A sealing and guiding structure of a plunger and a cylinder of a plunger pump

Abstract

The utility model relates to sealing guide structure technical field, concretely relates to a sealing guide structure of plunger pump plunger and cylinder, including main cylinder, the inner side wall fixed connection of main cylinder has compound guide bush, compound guide bush is drum -shaped, the inside slide of compound guide bush has plunger body, the inner side wall of compound guide bush is equipped with several groups of micro -pit array, the inner side wall of compound guide bush is equipped with several groups of micro -groove array, micro -pit array and micro -groove array staggered arrangement. The utility model discloses through the cooperation of main cylinder and plunger body, through the drum -shaped design of compound guide bush, the micro -pit array and micro -groove array constitute the microscopic lubrication texture and the multiple synergies of polyether ether ketone base composite coating, realize the leapwise promotion of guiding precision and wear -resisting life, this drum -shaped curved surface can adaptive compensation plunger body's deflection, will harmful edge contact stress be converted into even face load, has guaranteed the high -degree centring and the stability of movement.

Description

Technical Field

[0001] This utility model relates to the field of sealing and guiding structure technology, specifically to a sealing and guiding structure between the plunger and cylinder of a plunger pump. Background Technology

[0002] As the core power component of a hydraulic system, the reliability, efficiency, and lifespan of the piston pump directly determine the overall technical level of the hydraulic system. Among these components, the sealing and guiding structure between the piston and the cylinder is one of the most critical friction pairs in a piston pump, and its design quality directly affects the pump's volumetric efficiency, power density, operating pressure, service life, and noise level.

[0003] Currently, most plunger pumps, both domestically and internationally, employ a traditional structure consisting of a metal cylinder bore and a metal plunger. The plunger reciprocates at high speed within the cylinder, and its guiding function is typically achieved through a direct, precise fit between the plunger and the cylinder bore. The sealing function relies on the minute clearance between the plunger and the cylinder bore, or additional sealing elements. This traditional structure has several inherent drawbacks: First, to simultaneously meet the dual requirements of guidance and sealing, the machining accuracy, geometric tolerances, and surface finish of the plunger and cylinder bore are extremely demanding, resulting in high manufacturing costs. Second, under high-pressure operating conditions, the plunger is subjected to enormous lateral forces, making it prone to micro-deformation or misalignment. This leads to edge contact with the cylinder bore, causing severe uneven wear and scoring, rapidly increasing the clearance, drastically reducing volumetric efficiency, and ultimately leading to premature pump failure. Furthermore, the friction pair is in a state of boundary lubrication or even dry friction, resulting in high frictional losses and increased temperature, further exacerbating wear and material failure, and limiting the increase in pump operating pressure and speed.

[0004] Therefore, it is necessary to invent a sealing and guiding structure between the plunger and the cylinder of a plunger pump to solve the above problems. Utility Model Content

[0005] The purpose of this utility model is to provide a sealing and guiding structure for the plunger and cylinder of a plunger pump. By cooperating with the main cylinder and plunger body and other parts, it solves the problem in the prior art where the plunger is subjected to huge lateral forces, which easily causes micro-deformation or skew, resulting in edge contact with the cylinder bore and causing serious uneven wear and scoring.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a sealing and guiding structure for a plunger and cylinder of a plunger pump, comprising a main cylinder, a composite guide bushing fixedly connected to the inner wall of the main cylinder, the composite guide bushing being drum-shaped, a plunger body sliding inside the composite guide bushing, a plurality of micro-pit arrays and a plurality of micro-groove arrays formed on the inner wall of the composite guide bushing, the micro-pit array and the micro-groove array being arranged alternately, the inner wall of the composite guide bushing being coated with a polyether ether ketone-based composite coating, and sealing mounting grooves formed on both sides of the inner wall of the main cylinder located within the composite guide bushing, wherein sealing rings for sealing are installed in the sealing mounting grooves, thereby improving reliability through the cooperation of the composite guide bushing and other components.

[0007] Preferably, a friction-reducing bushing is fixedly connected to the inner wall of the plunger body, and a ball socket is provided at the left end of the friction-reducing bushing. The structural strength is enhanced by the cooperation between the plunger body and the friction-reducing bushing.

[0008] Preferably, the ball socket is provided with a ball head inside, and a connecting rod is fixedly connected to the end of the ball head away from the plunger body, so that the linkage is achieved by the cooperation of the ball head and the connecting rod.

[0009] Preferably, two sets of buffer pads are fixedly connected inside the ball socket, and the buffer pads are located on the rear side and the front side of the ball head, respectively, to reduce wear.

[0010] Preferably, the outer wall of the ball head is coated with a nickel-chromium alloy plating, and the outer wall of the nickel-chromium alloy plating is coated with a friction-reducing plating, thereby improving service life through the cooperation of the nickel-chromium alloy plating and other components.

[0011] Preferably, the composite guide bushing is made of fiber-reinforced polymer composite material, and the surface of the plunger body is chrome-plated to further enhance the durability of the structure.

