Pilot-operated type corrugated pipe sealing type sleeve adjusting valve

Abstract

The invention discloses a pilot-operated type corrugated pipe sealing type sleeve adjusting valve which comprises a valve body, a valve seat and a valve cover and further comprises a valve cage, a valve rod, a valve rod, a valve rod, a valve rod, a valve rod and a valve rod, and the valve cage is provided with a quick-opening window with the radial size larger than the axial size; an annular piston groove is formed in the upper end of the main valve element, an opening piston ring is embedded in the groove, and the outer wall of the piston ring is in clearance fit with the inner wall of the valve cage; the pilot valve core valve rod is of an integrally formed structure; the valve rod is sleeved with the corrugated pipe component, the corrugated pipe component is locked and fixed through a nut, and the contact face of the valve rod and the contact face of the corrugated pipe component are of conical face sealing structures matched with each other. According to the quick-opening valve cage window, the radial flow area is increased, the axial size is shortened, the medium throughput is improved under the same stroke, the rigidity of the valve cage is enhanced in cooperation with a supporting rib structure, and the contradiction between insufficient flow capacity and vibration of a traditional valve is solved.

Description

Technical Field

[0001] The invention relates to the technical field of regulating valves, in particular to a pilot bellows-sealed sleeve regulating valve. Background Art

[0002] As a commonly used fluid control element, solenoid valves are widely used in various fluid control systems. The structure of traditional solenoid valves mainly includes valve body, solenoid coil, spring and sealing element. They play an important role in industrial automation, household appliances and automobile industry, and are mainly used to control the opening, closing or flow regulation of fluids. Most of the existing automotive solenoid valves are two-way valves, which have the function of opening and closing normally in both forward and reverse directions and are easy to use. The market demand for solenoid valves for automotive multi-chamber air springs is increasing, but the price of this product is relatively high at present. The main reason is that during use, it is difficult to achieve balance between the internal and external air pressures of the solenoid valve. During use, due to the large air pressure difference, the solenoid valve has the risk of being pushed open. Therefore, a large coil is required to form a high electromagnetic force to keep the valve body stable, which undoubtedly increases the manufacturing cost.

[0003] Therefore, some solutions have been proposed in the industry to address the above problems. For example, the "bidirectional solenoid valve" disclosed in Chinese patent documents, with the announcement number "CN212203326U", includes a valve body, a booster rod, a moving iron core, a non-magnetic tube and a coil. An air nozzle is provided in the valve body, and a first inlet and a second inlet and a second inlet connected to the air nozzle are respectively provided on both sides of the valve body. The lower end of the non-magnetic tube is connected to the valve body, the moving iron core is movably installed in the non-magnetic tube, and a spring is provided between the moving iron core and the non-magnetic tube. The booster rod is movably installed at the air nozzle in the valve body, and the upper end of the booster rod is fixedly connected to the lower end of the moving iron core, and the coil is installed outside the non-magnetic tube.

[0004] In the above solution, although the solenoid valve can be used in both directions, it still cannot solve the difficulty of using high electromagnetic force to control the opening and closing of the valve body. This undoubtedly increases the sealing pressure and the overall manufacturing cost, and therefore needs to be optimized. Summary of the invention

[0005] In view of the problems mentioned above, such as the poor sealing performance of the valve body in the prior art, which leads to high manufacturing costs, a pilot-operated bellows-sealed sleeve regulating valve is provided, which effectively solves the problem of insufficient sealing performance of the traditional solenoid valve through a multi-level sealing structure. At the same time, by optimizing the valve body size to match the valve port size, the additional pressure on the moving iron core during operation is eliminated, thereby reducing the valve body manufacturing cost while ensuring performance.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A pilot-operated bellows-sealed sleeve control valve, comprising a valve body, a valve seat and a valve cover, including: a valve cage, the valve cage is provided with a quick-opening type window with a radial dimension larger than the axial dimension; a main valve core, an annular piston groove is arranged at the upper end of the main valve core, an open piston ring is embedded in the groove, and the outer wall of the piston ring is in clearance fit with the inner wall of the valve cage; a pilot valve core valve stem, the pilot valve core valve stem is an integrally formed structure; a bellows component, the bellows component is sleeved outside the valve stem and is locked and fixed by a nut, and the contact surface between the valve stem and the bellows component is a conical sealing structure that matches each other.

[0007] In this solution, the quick-opening type valve cage window expands the flow area within a limited stroke by increasing the radial dimension and shortening the axial dimension, solving the problem of low flow capacity caused by insufficient stroke in traditional valves. The open piston ring in the annular piston groove at the upper end of the main valve core adopts a floating fit design, allowing a radial displacement difference between the valve core and the valve cage during high-temperature expansion without jamming, and at the same time maintaining the guiding accuracy by using the clearance fit between the outer wall of the ring and the valve cage. The integrally formed pilot valve core valve stem eliminates the assembly interface, improves the structural rigidity and movement coaxiality. The bellows conical sealing structure realizes metal sealing through the line contact of the matching cones. After canceling the welded connection, the bellows assembly can be disassembled and assembled as a whole, greatly shortening the maintenance time.

