakage, poor lubricity, and easy corrosion, and when the nominal pressure of the pilot valve is high, the static difference will also increase. . At present, the commonly used measure to reduce the static difference is to divide the pressure regulation range into four grades (0.6~0.8MPa, 4~16MPa, 8~20MPa, 16~32MPa), and design four free heights with the same inner diameter according to the pressure requirements. The pressure regulating springs with different rigidities and steel wire diameters are used for pressure regulation in four levels. Choose the appropriate spring according to the different working pressure to ensure the static difference as small as possible. But in essence, the additional spring force and steady-state hydraulic force still exist, so the static difference always exists.

Utility model content

The purpose of the utility model is to provide a pilot-operated non-static difference water pressure overflow valve, which solves the problem that the static difference still exists in the existing device due to the additional spring force and the steady-state hydraulic force.

The utility model pilot-operated non-static differential hydraulic pressure relief valve comprises a pilot valve, a main valve and a feedback control system in a closed-loop valve channel; the pilot valve includes a pilot valve sleeve, a pilot valve core, a pilot valve body, a buffer spring and a Cover, the pilot valve sleeve is installed in the hole of the pilot valve body, the pilot valve core is installed in the pilot valve sleeve, the buffer spring is between the pilot valve core and the end cover, the main valve includes the main valve body, the main valve core, the main The valve sleeve, the main valve seat and the main valve return spring, the main valve sleeve and the main valve seat are installed in the hole in the main valve body, the main valve seat is below the main valve sleeve, and the main valve sleeve, the main valve seat and the main valve body There is a sealing ring 2 between the holes, the main valve core is installed in the main valve sleeve, and the main valve return spring is installed in the spring cavity at the end of the main valve core; the feedback control system in the closed loop of the valve channel includes a miniature pressure sensor, a driver And the hole connecting the pilot valve and the main valve, the hole connecting the main valve and the pilot valve is provided with a sealing ring 4, the miniature pressure sensor is set at the oil inlet, the pull rod of the driver is connected to one end of the pilot spool, and the pilot spool is unilateral Zero-opening two-way slide valve, the slide valve core is relatively stable during opening and closing, the slide valve core can effectively suppress self-excited vibration, and can effectively reduce noise. The pilot valve core and pilot valve sleeve adopt clearance fit, zero The open spool valve has linear flow gain and the best performance. The unilateral spool valve is easy to manufacture. Three pressure equalization grooves are evenly opened on the shoulder cylindrical surface at both ends of the pilot valve core; the inner side of the driver is provided with a sealing ring. The driver is a giant magnetostrictive precision displacement driver, and the driver has its own signal receiving device inside.

The main valve core adopts a three-section concentric structure, which is not easy to generate vibration and works stably. The head of the main valve core adopts a parabolic structure, which balances the impact force of the water pressure on the head of the main valve core and extends backwards, reducing the damage of cavitation. The main valve core and the main valve seat form a two-stage throttle valve port, which reduces the working pressure difference of each valve port and improves the cavitation resistance of the throttle valve. The throttle port adopts a long straight channel type. Effectively reduce the cavitation, wire drawing, noise and vibration of the valve, and ensure the control accuracy and service life of the valve.

The end face of the pilot spool on one side of the end cover is provided with an arc-shaped groove to increase the motion damping of the pilot spool and improve the stability of the pilot valve. A buffer pad is fixed inside the end cover to make the movement of the spool more stable.

The oil inlet is connected to the left end of the pilot valve sleeve with a pilot hole, the pilot hole is provided with a fixed damper, the upper chamber of the main valve body is provided with an oil passage connected to the middle of the pilot valve sleeve, and the oil passage is provided with a dynamic damper, and the oil The channel communicates with the pilot channel.

The middle part of the main valve body is provided with a water outlet, and the water outlet adopts a right-angle structure with a smooth arc transition. The eddy current, noise and cavitation caused by the uneven flow area of the return cavity are reduced.

The pilot valve is provided with a safety valve, the safety valve includes a safety valve body, a safety valve return spring and a safety valve spool, the safety valve spool is installed in the hole of the safety valve body, and one end is connected to the safety valve return spring , the other end of the safety valve return spring is installed in the spring chamber, the other end of the safety valve core forms a cone seal with the hole of the safety valve body, and the other end of the hole of the safety valve body is connected to the pilot channel, and the hole of the safety valve body The upper end of the middle part is connected with the middle part of the pilot valve sleeve, and the lower end is connected with the water outlet. The safety valve and the main valve form a traditional pilot-operated relief valve. When the system pressure changes suddenly or the electronic circuit fails, it can be opened immediately to release the system pressure and keep the system pressure constant. A screw plug is arranged at the pilot hole.

