Crosshead block and plunger pump

Abstract

The present disclosure relates to a crosshead block which is a substantially rectangular block formed by an integrated molding process and has a front end surface, a rear end surface, an upper end surface, a lower end surface, and side end surfaces, the crosshead block being provided with a plurality of crosshead internal cavities each extending in a longitudinal direction of the crosshead block and penetrating through the block, the plurality of crosshead internal cavities being arranged in a lateral direction of the crosshead block. The crosshead block is further provided with an embedded lubricating oil passage which is oil holes and oil passages formed in the block of the crosshead block and communicate with each other, and the embedded lubricating oil passage includes a main oil passage and branch oil passages. The present disclosure also relates to a plunger pump provided with the above crosshead block. The crosshead block and the plunger pump according to the present disclosure make the lubricating oil passage system easy to manufacture, more reliable, and easier to maintain by providing the embedded lubricating oil passage.

Description

Technical Field

[0001] The present invention relates to a crosshead housing for a plunger pump and a plunger pump having said crosshead housing, the crosshead housing having an integrally formed structure. Background Technology

[0002] Fracturing pumps (also known as plunger pumps) are widely used in the petroleum industry as essential equipment for increasing oil and gas production. They play a particularly important role in enhancing production in older, mid-to-late-stage oilfields and in the development of emerging shale gas fields.

[0003] A fracturing pump mainly consists of three subsystems: a gearbox, a power unit, and a hydraulic unit. The gearbox reduces the high-speed power input from the power source to low-speed power before sending it to the power unit. The power unit connects the gearbox and the hydraulic unit valve box, converting the rotational mechanical energy from the gearbox into reciprocating mechanical energy to drive the hydraulic unit's suction and discharge operations. The hydraulic unit pressurizes the low-pressure fluid to high-pressure fluid and outputs it to the high-pressure manifold.

[0004] The power-end assembly mainly consists of a housing, crankshaft and connecting rod assembly, crosshead and tie rod assembly, and lubrication system. The power-end housing primarily comprises a crankcase and a crosshead housing. One end of the crankcase is connected to the crosshead housing, and the other end of the crosshead housing is connected to the hydraulic pump head body via a connecting device. Currently, the most common fracturing pumps in the industry are five-cylinder fracturing pumps, meaning their crankshaft is often a six-support, five-crankshaft integral structure. The crankshaft connects to the big end of the connecting rod, and the small end, small end bearing, and pins connect to the crosshead in the crosshead housing. As the crankshaft rotates, the crosshead reciprocates within the crosshead housing, thereby driving the connected plunger to reciprocate.

[0005] The housing of the power unit is a key component of the fracturing pump, housing all power unit parts and bearing all loads generated by these parts during operation. Therefore, the superior mechanical properties of the power unit housing have a decisive impact on the service life of the fracturing pump. Based on different housing structure compositions, the power unit housing can be divided into integral and split structures.

[0006] Currently, the split-type structure is assembled from a crankcase and a crosshead housing welded from high-strength alloy plates. Common processes include welding, heat treatment (stress-relieving annealing), rough machining, defect grinding, re-welding, heat treatment of the welded parts, and inspection before completion. For example, the power end housing of the fracturing pump developed by FMC uses a split-welded structure. GD's 5000thunder power end also adopts a long-stroke (11-inch) and split-type structure design (crankcase + crosshead housing separate design). Furthermore, because welding is a localized, rapid heating and cooling process, the welded area cannot freely expand and contract due to the constraints and limitations of the surrounding material. When the tensile stress at the weld joint approaches the material's yield limit after cooling, adverse consequences such as weld cracking and housing deformation may occur. While the defects at the aforementioned welds can be mitigated to some extent by eliminating internal stress through appropriate welding processes and heat treatment, the unmelted base material around the weld (heat-affected zone) undergoes changes in its metallographic structure and mechanical properties due to heat. Under the influence of welding thermal cycles, this results in uneven microstructure distribution, inevitably leading to welding internal stress and becoming a source of fatigue cracks in the component. The application scenarios and operating environments of fracturing pumps are extremely harsh, with the power end casing subjected to continuous impacts from high-pressure, cyclical pulse loads. Welded power end casings have poor impact resistance and are highly susceptible to cracking near the welds, leading to casing cracking, ultimately causing support failure, affecting fracturing operation efficiency, and even posing safety hazards. Currently available welded power end casings have a lifespan of at most 2000 to 3000 hours, and even after repairs following a single failure, it is difficult to exceed the system's design life (5000 hours). Furthermore, the gradual propagation of weld cracks significantly reduces the internal consistency and connection strength of the support material, resulting in insufficient overall casing stiffness and strength, causing deformation of the casing under high-pressure pulse loads. This abnormal housing deformation will change the clearance between the sliding surfaces, affecting the input and establishment of the lubricating oil film, leading to abnormal wear or even burning on the surfaces of key components such as main bearings and bushings.

[0007] Furthermore, during the high-speed reciprocating motion of the power unit, if a large amount of heat is not dissipated in time, critical components such as the crankshaft, crosshead, connecting rod, and plunger will malfunction due to overheating. Therefore, the design of the lubrication system is crucial for the continuous operation of the power unit. The fracturing pump relies on the reciprocating motion of the plunger within the cylinder to change the volume of the sealed working cavity, thus achieving fluid suction and discharge. Therefore, the lubricating oil also serves as an auxiliary seal. Power unit lubrication often employs forced lubrication, with an external lubrication system providing lubricating oil at a certain pressure. In current power unit housings with welded structures, due to the high hardness and limited thickness of the alloy plates, the lubrication circuit mainly relies on adding external connecting oil pipes and internal oil pipes to establish the oil path. This delivers the lubricating oil to lubrication points (such as the crankshaft, multiple bearings, connecting rod small end bearings, etc.), and then through overall or partial recovery, filtration, and cooling, ensures the fracturing pump has optimal operating performance and the longest service life. Such a lubrication circuit requires a large number of high and low pressure lubrication oil pipes, resulting in numerous joints and a complex pipeline layout. The installation process for pipelines is cumbersome, and the reliability of connections is difficult to control, potentially leading to loosening under the pressure of internal lubricating oil. Furthermore, for ease of installation, lubricating oil pipes often use flexible hoses, which, when exposed to air for extended periods, are prone to corrosion and wear, increasing the risk of leaks and resulting in high maintenance and repair costs. In addition, insufficient rigidity in welded housings can cause deformation, altering the relative positions of the originally tightly contacting sealing surfaces, affecting the sealing effect, making it difficult to establish the pressure required for forced lubrication, thus impacting lubrication efficiency and causing oil and gas leaks. Moisture ingress due to seal failure can also affect lubricating oil performance, altering viscosity, weakening oil film support strength, and accelerating oil oxidation. Hydrolysis of additives weakens or even eliminates the basic properties of lubricating oil, such as oxidation stability, extreme pressure anti-wear properties, and detergency and dispersancy, leading to poor anti-foaming properties, excessive foaming in the lubrication system, reduced lubrication effectiveness, and in severe cases, cavitation and hydrogen embrittlement of metal materials.

[0008] To address the various problems associated with the welded housing, increasing the housing thickness and weld radius are relatively simple and reliable solutions. However, these measures increase the overall pump weight, increase the load on the chassis / skid, and waste transportation resources. Furthermore, under load, excessively thick housings cause large areas of internal structure to be compressed, leading to stress accumulation and inability to release, resulting in localized stress concentration and significantly impacting the housing's service life. Even if weight can be reduced by designing grooves in the housing's inner wall and supports, this greatly increases the number of machining steps, resulting in significant material waste and hindering cost reduction.