[0008] Preferably, the edges of the quick-opening type windows are chamfered, and the windows are evenly distributed at equal intervals along the circumferential direction of the valve cage; support ribs are formed between adjacent windows. Chamfering the windows can effectively reduce the sudden change in local flow velocity when the medium passes through, and reduce the vibration energy caused by turbulence. The circumferentially equally spaced windows and the support ribs form a symmetric flow channel structure, which not only ensures the overall stiffness of the valve cage to prevent compression deformation, but also makes the medium acting force evenly distributed in the circumferential direction, eliminating the lateral thrust caused by traditional asymmetric windows. The width of the support ribs is optimized by fluid-structure interaction, maximizing the effective flow area on the premise of maintaining the structural strength and avoiding the throttling effect caused by too wide stiffeners.

[0009] Preferably, the lower end of the main valve core is provided with a flow regulating part with a continuous curved surface, and the curvature of the curved surface decreases from the center to the edge. The main valve core flow regulating curved surface adopts a design with continuous curvature change, and realizes the predetermined flow characteristics through the precise correspondence between the curved surface shape and the opening degree. The structure with the curvature decreasing from the center to the edge makes the medium generate a large throttling effect at the initial stage of the valve core stroke, and gradually changes to mainly control the flow area as the opening degree increases. This composite regulation method can better match the system regulation requirements compared with the straight valve core. The stepped flow channel formed by the end curved surface and the valve seat forms a secondary throttle at the closed position, improving the control accuracy under small flow conditions.

[0010] Preferably, a stepped flow passage is formed between the end surface of the flow regulating portion and the inner wall of the valve seat; a spiral flow guiding structure is arranged in the flow passage. The spiral flow guiding structure induces the medium to rotate in the stepped flow passage, and utilizes the action of the centrifugal force field to convert the fluid kinetic energy into rotational kinetic energy, reducing the vibration and noise caused by the direct impact. The angle design of the spiral blades takes into account both the flow guiding effect and the pressure loss control, enhancing the flow stability while avoiding excessive increase in flow resistance. The Venturi effect generated by the change of the cross-section of the stepped flow passage accelerates the medium passing through the throat region, improving the flow efficiency while suppressing the occurrence of cavitation phenomenon.

[0011] Preferably, the conical surface sealing structure includes a first conical surface on the valve stem and a second conical surface in the bellows component; the two conical surfaces form a line contact seal. The conical surface sealing structure realizes self-centering sealing through the matching conical angles. When assembled, the axial force generated by the nut tightening is converted into the radial sealing specific pressure. The line contact form is more likely to reach the pressure threshold required for sealing than the surface contact. The double conical surface cooperation has the ability of error compensation, can absorb the minor assembly deviation between the valve stem and the bellows component, and avoids the harsh requirements for machining accuracy of the traditional plane seal. The characteristic that the sealing surface does not need to be welded enables the components to be disassembled completely during maintenance, solving the drawback of the destructive disassembly of the original structure.

[0012] Preferably, the external thread section of the pilot valve core valve stem is matched with the internal thread of the valve cover; a push rod is connected to the end of the pilot valve core valve stem, and an actuator is arranged at the end of the push rod. The external thread connection structure realizes the axial positioning and load transfer of the valve stem through the thread pair. Compared with the integral valve stem, it has the advantage of being adjustable and can compensate for the assembly error caused by manufacturing tolerances. The actuator at the end of the push rod adopts a modular connection design, which is convenient for adapting to different types of actuators. The split half joint allows for quick disassembly while ensuring the connection rigidity. The side scale line provides a visual stroke reference benchmark to ensure the position consistency during the assembly of multiple components.

[0013] Preferably, the push rod is connected to the pilot valve core valve stem through a split half joint; a scale line arranged axially is provided on the side of the split half joint. The split surface structure of the half joint breaks through the installation limitation of the traditional integral connector, and the push rod connection operation can be completed without moving the actuator. The axial scale line forms an accurate displacement reference system, enabling the assembler to visually confirm the relative position of the components and eliminating the cumulative error generated by the traditional estimation based on experience. The stress release characteristic of the split structure can avoid the additional stress generated by the thermal expansion difference of the integral connector.

[0014] Preferably, a stepped mating structure is formed between the bottom of the valve cage and the valve seat; an annular flow guide groove is provided on the upper end surface of the valve seat, and the annular flow guide groove communicates with the bottom of the valve cage window. The stepped mating forms a mechanical stop between the valve cage and the valve seat, ensuring automatic centering during assembly and increasing the contact pressure of the sealing surface. The annular flow guide groove guides the medium from the radial direction to the bottom inlet of the valve cage window, eliminating the kinetic energy loss caused by right-angle turns. The continuous annular structure of the flow guide groove makes the medium distribution more uniform, avoiding erosion wear caused by excessive local flow velocity. The depth of the groove body is optimized through the flow field, maintaining sufficient structural strength while guiding the medium.

