A pilot oil source valve group system integrated with safety function

Abstract

The utility model discloses a pilot oil source valve group system of integrated safety function, it includes safety pressure relief overflow valve, check valve, energy accumulator, first solenoid valve, second solenoid valve and valve block, is equipped with P oil inlet interface, Pr interface, Bv interface and T oil outlet interface on the valve block, P oil inlet interface is connected with safety pressure relief overflow valve import through pipeline, and safety pressure relief overflow valve export is connected with check valve import through pipeline, and check valve export is connected with energy accumulator, first solenoid valve first import and second solenoid valve first import respectively through pipeline, and Pr interface is connected with first solenoid valve second import through pipeline, and Bv interface is connected with second solenoid valve second import through pipeline, and the export of first solenoid valve and the export of second solenoid valve are connected with T oil outlet interface respectively through pipeline. The utility model adopts safety pressure relief overflow valve to integrate pressure relief overflow function and pressure safety function into one, make the hydraulic system of pilot oil source control valve group with pressure reduction circuit more simplified.

Description

Technical Field

[0001] This utility model relates to the field of control valve technology, specifically to a pilot oil source valve group system with integrated safety functions. Background Technology

[0002] In the construction machinery industry, hydraulically controlled multi-way valves are widely used to control various actuators. This requires a pilot-operated hydraulic control valve assembly to supply low-pressure control oil to the pilot handle, while also controlling the main valve or motor. Because the main working hydraulic circuit pressures in construction machinery are very high, such as 350 bar or even 420 bar, the pilot-operated hydraulic control valve assembly is necessary to reduce the high-pressure oil to a low-pressure control oil between 35 and 42 bar.

[0003] like Figure 1 The diagram shown is a schematic of a pilot oil source valve assembly in the prior art. It includes a pressure-reducing relief valve 1, a direct-acting relief valve 2, solenoid directional valves 3 and 4, an accumulator 5, a check valve 6, and a valve block 7. The pilot oil source valve assembly is implemented using a combination of the pressure-reducing relief valve 1 and a direct-acting relief valve 2. The pressure-reducing relief valve 1 primarily reduces high pressure to low pressure (e.g., from 350 bar to 35 bar), while the direct-acting relief valve 2 is set with a safety pressure value (e.g., 45 bar) to protect the filter housing, motor control chamber, and main valve control chamber from high-pressure impact damage. It also protects the pilot control system from damage if the pressure-reducing relief valve 1 fails to catch, in which case all flow will overflow through the safety valve. Since the flow rate of the pilot oil source valve assembly is generally between 15-25 L / min, existing systems all use direct-acting pressure-reducing relief valves. However, because direct-acting pressure-reducing relief valves have a fast response, they are prone to whistling and vibration, severely affecting the operability of the equipment. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the existing technology by providing a pilot oil source valve group system with integrated safety functions, which can not only improve response speed but also reduce whistling and vibration.

[0005] The technical solution adopted in this utility model is as follows: A pilot oil source valve group system with integrated safety functions includes a safety pressure reducing relief valve, a check valve, an accumulator, a first solenoid valve, a second solenoid valve, and a valve block. The valve block is provided with a P inlet port, a Pr port, a Bv port, and a T outlet port. The P inlet port is connected to the inlet of the safety pressure reducing relief valve through a pipeline. The outlet of the safety pressure reducing relief valve is connected to the inlet of the check valve through a pipeline. The outlet of the check valve is connected to the accumulator, the first inlet of the first solenoid valve, and the first inlet of the second solenoid valve through pipelines. The Pr port is connected to the second inlet of the first solenoid valve through a pipeline. The Bv port is connected to the second inlet of the second solenoid valve through a pipeline. The outlets of the first and second solenoid valves are respectively connected to the T outlet port through pipelines.

[0006] Preferably, the Pr interface is connected to the travel motor via the central rotary body; the Bv interface is connected to the pilot handle.

[0007] Preferably, the safety pressure reducing relief valve includes a spool valve, a main valve sleeve, and a plug. The plug is installed at the upper end of the main valve sleeve, and the spool valve is installed inside the main valve sleeve. A spring seat is sealed at the top of the spool valve, and an inner arc surface is provided at the bottom end of the spring seat. An obtuse angle is provided at the corresponding top end of the spool valve. The inner arc surface of the spring seat and the obtuse angle of the spool valve form line contact. The center of the sphere of the inner arc surface is located on the central axis of the spool valve. A spring is installed on the spring seat, one end of the spring is connected to the spring seat, and the other end of the spring is connected to the inner wall of the plug.

