CN103122883B - Adjustable pilot reduction valve - Google Patents

Abstract

The invention discloses an adjustable pilot pressure reducing valve. In order to solve the shortcomings of the existing pressure reducing valves that the opening device is easily damaged by impact and has a large noise, the invention provides a pressure reducing valve. The valve adopts a differential pilot valve, On one side of the pilot valve is the first cavity connected to the oil inlet of the pilot valve, and on the other side is the second cavity connected to the first cavity by the inter-cavity oil passage. The pilot valve core is slid in the pilot valve seat. The cone part is located in the first cavity and connected with the buffer spring, the second cavity side is equipped with a pressure regulating spring and a screw adjustment mechanism, the gap between the pilot valve seat and the pilot valve core, the radial through hole and the oil outlet of the pilot valve The port constitutes the leakage oil passage for the pilot valve to open, and the opening pressure is conveniently adjusted through the screw adjustment mechanism. The present invention reduces the impact force when the pilot valve is closed through the differential pilot valve, inverted pilot valve core, buffer spring, axially movable pilot valve seat and pilot valve core, and keeps the pilot valve core in a stable state all the time. The pressure reducing valve has the advantages of small impact of the pilot valve, long service life, stability, low noise, and easy adjustment.

Description

Adjustable pilot pressure reducing valve

technical field

The invention relates to a hydraulic component of a hydraulic system, in particular to an adjustable pilot pressure reducing valve in the hydraulic system.

technical background

The pressure reducing valve is a commonly used pressure control component in the hydraulic system. It is a pressure regulating valve and is often used to stabilize the working pressure of the oil circuit. Existing pressure reducing valves can be divided into direct-acting pressure reducing valves and pilot-operated pressure reducing valves according to different structures and working principles. Pilot-operated pressure reducing valves are especially widely used.

In the existing pilot-operated pressure reducing valve, the pilot valve seat is fixed, the pilot valve cone (also known as the pilot valve core) is supported on the pilot valve seat through the pressure regulating spring, and the oil inlet of the pilot valve is connected to the main valve of the pressure reducing valve. The return spring chamber of the spool communicates with the low-pressure oil outlet of the pressure reducing valve through an orifice, and the pressure regulating spring chamber of the pilot valve communicates with the circuit of the hydraulic oil tank. When the pressure at the outlet of the low-pressure oil of the pressure reducing valve is lower than the set pressure of the pressure-regulating spring, the pilot valve is in a closed state, and the pressure at the outlet of the low-pressure oil is equal to the pressure in the return spring cavity, and the main valve core is under the action of the elastic force of the return spring. Move down to increase the opening of the oil circuit valve from the high-pressure oil inlet to the low-pressure oil outlet of the pressure reducing valve, increase the flow of hydraulic oil entering the low-pressure oil outlet and increase the pressure at the low-pressure oil outlet; when the low-pressure oil outlet When the pressure at the pilot valve is higher than the set pressure of the pressure regulating spring of the pilot valve, the pilot valve opens to make the pressure of the return spring chamber drop rapidly, and the main valve core moves under the action of the high pressure oil to compress the return spring, reducing the pressure from the high pressure oil inlet. The valve port opening of the oil passage to the low-pressure oil outlet reduces the flow entering the low-pressure oil outlet and reduces the pressure at the low-pressure oil outlet.

Since there are multiple hydraulic actuators in the hydraulic system, the operation of these hydraulic actuators will cause fluctuations in the system pressure, and the pilot valve is frequently opened and connected with the fluctuation of the system hydraulic pressure in order to stabilize the pressure at the outlet of the low-pressure oil. closure. In the existing pilot-operated pressure reducing valve, the pilot valve seat is fixed, and when the pilot valve is closed, the pilot valve cone will impact the pilot valve seat under the push of the pressure regulating spring, and the pilot valve is frequently opened and closed, so that the pilot valve cone There are also frequent impacts between the pilot valve seat and the pilot valve seat. The pilot valve seat and the pilot valve cone are also easily damaged due to frequent impacts, resulting in a low service life of the pressure reducing valve. At the same time, when the pilot valve is opened, the pilot valve cone is in a suspended state, which is easy The collision with the valve seat causes a lot of noise, which increases the noise radiation of the machine.

Contents of the invention

The purpose of the present invention is to solve the disadvantages that the pilot valve of the existing pilot-operated pressure reducing valve is easily damaged due to a large impact and has a short service life, and the pilot valve core is in a floating state when the pilot valve is opened, and it is easy to generate vibration and howling. An adjustable pilot pressure reducing valve with good stability, low noise and long service life with adjustable pressure at the low pressure oil outlet.