[0015] Preferably, the open end of the open piston ring is provided with a staggered lapping structure; a corrugated spring that presses tightly against the bottom of the piston groove is provided on the inner ring of the open piston ring. The open piston ring adopts a staggered lapping structure, enabling the ring body to maintain a continuous sealing interface during thermal expansion, significantly reducing the internal leakage compared with traditional straight-end piston rings. The built-in corrugated spring provides continuous radial pre-tightening force, compensating for manufacturing tolerances and adapting to dimensional fluctuations caused by changes in working conditions and temperatures, ensuring that the piston ring always maintains an appropriate contact pressure with the valve cage under different working conditions. This combined design takes into account both the sealing reliability and the movement flexibility, solving the problem of easy jamming in traditional rigid connections.

[0016] Preferably, the actuator includes a tray coaxially arranged at the end of the push rod, an actuator spring mechanism is installed on the tray; a diaphragm is arranged outside the tray; disc gaskets are arranged at the connections between the inside and outside of the tray and the push rod. The actuator adopts a coaxial arrangement of the tray-spring system, isolating the medium from the actuator through the diaphragm. The elastic deformation ability of the disc gasket effectively absorbs mechanical vibration energy, preventing high-frequency vibrations from being transmitted to the valve core assembly. The stiffness curve of the actuator spring is specially designed to provide a smaller stiffness at the initial stage of opening and closing to ensure sensitivity, and the stiffness increases when approaching the fully closed position to ensure the pressing force required for sealing. This variable stiffness characteristic enables the valve to have both precise regulation performance and reliable cut-off.

[0017] Therefore, the present invention has the following beneficial effects: The fast-opening valve cage window increases the radial flow area and shortens the axial dimension, improving the medium throughput under the same stroke. The support rib structure is used to enhance the stiffness of the valve cage, solving the contradiction between insufficient flow capacity and vibration in traditional valves.

[0018] The main valve core piston ring and the corrugated spring form a dynamic compensation system, allowing the valve core assembly to generate a radial displacement difference during high-temperature expansion, eliminating the hidden danger of jamming between the valve core and the valve cage, and ensuring reliable operation under high-temperature conditions.

[0019] The bellows conical surface sealing structure replaces the welded connection, achieving non-destructive disassembly and assembly through self-aligning line contact sealing, shortening the maintenance cycle from several hours to the minute level, and significantly reducing the shutdown loss.

[0020] The flow - regulating curved surface and the spiral guiding structure act synergistically. By optimizing the flow - passage shape, the flow - rate characteristic curve approaches the theoretical value, and at the same time, the fluid kinetic energy is converted into an ordered swirl flow, achieving a double improvement in regulation accuracy and operation stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of the present invention.

[0022] Figure 2 It is Figure 1 a schematic structural diagram of the valve cage in

[0023] Figure 3 It is Figure 1 a schematic structural diagram of the main valve core in

[0024] Figure 4 It is Figure 1 a schematic structural diagram of the valve stem of the pilot valve core in

[0025] Figure 5 It is Figure 1 a schematic structural diagram of the bellows in

[0026] Figure 6 It is Figure 5 a partial enlarged view of part A in

[0027] Figure 7 It is Figure 1 a schematic structural diagram of the piston ring in

[0028] In the figure: 1 valve body, 2 valve seat, 21 annular pressure - reducing groove, 3 spring, 4 main valve core, 41 piston groove, 5 valve stem of the pilot valve core, 51 shoulder, 6 piston ring, 61 opening, 7 guide sleeve, 8 valve cage, 81 support rib, 9 valve cover, 10 bellows, 101 inner chamfer, 11 nut, 12 half - joint, 13 push rod, 14 diaphragm, 15 tray, 16 actuator spring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described below in conjunction with the drawings and the detailed embodiments. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout.

[0030] Embodiment 1 As Figure 1, as shown in Figure 2, the pilot-operated bellows-sealed sleeve control valve in this solution achieves stable operation and convenient maintenance under high-temperature conditions through multi-dimensional structural innovation. The valve cage adopts a quick-opening window design. The geometric feature that its radial dimension is significantly larger than the axial dimension saves the spool stroke space by shortening the axial extension length of the window while ensuring the flow cross-sectional area. The support ribs formed by the equally spaced distribution of the windows in the circumferential direction enhance the overall stiffness of the valve cage while reducing the medium impact load. As Figure 7 shown, an open piston ring 6 is installed in the annular piston groove at the upper end of the main spool. The outer wall of the piston ring forms a dynamic clearance fit with the inner wall of the valve cage. The staggered lap structure of its open end and the cooperation of the inner ring wave spring not only compensate for the dimensional changes caused by metal expansion at high temperatures but also establish a dynamic seal through the contact pressure between the outer wall of the piston ring and the inner wall of the valve cage, effectively controlling the clearance flow rate within the range of 0.5% - 1.2% of the rated flow rate.

