Floating liner device for a plunger pump

Abstract

The application provides a floating liner device for a plunger pump, which comprises a floating disc and a communication sleeve, the upper end surface of the floating disc is provided with uniformly distributed round holes, the communication sleeve is inserted into the round holes, the lower end surface of the floating disc is provided with uniformly distributed waist-shaped grooves, the round holes and the waist-shaped grooves are one-to-one corresponding and communicated, the center axis of the round hole passes through the center point of the corresponding waist-shaped groove, two adjacent waist-shaped grooves are communicated through a set of combined communication holes, each set of combined communication holes is composed of a piston hole and a process hole which are perpendicular to each other, the piston hole in each set of combined communication holes is communicated with one end of a waist-shaped groove, the center axis of the piston hole passes through the center point of the waist-shaped groove, and the process hole is communicated with one end of another waist-shaped groove adjacent to the waist-shaped groove. Through the design of the two-way piston embedded in the floating liner, the integration of the swash plate type plunger pump rotating assembly is improved, the flow backflow phenomenon in the flow distribution process is effectively reduced, the output flow and pressure pulsation of the plunger pump are reduced, and vibration and noise reduction in the flow distribution process of the swash plate type plunger pump are realized.

Description

Technical Field

[0001] This invention relates to a floating liner device for a plunger pump, belonging to the field of plunger pump technology. Background Technology

[0002] Axial piston pumps, characterized by high rated pressure, easily adjustable flow rate, high volumetric efficiency, and compact structure, are widely used in hydraulic systems in critical fields such as aerospace, military weaponry, and heavy machinery. With the development of my country's aerospace industry, there are increasing demands for lightweight and integrated aerospace hydraulic systems. Axial piston pumps using aviation kerosene as the medium are crucial energy conversion components in aerospace hydraulic equipment, and their lifespan and reliability directly affect the overall reliability of the aerospace equipment. Compared to traditional hydraulic oil, aviation kerosene has lower kinematic viscosity and higher permeability, making piston pumps more prone to leakage. Furthermore, due to the special properties of aviation kerosene, the noise and structural vibration generated during the piston pump distribution process increase. Under high-speed, high-pressure conditions, cavitation and vibration of the axial piston pump worsen. If a traditional high-viscosity oil pump structure is used with kerosene as the medium, internal leakage will increase significantly, not only reducing the piston pump efficiency but also potentially leading to system failure in severe cases.

[0003] The distributor plate is one of the three key friction pairs in a plunger pump. It mainly consists of a rotating cylinder and a distributor plate. When the plunger pump is working, the plunger, under the action of the swashplate, follows the plunger pump cylinder in a reciprocating rotational motion, periodically achieving the functions of oil suction and discharge. Traditional oil pumps use a floating cylinder with a fixed distributor plate. The cylinder can float up and down along the spline of the main shaft, automatically adjusting the distributor clearance to improve oil film leakage. When using low-viscosity fluids, this structure greatly increases the leakage flow at the distributor plate clearance, and the volumetric efficiency decreases sharply. Research on plunger pumps started earlier abroad. Similarly, the United States began developing plunger pumps for water-based fluid media in the 1960s. Subsequently, Germany, Japan, the United Kingdom, France, Finland, and other countries joined the competition and successively released finished plunger pump products.