[0009] In terms of manufacturing, the production process of welded power end housings is extremely complex, typically involving a series of steps including material preparation, assembly, spot welding, preheating, welding, grinding, heat treatment, flaw detection, rough machining, secondary heat treatment, and finish machining. During this process, the manufacturing precision and quality of each step must be strictly guaranteed; otherwise, dimensional and shape errors can easily accumulate and amplify. Errors generated in each of these steps can lead to abnormal subsequent fits, resulting in serious consequences such as connection failure, seal leakage, component wear, and housing vibration. Even if the accumulated errors from these complex processes can be controlled and compensated for through precision machining, the resulting enormous labor costs and time consumption are undeniable and unbearable. Summary of the Invention

[0010] Technical problems to be solved

[0011] Given the aforementioned problems with welded structures, some manufacturers have proposed using a split casting method to manufacture crosshead boxes. For example, KERR's patent application US2022 / 0163034 A1 discloses a crosshead box body manufactured using a split casting method. However, such cast crosshead boxes, due to design and manufacturing process issues, result in excessive weight and volume, making transportation and assembly inconvenient. In addition, other problems exist, such as concentrated stress at support points, leading to potential failure in overall strength and rigidity; a loose overall structure resulting in higher torque during operation and reduced service life; a shared high- and low-pressure oil circuit in the lubrication system, leading to insufficient lubrication for some components while excessive lubrication for others, resulting in poor overall lubrication; external lubrication pipelines increasing the process flow and diminishing the advantages of casting; and poor overall sealing, making oil and gas leaks likely.

[0012] In view of the above problems, this disclosure aims to provide an integrated crosshead box that allows for easy installation of a more reliable and easy-to-maintain lubrication system. Furthermore, it fully leverages the advantages of a one-piece casting process, facilitating manufacturing and processing, resulting in a relatively light overall weight, high structural strength and rigidity, and a longer service life.

[0013] Technical solutions to solve technical problems

[0014] This disclosure provides a crosshead housing, which is a generally rectangular housing formed by an integral molding process, and has a front end face, a rear end face, an upper end face, a lower end face, and a side end face. The crosshead housing is provided with a plurality of crosshead cavities, each of which extends longitudinally along the crosshead housing and penetrates the housing body. The plurality of crosshead cavities are arranged transversely along the crosshead housing. The crosshead housing is also provided with an embedded lubricating oil passage, which is an interconnected oil hole and oil channel formed within the housing body of the crosshead housing, and the embedded lubricating oil passage includes a main oil passage and branch oil passages.

[0015] Preferably, the main oil passage extends laterally along the crosshead box, and the branch oil passage extends longitudinally along the crosshead box.

[0016] Preferably, the embedded lubrication circuit includes a high-pressure lubrication circuit. The high-pressure lubrication circuit lubricates the crosshead bearings and connecting rod bearings operating within the crosshead housing. The high-pressure lubrication circuit may include a high-pressure inlet located on the side end face of the crosshead housing. The high-pressure inlet may be located on a flat connecting plane formed on the side end face. The high-pressure lubrication circuit may include a filter and an overflow valve.

[0017] Preferably, the embedded lubrication circuit includes a low-pressure lubrication circuit. The low-pressure lubrication circuit lubricates the crosshead sleeve. The low-pressure lubrication circuit may include a low-pressure inlet located on the side end face of the crosshead housing. The low-pressure inlet may be located on a flat connecting plane formed on the side end face. The low-pressure lubrication circuit may include a filter and an overflow valve.

[0018] Preferably, the embedded lubrication circuit is provided with a branch circuit for supplying oil to the crankcase, and the branch circuit for supplying oil to the crankcase has an oil outlet leading to the crankcase on the rear end face of the crosshead housing.

[0019] Preferably, a sealing ring is provided on the outer periphery of the oil outlet as a local sealing element.

[0020] Preferably, the inner cavity of each crosshead is approximately cylindrical.

[0021] Preferably, the crosshead box further includes a crosshead slide sleeve having a shape that matches the inner cavity of the crosshead and can be embedded in the inner cavity of the crosshead.

[0022] Preferably, the crosshead sleeve is provided with an oil hole penetrating the sleeve wall, and the oil hole is part of the branch oil passage.

[0023] Preferably, one end of the crosshead slide sleeve is provided with at least one recessed portion that is recessed inward along the longitudinal direction of the crosshead slide sleeve. Alternatively or alternatively, the other end of the crosshead slide sleeve is provided with at least one protruding portion that protrudes outward along the longitudinal direction of the crosshead slide sleeve.

[0024] Preferably, there are two recesses and / or two protrusions, and when the crosshead slide is inserted into the crosshead cavity, the two recesses are located at the top and bottom of the crosshead cavity, and the two protrusions are also located at the top and bottom of the crosshead cavity.

[0025] Preferably, the front end face of the crosshead inner cavity is provided with a limiting groove, and the end head of the crosshead slide sleeve located at one end of the front end face is provided with a positioning pin hole. The positioning pin hole and the limiting groove are connected by a pin inserted into the pin hole to axially position the crosshead slide sleeve in the crosshead inner cavity.

[0026] Preferably, the crosshead box is further provided with at least one first bolt hole, each first bolt hole being located above and below the inner cavity of the plurality of crossheads and extending longitudinally along the crosshead box and penetrating the box body.

[0027] Preferably, the crosshead box is further provided with at least one second bolt hole, each second bolt hole extending longitudinally along the crosshead box and penetrating the box body, and on both the front end face and the rear end face, the second bolt hole is located outside the first bolt hole.

[0028] Preferably, the second bolt holes are also provided on the front end face of the crosshead box, at the edges on both sides of the crosshead box body.

[0029] Preferably, a flange is provided on the front end face of the crosshead box on the outer periphery of the crosshead box, and the second bolt hole is provided on the flange.

[0030] Preferably, on the rear end face of the crosshead box, flange portions are provided on both the upper and lower edges of the crosshead box, and the second bolt hole is provided on the flange portions.

[0031] Preferably, sealing grooves are provided on the front end face and the rear end face of the crosshead box, and the sealing area surrounded by the sealing grooves includes at least the inner cavity of the crosshead and the exhaust cavity.

[0032] Preferably, the crosshead housing also includes a process hole penetrating the housing body. The process hole can be formed at a position corresponding to the inner cavity of the crosshead. Furthermore, the process hole can be located at least near the embedded lubrication passage.

[0033] Preferably, the process hole formed on the top of the crosshead box has a downward protruding structure that protrudes towards the inner cavity of the crosshead.

[0034] Preferably, the process hole formed at the bottom of the crosshead box has an upwardly protruding structure that protrudes towards the inner cavity of the crosshead.

[0035] Preferably, the crosshead box is further provided with a mounting boss formed on the side end face.

[0036] A second aspect of this disclosure provides a plunger pump comprising a crankcase, a crosshead housing as described above, and a spacer.

[0037] Preferably, locating pin holes are provided on the mating end faces of the crankcase, the crosshead housing, and the spacer, for aligning and positioning the crankcase, the crosshead housing, and the spacer.

[0038] Preferably, the plunger pump further includes a gearbox and a support lug is provided on a mounting boss formed on the side end face of the crosshead housing, the support lug being connected to a support assembly of the gearbox.

[0039] Beneficial effects

[0040] According to this disclosure, a novel one-piece molded crosshead box is provided, featuring a more reliable and easier-to-maintain lubrication system that is readily manufactured. The crosshead box of this disclosure also has excellent internal fluid passages, ensuring that the internal air pressure remains balanced during operation, improving the smoothness of equipment operation and service life. Furthermore, the crosshead box of this disclosure features a more reliable and easier-to-maintain lubrication system that is readily manufactured. The crosshead box of this disclosure also significantly reduces overall weight while increasing strength and rigidity. Minimal deformation at key mating points enhances lubrication, sealing, and connection reliability. It exhibits good resistance to bending and torsion, shock absorption, and low notch sensitivity. Additionally, it greatly simplifies the manufacturing process, reducing time, labor, and raw material costs. Combined with this one-piece molded crosshead box, improvements and optimizations to various pump components can lead to a revolutionary fracturing pump design, while simultaneously fostering a platform-based development approach. Attached Figure Description

[0041] Figure 1 This is a perspective view illustrating a schematic structure of a crosshead box according to an embodiment of the present disclosure;

[0042] Figure 2 This is a perspective view illustrating a schematic structure of a crosshead box according to an embodiment of the present disclosure;

[0043] Figure 3 This is a schematic diagram illustrating the structure of the crosshead cavity of the crosshead box according to an embodiment of the present disclosure;

[0044] Figure 4 This is a schematic diagram illustrating the shape of the crosshead cavity in a prior art crosshead box as a comparative example.