[0031] As Figure 3 , as shown in Figure 4, in this embodiment, the flow regulation part with a continuous curved surface at the lower end of the main spool 4 adopts a design with a decreasing curvature. The stepped flow channel formed between its end and the inner wall of the valve seat is embedded with a spiral flow guiding structure, which reduces the turbulence intensity by guiding the medium to flow along a spiral trajectory. The measured pressure drop coefficient is reduced by 18% - 22% compared with the traditional structure. The valve stem of the pilot spool adopts an integral forming process to eliminate the assembly error of the traditional split structure. The precise fit between its external thread section and the internal thread in the valve cover makes the axial positioning accuracy reach ±0.05 mm. The axial scale line on the side of the split half-coupling at the end of the push rod can achieve micron-level calibration of the actuator stroke.

[0032] The conical seal structure between the bellows 10 and the valve stem 5 forms a metal hard seal through the line contact of the two conical surfaces. The contact pressure is verified by finite element analysis to reach 35 - 45 MPa. After canceling the welding structure, the axial pre-tightening force generated by nut locking is converted into a radial sealing force, and only the nut torque needs to be adjusted during the disassembly process to achieve lossless separation. The stepped mating structure between the bottom of the valve cage and the valve seat, combined with the annular flow guiding groove, enables the medium to form a stable laminar flow state in the valve seat area. Experimental data shows that this structure can suppress the valve vibration amplitude below 0.02 mm. The disc-shaped gaskets arranged inside and outside the actuator tray absorb the impact load during the diaphragm actuation through elastic deformation. Combined with the non-linear stiffness characteristics of the actuator spring mechanism, the valve step response time is shortened to 60% of the traditional structure.

[0033] Specifically, the valve cage of the regulating valve is integrally forged from chrome molybdenum steel. The radial dimension of the quick-opening window is designed to be 2.5 - 3 times the axial dimension. The radius of the rounded corner at the edge of the window is controlled within 1 / 8 - 1 / 6 of the window width. Trapezoidal cross-section support ribs with a thickness of 8 mm are formed between 12 equally spaced circumferential windows, and the root of the ribs is treated with a stress relief groove. The main spool body is precision cast from nickel-based alloy. The depth of the upper annular piston groove is 6 mm, and a waveform spring installation groove with a depth of 0.5 mm is provided at the bottom of the groove. The open piston ring is made of filled polytetrafluoroethylene composite material. The cross-section of the ring body is circular, and the open end is designed with a 30° bevel staggered lap structure, with a disc spring sheet with a wave crest spacing of 2 mm embedded. After assembly, the outer diameter of the ring body and the inner wall of the valve cage maintain a dynamic clearance of 0.08 - 0.12 mm.

[0034] In this embodiment, the flow regulation curved surface at the lower end of the main spool is constructed by a fifth-order Bessel curve. The radius of curvature gradually changes from 25 mm at the center to 8 mm at the edge. A stepped clearance of 0.5 mm is formed between the end curved surface and the inner wall of the valve seat. The lead of the spiral flow guiding structure in the flow channel is 32 mm, and the helix angle is 15°. The thickness of the flow guiding vane is 2 mm, and its surface is micro-textured. The valve stem of the pilot spool is integrally machined from 42CrMo4 quenched and tempered steel. The external thread is a fine thread of M24×1.5, and the mating length with the internal thread in the valve cover is 35 mm. The end half-coupling of the push rod adopts a split structure, with a 60° V-shaped positioning groove machined on the contact surface. The axial scale line spacing on the side is 0.5 mm, and the surface is nitrided to a hardness of HRC58 - 62. The bellows component is selected as a multi-layer structure of Inconel alloy. The conical sealing angle is designed to be 57°, and a line contact width of 0.3 mm is formed with the conical surface of the valve stem. The nut adopts a lock tooth structure. When the pre-tightening torque is set to 85 - 95 N·m, a sealing pressure of 38 - 42 MPa can be generated on the contact surface. The depth of the flow guiding groove in the valve seat is 2 mm, the width is 4 mm, and the stepped mating clearance formed with the bottom of the valve cage is 0.2 mm. An array of pressure equalizing holes with a diameter of Φ1.2 mm is opened at the bottom of the flow guiding groove. The actuator tray is formed by stamping duplex stainless steel. The thickness of the disc-shaped gasket is 0.8 mm, and the radius of curvature is 15 mm. Radial micro-grooves are machined on the contact surface with the diaphragm to improve stress distribution. Under high-temperature working conditions, the expansion difference between the main spool and the valve cage is adaptively compensated by the 0.15 - 0.25 mm compression amount of the piston ring waveform spring. The friction coefficient of the open piston ring is experimentally determined to remain in the range of 0.08 - 0.12 at 400 °C.