[0004] Patent CN201220722007.0 (CN203081669U) provides a half-shaft type pure water hydraulic axial piston pump, mainly composed of a floating disc, a connecting sleeve, gaskets, and O-rings. The floating disc is an improved design for the distribution pair structure of low-viscosity fluids. The original floating cylinder structure is separated into a cylinder section containing piston channels and a cylinder section containing waist-shaped grooves. The former is interference-fitted to the main shaft, while the latter is modified into a floating disc. The connecting sleeve of the floating disc is fully pressed into the piston channel cylinder section. Due to the elasticity of the O-rings, the floating disc has three degrees of freedom relative to the rotating cylinder within a small range: axial translation and slight radial displacement. In this structure, the O-rings achieve sealing between the floating disc assembly and the piston channels during movement. The floating disc fine-tunes its posture according to the magnitude of the unbalanced torque it bears to maintain stable water film contact with the distribution disc. This effectively reduces leakage in the distribution pair under low-viscosity fluid media and improves the lubrication performance of the distribution pair to a certain extent. However, when using this structure, the stability of the rotating components decreases due to the splitting of the original one-piece cylinder into two parts, leading to increased vibration and noise during the distribution of low-viscosity fluids. The reason for this is that this structure does not change the fluid pressure energy transfer process between the plunger channel and the distribution plate. The inherent working principle of the plunger pump dictates that flow and pressure pulsations are inevitable. Therefore, effectively controlling the flow and pressure pulsations of the existing floating liner-type distribution structure is crucial for vibration and noise reduction control of end-face distribution swashplate plunger pumps used for low-viscosity fluids.

[0005] Patent CN200910272425.7 (CN101694211A) provides a distribution plate for a plunger pump. The movement of the plunger channel on the distribution plate can be simplified as the channel sequentially passing through a low-pressure zone, a low-pressure transition zone, a high-pressure zone, and a high-pressure transition area. When the plunger channel enters the low-pressure transition zone, its internal pressure may still remain at the low-pressure state of the suction zone. When the plunger cavity comes into contact with the high-pressure zone at this time, the oil in the high-pressure zone will flow back to the low-pressure zone through the plunger cavity due to the pressure difference. That is, the oil that should be discharged to the high-pressure zone flows back to the low-pressure zone. This phenomenon is called flow backflow. Flow backflow reduces the effective output flow of the pump, reduces the volumetric efficiency of the pump, and during the flow backflow process, the oil repeatedly flows between the plunger cavity and the high-pressure zone, aggravating the wear of the internal parts of the plunger pump, resulting in increased pump output flow and pressure fluctuations, significantly increased vibration and noise levels, and affecting the stability and reliability of the entire hydraulic system. In severe cases, this can lead to the failure and collapse of sensitive hydraulic components in the hydraulic system, shortening the service life of the hydraulic system. In existing distributor plate designs, to mitigate the hazards of backflow, vibration damping grooves are often incorporated at the inlets of the waist-shaped grooves in both the low-pressure and high-pressure zones along the cylinder's movement direction. These damping groove structures include vibration-damping orifice types, triangular groove types, and multi-stage U-shaped groove types. All of these structures, to some extent, reduce pressure gradient changes by extending the contact time between the plunger channel and the high-pressure zone. However, the impact and vibration generated by changes in the pressure gradient within the pump are still significant, posing new requirements for vibration reduction and noise reduction in the pump's internal structure. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a floating liner device for a plunger pump that improves backflow phenomenon, reduces outlet flow and pressure pulsation, and realizes vibration reduction and noise reduction control of the plunger pump.

[0007] The technical solution of the present invention: A floating liner device for a plunger pump, comprising a floating disc and a connecting sleeve. The upper end face of the floating disc is provided with uniformly distributed circular holes, into which the connecting sleeve is inserted. The lower end face of the floating disc is provided with uniformly distributed waist-shaped grooves. The circular holes and the waist-shaped grooves correspond one-to-one and are connected. The central axis of the circular hole passes through the center point of the corresponding waist-shaped groove. Two adjacent waist-shaped grooves are connected through a set of combined communication holes. Each set of combined communication holes consists of a piston hole and a process hole with mutually perpendicular central axes. The piston hole in each set of combined communication holes is connected to one end of a waist-shaped groove, and the central axis of the piston hole passes through the center point of the waist-shaped groove. The process hole is connected to one end of another waist-shaped groove adjacent to the waist-shaped groove.

[0008] The piston hole is provided with a bidirectional piston and a screw. The screw encapsulates the bidirectional piston in the piston movement section at the front end of the piston hole, and the bidirectional piston can move in both directions within the piston movement section.

