High pressure hard sealed pressure selector reversing valve

Abstract

The application discloses a high-pressure hard-sealed pressure selection reversing valve, which comprises a valve body, a valve cavity is arranged in the valve body, one end of the valve cavity is processed into an opening, the other end is processed with a second channel, a second inlet, an outlet and a first inlet are processed on one side of the valve body; the second inlet is communicated with the second channel, a flow guide ring is arranged in the valve cavity, flow guide holes are processed on the side surface of the flow guide ring and communicated with the outlet, and a ceramic ball is movably arranged in the flow guide ring; the reversing valve is a two-position three-way reversing valve, which comprises a first valve position and a second valve position, and valve position switching is realized through the hydraulic pressure difference value of the first inlet and the second inlet. The hard sealing mode of the spherical surface pressure and the reverse angle can only guarantee the machining quality of the valve port and can have good sealing effect; meanwhile, the hard sealing structure can guarantee that the pressure selection reversing valve has "zero leakage" under the high pressure difference of the oil inlet pipe, can avoid cavitation erosion caused by hydraulic oil, greatly prolongs the service life of the valve, and guarantees the reliability of the valve.

Description

Technical Field

[0001] This invention relates to a high-pressure hard-seal pressure selective directional valve. Background Technology

[0002] Existing pressure selective directional valves are extremely difficult to manufacture and are susceptible to cavitation corrosion in high-hydraulic environments, damaging the sealing surface and reducing the valve's service life. They also struggle to meet the requirements of long-life, high-pressure differential, and zero-leakage conditions. For example, Chinese patent application CN111852976B discloses a hydraulic directional valve with a two-stage structure. The valve core and sliding sleeve are machined independently and connected by a dovetail key. It uses a metal conical seal, and the sealing ring does not pass through the oil port, ensuring a good seal under high-pressure hydraulic conditions. This high-pressure hydraulic directional valve mainly relies on a hard seal method of conical surfaces pressing against each other, which has the following shortcomings: 1. The sealing method has extremely high machining requirements; the angles, coaxiality, and concentricity of the two conical surfaces must be closely matched, leading to increased machining difficulty and cost; 2. The sealing structure uses chamfers instead of rounded corners, resulting in sharp parts that are easily cavitated in high-hydraulic environments, damaging the sealing surface and shortening the service life, making it difficult to meet the requirements of long-life, high-pressure differential, and zero-leakage conditions. Summary of the Invention

[0003] The purpose of this invention is to address the problems of short service life and easy leakage in existing pressure selective directional valves by providing a high-pressure hard-seal pressure selective directional valve, which reduces the difficulty of processing and assembly, achieves zero leakage under high pressure differential, and extends service life.

[0004] The technical solution of this invention: A high-pressure hard-seal pressure selective directional valve includes a valve body with a valve cavity inside. One end of the valve cavity is machined into an opening, and the other end is machined into a second channel. A second inlet, an outlet, and a first inlet are machined on one side of the valve body. A plug is installed in the opening through a sealing element. The plug has a first channel machined inside, which communicates with the valve cavity. A through hole is machined on the side of the plug to connect the first channel with the first inlet. The second inlet communicates with the second channel. A guide ring is installed in the valve cavity. A guide hole is machined on the side of the guide ring to communicate with the outlet. A ceramic ball is movably installed in the guide ring. This directional valve is a two-position three-way directional valve, including a first valve position and a second valve position. The valve position is switched by the hydraulic pressure difference between the first inlet and the second inlet.

[0005] The first and second channels form a stepped structure with the valve cavity, and the first valve port and the second valve port are respectively installed at the step through the sealing element. The first valve port, the second valve port and the ceramic ball constitute a high-pressure hard seal structure, which, together with the sealing element, achieves double sealing.

[0006] The first and second valve ports have a flat surface at one end, which contacts both ends of the guide ring, and a tapered central hole at the other end, with the minimum diameter of the hole being smaller than the diameter of the ceramic ball. The contact surfaces of the first and second valve ports with the ceramic ball are rounded to form a hard seal fit where the spherical surface presses against the rounded corners.

[0007] The rounded corners of the first and second valve ports ensure good coaxiality and roughness, guaranteeing a hard seal with the ceramic ball.

[0008] The outer side of the guide ring is machined with an annular groove in the middle, and there are 8 guide holes evenly machined in the middle of the annular groove. The guide holes are aligned with the outlet by the length chain of the first valve port, the guide ring, the second valve port, and the plug.

[0009] The sealing components include gaskets and rubber rings. When installing the gaskets and rubber rings into the valve body, lubricating grease must be applied and special assembly tools must be used.

[0010] The plug is fixed to the valve body by a baffle, and the baffle is fixed to the valve body by fixing bolts. The one-sided through hole of the plug is aligned with the first inlet by a dimensional chain fit.