[0035] When the regulating valve in this embodiment is working, the actuator spring 16 is compressed to push the push rod 13 to move axially. The split half coupling 12 at the end of the push rod drives the pilot valve stem 5 to produce a precise displacement through the V-shaped positioning groove. The external threaded section of the valve stem 5 is matched with the internal thread of the valve cover 9 to produce a guiding effect, enabling the valve stem to move smoothly along the axis. When the medium pressure acts on the lower end of the main valve core 4, the main valve core slides along the inner wall of the valve cage 8 under the constraint of the guide sleeve 7. At this time, a dynamic sealing gap is formed between the outer wall of the opening piston ring 6 and the inner wall of the valve cage, and the wave spring inside its inner ring can adaptively compensate for the dimensional changes caused by high-temperature expansion. During the downward movement of the main valve core 4, the stepped flow channel formed by the continuous curved surface at its lower end and the inner wall of the valve seat 2 is gradually opened, and the spiral flow guiding structure arranged in the flow channel guides the medium to form a swirling flow to reduce the turbulence intensity. The bellows 10 is locked on the middle conical surface of the valve stem 5 through the nut 11, and the line contact seal formed by the two conical surfaces maintains a dynamic sealing state along with the movement of the valve stem. During installation, it is necessary to ensure that the stepped matching structure at the bottom of the valve cage 8 and the valve seat 2 is accurately aligned, and the annular flow guiding groove on the upper end surface of the valve seat 2 is continuously connected with the bottom of the valve cage window. During the debugging stage, the stroke of the push rod 13 is finely adjusted through the scale line on the side of the half coupling 12 to make the displacement of the diaphragm 14 accurately correspond to the position of the tray 15. During production, it is found that the flange connection surface between the valve body 1 and the valve cover 9 needs to ensure flatness to avoid eccentric wear of the guide sleeve 7.

[0036] During actual assembly, the sunken structure in the inner cavity of the main valve core 4 provides sufficient movement space for the spring 3 and the pilot valve core. The pre-tightening force of the spring 3 is set by adjusting the axial position of the nut 11. When the valve is closed, the flow regulating curved surface of the main valve core 4 and the valve seat 2 form a multi-stage throttle, and the radial expansion design of the quick-opening window of the valve cage 8 ensures sufficient flow area within a limited stroke. During maintenance, only the nut 11 needs to be loosened to separate the bellows 10 from the valve stem 5, without destructive cutting operations. The conical surface sealing structure of the valve stem 5 can still maintain reliable sealing after repeated disassembly and assembly.

[0037] As Figure 1 shown, an annular pressure relief groove 21 is provided in the contact area between the inner wall of the valve seat 2 and the main valve core 4, and micro-flow guiding holes are evenly distributed at the bottom of the groove. This structure can decompose the medium impact force into a radial component, reducing the vibration amplitude of the valve core by more than 60%. Axial heat dissipation fins are processed on the outer surface of the guide sleeve 7, and the height of the fins forms a convection channel with the inner cavity of the valve cover 9. It is measured that the working temperature of the guide sleeve can be reduced by 80 - 100 °C.

[0038] As Figure 3As shown in the figure, the edge of the quick-opening window on the valve cage 8 in this embodiment adopts a double-arc transition design, where the radius of the inlet arc is greater than that of the outlet arc. This streamlined structure reduces the pressure loss of the medium passing through the window by approximately 25%. The end of the support rib 81 is provided with a 45° chamfer, and the chamfer surface forms a wedge-shaped gap with the movement trajectory of the main valve core 4, which can generate a hydrodynamic lubrication effect when the valve core moves at high speed. The bottom flange connection surface of the valve cage 8 is machined with an annular labyrinth seal groove, and the groove is filled with an expanded graphite ring. This structure can still maintain effective sealing at a high temperature of 450°C, and the leakage rate is lower than 0.01% of the rated flow rate.

[0039] As Figure 4 shown, at the bottom of the sunken structure of the inner cavity in the cross-section of the main valve core 4, there is a conical guide boss. The angle of the inclined surface of the boss matches the movement trajectory of the pilot valve core valve stem 5, which can evenly transmit the force of the spring 3 to the bottom of the valve core. The bottom of the piston groove 41 is machined with an annular oil storage groove, and a porous bronze bushing is embedded in the groove. It can continuously release solid lubricant under high-temperature working conditions, keeping the friction coefficient of the piston ring 6 stable within the range of 0.1 - 0.15. A stress relief groove is set at the root of the flow rate adjustment curve surface, and the groove depth is 1 / 3 of the maximum thickness of the curve surface. Through finite element analysis, the thermal stress concentration coefficient can be reduced by 55%.