[0009] The beneficial effects of this invention compared to the prior art are as follows:

[0010] (1) The present invention improves the integration of the rotating components of the swashplate plunger pump by using a floating liner embedded bidirectional piston design, effectively reduces the backflow phenomenon in the flow distribution process, reduces the output flow and pressure pulsation of the plunger pump, and realizes vibration reduction and noise reduction in the flow distribution process of the swashplate plunger pump.

[0011] (2) The bidirectional piston of the present invention adaptively balances the pressure on both sides according to the contact pressure difference between the plunger cavity and the inlet and outlet, thereby reducing vibration and noise, weakening cavitation and reducing pulsation.

[0012] (3) The present invention uses a machining channel to connect adjacent waist-shaped grooves, and uses a plug-in bidirectional piston assembly to seal the fluid on both sides, realizing the integrated design of floating liner base, piston and screw assembly. The structure is compact and highly integrated, which improves the dynamic performance and volumetric efficiency of the plunger pump.

[0013] (4) The present invention has outstanding advantages in end-face distribution axial piston pumps with low viscosity working medium such as aviation kerosene, and can also be applied to oil piston pumps with various medium and high viscosity mineral oils as working medium. Attached Figure Description

[0014] Figure 1 This is a perspective view of the present invention;

[0015] Figure 2 This is a side view of the present invention;

[0016] Figure 3 for Figure 2 AA section view;

[0017] Figure 4 This is a cross-sectional view of the floating liner of the present invention;

[0018] Figure 5 This is a schematic diagram of the assembly of the present invention with the cylinder block and the distributor plate;

[0019] Figure 6 This is a schematic diagram of the operation of the floating liner rotating on the distribution plate according to the present invention;

[0020] Among them, 1. Floating disc, 2. Connecting sleeve, 3. O-ring, 4. Washer, 5. Piston, 6. Dynamic seal, 7. Screw, 8. Plug, 9. Waist groove, 10. Piston hole, 11. Process hole, 12. Cylinder block, 13. Piston cavity, 14. Distribution plate, 15. Piston cavity A, 16. Piston cavity B, 17. Piston cavity C, 18. Low-pressure zone, 19. Low-pressure transition zone, 20. High-pressure zone, 21. High-pressure transition zone, 22. External stop section, 23. Threaded section, 24. Fluid communication section, 25. Piston movement section. Detailed Implementation

[0021] This invention provides a floating liner device for a plunger pump, comprising a floating disc and a connecting sleeve. The upper surface of the floating disc has evenly distributed circular holes, into which the connecting sleeve is inserted. The lower surface of the floating disc has evenly distributed oblong grooves, with each circular hole corresponding to and communicating with one of the oblong grooves. The central axis of the circular hole passes through the center point of the corresponding oblong groove. Adjacent oblong grooves are connected by a set of combined connecting holes. Each set of combined connecting holes consists of a piston hole and a process hole with mutually perpendicular central axes. The piston hole in each set of combined connecting holes is connected to one end of an oblong groove, and the central axis of the piston hole passes through the center point of that oblong groove. The process hole is connected to one end of another oblong groove adjacent to that oblong groove.

[0022] The present invention provides a bidirectional piston and a screw inside the piston hole. The screw encapsulates the bidirectional piston in the piston movement section at the front end of the piston hole. The bidirectional piston can move in both directions within the piston movement section. The direction of movement of the bidirectional piston is determined by the pressure difference between the two adjacent waist-shaped grooves connected by the combined communication hole.

[0023] Furthermore, the piston bore is arranged in a stepped bore configuration, consisting of an outer stop section, a threaded section, a fluid communication section, and a piston movement section, from the outside in.

[0024] Furthermore, the screw is screwed into the piston hole through the outer stop section and threadedly connected to the threaded section, with the front end of the screw and the fluid communication section of the piston hole having a clearance fit.