The pilot valve body is made of stainless steel, and the valve core and valve sleeve are made of engineering ceramic materials, which can effectively resist water cavitation and wire drawing damage, and the fit clearance between the pilot valve core and pilot valve sleeve can be controlled very small. The main valve body and main valve seat are made of stainless steel, the main valve core is made of engineering plastic material, the main valve core and the main valve seat are made of soft and hard materials, which can ensure the sealing performance when the valve port is closed, and can reduce the Shock and vibration when closed for extended life.

Compared with the prior art, the utility model has the advantages of:

1. The pressure sensor is used to directly detect the change of the inlet pressure of the main valve, and the detected signal is directly transmitted to the driver to control the opening of the pilot valve, forming a closed-loop pressure feedback control, with high control precision, fast response speed and good stability. poor control.

2. The pilot spool adopts a one-sided zero-opening two-way slide valve, which is more stable. Three pressure equalization grooves are evenly opened on the cylindrical surface of the convex shoulder at both ends of the spool to reduce the hydraulic clamping force and avoid the friction between the spool and the valve sleeve. Jamming phenomenon.

3. The main valve core adopts a three-section concentric structure, the head of the main valve core adopts a parabolic structure, the main valve core and the main valve seat form a two-stage throttling valve port, and the throttling port adopts a long straight channel type; effectively reducing the air pressure of the valve Corrosion, wire drawing, noise and vibration phenomena ensure the control accuracy and service life of the valve; the water outlet adopts a right-angle structure with a smooth arc transition, which reduces the eddy current, noise and cavitation caused by the uneven flow area of the return chamber.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the schematic diagram of the enlarged structure of place A in Fig. 1;

In the figure: 1. Cushion pad, 2. Cushion spring, 3. Pilot valve sleeve, 4. Pilot valve core, 5. Pilot valve body, 6. Pull rod, 7. Sealing ring 1, 8. Driver, 9. Safety valve Body, 10. Safety valve return spring, 11. Safety valve spool, 12. Main valve body, 13. Main valve core, 14. Main valve sleeve, 15. Main valve seat, 16. Miniature pressure sensor, 17. Pilot hole , 18, main valve return spring, 19, fixed damper, 20, dynamic damper, 21, end cover, 22, pressure equalizing groove, 23, arc-shaped groove.

Detailed ways

The specific embodiment of the utility model will be described in further detail below with reference to the accompanying drawings.

The pilot-operated non-static differential water pressure relief valve shown in Figure 1 and Figure 2 includes a pilot valve, a main valve, and a feedback control system in a closed-loop valve channel; the pilot valve includes a pilot valve sleeve 3, a pilot valve core 4, The pilot valve body 5, the buffer spring 2 and the end cover 21, the pilot valve sleeve 3 is installed in the hole of the pilot valve body 5, the pilot valve core 4 is installed in the pilot valve sleeve 3, the buffer spring 2 is installed between the pilot valve core 4 and the end cover 21, the main valve includes a main valve body 12, a main valve core 13, a main valve sleeve 14, a main valve seat 15 and a main valve return spring 18, and the main valve sleeve 14 and the main valve seat 15 are installed on the main valve body 12 In the inner hole, the main valve core 13 is installed in the main valve sleeve 14, and the main valve return spring 18 is installed in the spring chamber at the tail of the main valve core 13; the feedback control system in the closed loop of the valve channel includes a miniature pressure sensor 16, a driver 8 and the channel connecting the pilot valve and the main valve, the miniature pressure sensor 16 is set at the oil inlet, the tie rod 6 of the driver 8 is connected to one end of the pilot spool 4, the pilot spool 4 is a one-sided zero-opening two-way slide valve, and the pilot valve Three pressure equalizing grooves 22 are evenly formed on the cylindrical surface of the shoulders at both ends of the core 4 . The inner side of the driver 8 is provided with a sealing ring 1 7 .

The main valve core 13 adopts a three-section concentric structure, the head of the main valve core 13 adopts a parabolic structure, the main valve core 13 and the main valve seat 15 form a two-stage throttling valve port, and the throttling port adopts a long straight channel type.