The technical solution of the present invention is achieved by constructing an adjustable pilot pressure reducing valve, which includes a main valve and a main valve opening device fixedly connected with the main valve. Spool cavity, high-pressure oil inlet, low-pressure oil outlet; the main spool cavity is provided with a main spool that can move axially in it, and one end of the main spool is connected with a return spring, and the main spool is on the same side of the return spring. There is an upper chamber adjacent to the main spool on the side. The upper chamber is a control chamber opened by the main spool. When the pressure in the upper chamber drops by a certain value, the force on both sides of the main spool is unbalanced and moves toward the upper chamber. As the main spool moves along the axial direction of the main spool in the main spool cavity, the opening of the valve port changes from the high-pressure oil inlet to the low-pressure oil outlet. The main valve opening device includes a valve body, a valve cavity is set in the valve body, and a pilot valve is slid in the valve cavity. One side of the pilot valve is the first cavity, and the other side has the second cavity. The cavity is connected with the upper cavity, and the first cavity is connected with the low-pressure oil outlet through the oil pressure detection oil circuit. There is a main valve throttle hole on the oil pressure detection oil circuit, and the liquid in the first cavity acts on the pilot valve. The axial area is larger than the axial area of the liquid in the second cavity acting on the pilot valve. The pilot valve is provided with an inter-chamber oil circuit connecting the first cavity and the second cavity. The pilot valve includes a pilot valve core and a pilot valve. Seat, the pilot valve seat and the inner wall of the valve cavity are slidingly fitted, and a pilot valve hole axially penetrating the pilot valve seat is provided on the pilot valve seat. The connecting part, the guiding part is in sliding fit with the pilot valve hole, there is a pilot valve gap between the connecting part and the hole wall of the pilot valve hole, the cone part is located in the first cavity, and when the cone part is out of contact with the sharp edge of the pilot valve seat The first cavity communicates with the pilot valve gap, the pilot valve seat is provided with a radial through hole communicating with the pilot valve gap, and the valve body is provided with a pilot valve oil outlet connected to the radial through hole; the first cavity is provided with Buffer spring, one end of the buffer spring is in contact with the valve body, the other end is in contact with the taper of the pilot valve core, the pilot valve core exerts elastic force toward the second chamber, and a pressure regulating spring and adjustment One end of the pressure regulating spring is in contact with the pilot valve seat, and the other end is in contact with the valve body. The adjustment device makes the movement stroke of the pilot valve core to the direction of the second cavity less than the movement stroke of the pilot valve seat to the direction of the second cavity and The end-of-travel position of the pilot spool can be adjusted.

The working principle of the adjustable pilot pressure reducing valve of the present invention is as follows: when the pressure at the low pressure oil outlet is not higher than the opening pressure of the pilot valve of the pressure reducing valve, the first cavity of the pilot valve, the upper cavity of the main valve and the low pressure outlet The oil port has the same pressure, and the main valve core is kept balanced by the return spring, the hydraulic oil in the upper chamber, and the hydraulic oil at the low-pressure oil outlet. The gap from the high-pressure oil inlet to the low-pressure oil outlet is different in size. Change, keep the pressure at the low pressure oil outlet at a certain value.

When the pressure of the low-pressure oil outlet gradually increases, since the axial stress area of the pilot valve in the first cavity is larger than the axial force area of the pilot valve in the second cavity, the hydraulic pressure in the first cavity The increased force of the oil acting on the pilot valve is greater than the increased force of the hydraulic oil in the second cavity acting on the pilot valve. When the pressure in the first cavity reaches the set pressure of the opening device, the second The force of the hydraulic oil in the first cavity and the buffer spring on the pilot valve is greater than the force of the hydraulic oil in the second cavity and the pressure regulating spring on the pilot valve, so that the pilot valve moves to the second cavity (the second cavity The hydraulic oil also flows to the first chamber through the inter-chamber oil passage), when the pilot valve core contacts with the adjustment device, the pilot valve core stops moving, and the pilot valve seat continues to move to the direction of the second chamber, at this time the pilot valve core The cone part is out of contact with the sharp edge of the pilot valve seat, so that the first cavity communicates with the gap of the pilot valve, and the hydraulic oil in the first cavity flows out of the first cavity through the gap of the pilot valve, the radial through hole, and the oil outlet of the pilot valve , so that the pressure in the first chamber decreases rapidly, thereby reducing the pressure in the upper chamber of the main valve core connected to the first chamber, so that the main valve core moves toward the upper chamber, from the high-pressure oil inlet to the low-pressure oil outlet The gap of the port is reduced, that is, the opening of the valve port is reduced, so that the pressure of the low-pressure oil outlet port is reduced. When the pressure in the first chamber drops to the set pressure for the opening device to close, the axial force of the hydraulic oil and the buffer spring in the first chamber on the pilot valve is smaller than that of the hydraulic oil and the pressure regulating spring in the second chamber For the axial force of the pilot valve, the pilot valve seat moves toward the direction of the first cavity under the action of the pressure regulating spring, so that the sharp edge of the pilot valve seat contacts the tapered surface of the cone of the pilot valve core, disconnecting from the first The oil path between the cavity and the pilot valve gap increases the pressure of the first cavity and the upper cavity, and the main valve core regains the force balance and maintains the current position, keeping the valve opening from the high-pressure oil inlet to the low-pressure oil outlet. Degree, that is, to maintain the pressure of the low pressure oil outlet. In the present invention, the stroke of the pilot valve core is adjusted by the adjusting device, that is, when the pilot valve core and the adjusting device are in contact with the limit position, that is, the compression length of the pressure regulating spring compressed by the pilot valve seat when the pilot valve is opened, that is, adjusting the adjustment The elastic force of the compression spring when the pilot valve is opened realizes the adjustment of the cracking pressure of the opening device, that is, the pressure at the low-pressure oil outlet. In the present invention, the differential pilot valve, the inverted pilot valve core, that is, the pilot valve core is installed on the oil inlet side of the pilot valve, the buffer spring, the axially movable pilot valve seat and the pilot valve core, etc. When closing, the impact force will keep the pilot valve core in a stable state all the time, so as to realize the advantages of small impact, long life and low noise of the pilot valve.