[0025] Furthermore, both the piston hole and the process hole are located on the circumferential side of the floating disk. The piston hole is connected to the waist-shaped groove of the floating disk, and the process hole is connected to another adjacent waist-shaped groove. The central axis of the piston hole and the process hole are perpendicular, and the fluid in the two adjacent waist-shaped grooves communicates through the piston hole and the process hole.

[0026] Furthermore, the number of piston holes and process holes on the floating disk is the same as the number of waist-shaped grooves, and the central axis of the piston hole passes through the center point of the waist-shaped groove that communicates with it.

[0027] Furthermore, the surface roughness of the piston movement section of the piston bore reaches Ra0.4 or higher, and the cylindricity tolerance is less than 0.015. Preferably, the piston movement section is fitted with a bidirectional piston, which undergoes surface carburizing and nitriding treatment, and a bidirectional dynamic seal is provided in the circumferential direction of the bidirectional piston.

[0028] Furthermore, the fluid communication section of the piston bore maintains a clearance fit with the screw to reduce the flow resistance of the fluid.

[0029] Furthermore, the threaded section of the piston bore is connected to the screw. The diameter of the screw tip is smaller than the diameter of the piston movement section inside the piston bore. After assembly, the screw tip extends into the movement section of the piston bore, with the extension dimension limited to 1-3mm, thus restricting the piston's movement space.

[0030] Furthermore, the outer stop section of the piston bore mates with the screw for axial positioning, and the rear end face of the screw extends less than 5mm beyond the circumference of the floating disc. There is an end face seal at the connection between the screw and the outer stop section of the piston bore to prevent fluid leakage.

[0031] Furthermore, a plug is provided on the outside of the process hole, which is welded or press-fitted into the process hole.

[0032] Furthermore, the present invention provides a stepped groove machined circumferentially in the connecting sleeve, and the O-ring and washer are coaxially and sequentially installed in the stepped groove of the connecting sleeve.

[0033] Further preferred, the washer of the present invention is an open ring with a beveled cut, and the material is selected as engineering plastic or alloy material according to the pressure level. The material itself has a certain toughness, and the outer diameter of the washer is 0.05 to 0.15 mm smaller than the inner diameter of the piston hole under full compression.

[0034] The following will be based on embodiments of the present invention. Figures 1-6 The embodiments of the present invention will be described in more detail below. Obviously, the described embodiments are only a part of all embodiments of the present invention. Other embodiments that can be directly obtained or conceived by those skilled in the art from the disclosure of the present invention without creative effort are all within the protection scope of the present invention.

[0035] This example describes a vibration-damping and noise-reducing floating liner device for a plunger pump, as shown in 1, 2, and 3. It includes a floating disc 1, a connecting sleeve 2, an O-ring 3, a washer 4, a piston 5, a dynamic seal 6, a screw 7, and a plug 9.

[0036] like Figure 1 , 4 As shown, five evenly distributed circular holes 26 are provided on the upper end face of the floating disk 1. The connecting sleeve 2 is press-fitted into the circular holes, and the O-ring 3 and washer 4 are coaxially installed in the stepped groove of the connecting sleeve 2.

[0037] like Figure 2 , 3 As shown, five evenly distributed waist-shaped grooves 9 are provided on the lower end face of the floating disk 1. Two adjacent waist-shaped grooves are connected through piston holes 10 and process holes 11. Piston holes 10 are drilled along the circumferential side of the floating disk 1 and are connected to the waist-shaped grooves on the lower end face of the floating disk 1. The axis of the process holes 11 intersects the axis of the piston holes 10. The number of piston holes 10 and process holes 11 opened circumferentially on the floating disk 1 is the same as the number of waist-shaped grooves 9.

[0038] like Figure 4 As shown, the piston hole 10 is arranged in a stepped hole pattern, consisting of an outer stop section 22, a threaded section 23, a fluid communication section 24, and a piston movement section 25, from the outside to the inside.