[0008] Preferably, the bottom of the main valve sleeve is provided with a stepped hole, the spool is in the shape of an inverted "T", the inverted "T" shaped spool and the stepped hole cooperate with each other, and a steel wire retaining ring is provided for sealing inside the stepped hole.

[0009] Preferably, the outer wall of the main valve sleeve is fixed with a first double lip ring, a second double lip ring and a first O-ring at intervals from bottom to top.

[0010] Preferably, a second O-ring is installed on the contact surface between the plug and the main valve sleeve.

[0011] Preferably, the valve core has a groove in the middle, and four side holes are evenly spaced on the circumference of the groove.

[0012] Preferably, the lower end of the spring seat is concave.

[0013] Preferably, the wire retaining ring is made of spring steel and has an opening in the circumferential direction.

[0014] The beneficial effects of this utility model are as follows: (1) This utility model adopts a safety pressure reducing overflow valve to integrate the pressure reducing overflow function and the pressure safety function into one, which makes the hydraulic system with pressure reducing circuit of pilot oil source control valve group more simplified, smaller in size, lighter in weight and lower in cost. (2) The present invention forms a "pump effect" through the structure of the slide valve core and the main valve sleeve, which creates a good damping effect, making the pressure output of the pressure reducing relief valve more stable; (3) The spring seat of this utility model can generate a certain deflection, which reduces the howling and shaking caused by poor spring perpendicularity and uneven stiffness; (4) The main valve sleeve in this utility model can limit the position of the slide valve core by installing a steel wire retaining ring, effectively controlling the opening of the slide valve core, making the safety pressure reducing relief valve more stable and reliable, and not affected by hydraulic force. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a pilot oil source valve assembly based on existing technology. Figure 2 This is a schematic diagram of the present invention; Figure 3 This is a cross-sectional view of the safety pressure reducing relief valve in this utility model; Figure 4 This is a schematic diagram of the effective area of ​​the safety pressure reducing overflow valve in this utility model. From left to right, the states are normal, pressure reducing, overflow, and safety pressure reducing overflow. Figure 5 This is a schematic diagram of the sliding valve core and the main valve sleeve in this utility model; Figure 6 This is a schematic diagram illustrating the damping principle of the sliding valve core for oil discharge and suction in this utility model. In the diagram: 1. Safety pressure reducing relief valve; 2. Check valve; 3. Accumulator valve; 4. First solenoid valve; 5. Second solenoid valve; 6. Valve block; 7. Wire retaining ring; 8. First double lip ring; 9. Second double lip ring; 10. Spool valve core; 11. Spring seat; 12. Spring; 13. Main valve sleeve; 14. First O-ring; 15. Second O-ring; 16. Plug. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings: like Figure 2-6As shown, the pilot oil source valve group system with integrated safety functions of this utility model includes a safety pressure reducing overflow valve 1, a one-way valve 2, an accumulator 3, a first solenoid valve 4, a second solenoid valve 5, and a valve block 6. The valve block 6 is provided with a P oil inlet port, a Pr port, a Bv port, and a T oil outlet port. The P oil inlet port is connected to the inlet of the safety pressure reducing overflow valve 1 through a pipe. The outlet of the safety pressure reducing overflow valve 1 is connected to the inlet of the one-way valve 2 through a pipe. The outlet of the one-way valve 2 is connected to the first inlet of the accumulator 3, the first inlet of the first solenoid valve 4, and the first inlet of the second solenoid valve 5 through pipes. The Pr port is connected to the second inlet of the first solenoid valve 4 through a pipe. The Bv port is connected to the second inlet of the second solenoid valve 5 through a pipe. The outlets of the first solenoid valve 4 and the second solenoid valve 5 are respectively connected to the T oil outlet port through pipes.

[0017] In this invention, the Pr interface is connected to the travel motor via the central rotating body; the Bv interface is connected to the pilot handle.

[0018] The safety pressure reducing relief valve 1 of this utility model includes a slide valve core 10, a main valve sleeve 13, and a plug 16. The plug 16 is installed on the upper end of the main valve sleeve 13, and a second O-ring 15 is installed on the contact surface between the plug 16 and the main valve sleeve 13 for sealing. The slide valve core 10 is installed inside the main valve sleeve 13, and a spring seat 11 is sealed on the top of the slide valve core 10. The lower end of the spring seat 11 is concave, and its surrounding area can form a baffle plate effect, improving the opening and closing rate of the safety pressure reducing relief valve 1, and making the pressure control of the safety pressure reducing relief valve 1 more accurate. The bottom end of the spring seat 11 is provided with an inner arc surface, and the corresponding top end of the slide valve core 10 is provided with an obtuse angle. The inner arc surface of the spring seat 11 and the obtuse angle of the slide valve core 10 form a line contact. In order to ensure that the area of ​​the pressure acting on the slide valve core 10 after decompression is A1, the obtuse angle of the slide valve core 10 needs to be kept sharp. At the same time, the inner arc surface of the spring seat 11 needs to be precision machined, with a contour accuracy of 0.003mm and a surface finish of 0.4 or higher, so as to ensure effective sealing between the slide valve core 10 and the spring seat 11.