[0045] Figure 5a and Figure 5b This is a schematic diagram illustrating an alternative example of the structure of the crosshead cavity of the crosshead box according to an embodiment of the present disclosure;

[0046] Figure 6 This is a schematic diagram illustrating the structure of the crosshead slide sleeve of the crosshead box according to an embodiment of the present disclosure;

[0047] Figure 7 This is a schematic diagram illustrating the structure of the crosshead slide sleeve of the crosshead box according to an embodiment of the present disclosure;

[0048] Figure 8 This is a schematic diagram illustrating the positioning element of the crosshead slide sleeve of the crosshead box according to an embodiment of the present disclosure;

[0049] Figure 9 This is a schematic diagram illustrating the structure of the protrusion of the crosshead slide sleeve of the crosshead box according to an embodiment of the present disclosure.

[0050] Figure 10 This is a cross-sectional schematic diagram illustrating the positional fit between the protrusion of the crosshead slide sleeve and the end of the crosshead oil groove in an embodiment of the present disclosure.

[0051] Figure 11 This is a perspective view illustrating the structure of the exhaust chamber of a crosshead box according to an embodiment of the present disclosure;

[0052] Figure 12 This is a schematic end view illustrating the structure of the exhaust chamber of the crosshead box according to an embodiment of the present disclosure.

[0053] Figure 13 This is a cross-sectional schematic diagram illustrating the structure of the exhaust chamber of a crosshead box according to an embodiment of the present disclosure;

[0054] Figure 14 This is a partially enlarged view illustrating an exemplary structure of a fluid channel at the front end face of a crosshead box according to an embodiment of the present disclosure;

[0055] Figure 15 This is a partially enlarged view illustrating another exemplary structure of the fluid passage at the front end face of the crosshead box according to an embodiment of the present disclosure;

[0056] Figure 16This is a partially enlarged view illustrating yet another exemplary structure of the fluid passage at the front end face of the crosshead box according to an embodiment of the present disclosure;

[0057] Figure 17 This is a schematic diagram illustrating the principle of the function of the exhaust chamber and fluid passage of the crosshead box according to an embodiment of the present disclosure;

[0058] Figure 18 This is a schematic diagram illustrating the principle of the function of the exhaust chamber and fluid passage of the crosshead box according to an embodiment of the present disclosure;

[0059] Figure 19 This is a schematic diagram illustrating the structure of the reinforcing beam of the crosshead box according to an embodiment of the present disclosure;

[0060] Figure 20 This is a schematic diagram illustrating another structure of the reinforcing beam of the crosshead box according to an embodiment of the present disclosure;

[0061] Figure 21 This is a cross-sectional view illustrating an example of the cross-sectional shape of the reinforcing beam of a crosshead box according to an embodiment of the present disclosure;

[0062] Figure 22 This is a schematic diagram illustrating the structure of the transition region of the reinforcing beam of a crosshead box according to an embodiment of the present disclosure;

[0063] Figure 23 This is a cross-sectional view illustrating the structure of the multifunctional structural hole of the crosshead box according to an embodiment of the present disclosure;

[0064] Figure 24 This is a schematic cross-sectional view of the embedded lubrication oil passage of a crosshead box according to an embodiment of the present disclosure;

[0065] Figure 25 This is a schematic diagram illustrating the manufacturing process of the embedded lubrication oil passage of the crosshead box according to an embodiment of the present disclosure;

[0066] Figure 26 This is a schematic diagram illustrating the manufacturing process of the embedded lubrication oil passage of the crosshead box according to an embodiment of the present disclosure;

[0067] Figure 27 This is a schematic diagram illustrating the overall layout of the embedded lubrication oil passage of a crosshead gearbox according to an embodiment of the present disclosure;

[0068] Figure 28 This is a schematic diagram illustrating the alignment position of the oil outlet of the embedded lubrication oil passage in a crosshead box according to an embodiment of the present disclosure.

[0069] Figure 29This is a schematic diagram illustrating the lubricating oil recovery path of the embedded lubricating oil circuit of the crosshead box according to an embodiment of the present disclosure.

[0070] Figure 30 This is a schematic diagram illustrating the structure of the oil injection hole in the lubrication circuit of a crosshead box according to an embodiment of the present disclosure;

[0071] Figure 31 This is a schematic diagram illustrating the connection end face of the crosshead housing and crankcase according to an embodiment of the present disclosure;

[0072] Figure 32 This is a schematic diagram illustrating the connection end face of the crosshead box and the spacer according to an embodiment of the present disclosure;

[0073] Figure 33 This is an exploded view illustrating the connection assembly of the crosshead housing, crankcase, and spacer according to an embodiment of the present disclosure.

[0074] Figure 34a and Figure 34b This is a schematic diagram illustrating the arrangement of the connecting seals between the crosshead housing, crankcase, and spacer according to an embodiment of the present disclosure;

[0075] Figure 35 This is a schematic diagram illustrating a partial seal around the oil outlet of the lubrication passage in a crosshead box according to an embodiment of the present disclosure.

[0076] Figure 36 This is a schematic diagram illustrating the connection and positioning of the crosshead housing, crankcase, and spacer according to an embodiment of the present disclosure;

[0077] Figure 37 This is a schematic diagram illustrating the structure of the process hole and / or observation window of the crosshead box according to an embodiment of the present disclosure;

[0078] Figure 38 This is a partial enlarged view illustrating the structure of the boss of the process hole and / or observation window of the crosshead box according to an embodiment of the present disclosure.

[0079] Figure 39 This is a schematic diagram illustrating the structure of a mounting boss of a crosshead box according to an embodiment of the present disclosure, and a support lug and a lifting lug mounted thereon. Detailed Implementation

[0080] The technical solutions of various embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0081] It should be noted that the use of terms such as "approximately" and "about" in the following detailed description and claims is to take into account factors such as manufacturing tolerances and machining accuracy that are understood by those skilled in the art, and will not lead to ambiguity in the description or unclear scope of protection. Furthermore, the orientations such as "upper," "lower," "left," "right," "front," and "rear" appearing herein are merely directions defined in conjunction with the accompanying drawings for ease of explanation. Those skilled in the art, after reading this document, will be able to easily discern the orientation corresponding to the orientation described herein when the device is rotated or moved and exhibits an orientation inconsistent with that described herein.

[0082] Note that the same structures, elements, or parts in the accompanying drawings are indicated by the same reference numerals.