[0039] The inner surface roughness of the piston moving section 25 of the piston bore 10 reaches Ra0.4 or above, and the cylindricity tolerance is less than 0.015. The piston moving section 25 is matched with the bidirectional piston 5, which is surface carburized and nitrided, and a bidirectional dynamic seal 6 is provided in the circumferential direction of the bidirectional piston 5.

[0040] The fluid communication section 24 of the piston bore 10 is clearance-fitted with the screw 7 to reduce flow resistance.

[0041] The threaded section 23 of the piston bore 10 is connected to the screw 7. The diameter of the front end of the screw 7 is smaller than the diameter of the piston movement section inside the piston bore 10. After assembly, the front end of the screw 7 extends into the movement section of the piston bore 10, and the extension dimension is limited to 1-3mm, which restricts the movement space of the piston 5.

[0042] The outer stop section 22 of the piston bore 10 mates with the screw 7 and provides axial positioning. The rear end face of the screw 7 extends out of the floating disk 1 by less than 5 mm. There is an end face seal at the connection between the screw 7 and the outer stop section 22 of the piston bore 10 to prevent fluid leakage.

[0043] A plug 9 is provided on the outside of the process hole 11, which is welded or press-fitted into the hole.

[0044] Washer 4 is an open ring with a beveled cut. Depending on the pressure rating, the material is selected as engineering plastic or alloy. The material itself has a certain degree of toughness. Under full compression, the outer diameter of the washer is 0.05 to 0.15 mm smaller than the inner diameter of the piston bore 10.

[0045] like Figure 5 , 6 As shown, taking the movement process of the waist-shaped groove corresponding to the plunger cavity on the distribution plate 14 as an example, the working principle of piston 5 achieving vibration reduction and noise reduction through pre-pressurization and pre-depressurization in this example is explained.

[0046] Pre-pressurization process: The plunger chamber is set to rotate clockwise. The left gray waist-shaped groove represents low pressure, and the right gray waist-shaped groove represents high pressure. During this process... Figure 6 The location of the middle plunger cavity A15 is the low-pressure transition area of ​​the distribution plate 14, and the opposite sealing transition area is the high-pressure transition area.

[0047] like Figure 6As shown, when plunger cavity A15 is located in the low-pressure transition zone of distribution plate 14, the fluid inside the plunger cavity is in a sealed state. Plunger cavity B16 is located in the high-pressure outlet region of distribution plate, and the pressure in plunger cavity B16 is high. Due to the pressure difference between plunger cavity A15 and plunger cavity B16, the bidirectional piston 5 moves towards plunger cavity A15 under pressure, compressing the working volume of plunger cavity A15, increasing the working pressure of plunger cavity A15, and achieving pre-pressurization. Cylinder body 12 and floating plate 1 continue to rotate, and plunger cavity A begins to contact the high-pressure outlet region of distribution plate 14. Due to the pre-pressurization effect of piston 5 on plunger cavity A15, the pressure gradient difference between plunger cavity A15 and the high-pressure outlet is greatly reduced, the backflow rate is reduced, the pressure and flow pulsation is improved, and the vibration of the machine body and the amplitude of fluid noise decrease.

[0048] Pre-depressurization process: The plunger chamber is set to rotate counterclockwise. The left gray waist-shaped groove represents low pressure, and the right gray waist-shaped groove represents high pressure. During this process... Figure 6 The middle piston cavity A15 is located in the high-pressure transition area of ​​the distribution plate 14, and the opposite sealing transition area is the low-pressure transition area.

[0049] Conversely to the pre-pressurization process, when plunger cavity A15 is located in the high-pressure transition zone of distribution plate 14, the fluid inside the plunger cavity is in a sealed state. Due to the presence of gap leakage, the pressure in plunger cavity A15 is sub-high pressure, while plunger cavity C17 is located in the low-pressure inlet region of distribution plate, and the pressure in plunger cavity C17 is low pressure. Due to the pressure difference between plunger cavity A15 and plunger cavity C17, the bidirectional piston 5 moves towards plunger cavity C under pressure, increasing the working volume of plunger cavity A15 and reducing the working pressure of plunger cavity A15, thus achieving pre-pressure relief. Cylinder body 12 and floating plate 1 continue to rotate, and plunger cavity A15 contacts the low-pressure inlet region of distribution plate 14. Due to the pre-pressure relief effect of the bidirectional piston 5 on plunger cavity A15, the pressure gradient between plunger cavity A15 and the low-pressure inlet is greatly reduced, the vibration amplitude of the engine body decreases, and cavitation, cavitation, and fluid noise in the plunger cavity are improved.