In the present invention, a pilot valve orifice is provided on the inter-cavity oil circuit. When the pilot valve is closed, the pressure-regulating spring pushes the pilot valve seat to move toward the first chamber, and the volume of the second chamber increases. The oil flows from the first cavity to the second cavity through the inter-cavity oil circuit. Because the orifice is set on the inter-cavity oil circuit, it has a damping effect on the hydraulic oil flowing into the second cavity, so it can slow down the flow of the pilot valve seat to the second cavity. The speed of moving in the direction of a cavity, thereby reducing the impact between the pilot valve seat and the pilot valve core.

In the present invention, the adjusting device includes an adjusting rod. One end of the adjusting rod is a position-limiting adjusting end in contact with the end of the guiding part of the pilot valve core, and the other end is a connecting end connected to the valve body through a screw mechanism. By adjusting the position of the adjustment end of the adjustment rod through the screw mechanism, the stroke and position of the contact between the pilot valve core and the adjustment rod can be adjusted. The screw mechanism includes an adjusting rod mounting hole on the valve body that communicates with the inside and outside of the valve body and an adjusting nut that is screwed on the outside of the mounting hole and the valve body. contact connection. By rotating the nut, the adjustment rod slides in the installation hole to adjust the stroke and position of the pilot valve core when it contacts the adjustment rod. The screw mechanism can also include an adjusting rod mounting hole arranged on the valve body to communicate with the inside and outside of the valve body. The connecting end of the adjusting rod is arranged in the mounting hole. An inner hexagonal hole is arranged on the end face of the connecting end of the adjusting rod.

In the present invention, the pilot valve seat is provided with a cavity adjacent to the end surface of the adjustment device, and the side wall of the cavity cooperates with the side of the adjustment rod to form the second cavity.

In the present invention, the inter-chamber oil passage can be arranged on the pilot valve seat or on the pilot valve core. When the limit adjustment end is in contact with the pilot valve core, the inter-chamber oil passage can communicate with the second chamber through the oil passage. The oil passage can take various forms. For example, a counterbore is provided on the end surface of the limit adjustment end, and a perforation is provided on the side through the side wall of the counterbore. Or the end surface of the limit adjustment end is provided with an end face oil groove that runs through the entire limit adjustment end. When the pilot valve core is in contact with the limit adjustment end, the end surface oil groove communicates with the inter-chamber oil circuit.

The present invention provides another technical solution to solve the technical problem. The solution is to construct an adjustable pilot pressure reducing valve, which includes a main valve and a main valve opening device fixedly connected with the main valve. The main valve includes a main valve body, The main valve body is provided with a main spool cavity, a high-pressure oil inlet, and a low-pressure oil outlet; the main spool cavity is provided with a main spool that can move in the axial direction, and one end of the main spool is connected with a return spring. The spool is provided with an upper cavity adjacent to the main spool on the same side of the return spring, and the upper cavity is a control cavity opened by the main spool. When the pressure in the upper cavity drops by a certain value, the force on both sides of the main spool is unbalanced and Move towards the upper cavity. As the main spool moves along the axial direction of the main spool in the main spool cavity, the opening of the valve port changes from the high-pressure oil inlet to the low-pressure oil outlet. The main valve opening device includes a valve body, a valve cavity is set in the valve body, and a pilot valve is slid in the valve cavity. One side of the pilot valve is the first cavity, and the other side has the second cavity. The chamber is connected with the upper chamber, and the first chamber is connected with the low-pressure oil outlet through the oil pressure detection oil circuit. The main valve throttle hole is arranged on the oil pressure detection oil circuit, and the liquid in the first chamber acts on the shaft on the pilot valve. The direction area is larger than the axial area of the liquid in the second cavity acting on the pilot valve, and the pilot valve is provided with an inter-chamber oil circuit connecting the first cavity and the second cavity, and the pilot valve includes a pilot valve core and a pilot valve. The valve seat, the pilot valve seat is in sliding fit with the inner wall of the pilot valve cavity, and a pilot valve hole axially penetrating the pilot valve seat is provided on the pilot valve seat, and the pilot valve core includes a guide part at the head, a cone part at the tail, The connection part connecting the guide part and the cone part, the guide part is in sliding fit with the pilot valve hole, there is a pilot valve clearance between the connection part and the hole wall of the pilot valve hole, and the cone part is located in the first cavity , when the taper part is out of contact with the sharp edge of the pilot valve seat, the first cavity communicates with the pilot valve clearance, the pilot valve seat is provided with a radial through hole communicating with the pilot valve clearance, and the valve body is provided with a pilot valve connecting the radial through hole. The oil outlet of the valve; a buffer spring is provided in the first chamber, one end of the buffer spring is in contact with the valve body, and the other end is in contact with the taper of the pilot valve core, and the pilot valve core exerts an elastic force toward the second chamber. A pressure regulating spring and a screw regulating mechanism are arranged on the side of the second chamber, one end of the pressure regulating spring is in contact with the pilot valve seat, and the other end is connected with the screw regulating mechanism, and the preload elastic force of the pressure regulating spring can be adjusted by the spiral regulating mechanism A limit shoulder is provided on the side wall of the first cavity, and a limit protrusion corresponding to the limit shoulder is provided on the cone of the pilot valve core. When the pressure reducing valve in the present invention works, when the pressure in the first cavity is higher than the setting value of the pressure regulating spring, the limit boss on the cone of the pilot valve core and the limit platform on the side wall of the first cavity will The contact of the shoulder causes the pilot valve core to stop moving, and the pilot valve seat continues to move to cause the pilot valve to open, reducing the pressure in the first cavity. In the present invention, the opening pressure of the pilot valve can be adjusted by adjusting the pre-tightening elastic force of the spring through the screw adjusting mechanism, so as to realize the pressure adjustment of the low pressure oil outlet of the pressure reducing valve.