[0083] 1. Overview of the crosshead box

[0084] Figure 1 and Figure 2 A perspective view of a crosshead box 1000 according to a preferred embodiment of the present disclosure is shown. Figure 1 and Figure 2 The present invention uses a 5-cylinder crosshead box 1000 as an example. However, the crosshead box 1000 disclosed herein can obviously also be used for crosshead boxes 1000 with other cylinder numbers, such as 3-cylinder and 7-cylinder models. Figure 1 and Figure 2As shown, the crosshead housing 1000 is generally rectangular in shape and is integrally manufactured using a casting process. It has a front end face 1001 connected to the spacer 3000, a rear end face 1002 connected to the crankcase 2000, an upper cover plate 1003 and a lower cover plate 1004 located above and below the main body of the crosshead housing, side end plates 1005 located on both sides of the housing, and vertical plates located between the crosshead cavities. It should be noted that in this specification, the direction of the reciprocating motion of the crossheads between the front end face 1001 and the rear end face 1002 within the crosshead housing 1000 is referred to as the axial direction or longitudinal direction of the crosshead housing 1000, and the arrangement direction of the multiple crossheads within the crosshead housing 1000 is referred to as the transverse direction of the crosshead housing 1000. Furthermore, the side of the crosshead housing 1000 connected to the spacer 3000 is referred to as the front side or front end of the crosshead housing 1000, and the side of the crosshead housing 1000 connected to the crankcase 2000 is referred to as the rear side or rear end of the crosshead housing 1000. Additionally, the upper cover plate 1003, lower cover plate 1004, side end plate 1005, and spacer plate 1101 described below are all conventional names used in the art for ease of reading by those skilled in the art. However, it should be understood that since the crosshead housing 1000 according to the embodiments of this disclosure is integrally formed using a casting process, the upper cover plate 1003, lower cover plate 1004, side end plate 1005, and spacer plate 1101 are not necessarily separate plates, but rather different components of an integrally formed housing. Therefore, the upper mask 1003 can sometimes be regarded as the upper end face of the crosshead box in this article, the lower mask 1004 can sometimes be regarded as the lower end face of the crosshead box in this article, and the side end plate 1003 can sometimes be regarded as the side end face of the crosshead box in this article.

[0085] Depend on Figure 1 and Figure 2 As can be seen from the embodiments of this disclosure, the entire crosshead box 1000 is integrally formed by casting. By employing casting, defects caused by welding are avoided, structural rigidity is ensured, fatigue strength is increased, and service life is extended. Furthermore, integral casting greatly reduces process complexity, saves time, labor, and raw material costs, and improves yield. It should be understood that other casting materials known in the art can also be selected to form the crosshead box 1000, depending on the requirements.

[0086] like Figure 1 and Figure 2As shown, a plurality of crosshead cavities 1100 are formed in the crosshead housing 1000. The crosshead cavities 1100 extend longitudinally within the crosshead housing 1000, extending from the front end face 1001 to the rear end face 1002. The crosshead cavities 1100 accommodate the crosshead assembly and the sliding sleeve described below. The crosshead assembly reciprocates within the crosshead cavities 1100 along the axial direction of the crosshead housing 1000. The plurality of crosshead cavities 1100 are arranged side-by-side transversely along the crosshead housing 1000. The number of crosshead cavities 1100 depends on the number of crosshead assemblies.

[0087] Preferably, an exhaust chamber 1200 is provided above and / or below the crosshead cavity 1100. Each exhaust chamber 1200 has a flat polygonal shape and extends longitudinally within the crosshead housing 1000, penetrating from the front end face 1001 to the rear end face 1002 of the crosshead housing 1000. The front end of the exhaust chamber 1200 is in fluid communication with an exhaust passage (described in detail later) provided on the front end face 1001 of the crosshead housing 1000, and the rear end of the exhaust chamber 1200 is in fluid communication with the cavity of the crankcase 2000.

[0088] Preferably, at the junction between the crosshead inner cavities 1100 and 1100, at least one multi-functional structural hole 1300, which will be described in detail below, is provided. The multi-functional structural hole 1300 may, for example, have a circular or triangular shape as illustrated, and extend longitudinally within the crosshead housing 1000, penetrating from the front end face 1001 to the rear end face 1002 of the crosshead housing 1000. The multi-functional structural hole 1300 may be provided in the upper and / or lower parts of the crosshead housing 1000 as needed.

[0089] Preferably, an embedded lubrication passage 1500 is provided within the crosshead housing 1000. Unlike oil passages in the prior art that are provided through additional connecting oil pipes and hoses, the embedded lubrication passage 1500 is an interconnected oil hole and oil channel formed within the housing of the crosshead housing 1000 (e.g., formed by drilling). Furthermore, the embedded lubrication passage 1500 typically includes at least one main oil passage and at least one branch oil passage.

[0090] In addition, such as Figure 1 and Figure 2 As shown, the crosshead box 1000 is also equipped with components such as connection holes and observation windows, which will be described in detail below.

[0091] 2. Crosshead inner cavity and sliding sleeve

[0092] 2.1 Shape of the inner cavity of the crosshead

[0093] Figure 3A schematic diagram of the structure of the crosshead cavity 1100 in the crosshead box 1000 according to this disclosure is shown. Figure 3 As shown, the crosshead cavity 1100 has, for example, a generally cylindrical shape. In other words, the crosshead cavity 1100 has a generally circular shape in a cross section perpendicular to the axial direction of the crosshead housing 1000. In this case, the spacer plate 1101 between the crosshead cavities 1100 has a corresponding double-arc shape that is thicker at the top and bottom and thinner in the middle. The cylindrical shape of the crosshead cavity 1100 reduces the size of the crosshead housing 1000, facilitates casting, and facilitates subsequent assembly of the sliding sleeve.

[0094] In existing technology, the crosshead cavity 1100 is basically... Figure 4 The crosshead housing shown is similar to a running track, with straight sides and rounded top and bottom edges, resembling a cuboid. This is because if a near-circular crosshead cavity were formed through welding, the resulting upper and lower parts would be relatively flat, requiring a larger cylinder spacing. Furthermore, while theoretically the "track-shaped" design could reduce the contact surface pressure between the crosshead assembly and the crosshead cavity, and the rectangular sides could reduce the cylinder spacing, local deformation under heavy loads would cause the crosshead assembly and cavity to change from surface contact to line contact, resulting in actual surface pressure much greater than the theoretical value. In the crosshead housing 1000 according to this disclosure, due to the use of integral molding technology, the spacer 1101 between the crosshead cavities 1100 and the outer shell of the crosshead housing 1000, including the side end plates 1005 and the upper and lower cover plates 1004, are integrally cast. Therefore, the crosshead cavity 1100 can be easily cast into a roughly cylindrical shape as needed. Furthermore, due to the use of one-piece casting, the structure has good rigidity and easily meets the cylinder diameter requirements, so there is no need to use a "racetrack-shaped" design, and a simpler cylindrical shape can be used instead.

[0095] It should be understood that the crosshead cavity 1100 according to this disclosure can, of course, also be designed into an approximate cuboid shape similar to that in the prior art, or any other desired shape, fully leveraging the advantages of casting. For example, when the crosshead cavity 1100 according to this disclosure is designed into an approximate cuboid shape similar to that in the prior art, such as... Figure 5a and Figure 5bAs shown, the spacers 1101 between the crosshead cavities 1100 can be formed as multiple vertically extending spacers 1102 arranged side-by-side along the crosshead axis. The gaps between the spacers allow fluid communication between adjacent crosshead cavities 1100, which can be used for oil and air venting, as will be described in detail later. In this case, combined with the venting chamber and fluid channel described later, further improved venting performance can be expected. Furthermore, in this case, in the two crosshead cavities 1100 located at the outermost ends on both sides of the crosshead housing 1000, there is also a gap between the crosshead assembly and the side end plates 1005 on both sides of the crosshead housing 1000, which can also serve the oil and air venting function described in detail later. Additionally, in this case, the sliding sleeve also adopts a tile-shaped, two-piece structure commonly used in the art. This will not be elaborated further here.