[0011] The roughness of the first channel, the second channel, the first inlet, the second inlet, the outlet, the guide ring, and the valve cavity is no greater than Ra1.6μm; the reversing valve can withstand a high pressure difference of 40-120MPa, the internal leakage rate is ≤2cc / min, and the valve position switching time is less than 500ms.

[0012] The beneficial effects of this invention are as follows: The use of a spherical, rounded-corner hard seal method only requires ensuring the machining quality of a single component, namely the valve port, greatly reducing machining costs and assembly difficulty. Simultaneously, this hard seal structure ensures "zero leakage" of the pressure-selective directional valve under high pressure differential conditions of 40-120 MPa between the inside and outside of the inlet pipe, i.e., an internal leakage rate ≤2 cc / min. Furthermore, the hard seal structure prevents cavitation erosion caused by hydraulic oil during instantaneous switching within less than 500 ms, significantly extending the valve's service life and ensuring its reliability. Attached Figure Description

[0013] Figure 1 This is a cross-sectional view of the pressure selective directional valve of the present invention; Figure 2 A fluid distribution diagram for the first valve position of the pressure-selective directional valve of the present invention; Figure 3 This is a high-pressure hard-seal structure diagram of the pressure-selective directional valve of the present invention.

[0014] Reference numerals: 1-baffle, 2-fixing bolt, 3-gasket, 4-rubber ring, 5-plug, 6-first valve port, 7-guide ring, 8-second valve port, 9-ceramic ball, 10-valve body, 11-second inlet, 12-outlet, 13-first inlet, 14-guide hole, 15-second channel, 16-valve cavity, 17-first channel. Detailed Implementation

[0015] This invention discloses a high-pressure hard-seal pressure selective directional valve, comprising a baffle 1, a fixing bolt 2, a gasket 3, a rubber ring 4, a plug 5, a first valve port 6, a flow guide ring 7, a second valve port 8, a ceramic ball 9, and a valve body 10. The connection relationships of each component are as follows: A valve cavity 16 is opened inside the valve body 10. One end of the valve cavity 16 is open, and the other end is machined with a second channel 15. A second inlet 11, an outlet 12, and a first inlet 13 are machined in sequence on one side of the valve body 10. The second inlet 11 is connected to the second channel 15.

[0016] The valve cavity 16 is sealed at the open end by a gasket 3 and a rubber ring 4, and a plug 5 is installed. A first channel 17 is machined inside the plug 5, which is connected to the valve cavity 16. The through hole on the side of the plug 5 allows the first channel 17 to connect with the first inlet 13.

[0017] The plug 5 is fixed by the baffle 1, and the baffle 1 is fastened to the valve body 10 by means of the fixing bolt 2.

[0018] A flow guide ring 7 is installed inside the valve cavity 16. Eight flow guide holes 14 are evenly distributed on the annular groove in the middle of the outer side of the flow guide ring 7. The flow guide holes 14 are precisely aligned with the outlet 12.

[0019] A first valve port 6 is installed at the step between the first channel 17 and the valve chamber 16, and a second valve port 8 is installed at the step between the second channel 15 and the valve chamber 16. The flat ends of the first valve port 6 and the second valve port 8 are respectively attached to the two ends of the guide ring 7.

[0020] A ceramic ball 9 is movably arranged inside the flow guide ring 7. The minimum diameter of the conical center hole of the first valve port 6 and the second valve port 8 is smaller than the diameter of the ceramic ball 9, and the contact surface is rounded to form a spherical-rounded hard seal fit.

[0021] The sealing system consists of a hard seal formed by the first valve port 6, the second valve port 8 and the ceramic ball 9, and a traditional rubber seal formed by the gasket 3 and the rubber ring 4, providing double protection for the sealing effect.

[0022] The directional valve automatically switches positions based on the hydraulic pressure difference between the first inlet 13 and the second inlet 11. The specific process is as follows: The first valve position operation is as follows: When the hydraulic pressure at the first inlet 13 is greater than the hydraulic pressure at the second inlet 11, hydraulic oil enters the first channel 17 through the single-sided through-hole of the plug 5, generating a thrust on the ceramic ball 9 towards the second valve port 8, causing the ceramic ball 9 to press against the rounded corner of the second valve port 8, forming a high-pressure hard seal. At this time, the hydraulic oil at the first inlet 13 flows sequentially through the internal channels of the first channel 17, the first valve port 6, and the guide ring 7, and then converges at the outlet 12 through eight evenly distributed guide holes 14, realizing the output of hydraulic oil.

[0023] The second valve position operation process is as follows: When the hydraulic pressure at the second inlet 11 is greater than the hydraulic pressure at the first inlet 13, the hydraulic oil acts on the ceramic ball 9 through the second channel 15, pushing the ceramic ball 9 towards the first valve port 6 and pressing it against its rounded corner, forming a high-pressure hard seal. At this time, the hydraulic oil at the second inlet 11 flows sequentially through the internal channels of the second channel 15, the second valve port 8, and the guide ring 7, and is output from the outlet 12 through the guide hole 14, completing the valve position switching and hydraulic oil reversal delivery.