[0019] In this invention, the area of ​​the pressure acting on the valve core 10 after pressure reduction is A1, and the area of ​​the annular region formed by the obtuse angle is A2. A1:A2 = Safety valve set pressure: Pressure reducing valve set pressure. Because the elastic elements used for both pressure reduction and safety functions are springs 12, the areas acting for pressure reduction and safety functions must have a certain proportional relationship. This area ratio also ensures that the valve core 10 and spring seat 11 remain in contact and have a certain amount of stress relief during pressure reduction and overflow functions, ensuring a sealing state. The magnitude of the stress relief is exactly the pressure reduced by multiplying by (A1-A2).

[0020] When high-pressure oil enters through port ②, it passes through the throttling edge of the spool valve 10 and enters its inner cavity. Since the spool valve 10 and the spring seat 11 are in a sealed state due to the line contact, the area of ​​the oil pressure acting on the valve core is A1. Since port ③ leads to the return port, the pressure in the spring cavity is very low. Therefore, the spool valve 10 moves upward under the action of the force. At this time, the throttling edge also moves with the spool valve 10, gradually reducing the opening of the spool valve 10. Under the action of the throttling edge, the pressure in the inner cavity of the spool valve 10 will decrease accordingly, playing a role in pressure reduction. During the upward movement of the spool valve 10, the spring 12 will also be compressed. When the compression force of the spring 12 is equal to the force acting on the area A1 after pressure reduction, the spool valve 10 will no longer move upward, reaching a stable pressure after pressure reduction. At the same time, if the pressure inside the valve core 10 increases due to the inertial force of the load or other external forces, the hydraulic pressure on the valve core 10 will also increase. This will continue to push the valve core 10 upward, causing the side hole at the upper end of the valve core 10 to be exposed through the stepped hole of the main valve sleeve 13. The pressure oil will overflow from port ③, causing the pressure inside the valve core 10 to decrease. Under the action of the spring 12, the valve core 10 will move downward until it reaches a balanced state.

[0021] In this invention, the center of the ball on the inner arc surface of the spring seat 11 is located on the central axis of the valve core 10. A spring 12 is installed on the spring seat 11, with one end connected to the spring seat 11 and the other end connected to the inner wall of the plug 16. This allows the spring seat 11 to oscillate around the center of the ball within a certain range, thus eliminating the shaking and whistling caused by poor perpendicularity of the spring 12.

[0022] In this utility model, the sliding valve core 10 has a larger diameter inner hole, which allows for a larger flow rate of the safety relief function when connected to port ① of the safety pressure reducing overflow valve 1.

[0023] The main valve sleeve 13 of this invention has a stepped hole at its bottom, and the spool valve core 10 is inverted "T" shape. The inverted "T" shaped spool valve core 10 cooperates with the stepped hole, forming a certain gap at the outer diameter, generally between 0.06-0.1mm. When the spool valve core 10 moves upward, the volume of the closed cavity formed by the spool valve core 10 and the main valve sleeve 13 decreases, requiring oil to be discharged outward through a very small annular gap. When the spool valve core 10 moves downward, the volume of the cavity increases, requiring oil to be drawn inward through the annular gap. This generates a "pumping effect." Because the annular gap is small, the pumping and drawing processes generate a certain resistance, thus creating good damping and eliminating the whistling and shaking phenomena of the safety pressure relief valve 1 itself.

[0024] In this invention, a wire retaining ring 7 is provided inside the stepped hole to restrict the range of motion of the valve core 10 and ensure that the valve core 10 will not fall off. The wire retaining ring 7 is made of spring steel and has an opening in the circumferential direction for easy installation.

[0025] In this utility model, the outer wall of the main valve sleeve 13 is fixed with a first double lip ring 8, a second double lip ring 9 and a first O-ring 14 at intervals from bottom to top, to ensure that the safety pressure relief valve 1 is more sealed.

[0026] The slide valve core 10 of this utility model has a groove in the middle, and four side holes are evenly spaced on the circumference of the groove. The side holes form a valve port for pressure reduction function. There are four side holes around the groove for overflow function. The side holes without the groove can achieve good guidance of the valve core and can reduce the flow gain during overflow, making the pressure and flow more stable during overflow.