[0096] 2.2 Crosshead Sliding Sleeve

[0097] A crosshead slide sleeve 1400 is disposed in the crosshead cavity 1100. The crosshead slide sleeve 1400 contacts the crosshead and bears the reciprocating motion of the crosshead within the crosshead cavity 1100. In one embodiment of the crosshead housing 1000 according to this disclosure, as... Figure 6 As shown, the crosshead sleeve 1400 has a cylindrical shape that can be embedded in the cylindrical crosshead cavity 1100. Compared to the two-piece split structure mentioned above, this one-piece crosshead sleeve 1400 can enhance the bending and torsional stiffness of the structure, reduce bearing wear at the crosshead position, and solve problems such as bearing fatigue fracture. Figure 6 and Figure 7 As shown, the crosshead sleeve 1400 is designed with an oil hole 1401 penetrating the sleeve wall. This oil hole 1401 is used for fluid communication with the lubrication oil passage described below, allowing lubricating oil to flow. The oil hole can be located at any position outside the ends of the crosshead sleeve 1400 as needed. The location, number, and shape of the oil holes 1401 can be determined according to the oil passage and the lubrication requirements of the lubricated components.

[0098] In addition, such as Figure 7 and Figure 8As shown, the end of the crosshead slide sleeve 1400 near the spacer 3000 (i.e., the front end) is designed with a slide sleeve positioning pin hole 1402, in which a flexible cylindrical pin for positioning the crosshead slide sleeve 1400 can be installed. The position of the pin hole 1402 is not limited, as long as it meets the positioning requirements and does not affect other structural functions. Preferably, the pin holes 1402 should not be simultaneously arranged in circumferentially symmetrical positions such as directly above and below, or directly to the left and right, to prevent difficulty in determining the correct angle and orientation of the slide sleeve during installation. During the assembly of the crosshead slide sleeve 1400, the pin hole 1402 can, for example, cooperate with the limiting groove 1006 located at the edge of the front end face 1001 of the crosshead box 1000 in the inner cavity 1100 of the crosshead to achieve axial positioning of the crosshead slide sleeve 1400 along the crosshead box 1000. For example, during installation, the elastic cylindrical pin is securely installed into the locating pin hole 1402 of the crosshead slide sleeve 1400. The crosshead slide sleeve 1400 is inserted axially from the front end of the crosshead housing 1000 into the crosshead inner cavity 1100 until the side of the elastic pin contacts the surface of the limiting groove, thus completing the installation. During installation, the slide sleeve can be cooled with liquid nitrogen first, and the thermal expansion and contraction effect will cause the slide sleeve size to shrink. Then, the cooled slide sleeve is inserted into the crosshead inner cavity in a short time. After the slide sleeve temperature rises to room temperature, its size expands, creating an interference fit with the crosshead inner cavity, thereby ensuring that the slide sleeve will not come out of the crosshead inner cavity during the operation of the crosshead assembly. It should be understood that the positioning parts are not limited to elastic cylindrical pins, and the cross-sectional dimensions of the pins can also be adjusted as needed to accommodate the size changes of the pin hole caused by the warming of the crosshead slide sleeve 1400 after cold installation. The shape, position, and quantity of the aforementioned pins and grooves can also be selected according to the actual situation, as long as they correspond. In addition, other positioning methods can be used, such as first aligning the limiting groove of the crosshead box 1000 with the positioning pin hole of the crosshead slide sleeve 1400, and then driving in the positioning pin for positioning.

[0099] like Figure 7 As shown, the front end of the crosshead sleeve 1400 is provided with a recess 1404. This recess 1404 is recessed from the front end of the crosshead sleeve 1400 toward the rear end in the axial direction of the crosshead housing 1000, thereby matching the shape of the groove on the front end face 1001 of the crosshead housing 1000, which will be described below, to jointly form a fluid passage 1201 for oil and air drainage. Figure 7 and Figure 9As shown, the top and bottom of the end of the crosshead sleeve 1400 connected to the crankcase 2000 (i.e., the rear end) are respectively formed with extended protrusions 1403. These protrusions 1403 extend from the rear end of the crosshead sleeve 1400 toward the crankcase 2000 in the axial direction of the crosshead case 1000. For example, when the crosshead sleeve 1400 is installed in the crosshead cavity 1100, the recess 1404 and the protrusion 1403 are located at the top and bottom of the crosshead cavity 1100, respectively. Figure 7 As shown, a transition fillet is preferably formed in the transition area between the protrusion 1403 and the non-protrusion of the rear end face 1002 of the crosshead slide 1400, so as to maximize the rigidity at the root of the protrusion 1403 and reduce the stress accumulation caused by the pressure of the sealing oil pressure at the bottom of the crosshead. Figure 7 The illustration shows an example where there are two recesses 1404 and two protrusions 1403. However, it should be understood that the recesses 1404 and protrusions 1403 are not limited to two; there may be one or more.

[0100] The presence of the protrusion 1403 allows the crosshead sleeve 1400 to be adapted to crosshead boxes 1000 of different lengths, satisfying the sealed space required for contact between the crosshead assembly and the oil film on the sleeve contact surface for crossheads of different running lengths, thereby enabling the production of a common platform for the one-piece molded crosshead box 1000. Figure 10 As shown, the size of the protrusion 1403 is related to the size and position of the oil groove at the bottom of the crosshead. Specifically, in the actual working state of the crosshead and crosshead housing, the protrusion 1403 of the sliding sleeve needs to cooperate with the oil groove at the bottom of the crosshead to form a seal. Therefore, the size of the protrusion 1403 of the sliding sleeve must be sufficient to cover the sealing length of the oil groove at the bottom of the crosshead. Figure 10 In the diagram, the dark shading at the bottom of the crosshead indicates the oil groove at the bottom of the crosshead. The "sealing length" of the oil groove refers to the length between the two ends of the oil groove 1502. The portions of the oil groove outside the ends 1502 at both ends mate with the sliding sleeve 1400 to form a straight seal structure. When the crosshead travels to its extreme position on the crankcase side within the crosshead sliding sleeve 1400, a portion of the oil groove may be outside the crosshead inner cavity 1100. That is, in Figure 10As can be seen, a portion of the dark shade representing the oil groove is located outside the crosshead inner cavity 1100. In this case, the presence of the protrusion 1403 of the sleeve ensures that the lubricating oil in the crosshead oil groove will not leak out under certain pressure. In other words, the protrusion 1403 needs to meet the sealing requirements of the oil groove end 1502 when the crosshead is located in the crosshead housing 1000 closest to the crankcase 2000. At the same time, the protrusion 1403 can be adapted to a wide range of plunger lengths and their plunger strokes. When the plunger is installed and the plunger is in stroke motion within the adaptation range, it is not necessary to replace the sleeve 1400 with other specifications and lengths.

[0101] It should be noted that in the crosshead box 1000 according to this disclosure, the aforementioned crosshead sliding sleeve 1400 is preferred, but it is also possible to omit the crosshead sliding sleeve 1400, that is, to use the inner surface of the crosshead cavity 1100 as a sliding sleeve. This is because the crosshead box 1000 according to the embodiment of this disclosure is made of ductile iron using an integral casting process. Ductile iron material has a high spheroidization rate, and graphite can act as a self-lubricant under unlubricated conditions. Under lubricated conditions, graphite can not only absorb and retain lubricating oil, but also maintain the continuity of the oil film, thus it can also act as a sliding sleeve. In this case, to improve the sliding effect of the crosshead, fine mesh-like oil-retaining structures can also be machined on the inner surface of the crosshead cavity 1100 to enhance the lubricating effect of the lubricating oil. Compared with the integrated copper sliding sleeve mentioned in the above embodiments, the ductile iron material of the crosshead inner cavity 1100 has better lubrication performance and a simpler structure. It does not require high-precision installation and alignment, thus it is more economical and saves costs.

[0102] Furthermore, when the inner surface of the crosshead cavity 1100 also serves as a sliding sleeve, the casting material needs to achieve the spheroidization rate required for the sliding sleeve performance, and the corresponding protrusions 1403 and concave portions 1404 need to be cast and machined. For example, a spheroidization rate greater than 80% is preferred. In addition, features such as oil holes, concave portions that mate with the venting cavity 1200 (described later), and rounding and contact surfaces where high precision is required or casting technology cannot meet these requirements can also be achieved through subsequent machining or other general methods.