In the present invention, the screw adjustment mechanism includes an adjustment rod, a guide hole for slidingly fitting with the adjustment rod on the valve body, and a nut that is arranged on the outside of the guide hole and threadedly connected with the valve body. The pressure spring is contacted and connected, and the outer end is connected with the nut. In addition, the screw adjusting mechanism can also be an adjusting rod directly screwed to the valve body, the inner end of the adjusting rod is in contact with the pressure regulating spring, and the outer end is located outside the valve body, and the adjusting rod can be rotated by a tool.

Compared with the prior art, the present invention has the following beneficial effects:

1. In the adjustable pilot pressure reducing valve of the present invention, both the pilot valve core and the pilot valve seat can slide axially. When the pilot valve is closed, the pilot valve seat guides the valve core to move. Buffer the impact when the pilot valve seat contacts the pilot valve core; in addition, the present invention can make the force bearing area of the pilot valve subjected to the axial action of the hydraulic oil in the second cavity be slightly smaller than the axial force of the pilot valve by the hydraulic oil in the first cavity. The pressure-bearing area acting in the opposite direction, so that the pressure-regulating spring with smaller stiffness can be selected to reduce the impact of the pilot valve seat and the pilot valve core when the pilot valve is opened and closed. The invention reduces the impact force when the pilot valve seat and the pilot valve core are closed through the axially movable pilot valve seat, the pilot valve core and the buffering of the buffer spring, thereby prolonging the service life of the pilot valve.

2. In the present invention, the pilot valve core slides with the valve hole through its guide rod, so that it can only slide axially along the pilot valve hole without radial deviation. In addition, when the pilot valve is opened, the pilot valve One end of the core is squeezed by the buffer spring, and the other end is in contact with the adjustment mechanism or the limit shoulder, so that it is in a stable state, so there will be no vibration or even howling, and it will not increase the noise radiation of the machine.

3. In the present invention, the stroke and end position of the guide valve core when in contact with the regulating device are adjusted by the regulating device or the elastic force of the spring is adjusted by the screw regulating mechanism, so as to facilitate the adjustment of the opening pressure of the pressure reducing valve and the adjustment of the opening pressure during use. Calibration adjustment.

Description of drawings

Fig. 1 is a schematic structural view of an adjustable pilot pressure reducing valve in Embodiment 1 of the present invention;

Fig. 2 is a schematic structural view of the main valve opening device in the adjustable pilot pressure reducing valve in embodiment 1;

Fig. 3 is the structural representation of pilot valve and adjusting mechanism in embodiment 1;

Fig. 4 is the structural representation of main valve in embodiment 1;

Fig. 5 is a schematic structural view of an adjustable pilot pressure reducing valve in Embodiment 2 of the present invention;

Fig. 6 is a schematic structural view of an adjustable pilot pressure reducing valve in Embodiment 3 of the present invention;

Fig. 7 is a schematic structural view of an adjustable pilot pressure reducing valve in Embodiment 4 of the present invention;

Fig. 8 is a schematic structural view of the adjustable pilot pressure reducing valve in Embodiment 5 of the present invention.

Part names and serial numbers in the figure:

1. Screw plug 11, valve sleeve 12, pilot valve oil inlet 13, pilot valve oil outlet 14, valve seat 15, limit shoulder 16, oil pressure detection oil circuit inlet 17;

2. The first cavity 21, the second cavity 22, the buffer spring 23, the pressure regulating spring 24;

3. Main valve core 3, main valve orifice 31, upper cavity 34, main valve sleeve 35;

4. Pilot valve core 4, guide part 41, cone part 42, connecting part 43, inter-chamber oil passage 44, pilot valve gap 45, pilot valve throttle hole 46, limit protrusion 47;

5. Pilot valve seat 5, radial through hole 51;

6. Main valve body 61, main valve oil pressure detection oil circuit 62, return spring 64, pilot valve overflow oil circuit 65, high pressure oil inlet 66, low pressure oil outlet 67;

8. Adjusting rod 8, counterbore 81, radial perforation 82, end surface oil groove 83, inner hexagonal hole 84, limit section 85, adjustment section 86, ball joint 87;

9, nut 9, and tighten nut 91.

Detailed ways

The adjustable pilot pressure reducing valve of the present invention will be described below with reference to the accompanying drawings and embodiments.