[0012] The technical effects and advantages provided by this utility model in the above technical solution are as follows: Through the cooperation of the main cylinder and the plunger body, and the synergistic effect of the composite guide bushing's drum-shaped design, the micro-lubricating texture composed of micro-pit array and micro-groove array, and the polyetheretherketone-based composite coating, a leap in guiding accuracy and wear resistance life is achieved. The drum-shaped curved surface can adaptively compensate for the plunger body's skewness, transforming harmful edge contact stress into uniform surface load, ensuring the high degree of alignment and stability of the plunger's reciprocating motion. At the same time, the combination of micro-texture and high-performance coating greatly reduces the coefficient of friction and operating temperature rise, exhibiting excellent friction-reducing and wear-resistant characteristics, especially under boundary lubrication conditions. Meanwhile, the sealing ring is independently installed in the sealing mounting groove of the main cylinder, allowing it and the composite guide bushing to perform their respective functions, forming an optimized layout where guiding and sealing functions are separated yet complementary. This not only avoids motion interference but also ensures the stability and reliability of the sealing interface under high-pressure conditions, effectively suppressing leakage of the working medium, thereby ensuring the pump's high volumetric efficiency. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the internal structure of the present invention; Figure 3 This is a schematic diagram of the composite guide bushing structure of this utility model; Figure 4 For the present utility model Figure 2 Enlarged structural diagram at point A in the middle.

[0015] Explanation of reference numerals in the attached figures: 1. Main cylinder block; 2. Plunger body; 3. Anti-friction coating; 4. Sealing ring; 5. Connecting rod; 6. Anti-friction bushing; 7. Ball head; 8. Composite guide bushing; 9. Polyether ether ketone-based composite coating; 10. Micro-dimple array; 11. Micro-groove array; 12. Ball socket; 13. Buffer pad; 14. Nickel-chromium alloy coating. Detailed Implementation

[0016] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0017] This utility model provides, for example Figure 1-4The diagram illustrates a sealing and guiding structure for a plunger pump plunger and cylinder body, comprising a main cylinder body 1. A composite guide bushing 8 is fixedly connected to the inner wall of the main cylinder body 1. The composite guide bushing 8 is drum-shaped, and a plunger body 2 slides inside the composite guide bushing 8. The inner wall of the composite guide bushing 8 has several sets of micro-pit arrays 10 and several sets of micro-groove arrays 11, arranged alternately. The inner wall of the composite guide bushing 8 is coated with a polyetheretherketone (PEEK) composite coating 9. A sealing mounting groove is provided on both sides of the inner wall of the composite guide bushing 8. A sealing ring 4 for sealing is installed in the sealing mounting groove. The reliability is improved by the cooperation of the composite guide bushing 8 and other parts. A friction-reducing bushing 6 is fixedly connected to the inner wall of the plunger body 2. A ball socket 12 is provided at the left end of the friction-reducing bushing 6. The structural strength is strengthened by the cooperation between the plunger body 2 and the friction-reducing bushing 6. A ball head 7 is provided inside the ball socket 12. A connecting rod 5 is fixedly connected to the end of the ball head 7 away from the plunger body 2. The linkage is realized by the cooperation between the ball head 7 and the connecting rod 5.

[0018] Refer to the instruction manual appendix Figure 1-4 Two sets of buffer pads 13 are fixedly connected inside the ball socket 12. The buffer pads 13 are located on the rear and front sides of the ball head 7, respectively. The buffer pads 13 reduce wear. The outer wall of the ball head 7 is coated with a nickel-chromium alloy plating layer 14, and the outer wall of the nickel-chromium alloy plating layer 14 is coated with a friction-reducing plating layer 3. The service life is improved by the cooperation of the nickel-chromium alloy plating layer 14 and other parts. The composite guide bushing 8 is made of fiber-reinforced polymer composite material. The surface of the plunger body 2 is chrome-plated to further enhance the durability of the structure. Through the cooperation of the main cylinder 1 and the plunger body 2, and through the multiple synergistic effects of the drum-shaped design of the composite guide bushing 8, the micro-lubricating texture formed by the micro-dimple array 10 and the micro-groove array 11, and the polyetheretherketone-based composite coating 9, the guiding effect is achieved. To achieve a leap in precision and wear resistance, the drum-shaped curved surface can adaptively compensate for the skewness of the plunger body 2, transforming harmful edge contact stress into a uniform surface load. This ensures the high degree of alignment and stability of the plunger's reciprocating motion. At the same time, the combination of microtexture and high-performance coating greatly reduces the coefficient of friction and operating temperature rise, exhibiting excellent friction-reducing and wear-resistant properties, especially under boundary lubrication conditions. Furthermore, the sealing ring 4 is independently installed in the sealing mounting groove of the main cylinder 1, allowing it and the composite guide bushing 8 to perform their respective functions. This forms an optimized layout where the guiding and sealing functions are separated yet complementary. This not only avoids motion interference but also ensures the stability and reliability of the sealing interface under high-pressure conditions, effectively suppressing leakage of the working medium and thus guaranteeing the pump's high volumetric efficiency.