The end surface of the pilot valve core 4 on one side of the end cover 21 is provided with an arc-shaped groove 23 , and the inner side of the end cover 21 is fixed with a buffer pad 1 .

The oil inlet and the left end of the pilot valve sleeve 3 are connected with a pilot hole 17, the pilot hole 17 is provided with a fixed damper 19, the upper chamber of the main valve body 12 is provided with an oil passage connected to the middle of the pilot valve sleeve 3, and the oil passage is provided with The dynamic damper 20, and the oil passage communicates with the pilot hole 17. The upper cavity of the main valve is provided with a hole communicating with the right cavity of the pilot valve.

The middle part of the main valve body 12 is provided with a water outlet, and the water outlet adopts a right-angle structure with a smooth arc transition.

The pilot valve is provided with a safety valve, the safety valve includes a safety valve body 9, a safety valve return spring 10 and a safety valve spool 11, the safety valve spool 11 is installed in the hole of the safety valve body 9, and one end is connected to the The safety valve return spring 10 is connected, the other end of the safety valve return spring 10 is installed in the spring chamber, the other end of the safety valve spool 11 forms a cone seal with the hole of the safety valve body 9, and the other end of the hole in the safety valve body 9 Connected with the pilot hole 17, the upper end of the middle part of the hole of the safety valve body 9 is connected with the middle part of the pilot valve sleeve 3, and the lower end is connected with the water outlet.

Working principle: remove the inner screw plug of the pilot hole 17, the liquid flow from the oil inlet port P into the relief valve is divided into two paths, one path directly acts on the main valve core 13, and the other path passes through the pilot hole 17 and the fixed damper 19 After entering the pilot valve, it is divided into two paths, one path enters the left cavity of the pilot valve, the other path enters the middle cavity of the pilot valve and enters the upper cavity of the main valve through the dynamic damper 20, and then enters the cavity of the pilot valve. In the right chamber, the safety valve is always in a closed state due to the high set pressure. As long as the pilot valve is not opened, the pressure of the upper and lower chambers of the main valve must be equal, and the main valve is in a closed state.

When the miniature pressure sensor 16 detects that the inlet pressure P exceeds the set value, the driver 8 generates a pulling force to move the pilot valve core 4 to the right. The liquid flow through the opening flows to the main valve outlet T, the liquid flow passes through the fixed damper 19 and produces a pressure drop, so that the pressure in the lower chamber of the main valve is higher than the pressure in the upper chamber, the main valve core 13 moves upward, the main valve opens to overflow, and Maintained in a balanced position, the valve port pressure P of the main valve changes linearly with the voltage signal of the driver 8. When encountering external disturbances, the miniature pressure sensor 16 senses this change and transmits the signal to the driver 8. By changing the voltage The signal dynamically adjusts the pressure to form a closed-loop feedback system. When the pilot spool 4 returns to the initial position, the main spool 13 stops moving, and the inlet pressure is basically equal to the given value.

When the external disturbance force acts on the main spool 13 and makes it move, the upper chamber of the main spool 13 will generate an additional flow, and when this additional flow passes through the dynamic damper 20, a pressure drop will occur. At this time, the pilot The pressures in the left and right cavities of the spool 4 are not equal, and the force balance of the pilot valve is destroyed, thereby generating additional dynamic adjustment force. For example, if the main spool 13 moves downward, the pressure in the left cavity of the pilot valve is greater than the pressure in the right cavity. At this time, the additional dynamic adjustment force makes the pilot spool 4 move to the right, and the opening of the pilot valve port increases, and then the left cavity The pressure drops rapidly until the pressure in the left and right chambers of the pilot valve is rebalanced, realizing dynamic feedback control, which is conducive to the rapid stabilization of the relief valve, and improves the dynamic characteristics and anti-interference ability of the relief valve.

In order to prevent the sudden change of the system pressure from being too high, a safety valve is embedded in the pilot-operated non-static pressure relief valve of the utility model, which forms a traditional pilot-operated relief valve with the main valve. (with a large pressure peak), or when the electronic circuit fails, the safety valve opens immediately to relieve the system pressure and keep the system pressure constant. The set pressure of the safety valve only needs to be slightly higher than the highest possible pressure in the system or circuit That's it.