Example 1:

As shown in Figure 1, the adjustable pilot pressure reducing valve includes a main valve B and a main valve opening device A fixedly connected with the main valve, as shown in Figure 4, the main valve B includes a main valve body 61, and the main valve body 61 is provided with There is a high-pressure oil inlet 66 and a low-pressure oil outlet 67, and a main valve sleeve 35 is arranged in the main valve body, and a main valve core 3 is slid inside the main valve sleeve 35;

The main valve core 3 can move axially in the main valve sleeve, the upper side of the main valve core 3 is an upper chamber 34, and a return spring 64 is arranged in the upper chamber 34, and one end of the return spring 64 is in contact with the main valve core 3 , the other end is in contact with the valve body of the main valve opening device A. The lower part of the main valve core 3 is cylindrical with an open lower end. 35 is also provided with a plurality of through holes in the circumferential direction, and the hydraulic oil flows from the high-pressure oil inlet 66 through the through hole on the main valve sleeve 35, the through hole on the main valve core 3, and the opening at the lower end of the main valve core 3 to Low pressure oil outlet 67. The axial movement of the main valve core 3 in the main valve sleeve 35 makes the through hole on the main valve core 3 and the through hole on the main valve sleeve 35 misaligned, resulting in the flow from the high pressure oil inlet to the low pressure oil outlet. The opening of the valve port changes to change the pressure of the low-pressure oil outlet. As shown in Figure 2 and Figure 3, the main valve opening device A includes a valve body, the valve body is composed of a valve sleeve 12 and a screw plug 11 screwed on the left end of the valve sleeve 12, a valve cavity is provided in the valve body, and in the valve cavity A pilot valve is slidably arranged, wherein the left side of the pilot valve is the first cavity 21, and the right side is the second cavity 22. The pilot valve includes a pilot valve core 4 and a pilot valve seat 5, and the pilot valve core 4 is provided with a connection The inter-chamber oil passage 44 between the first chamber 21 and the second chamber 22 is provided with a pilot valve orifice 46 on the inter-chamber oil passage 44 . The diameter of the left section of the pilot valve seat 5 is greater than the diameter of the right section, and the valve cavity also has corresponding large and small diameter sections. The effective axial force bearing area of the hydraulic oil in the second cavity 22 acting on the pilot valve is greater than the axial effective force bearing area of the hydraulic oil in the second cavity 22 acting on the pilot valve. The center of the pilot valve seat 5 is provided with a pilot valve hole axially penetrating the pilot valve seat 5, and the pilot valve core 4 is slidably arranged in the pilot valve hole. The connecting part 43 connecting the guide part 41 and the cone part 42 in the middle has a pilot valve gap 45 between the connecting part 43 and the hole wall of the pilot valve hole, the cone part 42 is located in the first cavity 21, and the cone part 42 can be connected with the pilot valve The sharp edge of the seat contacts to form a sealed contact, and the guide part 41 is in sliding fit with the inner wall of the pilot valve hole. A buffer spring 23 is arranged in the first cavity, one end of the buffer spring 23 is in contact with the screw plug 11 , and the other end is in contact with the taper 42 of the pilot valve core 4 . The pilot valve seat is provided with a radial through hole 51 communicating with the pilot valve gap 45; on the valve sleeve 12, the pilot valve oil inlet 13, the pilot valve oil outlet 14, and the oil pressure detection oil circuit inlet 17, wherein the pilot valve oil inlet The port 13 connects the first chamber 21 with the upper chamber 34 , and the oil outlet port 14 of the pilot valve communicates with the oil tank in the hydraulic system through the pilot valve overflow oil passage 65 . The inlet 17 of the oil pressure detection oil circuit communicates with the low pressure oil outlet 67 through the main valve oil pressure detection oil circuit 62 , and the main valve throttle hole 31 is arranged on the main valve oil pressure detection oil circuit 62 . A pressure regulating spring 24 is arranged in the second cavity 6, one end of the pressure regulating spring 24 is in contact with the pilot valve seat 5, and the other end is in contact with the valve sleeve 12, and an adjusting rod 8 is arranged in the middle of the pressure regulating spring 24 to adjust One end of the rod 8 is a limit adjustment end in contact with the end of the guide part 41 of the pilot valve core 4, and the other end is provided with a thread, and the threaded end forms a threaded connection with the valve sleeve 12 and extends to the outside of the valve sleeve 12. The end face of the threaded end is provided with an inner hexagonal counterbore 84 to rotate the adjusting rod 8 for use, and the threaded end of the adjusting rod 8 is provided with a tightening nut 9 to prevent the abnormal rotation of the adjusting rod. A counterbore 81 is provided on the end face of the limit adjustment end of the adjustment rod 8, and a radial perforation 82 that runs through the side wall of the counterbore 81 is provided on the side, so that the second capacity when the limit adjustment end of the adjustment rod 8 contacts the pilot valve core 4 The cavity 22 communicates with the inter-cavity oil passage 44 through the radial perforation 82 and the counterbore 81 .

In this embodiment, when the pressure at the low-pressure oil outlet 67 is lower than the cracking pressure of the pilot valve in the pressure reducing valve, that is, when the pressure in the first chamber is lower than the cracking pressure of the pilot valve, the buffer spring 23 and the regulator Under the action of the pressure spring 24, the taper 42 contacts with the sharp edge of the pilot valve seat to form a sealed contact, the pilot valve is in the closed state, and the main valve core 3 is in a certain position under the action of the return spring 64 and the hydraulic oil, so that the valve port is opened. maintain a certain value. When the pressure at the low-pressure oil outlet 67 rises, that is, after the hydraulic oil pressure in the first cavity 21 rises, the force acting on the left side of the pilot valve is greater than the force acting on the right side of the pilot valve, and the pilot valve The valve moves to the right. When the pilot valve core 4 is in contact with the regulating rod 8, the pressure in the first cavity 21 is equal to the cracking pressure of the pilot valve. If the pressure in the first cavity 21 is higher than the cracking pressure, the pilot valve The core 4 stops moving, and the pilot valve seat 5 continues to move to the right. At this time, the cone portion 42 of the pilot valve core 4 is out of contact with the sharp edge of the pilot valve seat, so that the first cavity 21 and the pilot valve gap 45 can be communicated, and the first cavity The hydraulic oil in the chamber 21 enters the oil tank through the pilot valve clearance 45, the radial through hole 51, the pilot valve oil outlet 14, and the pilot valve overflow oil passage 65, resulting in the pressure in the first chamber 21 and the pressure in the upper chamber 34 The pressure drops rapidly. Due to the damping effect of the main valve orifice 31, the pressure in the first chamber is lower than the pressure at the low-pressure oil outlet 67, and the pressure in the upper chamber is also lower than the pressure at the low-pressure oil outlet 67. The main spool 3 moves toward the upper chamber 34 under the action of the pressure difference on both sides, so that the degree of misalignment between the through hole on the main spool 3 and the through hole on the main valve sleeve 35 is aggravated, that is, the opening of the valve port is reduced. degree, the pressure at the low-pressure oil outlet 66 is reduced.