[0040] As Figure 1 shown, the end of the valve stem assembly is connected to the split half coupling 12. The inner hole of the valve stem is machined with a spiral grease channel, and the channel outlet is located at the bottom of the V-shaped positioning groove, which can inject high-temperature grease during assembly to form a continuous lubricating film. The mounting seat of the actuator spring 16 at the end of the push rod 13 is designed as a disc structure, which can compensate for the installation deviation between the actuator and the axis of the valve stem. It can actually tolerate an angular deviation within 0.5°. The contact surface between the diaphragm 14 and the tray 15 is machined with radioactive corrugations, and the corrugation depth increases gradually from the center to the edge. This structure increases the effective action area of the diaphragm by 18% and reduces the stress peak value by 30% at the same time.

[0041] As Figure 1 , as shown in Figure 5, the bellows 10 is locked by the nut 11. The locking surface is machined with serrated anti-loosening lines, with a line inclination angle of 60° and a tooth height of 0.3 mm. The vibration test shows that this structure can control the pre-tightening force attenuation rate within 5%. The surface of the conical seal part of the valve stem 5 is subjected to ultra-precision grinding treatment, with a surface roughness Ra ≤ 0.2 μm, and a continuous contact line is formed after mating with the conical surface of the bellows 10. The end flange of the bellows 10 is provided with a double-layer seal structure. The inner layer is a metal contact seal, and the outer layer is filled with a flexible graphite ring. The double-seal design reduces the overall leakage rate by two orders of magnitude.

[0042] Embodiment 2 In this embodiment, multi-parameter collaborative optimization is carried out on the basis of the structure of Embodiment 1. The radius of the rounded corner of the quick-opening window of the valve cage is adjusted to the range of 1 / 8 - 1 / 6 of the window width. The establishment of this ratio range is based on the boundary layer separation theory in fluid mechanics. When the medium flows through the edge of the window, a specific ratio of the rounded corner radius can effectively delay the generation of the flow separation point. The actual measurement shows that this design reduces the local resistance coefficient of the window by 18% - 22%. The window support ribs adopt a variable cross-section design. The root thickness is increased to 10 mm and gradually tapers to 6 mm at the end along the circumferential direction. The cross-sectional shape is optimized to a parabolic profile. This structure improves the bending stiffness of the ribs by 35% while reducing the eddy generation area during the flow of the medium by 40%. An array of micron-level annular grooves is machined in the matching area between the inner wall of the valve cage and the main valve core. The groove depth is 0.05 - 0.08 mm and the spacing is 0.3 mm, forming a surface texturing treatment. This design can store solid lubricants under high-temperature working conditions, reducing the movement friction torque of the valve core by 25% - 30%.

[0043] The piston ring of the main valve core is made of a graphite-impregnated nickel-based alloy composite material. The cross-section of the ring body is designed as a trapezoidal structure, and the bottom surface inclination angle is 12° - 15°. The establishment of this angle range is based on the finite element analysis of the contact stress distribution. The number of wave peaks of the wave spring is topologically optimized according to the medium temperature gradient. A dense wave peak design is adopted in the high-temperature area (>300 °C), and a sparse wave peak (wave peak spacing of 4 mm) is adopted in the low-temperature area (<200 °C). This differential design makes the spring compensation force linearly related to the temperature change. A wedge-shaped card slot is arranged on the inner ring of the piston ring, and a disc spring piece is installed at the bottom of the slot. This combined structure can generate an axial compensation displacement of 0.15 - 0.25 mm during thermal expansion at 400 °C, effectively avoiding the jamming of the ring body. The spiral guide structure of the flow regulation surface at the lower end of the main valve core adopts a variable pitch design. The lead gradually changes from the inlet end to the outlet end and gradually increases. The pitch change rate is set according to the viscosity characteristics of the medium. A 3% gradient increase is adopted for high-viscosity media (>50 cP), and a 7% gradient increase is adopted for low-viscosity media (<10 cP). This design improves the uniformity of the flow field velocity distribution by more than 40%.

[0044] The sealing angle of the valve stem cone surface is adjusted to 58° ± 2°. This angle range is optimized and determined through a sealing specific pressure calculation model, controlling the contact line width within the range of 0.25 - 0.35 mm. The cone surface is subjected to laser micro-cladding treatment to form a cobalt-based alloy strengthening layer with a thickness of 0.1 mm, and the microhardness reaches HV850, increasing the wear resistance to 3 times that of the base material. The cone surface angle of the bellows is synchronously adjusted to 58° matching the valve stem, and concentric sealing grooves are machined in the contact area. The groove depth is 0.02 mm and the spacing is 0.15 mm. This micro-structure undergoes plastic deformation under the action of the pre-tightening force, forming a mechanical interlocking effect, reducing the leakage rate of the sealing interface to 1 / 20 of that of the traditional plane seal.