[0019] The working principle of this practical application is as follows: Refer to the instruction manual appendix Figure 1-4The plunger body 2 reciprocates at high speed within the main cylinder 1 under power drive. The smoothness and precision of its movement are ensured by a composite guide bushing 8, which is interference-fitted and fixed to the inner wall of the main cylinder 1. This composite guide bushing 8, with its unique drum-shaped inner surface, adaptively envelops the plunger body 2, effectively compensating for minor plunger misalignment and deformation caused by lateral forces. It transforms concentrated edge contact stress into uniformly distributed surface contact stress, fundamentally eliminating uneven wear and ensuring the centering of the plunger movement. Simultaneously, the laser-processed micro-dimple array 10 and micro-groove array 11 on the inner wall of the composite guide bushing 8 together constitute an advanced micro-lubrication texture. During the plunger's movement, these microtextures efficiently capture and store lubricating oil, forming a stable hydrodynamic oil film between the friction pairs. This transforms solid dry friction into liquid friction, significantly reducing the coefficient of friction and operating heat. Furthermore, the polyether ether ketone (PEEK) composite coating 9 applied to the inner wall of the composite guide bushing 8 further provides an extremely low inherent coefficient of friction and excellent wear resistance. This coating, in synergy with the microtextures, achieves a multiplier effect in friction reduction and wear resistance, providing crucial protection, especially during moments of insufficient lubrication at startup. Reliable sealing performance is ensured by the sealing ring 4 installed in the sealing mounting groove of the main cylinder 1, which maintains contact with the surface of the high-speed moving plunger body 2. A constant interference contact forms the main sealing interface, effectively preventing leakage of the high-pressure working medium. The sealing ring 4 and the composite guide bushings 8 arranged before and after together constitute a functionally distinct unit. The guide component is responsible for bearing mechanical loads and ensuring motion accuracy, while the sealing component is responsible for establishing a pressure barrier. Both perform their respective functions and support each other, jointly ensuring the volumetric efficiency and long-term stability of the pump under high-pressure conditions. At the power transmission end, the connecting rod 5 forms a ball joint with the ball socket 12 fixed on the anti-friction bushing 6 inside the plunger body 2 through the ball head 7 at its end, converting the rotational driving force of the swashplate into the reciprocating motion of the plunger. The outer surface of the ball head 7 is innovatively made of nickel-chromium alloy. Alloy coating 14 serves as the bonding underlayer, supplemented by diamond-like carbon (DLC) anti-friction coating 3 as the working surface layer. This combined coating has extremely high surface hardness, extremely low coefficient of friction, and excellent anti-adhesion properties, ensuring the sensitivity and ultra-long life of the hinge under high specific pressure oscillation conditions. More importantly, the integral buffer pad 13 with interference fit on the inner wall of the ball socket 12 is made of high-performance engineering plastic. Its excellent elastic deformation capability can not only absorb the impact and vibration of motion, but also adaptively wrap the ball head 7, making the contact stress distribution more uniform, completely avoiding early fatigue failure caused by local stress concentration, and further improving the reliability and smoothness of power transmission.

[0020] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A sealing and guiding structure for a plunger and cylinder of a plunger pump, comprising a main cylinder (1), characterized in that: The inner wall of the main cylinder (1) is fixedly connected to a composite guide bushing (8). The composite guide bushing (8) is drum-shaped. A plunger body (2) slides inside the composite guide bushing (8). The inner wall of the composite guide bushing (8) is provided with a number of micro-pit arrays (10) and a number of micro-groove arrays (11). The micro-pit arrays (10) and micro-groove arrays (11) are arranged alternately. The inner wall of the composite guide bushing (8) is coated with a polyether ether ketone-based composite coating (9). The inner wall of the main cylinder (1) and the two sides of the composite guide bushing (8) are provided with sealing mounting grooves. Sealing rings (4) for sealing are installed in the sealing mounting grooves.

2. The sealing and guiding structure between the plunger and cylinder of a plunger pump according to claim 1, characterized in that: The inner wall of the plunger body (2) is fixedly connected to a friction-reducing bushing (6), and a ball socket (12) is provided at the left end of the friction-reducing bushing (6).

3. The sealing and guiding structure between the plunger and cylinder of a plunger pump according to claim 2, characterized in that: The ball socket (12) is provided with a ball head (7) inside, and a connecting rod (5) is fixedly connected to one end of the ball head (7) away from the plunger body (2).

4. The sealing and guiding structure between the plunger and cylinder of a plunger pump according to claim 2, characterized in that: The ball socket (12) is fixedly connected to two sets of buffer pads (13), which are located on the rear side and the front side of the ball head (7), respectively.

5. The sealing and guiding structure between the plunger and cylinder of a plunger pump according to claim 3, characterized in that: The outer wall of the ball head (7) is coated with a nickel-chromium alloy plating layer (14), and the outer wall of the nickel-chromium alloy plating layer (14) is coated with a friction-reducing plating layer (3).

6. The sealing and guiding structure between the plunger and cylinder of a plunger pump according to claim 1, characterized in that: The composite guide bushing (8) is made of fiber-reinforced polymer composite material, and the surface of the plunger body (2) is chrome-plated.

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