[0050] The parts of this invention not described in detail are techniques known to those skilled in the art.

Claims

1. A floating liner device for a plunger pump, characterized in that: The device includes a floating disk and a connecting sleeve. The upper end face of the floating disk is provided with evenly distributed circular holes, into which the connecting sleeve is inserted. The lower end face of the floating disk is provided with evenly distributed waist-shaped grooves. The circular holes and waist-shaped grooves correspond one-to-one and are connected. The central axis of the circular holes passes through the center point of the corresponding waist-shaped groove. Two adjacent waist-shaped grooves are connected through a set of combined communication holes. Each set of combined communication holes consists of a piston hole and a process hole with mutually perpendicular central axes. The piston hole in each set of combined communication holes is connected to one end of a waist-shaped groove, and the central axis of the piston hole passes through the center point of the waist-shaped groove. The process hole is connected to one end of another waist-shaped groove adjacent to the first waist-shaped groove. The piston hole is provided with a bidirectional piston and a screw. The screw encapsulates the bidirectional piston in the piston movement section at the front end of the piston hole, and the bidirectional piston can move in both directions within the piston movement section.

2. The floating liner device for a plunger pump according to claim 1, characterized in that: The piston bore is arranged in a stepped manner, consisting of an outer stop section, a threaded section, a fluid communication section, and a piston movement section from the outside to the inside.

3. The floating liner device for a plunger pump according to claim 2, characterized in that: The screw is screwed into the piston hole through the outer stop section and threadedly connected to the threaded section. The front end of the screw is clearance-fitted with the fluid communication section of the piston hole. The central axis of the process hole is located in the region of the fluid communication section.

4. The floating liner device for a plunger pump according to claim 3, characterized in that: The piston holes and process holes are distributed on the circumferential side of the floating disk, and the number of piston holes and process holes is the same as the number of waist-shaped grooves.

5. A floating liner device for a plunger pump according to claim 3, characterized in that: The inner surface roughness of the piston movement section of the piston bore reaches Ra0.4 or above, the cylindricity tolerance is less than 0.015, and a bidirectional dynamic seal is provided in the circumferential direction of the bidirectional piston.

6. A floating liner device for a plunger pump according to claim 5, characterized in that: The diameter of the screw tip is smaller than the diameter of the piston movement section inside the piston hole. After assembly, the screw tip extends into the movement section of the piston hole.

7. A floating liner device for a plunger pump according to claim 6, characterized in that: The outer stop section of the piston hole mates with the screw, and there is an end face seal at the connection between the screw and the outer stop section of the piston hole.

8. A floating liner device for a plunger pump according to claim 7, characterized in that: The surface of the bidirectional piston is carburized and nitrided. The front end of the screw extends into the floating disk by 1-3 mm, and the rear end of the screw extends out of the floating disk by less than 5 mm. A plug is provided on the outside of the process hole, which is welded or press-fitted into the process hole.

9. A floating liner device for a plunger pump according to any one of claims 1-8, characterized in that: The connecting sleeve is circumferentially machined with a stepped groove, and the O-ring and washer are coaxially installed sequentially in the stepped groove of the connecting sleeve.

10. A floating liner device for a plunger pump according to claim 9, characterized in that: The washer is an open ring with a beveled cut. Depending on the pressure rating, the material is selected as engineering plastic or alloy. Under full compression, the outer diameter of the washer is 0.05 to 0.15 mm smaller than the inner diameter of the piston bore.

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