[0027] The usage process of this utility model is as follows: In operation, 350 bar pressure oil enters through the P inlet port and is reduced to 35 bar by the safety pressure reducing relief valve 1. Because the valve core of the safety pressure reducing relief valve 1 has a damping structure, the pressure stabilizes after reduction, with fluctuations not exceeding ±1.5 bar. The stable pressure oil then fills the accumulator 3 via the one-way valve 2. The accumulator 3 can absorb pressure peaks and fluctuations caused by the rapid switching between the first solenoid valve 4 and the second solenoid valve 5. The first solenoid valve 4 controls the high and low speed switching of the travel motor, and the second solenoid valve 5 controls the oil supply to the pilot handle. When the pilot handle performs compound actions, the required flow rate is greater, and the accumulator 3 will quickly replenish the oil, preventing insufficient operation. When the main unit is stopped, the accumulator 3 still needs to supply oil to the pilot handle for a certain period of time, and the handle operation count must exceed 30 times. When the safety pressure reducing relief valve 1 jams during operation, it can also overflow through the valve core, effectively protecting the control system.

[0028] Other undescribed parts of this utility model are the same as those in the prior art.

Claims

1. A pilot oil source valve group system with integrated safety functions, characterized in that: It includes a safety pressure relief valve (1), a one-way valve (2), an accumulator (3), a first solenoid valve (4), a second solenoid valve (5), and a valve block (6). The valve block (6) is provided with a P inlet port, a Pr port, a Bv port, and a T outlet port. The P inlet port is connected to the inlet of the safety pressure relief valve (1) through a pipe. The outlet of the safety pressure relief valve (1) is connected to the inlet of the one-way valve (2) through a pipe. The outlet of the one-way valve (2) is connected to the first inlet of the accumulator (3), the first inlet of the first solenoid valve (4), and the first inlet of the second solenoid valve (5) through pipes. The Pr port is connected to the second inlet of the first solenoid valve (4) through a pipe. The Bv port is connected to the second inlet of the second solenoid valve (5) through a pipe. The outlet of the first solenoid valve (4) and the outlet of the second solenoid valve (5) are connected to the T outlet port through pipes.

2. The pilot oil source valve group system with integrated safety function according to claim 1, characterized in that: The Pr interface is connected to the travel motor via the central rotary body; the Bv interface is connected to the pilot handle.

3. The pilot oil source valve group system with integrated safety function according to claim 2, characterized in that: The safety pressure reducing overflow valve (1) includes a spool valve (10), a main valve sleeve (13), and a plug (16). The plug (16) is installed on the upper end of the main valve sleeve (13). The spool valve (10) is installed inside the main valve sleeve (13). A spring seat (11) is sealed on the top of the spool valve (10). The bottom end of the spring seat (11) is provided with an inner arc surface. The top end of the spool valve (10) is provided with an obtuse angle. The inner arc surface of the spring seat (11) and the obtuse angle of the spool valve (10) form a line contact. The center of the sphere of the inner arc surface is located on the central axis of the spool valve (10). A spring (12) is installed on the spring seat (11). One end of the spring (12) is connected to the spring seat (11), and the other end of the spring (12) is connected to the inner wall of the plug (16).

4. The pilot oil source valve group system with integrated safety function according to claim 3, characterized in that: The bottom of the main valve sleeve (13) is provided with a stepped hole, and the slide valve core (10) is in the shape of an inverted "T". The slide valve core (10) in the shape of an inverted "T" cooperates with the stepped hole, and a steel wire retaining ring (7) is sealed inside the stepped hole.

5. The pilot oil source valve group system with integrated safety function according to claim 4, characterized in that: The outer wall of the main valve sleeve (13) is fixed with a first double lip ring (8), a second double lip ring (9) and a first O-ring (14) at intervals from bottom to top.

6. The pilot oil source valve group system with integrated safety function according to claim 5, characterized in that: A second O-ring (15) is installed on the contact surface between the plug (16) and the main valve sleeve (13).

7. The pilot oil source valve group system with integrated safety function according to claim 6, characterized in that: The valve core (10) has a groove in the middle, and four side holes are evenly spaced on the circumference of the groove.

8. The pilot oil source valve group system with integrated safety function according to claim 7, characterized in that: The lower end of the spring seat (11) is concave.

9. The pilot oil source valve group system with integrated safety function according to claim 8, characterized in that: The wire retaining ring (7) is made of spring steel and has an opening in the circumferential direction.

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