[0045] The spiral guide vane at the end of the actuator push rod is equipped with a dynamic torsion mechanism, and a shape memory alloy hinge is installed at the root of the guide vane. When the medium flow rate exceeds 5m / s, the fluid impact force causes the guide vane to produce a 3°-7° dynamic torsion change, and the lead automatically increases by 12%-15%. This response mechanism is based on the principle of fluid-structure coupling dynamics. The relationship between the torsional deformation Δθ of the guide vane and the flow velocity v satisfies Δθ=K·v² (K is the structural stiffness coefficient). In actual measurements, the pressure fluctuation amplitude under high-speed flow can be reduced by 55%-60%. The surface of the guide vane is coated with a tungsten carbide coating with a thickness of 50μm, and the erosion rate is reduced to 1 / 8 of that of ordinary stainless steel.

[0046] In this embodiment, the transition area of ​​the variable cross-section structure of the supporting rib adopts a stress diffusion structure, and a transition arc with a radius of 5mm is set at the root. The surface of the rib is shot peened, and the residual compressive stress reaches -450MPa, and the fatigue life is extended to 2.5 times that of the conventional structure. A 45° guide slope is processed at the end of the rib, and the slope forms an angle of 15°-20° with the axis of the valve cage. This angle design generates a centripetal force when the medium flows through the rib, effectively suppressing the circumferential flow separation phenomenon. A heat dissipation fin array is set on the back of the rib, with a fin height of 3mm and a spacing of 8mm. By increasing the heat dissipation surface area, the working temperature of the rib is reduced by 80-100℃.

[0047] In terms of assembly process, the cone surface of the valve stem and the bellows adopts graded pre-tightening technology: 50N·m torque is applied during initial assembly to make the cone surface initially fit, and the sealing pattern is fully embedded by rotating the angle of 30° during secondary tightening. This assembly method improves the uniformity of contact stress distribution by 40%, and increases the length of the microscopic leakage channel of the sealing interface to more than 3 times that of the traditional assembly method. The V-shaped positioning groove of the split half joint is processed into a double-bevel structure, with bevel angles of 60° and 30° arranged alternately. This design enables the positioning accuracy to reach ±0.01mm, while allowing ±0.5° axis deflection compensation.

[0048] Furthermore, the dynamic torsion mechanism of the spiral guide vane can be driven by piezoelectric ceramics, and the lead change rate can be actively adjusted according to the real-time flow rate signal; the topological optimization of the wave spring can introduce a machine learning algorithm, and the optimal wave crest distribution model can be obtained through historical working condition data training; the fillet radius of the valve cage window can be designed as a gradual structure, with a 1 / 6 window width radius at the inlet end and a transition to a 1 / 8 radius at the outlet end, forming a streamlined acceleration channel. The implementation of these improvement plans requires the combination of advanced processes such as precision casting and additive manufacturing. For example, the selective laser melting (SLM) technology is used to form a valve cage structure with an internal cooling channel, which reduces the thermal deformation under high temperature conditions by more than 60%.

[0049] In actual production, when the graphite impregnation amount of the piston ring is controlled at 15%-18% volume fraction, the self-lubricating performance and mechanical strength can be balanced; the shape memory alloy of the dynamic torsion angle mechanism of the guide vane needs to go through more than 300 training cycles to obtain stable phase change response characteristics; when the thickness deviation of the laser cladding layer on the valve stem conical surface exceeds ±0.02 mm, it will cause uneven distribution of the sealing specific pressure, and an online monitoring system needs to be used to control the cladding process parameters. Application cases show that this optimized structure extends the service life of the control valve in the petrochemical device from 8000 hours to 15000 hours, reduces the maintenance frequency to 1 / 3 of the original structure, and the flow regulation accuracy under the conditions of 420 °C and 10 MPa reaches ±1.5%, improving the performance index by 40% compared with Example 1.

[0050] As Figure 6 shown, in this embodiment, a 45° internal chamfer 101 is machined on the inner side of the top hole of the bellows 10, and the chamfer depth is 1 / 3 of the wall thickness of the hole. The chamfer surface forms a wedge-shaped mating structure with the 30° external chamfer of the shoulder 51 of the pilot valve stem. The outer diameter of the shoulder is 0.05-0.08 mm larger than the inner diameter of the bellows hole. During assembly, an axial press-fitting force is applied through a hydraulic tool to cause an interference fit between the two. A relief groove with a width of 0.5 mm is provided at the root of the internal chamfer, and a flexible graphite braided tape is filled in the groove. During the press-fitting process, the graphite tape is extruded and deformed to fill the microscopic gaps, forming a secondary sealing barrier. A circular oil storage groove with a depth of 0.1 mm is machined on the end face of the shoulder, and high-temperature molybdenum disulfide grease is pre-coated in the groove. When the valve stem 5 moves axially, the grease forms a continuous lubricating film on the wedge-shaped mating surface, and the measured starting torque is reduced to 1 / 4 of the traditional flat shoulder structure.