When the pressure in the first cavity 21 is lower than the opening pressure of the pilot valve, the force acting on the right side of the pilot valve is greater than the force acting on the left side of the pilot valve, and the pilot valve seat 5 is pushed by the pressure regulating spring 24 Move down to the left, so that the sharp edge of the pilot valve seat is in contact with the cone 42, and the oil path from the first cavity 21 to the pilot valve gap 45 is disconnected, so that the pressure in the first cavity 21 can be increased to make the pilot valve left and right The forces on both sides are balanced. The pressure in the upper chamber 34 also increases, and the main spool reaches the force balance again to maintain the current position, and maintains the valve opening from the high-pressure oil inlet to the low-pressure oil outlet, that is, maintains the pressure of the low-pressure oil outlet. When the sharp edge of the pilot valve seat 5 is in contact with the cone 42, the pilot valve core 4 moves to the left under the action of the buffer spring 23 to buffer and absorb the impact of the pilot valve seat 5, reducing the impact of the pilot valve seat 5. During the closing process of the pilot valve, the pilot valve seat 5 moves to the left, causing the volume of the second cavity 22 to increase, and the hydraulic oil enters from the first cavity 21 to the second cavity 22 through the inter-cavity oil passage 44. The damping effect of the pilot valve orifice 46 on the inter-chamber oil passage 44 can slow down the inflow of hydraulic oil, that is, slow down the moving speed of the pilot valve seat 5, thereby further reducing the impact of the pilot valve seat on the pilot valve core. Extend the service life of the pilot valve. Due to the guiding effect of the guide part 41, the pilot valve core 4 does not collide radially with the pilot valve seat 5 to generate noise. Therefore, the pressure reducing valve in this embodiment has low operating noise. In this embodiment, the position of the limit adjustment end of the adjustment rod 8 can be changed by using a tool to rotate the adjustment rod 8. In the present invention, when the pilot valve core 4 is in contact with the adjustment rod 8, the pilot valve opens, and the limit adjustment end is at a different position. When the pilot valve core 4 is in contact with the regulating rod 8, the compression length of the pilot valve seat 5 to the pressure regulating spring 24 is different, that is, it has different cracking pressures. For example, when the regulating rod 8 is rotated to move the regulating rod to the right, the pilot valve is at Under the action of hydraulic oil, it moves to the right. When the pilot valve core 4 is in contact with the regulating rod 8, the compressed length of the pressure regulating spring 24 increases, so the opening pressure of the pilot valve also increases. Similarly, the rotating regulating rod makes the regulating rod When the limit adjustment end of 8 moves to the left, the compressed length of the pressure regulating spring 24 decreases when the pilot valve core 4 contacts the adjustment rod 8, so that the opening pressure decreases, so this implementation can be easily adjusted by rotating the nut 9 The cracking pressure of the pilot valve is used to adjust the pressure at the low-pressure oil outlet 66 of the pressure reducing valve.

Example 2:

As shown in Figure 5, compared with Embodiment 1, the difference of the pilot pressure reducing valve in this embodiment lies in the structure of the adjustment device and the main valve. In this embodiment, the end face of the limit adjustment end of the adjustment rod 8 is open There is an oil groove 83 on the end surface, and when the pilot valve core 4 is in contact with the adjusting rod 8, the oil circuit between the chambers communicates with the second cavity through the oil groove 83 on the end surface. The other end of the adjusting rod 8 passes through the adjusting rod installation hole on the valve sleeve 12 and is connected with the nut 9. The nut 9 is located outside the adjustment rod installation hole and is screwed with the valve sleeve 12, and the screw joint is provided with a tight The nut 91 prevents the nut 9 from moving abnormally. On the main valve, the main valve orifice 31 is arranged on the main valve core 3, and the main valve orifice 31 communicates the upper cavity 34 with the low-pressure oil outlet 67, the pilot valve oil inlet 13, the upper cavity 34, the main valve The orifice 31 constitutes an oil pressure detection circuit connecting the first cavity 21 and the low-pressure oil outlet 67, so that the first cavity 21, the upper cavity 34 and the low-pressure oil outlet 67 have the same pressure when the pilot valve is closed.