[0103] In the one-piece cast crosshead box 1000, an exhaust chamber 1200 is provided at the connection position between the upper mask 1003 and the lower mask 1004 and the inner cavity of the crosshead cylinder, in order to maintain the air pressure balance of the inner cavity 1100 of the crosshead when the crosshead assembly reciprocates.

[0104] 3. Exhaust chamber and fluid passage

[0105] 3.1 Structure of the exhaust chamber

[0106] In the crosshead housing 1000 according to an embodiment of the present disclosure, a plurality of crosshead exhaust chambers 1200 are respectively provided above and below the crosshead inner cavity 1100 to maintain the air pressure balance of the crosshead inner cavity 1100 when the crosshead assembly reciprocates in the crosshead inner cavity 1100. The exhaust chamber 1200 extends through the crosshead housing 1000 in the axial direction, its front end is in fluid communication with the fluid passage 1201 described later, and its rear end is in fluid communication with the internal cavity of the crankcase 2000. Figures 11 to 13 These are perspective views, end view views, and cross-sectional views showing an exemplary structure of the exhaust chamber 1200 of the crosshead box 1000.

[0107] like Figures 11 to 13 As shown, the exhaust chamber 1200 can be disposed, for example, between the crosshead inner cavity 1100 and the upper cover plate 1003 and lower cover plate 1004 of the crosshead box 1000. In other words, the exhaust chamber 1200 can be disposed, for example, between the main body of the crosshead box 1000 in which the crosshead inner cavity 1100 is formed and the upper cover plate 1003 and lower cover plate 1004 of the crosshead box 1000. The shape of the exhaust chamber 1200 can be designed as needed and has no special requirements. In the illustrated embodiment, the exhaust chamber 1200 has a flat, rounded-corner polygonal shape in a cross section perpendicular to the axial direction of the crosshead box 1000. This shape can make full use of the space above and below the crosshead inner cavity 1100, allowing the exhaust chamber 1200 to take full advantage of the casting process while taking into account both exhaust requirements and the structural rigidity requirements of the box. The exhaust chamber 1200 can also be disposed in other locations, as long as it does not affect the structural rigidity of the box or the structural function of other components.

[0108] It should be noted that the specific shape of the exhaust chamber 1200 is not limited to the shape shown in the figure. For example, it can also be circular or other regular or irregular shapes. When an exhaust chamber 1200 is provided above and below each crosshead cavity 1100, the shapes of the two exhaust chambers 1200 can be symmetrical or asymmetrical. From the perspective of ensuring the overall axial stiffness and bending stiffness of the crosshead box 1000, the symmetrical scheme is preferred. There are no special restrictions on the number and forming method of the exhaust chambers 1200, as long as they meet the exhaust function described below, avoid the bolt bearing area, and do not affect other structural functions. For example, only one exhaust chamber 1200 can be provided above or below each crosshead cavity. In addition, in the illustrated embodiment, the crosshead cavity 1100 and the two exhaust chambers 1200 located above and below it are centrally symmetrical in the transverse direction of the crosshead box 1000, and are also centrally symmetrical in the vertical direction perpendicular to the transverse direction. However, the crosshead cavity 1100 and the two exhaust cavities 1200 located above and below it can also be set to be symmetrical with respect to the horizontal and vertical axes, or even offset in an asymmetrical manner, depending on the design requirements.

[0109] 3.2 Structure of the fluid channel

[0110] Figure 14 This is a partially enlarged view illustrating a preferred embodiment of the fluid channel 1201 at the front end face 1001 of the crosshead box 1000 according to an embodiment of the present disclosure. Figure 14 As shown, at the front end face 1001 of the crosshead housing 1000 (i.e., the end face connected to the spacer 3000), a groove is formed inwardly (i.e., towards the crankcase side) along the axial direction of the crosshead housing 1000 within the housing between the crosshead inner cavity 1100 and the exhaust chamber 1200. This groove allows for fluid communication between the crosshead inner cavity 1100 and the exhaust chamber 1200 at the end face when the crosshead housing 1000 and the spacer 3000 are assembled. This groove is also referred to as the fluid channel 1201. The fluid channel 1201 and the exhaust chamber 1200 together constitute the exhaust passage of the crosshead housing 1000, serving to exhaust and discharge oil (lubricating oil) and maintain the oil-gas balance in the crosshead inner cavity 1100. Furthermore, the recessed shape of the inner recess 1404 of the crosshead slide 1400 described above matches the cross-sectional shape of the groove in the fluid channel 1201, so that when the crosshead slide 1400 is installed in the crosshead cavity 1100, the crosshead slide 1400 will not obstruct the exhaust passage between the crosshead cavity 1100 and the exhaust chamber 1200, and the crosshead cavity 1100 is in fluid communication with the exhaust chamber 1200 via the inner recess 1404 and the fluid channel 1201.

[0111] Figure 14The groove forming the exhaust channel shown has a wave-like arc shape. This is because the inwardly recessed groove at the end face causes the axial material extension length of the housing at the groove to differ from the extension length of the regions on both sides of the groove. Therefore, during the casting process, when transitioning from the groove region to the side regions, large internal stresses are easily generated near their junction, which reduces the structural strength of the casting. By adopting a smooth, wave-like shape design, the length of the junction region changes gradually in a smooth manner, thus reducing the risk of large internal stresses being generated near the intersection when transitioning from the middle region to the side regions, and therefore improving the structural stiffness at this point.

[0112] It is important to understand that, in addition to Figure 14 Besides the wave-like arc shape shown, the fluid channel 1201 can also be formed into other shapes. For example, Figure 15 The figure shows a fluid channel 1201 with an approximately trapezoidal cross section. Figure 16 The diagram illustrates a fluid channel 1201 with an approximately rectangular cross-section. When the fluid channel 1201 has a non-circular polygonal shape, such as a rectangle or trapezoid, etc., ... Figure 15 and 16 As shown, in order to achieve the aforementioned effects of minimizing stress and improving structural rigidity, the transition at the junction of the groove and the two side areas, i.e., the recessed bending area, is achieved by using rounded corners, bevels, or other smooth methods. Furthermore, the size of the fluid channel 1201 is not particularly limited and can be determined based on the size of the exhaust chamber 1200 and the principle of not affecting the structural function of the crosshead housing 1000. Moreover, although only an example of the fluid channel 1201 being formed on the front end face 1001 of the crosshead housing 1000 is shown in the accompanying drawings, it is understood that a similar fluid channel can also be formed on the rear end face 1002 of the crosshead housing 1000 to further facilitate communication between the crosshead inner cavity and the exhaust chamber on the connection side between the crosshead housing and the crankcase.

[0113] 3.3 Functions and roles of the exhaust chamber and fluid passage

[0114] Below, we will refer to Figure 17 and Figure 18 Explain how the exhaust chamber 1200 and fluid passage 1201 maintain the pressure balance within the crosshead cavity 1100. It should be noted that... Figure 17 and 18 The image shows the crosshead housing 1000 and crankcase 2000 joined together, because in use, most of the internal cavities of the crosshead housing 1000 and crankcase 2000 are fluidly connected and functionally closely related.