To sum up, the utility model uses a pressure sensor to directly detect the change of the inlet pressure of the main valve, and directly transmits the detected signal to the driver to control the opening of the pilot valve, forming a closed-loop pressure feedback control with high control precision, fast response speed and stability Good performance and no static difference control; the pilot spool adopts a one-sided zero-opening two-way slide valve, which is more stable, and three pressure equalization grooves are evenly opened on the cylindrical surface of the convex shoulder at both ends of the spool to reduce the hydraulic clamping force. Avoid the clamping phenomenon of the valve core and the valve sleeve; the main valve core adopts a three-section concentric structure, the head of the main valve core adopts a parabolic structure, the main valve core and the main valve seat form a two-stage throttle valve port, and the throttle port adopts a long straight channel type; effectively reduce the cavitation, wire drawing, noise and vibration of the valve, and ensure the control accuracy and service life of the valve; the water outlet adopts a right-angle structure with a smooth arc transition, which reduces the unevenness of the flow area caused by the return cavity eddy currents, noise and cavitation.

Claims (6)

1. A pilot-operated non-static differential water pressure relief valve, comprising a pilot valve, a main valve and a feedback control system in a closed-loop valve channel; the pilot valve comprises a pilot valve sleeve (3), a pilot spool (4), a pilot The valve body (5), buffer spring (2) and end cover (21), the pilot valve sleeve (3) is installed in the hole of the pilot valve body (5), the pilot valve core (4) is installed in the pilot valve sleeve (3) Inside, the buffer spring (2) is between the pilot spool (4) and the end cover (21), and the main valve includes the main valve body (12), the main valve core (13), the main valve sleeve (14), the main The valve seat (15) and the main valve return spring (18), the main valve sleeve (14) and the main valve seat (15) are installed in the hole in the main valve body (12), and the main valve core (13) is installed in the main valve In the sleeve (14), the main valve return spring (18) is installed in the spring chamber at the end of the main valve core (13); it is characterized in that: the feedback control system in the valve channel closed loop includes a miniature pressure sensor (16), a driver ( 8) and the hole connecting the pilot valve and the main valve, the miniature pressure sensor (16) is set at the oil inlet, the pull rod (6) of the driver (8) is connected to one end of the pilot spool (4), and the pilot spool (4) is In the one-sided zero-opening two-way slide valve, three pressure equalizing grooves (22) are evenly opened on the shoulder cylindrical surface at both ends of the pilot valve core (4). 2. The pilot-operated non-static hydraulic pressure relief valve according to claim 1, characterized in that: the main valve core (13) adopts a three-section concentric structure, the head of the main valve core (13) adopts a parabolic structure, and the main valve core (13) adopts a parabolic structure. The spool (13) and the main valve seat (15) form a two-stage throttling valve port, and the throttling port adopts a long straight channel type. 3. The pilot-operated non-static differential water pressure relief valve according to claim 1, characterized in that: the end surface of the pilot valve core (4) on the side of the end cover (21) is provided with an arc-shaped groove (23) , the inner side of the end cover (21) is fixed with a buffer pad (1). 4. The pilot-operated non-static differential water pressure relief valve according to claim 1, characterized in that: the oil inlet is connected to the left end of the pilot valve sleeve (3) with a pilot hole (17), and the pilot hole (17) A fixed damper (19) is arranged inside, an oil passage connected to the middle of the pilot valve sleeve (3) is arranged in the upper chamber of the main valve body (12), and a dynamic damper (20) is arranged in the oil passage, and the oil passage and the pilot hole ( 17) Connected. 5. The pilot-operated non-static differential water pressure relief valve according to claim 4, characterized in that: the middle part of the main valve body (12) is provided with a water outlet, and the water outlet adopts a right-angle structure with a smooth arc transition. 6. The pilot-operated non-static differential water pressure relief valve according to claim 5, characterized in that: the pilot valve is provided with a safety valve, and the safety valve includes a safety valve body (9), a safety valve return spring ( 10) and the safety valve spool (11), the safety valve spool (11) is installed in the hole of the safety valve body (9), and one end is connected with the safety valve return spring (10), and the safety valve return spring (10) The other end is installed in the spring cavity, the other end of the safety valve spool (11) forms a cone seal with the hole of the safety valve body (9), and the other end of the hole of the safety valve body (9) is connected to the pilot channel (17) , the upper end of the middle part of the hole of the safety valve body (9) communicates with the middle part of the pilot valve sleeve (3), and the lower end communicates with the water outlet.