Example 3:

As shown in Figure 6, compared with Embodiment 2, the difference of the pilot pressure reducing valve in this embodiment lies in the valve body of the main valve opening device A and the pilot valve seat 5. In this embodiment, the valve body is composed of the valve The seat 15 and the valve sleeve 12 are screwed together, the left section of the pilot valve seat 5 cooperates with the inner cavity side wall of the valve seat 15, the pilot valve oil inlet 13 and the pilot valve oil outlet 14 are arranged on the case valve seat 15, The pilot valve oil inlet 13 communicates the upper cavity 34 with the first cavity 21 , and the pilot valve oil outlet 14 communicates with the pilot valve overflow oil passage 65 and the radial through hole 51 . The right end surface of the pilot valve seat 5 is provided with a cavity, and the side wall of the cavity is slidably matched with the side of the regulating rod 8 to form a second cavity 22 between the pilot valve and the regulating rod 8, wherein the regulating rod 8 and the pilot valve The diameter of seat 5 fitting place is less than the diameter of pilot valve seat 5 left section and valve seat 15 lumen sidewall fitting places.

Example 4:

As shown in Figure 7, compared with Embodiment 3, the difference of the pilot pressure reducing valve in this embodiment lies in the composition of the adjustment rod 8. In this embodiment, the adjustment rod includes two sections, one of which is connected with the pilot The limiting section 85 matched with the valve seat 5, and the other section is an adjusting section 86 that is slidingly matched with the mounting hole of the adjusting rod on the valve sleeve 12. A ball joint 87 is provided at the end of the adjusting section to contact and connect with the limiting section 85, allowing adjustment Section 86 and limiting section 85 rotate within a certain angle range, which can reduce the coaxiality requirements of valve seat 15 inner cavity, pilot valve seat 5 and adjusting rod 8, and adjusting rod mounting hole, reduce processing difficulty, and prevent pilot valve seat from 5 is stuck by the adjustment lever.

Example 5:

As shown in Figure 8, compared with Embodiment 2, the difference of the pilot pressure reducing valve in this embodiment is that an annular limiting shoulder 16 is provided on the side wall of the first chamber 21, The tail of the core 4 is provided with a limit protrusion 47. When the pilot valve core 4 moves to the right, the limit protrusion 47 can contact the limit shoulder 16, thereby limiting the rightward stroke end position of the pilot valve core 4. In the second cavity 22, the pressure regulating spring 24 is in contact with the adjusting rod 8, and the pre-tightening elastic force of the pressure regulating spring 24 can be adjusted by rotating the nut 9 to realize the adjustment of different opening pressures. In this embodiment, the limit After the protrusion 47 contacts the limit shoulder 16, the pilot valve seat 5 continues to move to the right and the pilot valve opens.

Claims (10)