[0115] Figure 17The diagram illustrates the fluid flow path within the crosshead cavity 1100 as the crosshead assembly slides towards the front end (spacer side) within the crosshead cavity 1100. Figure 17 As shown, under this operating condition, the pressure at the front end of the crosshead cavity 1100 gradually increases. The oil and gas in the front end of the crosshead cavity 1100 flow upwards and downwards into the exhaust chamber 1200 through the fluid channel 1201 at the front end face, and then flow towards the crankcase via the exhaust chamber 1200. The oil and gas in the crankcase 2000 can pass through the connecting rod movable window 2001 of the crosshead case 1000 (see...). Figure 33 The fluid enters the rear end of the crosshead cavity 1100. As the crosshead continues to slide towards the front end, the space at the front end of the crosshead cavity 1100 continues to decrease, and the pressure at the front end of the crosshead cavity 1100 continues to increase. The increased pressure at the front end of the crosshead is transmitted to the exhaust chamber 1200 through the fluid channel 1201, causing a portion of the oil and gas in the exhaust chamber 1200 to enter the rear end of the crosshead cavity 1100 from the rear end of the exhaust chamber 1200 through the connecting rod movable window 2001 of the crankcase 2000, and causing another portion of the oil and gas in the exhaust chamber 1200 to flow into the crankcase 2000 and diffuse. Figure 18 The diagram illustrates the fluid flow path within the crosshead cavity 1100 as the crosshead assembly slides rearward (crankcase side) within the crosshead cavity 1100. Figure 18 As shown, as the crosshead slides towards the rear end (i.e., the crankcase side) within the crosshead cavity 1100, the pressure at the rear end of the crosshead cavity 1100 gradually increases. Oil and gas at the rear end of the crosshead cavity 1100 can enter the rear end of the exhaust chamber 1200 of the crankcase 2000 and the crosshead case 1000 through the connecting rod movable window 2001. As the crosshead continues to slide towards the rear end, the pressure at the rear end of the crosshead cavity 1100 continues to increase. This pressure is transmitted to the exhaust chamber 1200, causing the oil and gas in the exhaust chamber 1200 to flow from the rear end to the front end and enter the front end of the crosshead cavity 1100 through the fluid channel 1201.

[0116] As described above, since the crosshead housing 1000 according to this disclosure is integrally formed by casting, it is possible to achieve an axially penetrating exhaust channel and a fluid channel 1201 located near the crosshead inner cavity 1100, which allow for self-circulation of oil (lubricating oil) and gas in the crosshead inner cavity 1100 through the fluid channel 1201, exhaust chamber 1200, and connecting rod movable window 2001 without the need for external circulation equipment. This ensures that the crosshead inner cavity 1100 maintains pressure balance during the reciprocating motion of the crosshead assembly. The dedicated flow channel and exhaust chamber 1200 also reduce noise generated by high-speed gas flow during the reciprocating motion of the crosshead assembly, and facilitate component assembly and disassembly.

[0117] Furthermore, other design or molding methods can be considered to form an exhaust chamber that is fluidly connected to the crosshead cavity 1100 to achieve pressure balance. For example, the front and rear ends of the crosshead cavity 1100 can be fluidly connected by openings or forming channels at other locations inside the crosshead housing 1000 to assist ventilation. The molding method of such holes and channels is not limited, as long as their location does not affect the crosshead assembly, the cavity support structure, and the bolt fastening function.

[0118] 4. Reinforcing beams and multi-functional structural holes of the crosshead box

[0119] The crosshead box 1000 according to an embodiment of the present disclosure is integrally formed by a casting process. In order to overcome the disadvantage of excessive weight that is common in traditional castings, the crosshead box 1000 according to an embodiment of the present disclosure has undergone special structural optimization in terms of enhancing rigidity and reducing weight, so that the crosshead box 1000 according to an embodiment of the present disclosure is 10% to 16% lighter than the crosshead box 1000 of the same level of welding process while ensuring structural rigidity.

[0120] The structural optimization features of the crosshead box 1000 according to embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.

[0121] 4.1 Strengthening beam

[0122] like Figure 19As shown, within the exhaust cavity 1200, in order to reduce the weight of the crosshead housing 1000, at the position of the main body of the crosshead housing corresponding to the crosshead inner cavity 1100 (i.e., the inner wall of the exhaust cavity 1200 on the side of the crosshead inner cavity 1100), the forming material of the housing is thinned. Only at the front and rear end faces 1002 and between the front and rear end faces 1002, strengthening beams 1210 are provided, thereby forming a plurality of "I-shaped" frame structures to improve the overall bending stiffness, ensure the stiffness and stability of the crosshead inner cavity 1100, and prevent relative displacement and deformation. It should be noted that for the sake of clear illustration, Figure 19 in the subsequent relevant drawings, the upper cover plate 1003 is omitted, and only the main body part of the crosshead housing 1000 is shown. Additionally, it is easy to think that although Figure 19 only the strengthening beams in the upper part of the crosshead inner cavity 1100 are illustrated, obviously, within the exhaust cavity 1200 located in the lower part of the crosshead inner cavity 1100, the same or similar strengthening beam structures can also be formed. [[ID=**6]]

[0123] In this embodiment, strengthening beams 1210 are designed in both the upper and lower exhaust cavities 1200. In addition to Figure 19 the I-shaped strengthening beams 1210 shown, the strengthening beams 1210 can also adopt other shaped frame structures. The number, angle, and position of the longitudinal strengthening beams 1210 extending along the axial direction of the crosshead housing 1000 and the transverse strengthening beams 1210 extending along the transverse direction of the crosshead housing 1000 are not limited, as long as they can play a supporting role and do not affect the setting of the lubricating oil path and the bolt setting to be described below. For example, Figure 20 the king-shaped strengthening beams 1210 are illustrated. The additional middle cross beam further enhances the supporting stiffness in the middle of the crosshead housing 1000. In addition, strengthening beam 1210 structures such as "Ⅱ-shaped", "Ш-shaped", "field-shaped", or "eye-shaped" can also be adopted. The forming method of the strengthening beams 1210 is not limited to casting, and machining or other methods can also be used. In addition, other structures can also be adopted for the support of the crosshead assembly, such as irregular support plates arranged on the upper and lower sides or on one side.

[0124] As Figure 21 shown, the cross-section of the strengthening beam 1210 has a generally rectangular shape, but the cross-section can also be other shapes such as triangular, trapezoidal, circular, etc. The rectangle is preferred because, compared with other solid regular cross-sections of the same area (such as circular, trapezoidal, triangular, etc.), the moment of inertia of the cross-section of the rectangle along the long axis is larger, which can ensure that the reinforcing rib has sufficient bending stiffness and suppress the displacement and deformation between the spacer plates 1101 located between the crosshead inner cavities 1100.

[0125] In addition, as Figure 22As shown, a rounded transition structure 1211 is provided at the junction of the reinforcing beam 1210 and the first bolt hole 1610 (described below), and a rounded transition structure 1211 is also provided at the connection between the root of the reinforcing beam 1210 and the main body of the crosshead box 1000. The rounded transition structure 1211 can increase the bending strength of the corresponding part, reduce stress concentration, and meet the casting process requirements. The size and shape of the rounded corner are mainly affected by the shape and position of the reinforcing beam 1210 and the bolt hole. For example, the transition rounded corner at the junction of the reinforcing beam 1210 and the bolt hole should be as concentric as possible with the bolt hole and smoothly transition to the upper surface of the reinforcing beam 1210. The transition rounded corner at the connection between the root of the reinforcing beam 1210 and the main body of the crosshead box 1000 can smoothly transition to the main body of the crosshead box 1000 at the root of the reinforcing beam 1210 according to the shape of the reinforcing beam 1210, so that the overall extension arc remains concentric with the arc segment of the inner wall of the crosshead cavity 1100. In actual fillet processing, bevels or arcs (equal curvature or variable curvature) can be set according to requirements.