[0051] When the medium pressure acts on the outside of the bellows 10, the wedge-shaped contact surface between the internal chamfer and the shoulder decomposes the axial sealing force into a radial component force, increasing the contact stress to 1.8 times that of plane contact. Finite element analysis shows that under a working pressure of 10 MPa, the maximum stress concentration on the contact surface is in the area 1.2 mm away from the inner hole edge, and the stress value reaches 285 MPa, while the stress peak area of the traditional structure expands to a range of 3 mm and there is an obvious edge stress concentration phenomenon. The internal chamfer design improves the stress distribution uniformity by 60% and extends the fatigue life to 1.2 million pressure cycles. In terms of the assembly process, the interference fit assembly is carried out by the temperature difference method: the bellows 10 is heated to 200 °C to expand its hole, and the shoulder of the valve stem 5 is cooled to -50 °C to shrink. After they return to normal temperature, an interference amount of 0.02-0.03 mm is formed. This method avoids surface microcracks caused by mechanical press-fitting.

[0052] In addition, the inner chamfer structure and the conical sealing structure form a dual protection mechanism. When the conical sealing produces a small amount of leakage due to wear, the wedge-shaped shaft shoulder matching structure can block the path of the medium penetrating along the axial direction of the valve stem 5. Experimental data show that when the conical sealing gap reaches 0.01mm, the shaft shoulder structure can still control the leakage rate to 1×10⁻ 4 Pa·m³ / s or less. During maintenance, reverse hydraulic pressure can be applied to the shoulder through a special disassembly tool to separate the interference fit surface without loss. After repeated assembly for 5 times, the sealing performance attenuation rate is less than 3%. In the alternative scheme, the inner chamfer angle can be optimized to 40°-50° to adapt to different material combinations. When the valve stem 5 is made of titanium alloy, the mating surface needs to be plated with a 0.005mm thick diamond-like carbon film to prevent cold welding; the inner chamfer surface of the bellows 10 can be laser-clad with a nickel-based alloy layer, and the hardness of the cladding layer is controlled in the range of HV300-350 to match the hardness gradient of the valve stem shoulder. Practical applications have shown that this structure improves the sealing reliability of the regulating valve under frequent opening and closing conditions to 99.98%, which is 3.8 times longer than the failure interval of the flat shoulder structure in Example 1.

Claims

1. A pilot-operated bellows-sealed sleeve control valve, comprising a valve body, a valve seat and a valve cover, characterized in that Comprising: A valve cage, which is provided with a quick-opening type window with a radial dimension larger than an axial dimension; A main valve core, an annular piston groove is provided at the upper end of the main valve core, an opening piston ring is installed in the groove, and the outer wall of the piston ring is in clearance fit with the inner wall of the valve cage; A pilot valve core valve stem, which is an integrally formed structure; A bellows component, which is sleeved outside the valve stem and is locked and fixed by a nut, and the contact surface between the valve stem and the bellows component is a conical surface sealing structure that matches each other.

2. The regulating valve according to claim 1, wherein: The edge of the quick-opening type window is chamfered, and the windows are evenly distributed at equal intervals along the circumferential direction of the valve cage; support ribs are formed between adjacent windows.

3. The regulating valve according to claim 1, wherein: The lower end of the main valve core is provided with a flow regulating part with a continuous curved surface, and the curvature of the curved surface decreases from the center to the edge.

4. The regulating valve according to claim 3, wherein: The end curved surface of the flow regulating part and the inner wall of the valve seat form a stepped flow channel; A spiral flow guiding structure is provided in the flow channel.

5. The regulating valve according to any one of claims 1-4, wherein: The conical surface sealing structure includes a first conical surface on the valve stem and a second conical surface in the bellows component; the two conical surfaces form a line contact seal.

6. The regulating valve according to claim 1, wherein: The external threaded section of the pilot valve core valve stem is in threaded fit with the internal thread of the valve cover; A push rod is connected to the end of the pilot valve core valve stem, and an actuator is arranged at the end of the push rod.

7. The regulating valve according to claim 6, wherein: The push rod is connected to the pilot valve core valve stem through a split half joint; A scale line arranged along the axial direction is provided on the side of the split half joint.

8. The regulating valve according to any one of claims 1-4, wherein: A stepped mating structure is formed between the bottom of the valve cage and the valve seat; An annular flow guiding groove is provided on the upper end surface of the valve seat, and the annular flow guiding groove is communicated with the bottom of the valve cage window.

9. The regulating valve according to claim 1, wherein: The opening end of the opening piston ring is provided with an interleaved lapping structure; A corrugated spring that abuts against the bottom of the piston groove is provided on the inner ring of the opening piston ring.

10. The regulating valve according to claim 6, wherein: The actuator includes a tray coaxially arranged at the end of the push rod, and an actuator spring mechanism is installed on the tray; A diaphragm is arranged outside the tray; disc gaskets are arranged at the connections between the inside and outside of the tray and the push rod.

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