[0024] Example: Parts machining and assembly preparation: When machining the first valve port 6 and the second valve port 8, ensure that the coaxiality error of the rounded corner is ≤0.02mm and the roughness is controlled within Ra1.6μm. The ceramic ball 9 is made of zirconia ceramic material with a hardness of HRC≥90 and a surface roughness Ra≤0.8μm.

[0025] The eight guide holes 14 of the guide ring 7 are 8mm in diameter and are evenly distributed on the annular groove. The included angle between the centers of adjacent holes is 45°. Special tooling is used to ensure that the length dimensional chain error of the first valve port 6, the guide ring 7, the second valve port 8, and the plug 5 is ≤0.03mm. The seals are made of fluororubber resistant to high-pressure hydraulic oil, and the gasket 3 is made of copper. Before assembly, hydraulic system special lubricating grease is applied to the surface of the rubber ring 4.

[0026] Rubber ring 4 and gasket 3 are installed into the sealing groove of valve body 10 using a special assembly tool to avoid being cut by sharp edges when passing through the second inlet 11 and outlet 12. The second valve port 8, guide ring 7, and first valve port 6 are then installed into valve cavity 16 in sequence, ensuring that the guide hole 14 of guide ring 7 is aligned with outlet 12, and that the flat ends of the first valve port 6 and second valve port 8 are tightly fitted with both ends of guide ring 7. After inserting ceramic ball 9, plug 5 is installed into the open end of valve body 10, aligning the single-sided through hole of plug 5 with the first inlet 13. The baffle 1 is then placed on top and secured with fixing bolts 2, with the bolt tightening torque controlled at 25-30 N·m.

[0027] High pressure differential test: A pressure difference of 120MPa is applied between the first inlet 13 and the second inlet 11 and held for 30 minutes. The internal leakage of outlet 12 is detected by the flow sensor. The measured value is ≤1.5cc / min, which meets the zero leakage requirement.

[0028] Switching response test: The pressure of the first inlet 13 and the second inlet 11 was quickly switched by the hydraulic system. The movement time of the ceramic ball 9 was recorded by a high-speed camera. The actual switching time was 380ms, which is less than the design requirement of 500ms.

[0029] Service life test: 100,000 reciprocating switching tests were conducted under a high pressure difference of 80MPa. After the test, the sealing surfaces of the first valve port 6 and the second valve port 8 were checked and found to be free of cavitation erosion marks. The leakage rate was still maintained at ≤2cc / min, which meets the requirements for long service life.

Claims

1. A template, characterized in that: The valve includes a valve body (10), a valve cavity (16) is provided inside the valve body (10), one end of the valve cavity (16) is machined into an opening, and the other end is machined into a second channel (15). A second inlet (11), an outlet (12) and a first inlet (13) are machined on one side of the valve body (10). A plug (5) is installed in the opening through a sealing element. A first channel (17) communicating with the valve cavity (14) is machined in the plug (5). A through hole is machined on the side of the plug (5) to connect the first channel (17) with the first inlet (13). The second inlet (11) is connected with the second channel (15). A guide ring (7) is installed in the valve cavity (16). A guide hole (14) is machined on the side of the guide ring (7) to communicate with the outlet (12). A ceramic ball (9) is movably installed in the guide ring (7).

2. The high-pressure hard-seal pressure selective directional valve according to claim 1, characterized in that: The first channel (17) and the second channel (15) form a stepped structure with the valve cavity (10), and the first valve port (6) and the second valve port (8) are respectively installed at the step through the sealing element.

3. The high-pressure hard-seal pressure selective directional valve according to claim 2, characterized in that: The first valve port (6) and the second valve port (8) have a flat end that is in contact with both ends of the guide ring (7), and the other end is machined with a tapered central hole. The minimum diameter of the hole is smaller than the diameter of the ceramic ball (9).

4. The high-pressure hard-seal pressure selective directional valve according to claim 3, characterized in that: The contact surfaces of the first valve port (6) and the second valve port (8) with the ceramic ball (9) are rounded.

5. The high-pressure hard-seal pressure selective directional valve according to claim 1, characterized in that: The outer side of the guide ring (7) is machined with an annular groove, and the guide holes (14) are multiple and uniformly machined in the middle of the annular groove.

6. The high-pressure hard-seal pressure selective directional valve according to claim 1, characterized in that: The sealing element includes a gasket (3) and a rubber ring (4).

7. The high-pressure hard-seal pressure selective directional valve according to claim 1, characterized in that: The plug (5) is fixed inside the valve body (10) by a baffle (1), and the baffle (1) is fixed on the valve body (10) by a fixing bolt (2).

8. The high-pressure hard-seal pressure selective directional valve according to claim 1, characterized in that: The roughness of the first channel (17), the second channel (15), the first inlet (13), the second inlet (11), the outlet (12), the guide ring (7), and the valve chamber (16) is not greater than Ra1.6μm.

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