1. An adjustable pilot pressure reducing valve, comprising a main valve (B) and a main valve opening device (A) fixedly connected with the main valve, the main valve (B) includes a main valve body (61), the main valve body (61) is provided with a main valve core chamber, a high-pressure oil inlet (66), and a low-pressure oil outlet (67); One end of the core (3) is connected with a return spring (64), and the main valve core (3) is provided with an upper chamber (34) adjacent to the main valve core (3) on the same side of the return spring (64). The main spool (3) changes the valve opening from the high pressure oil inlet (66) to the low pressure oil outlet (67) as it moves in the main spool cavity along the axial direction of the main spool. That is, the main valve opening device (A) includes a valve body, a valve cavity is arranged in the valve body, and a pilot valve is slid in the valve cavity, one side of the pilot valve is the first cavity (21), and the other There is a second chamber (22) on the side, the first chamber (21) communicates with the upper chamber (34), and the first chamber (21) communicates with the low-pressure oil outlet (67) through the oil pressure detection oil circuit. A main valve orifice (31) is provided on the pressure detection oil circuit, and the axial area where the liquid in the first chamber (21) acts on the pilot valve is larger than the axial area where the liquid in the second chamber (22) acts on the pilot valve. In the pilot valve, there is an inter-cavity oil passage (44) connecting the first cavity (21) and the second cavity (22), and the pilot valve includes a pilot valve core (4) and a pilot valve seat (5 ), the pilot valve seat (5) is slidingly fitted with the side wall of the valve cavity, and a pilot valve hole axially penetrating the pilot valve seat is provided on the pilot valve seat (5), and the pilot valve core (4) includes the head The guide part (41), the taper part (42) at the tail part, the connecting part (43) connecting the guide part (41) and the taper part (42), the guide part (41) is slidingly fitted with the pilot valve hole, so There is a pilot valve gap (45) between the connecting portion (43) and the pilot valve hole wall, the cone portion (42) is located in the first cavity (21), the cone portion (42) and the sharp edge of the pilot valve seat When out of contact, the first cavity (21) communicates with the pilot valve gap (45), the pilot valve seat (5) is provided with a radial through hole (51) communicating with the pilot valve gap (45), and the valve body is provided with a communication hole (51). The pilot valve oil outlet (14) of the radial through hole (51); the first cavity (21) is provided with a buffer spring (23), and one end of the buffer spring (23) is connected to the valve body, The other end is in contact with the taper of the pilot valve core, and a pressure regulating spring (24) and an adjustment device are arranged on the side of the second cavity (22), and one end of the pressure regulating spring (24) is in contact with the pilot valve seat (5) The other end is in contact with the valve body, and the adjustment device makes the movement stroke of the pilot valve core (4) toward the second chamber (22) less than the movement of the pilot valve seat (5) toward the second chamber (22) stroke and adjust the end-of-stroke position of the pilot spool (4). 2. The adjustable pilot pressure reducing valve according to claim 1, characterized in that, the inter-cavity oil passage (44) is provided with a pilot valve orifice (46). 3. The adjustable pilot pressure reducing valve according to claim 1, characterized in that, the adjustment device includes an adjustment rod (8), and one end of the adjustment rod (8) is a guide part (41 ) end contact with the limit adjustment end connected, and the other end is the connection end connected with the valve body through the screw mechanism. 4. The adjustable pilot pressure reducing valve according to claim 3, characterized in that, the screw mechanism includes an adjusting rod installation hole arranged on the valve body to communicate with the inside and outside of the valve body, and an adjustment rod installation hole arranged on the outside of the installation hole to connect with the valve body screw. The adjusting nut (9) is connected, and the connecting end of the adjusting rod (8) is in sliding fit with the mounting hole and is connected in contact with the adjusting nut (9). 5. The adjustable pilot pressure reducing valve according to claim 3, characterized in that, the screw mechanism includes an adjusting rod mounting hole arranged on the valve body to communicate with the inside and outside of the valve body, and the connection of the adjusting rod (8) End is arranged in the mounting hole, and the connecting end of adjusting rod (8) is provided with the screw thread that cooperates with mounting hole hole wall, is provided with inner hexagonal hole (84) on the end face of adjusting rod connecting end. 6. The adjustable pilot pressure reducing valve according to claim 3, characterized in that, the end face of the pilot valve seat adjacent to the adjustment device is provided with a cavity, and the side wall of the cavity is in contact with the adjustment rod (8) The sides of the side cooperate to form the second cavity (22). 7. The adjustable pilot pressure reducing valve according to any one of claims 1 to 6, characterized in that, the inter-cavity oil passage (44) is arranged on the pilot valve seat. 8. The adjustable pilot pressure reducing valve according to any one of claims 3 to 6, characterized in that, the inter-chamber oil passage (44) is set on the pilot valve core, and the adjusting rod is provided with a limit position The oil channel that flows in from the end face of the adjustment end and flows out from the side of the adjustment rod. 9. An adjustable pilot pressure reducing valve, comprising a main valve (B) and a main valve opening device (A) fixedly connected with the main valve, the main valve (B) includes a main valve body (61), the main valve body (61) is provided with a main valve core chamber, a high-pressure oil inlet (66), and a low-pressure oil outlet (67); One end of the core (3) is connected with a return spring (64), and the main valve core (3) is provided with an upper chamber (34) adjacent to the main valve core (3) on the same side of the return spring (64). The main spool (3) changes the valve opening from the high pressure oil inlet (66) to the low pressure oil outlet (67) as it moves in the main spool cavity along the axial direction of the main spool. That is, the main valve opening device (A) includes a valve body, a valve cavity is arranged in the valve body, and a pilot valve is slid in the valve cavity, one side of the pilot valve is the first cavity (21), and the other There is a second chamber (22) on the side, the first chamber (21) communicates with the upper chamber (34), and the first chamber (21) communicates with the low-pressure oil outlet (67) through the oil pressure detection oil circuit. A main valve orifice (31) is provided on the pressure detection oil circuit, and the axial area where the liquid in the first chamber (21) acts on the pilot valve is larger than the axial area where the liquid in the second chamber (22) acts on the pilot valve. In the pilot valve, there is an inter-cavity oil passage (44) connecting the first cavity (21) and the second cavity (22), and the pilot valve includes a pilot valve core (4) and a pilot valve seat (5 ), the pilot valve seat (5) is slidingly fitted with the side wall of the valve cavity, and a pilot valve hole axially penetrating the pilot valve seat is provided on the pilot valve seat (5), and the pilot valve core (4) includes the head The guide part (41), the taper part (42) at the tail part, the connecting part (43) connecting the guide part (41) and the taper part (42), the guide part (41) is slidingly fitted with the pilot valve hole, so There is a pilot valve gap (45) between the connecting portion (43) and the pilot valve hole wall, the cone portion (42) is located in the first cavity (21), the cone portion (42) and the sharp edge of the pilot valve seat When out of contact, the first cavity (21) communicates with the pilot valve gap (45), the pilot valve seat (5) is provided with a radial through hole (51) communicating with the pilot valve gap (45), and the valve body is provided with a communication hole (51). The pilot valve oil outlet (14) of the radial through hole (51); the first cavity (21) is provided with a buffer spring (23), and one end of the buffer spring (23) is connected to the valve body, The other end is in contact with the taper of the pilot valve core; a pressure regulating spring (24) and a screw regulating mechanism are provided on the side of the second cavity (22), and one end of the pressure regulating spring (24) is connected to the pilot valve seat (5 ) contact connection, the other end is connected with the screw adjustment mechanism and the pre-tightening elastic force of the pressure regulating spring (24) is adjusted by the screw adjustment mechanism, and a limit shoulder (16) is set on the side wall of the first cavity (21). The taper portion (42) of the pilot valve core is provided with a limit projection (47) corresponding to the limit shoulder (16) to limit the stroke of the pilot valve core to move toward the second cavity. 10. The adjustable pilot pressure reducing valve according to claim 9, characterized in that, the screw adjustment mechanism includes an adjustment rod (8), a guide hole for sliding fit with the adjustment rod (8) is provided on the valve body, and A nut (9) threadedly connected to the valve body outside the guide hole, the inner end of the adjusting rod (8) is in contact with the pressure regulating spring (24), and the outer end is in contact with the nut (9).