[0126] 4.2 Multifunctional structural holes

[0127] As described above, the crosshead box 1000 according to an embodiment of the present disclosure is also provided with at least one multifunctional structural hole 1300. Figure 1 and Figure 2 As shown, preferably, a plurality of multifunctional structural holes 1300 are arranged, for example, in a portion of the crosshead box 1000 near the crosshead cavity 1100 and having a relatively thick thickness. For example, except for the outermost side of the crosshead box 1000, the multifunctional structural holes 1300 may be arranged, for example, in the shoulder between two crosshead cavities 1100. Figure 23 The figure shows a longitudinal cross-sectional view of the multi-functional structural hole 1300 taken along the axial direction of the crosshead housing 1000. As shown in the figure, the multi-functional structural hole 1300 penetrates the crosshead housing 1000 along its axial direction. As indicated, the first bolt hole, which will be described below, is arranged on the outer side of the multi-functional structural hole 1300. Preferably, as... Figure 1 , 2 As shown in Figure 22, each multi-functional structural hole 1300 can be positioned at the shoulder between the two crosshead cavities 1100 in a manner centered with the first bolt hole located on its outer side in a direction perpendicular to the transverse direction of the crosshead box, so as to make the stress distribution more uniform. Of course, depending on the specific design requirements, the multi-functional structural hole 1300 and the first bolt hole can also be offset from each other by a certain distance. In addition, considering the circular shape of the crosshead cavities 1100 on both sides of the multi-functional structural hole 1300 and the lubrication oil passages that need to be avoided inside the crosshead box 1000 (e.g., Figure 23(As shown in the diagram, at the circular hole), therefore, although the multifunctional structural hole 1300 can have any polygonal cross-sectional shape, it is preferably a triangular shape with rounded corners and can be designed with appropriate dimensions. By selecting the shape and size, the wall thickness of the functional structure around the multifunctional structural hole 1300 can be made uniform, that is, the thickness is basically the same. For example, the triangular multifunctional structural hole 1300 is provided on the shoulder between the two crosshead cavities 1100. One apex of the multifunctional structural hole 1300 located on the upper shoulder of the crosshead cavity 1100 points downward, and one apex of the multifunctional structural hole 1300 located on the lower shoulder of the crosshead cavity 1100 points upward, to ensure that the wall thickness is the same with the two adjacent crosshead cavities 1100, and to avoid damage to the crosshead box 1000 caused by support displacement during operation. Two multifunctional structural holes 1300 can also be arranged symmetrically on the outermost lateral edge of the crosshead box 1000 to ensure uniform force on the crosshead cavity 1100. Of course, in actual design, the shape of the multi-functional structural hole 1300 can also be round, rhomboid or other shapes, as long as the casting structure requirements mentioned above are met.

[0128] By incorporating a multi-functional structural hole 1300 in a thicker section between the two crosshead cavities 1100, the weight of the entire crosshead box 1000 can be significantly reduced while meeting structural rigidity requirements. Furthermore, since the multi-functional structural hole 1300 is also located in the area between the crosshead cavity 1100 and the bolt hole, the stress on the crosshead cavity 1100 and the bolt hole can be released at this hole, preventing structural damage caused by compression of the internal structure surrounding the multi-functional structural hole 1300. In addition, this multi-functional structural hole 1300 can also serve as an anti-shrinkage porosity feature in the casting process. During casting, hot cracking and cold cracking are common problems. After liquid metal is injected into the mold cavity, it begins to solidify. When the crystal skeleton has formed and linear shrinkage begins, the internal molten steel is not completely solidified, hindering shrinkage and causing stress or plastic deformation in the casting. When the stress or deformation exceeds the material's strength limit at this high temperature, the casting will crack, which is called hot cracking. Cold cracking refers to the cracking that occurs when a casting cools to its elastic state after solidification, caused by localized casting stress exceeding the alloy's ultimate strength. Cold cracking always occurs in areas subjected to tensile stress during cooling, especially in areas where tensile stress is concentrated. Therefore, the casting process also needs to incorporate anti-shrinkage structures to avoid casting defects, ensure the uniformity of the 1100mm inner wall of the cylindrical crosshead, and reduce stress concentration.

[0129] Therefore, the crosshead box 1000 according to the embodiments of this disclosure, by providing a multifunctional structural hole 1300 between the bolt hole and the crosshead inner cavity 1100, not only greatly reduces the weight of the crosshead box 1000 and reduces the stress concentration in the crosshead inner cavity 1100 and bolt hole under use, but also greatly reduces the possibility of cold cracking and hot cracking of the molding material around the bolt hole and crosshead inner cavity 1100 during the casting process of the crosshead box 1000, thus providing structural and functional protection for the design of the crosshead box 1000.

[0130] It should be noted that, as mentioned above, Figure 5a and Figure 5b In the case where spacer posts 1102 are provided between the crosshead cavities 1100 to replace spacer plates 1101, multifunctional structural holes 1300 can be formed in similar positions, although not shown in the figure.

[0131] 4.3 Side end plates of the crosshead box

[0132] The side end plates 1005 on both sides of the crosshead box 1000 can also have a curved shape to reduce the overall weight of the crosshead box 1000 and make the wall thickness of the crosshead cavity 1100 as uniform as possible to reduce stress concentration. The side end plates 1005 can also be selected to have other structural features such as grooves or multiple cut sections to achieve similar effects.

[0133] 5. Lubrication circuit

[0134] In conventional crosshead box 1000s manufactured using welding processes, lubrication passages can only be established through additional oil passage pipes. This is because alloy plates have high hardness and density, and limited thickness, making it difficult to create oil passages within the plate through processes such as drilling. According to this disclosure, the crosshead box 1000 utilizes a casting process, allowing the box body to be made of relatively soft materials such as ductile iron. Furthermore, the casting process enables flexible control over the local thickness of components, making it possible to directly create embedded oil passage structures within the molding material forming the integral crosshead box.

[0135] Figure 24The figure shows a cross-sectional schematic diagram of the embedded lubrication oil passage 1500 of the crosshead box 1000 according to an embodiment of the present disclosure. Oil holes and oil passages are machined within the molding material of the crosshead box 1000's housing. Compared to external oil passages, this reduces a series of complex piping installation steps, simplifies the overall layout, reduces the consumption of a large number of lubrication pipes and pipe joints, ensures reliable sealing of the lubricating oil, and prevents oil and gas leakage. The arrangement of the main oil passage and branch oil passages inside the crosshead cavity 1100 needs to avoid the stress-bearing area of ​​the threaded holes to avoid weakening the strength of the threaded connection or causing deformation and blockage of the oil holes due to bolt tightening. Furthermore, it should also avoid affecting the function of the surrounding structure (such as the supporting function of the reinforcing beam 1210). As long as the above conditions are met, the angle, extension direction, and number of oil passages can be flexibly designed according to lubrication needs. Figure 25 As shown, the lubrication passage 1500 can be formed by machining a through hole downwards through the process hole / observation window 1810 as described later, or it can be formed as follows: Figure 26 The hole is formed by drilling from the inside out in the inner cavity 1100 of the crosshead using a right-angle drill. Other methods can also be used to form the embedded oil passage according to actual needs.

[0136] During operation, the crosshead assembly reciprocates at high speed within the crosshead housing 1000, and numerous components require lubrication to function properly. Because different components operate under different conditions, the required lubricant quantity and flow rate also vary. Therefore, separate high-pressure lubrication lines 1510 and 1520 are necessary. For example, high-pressure lubrication line 1510 lubricates the crosshead bearings and connecting rod bearings operating within the crosshead housing 1000 during operation, while low-pressure lubrication line 1520 lubricates the crosshead sleeve 1400. The rated lubrication pressure of high-pressure lubrication line 1510 is, for example, 200-350 PSI, and the rated lubrication pressure of low-pressure lubrication line 1520 is, for example, 60-150 PSI.

[0137] Figure 27 The illustration shows a schematic diagram of the overall layout of the embedded lubrication passage 1500 of the crosshead box 1000 according to an embodiment of the present disclosure. It should be noted that... Figure 27 In order to clearly illustrate the layout of the embedded lubrication circuit, illustrations of some components in the crosshead housing 1000, such as the sliding sleeve 1400, are omitted. Figure 27 As shown, in the crosshead housing 1000 according to the embodiments of this disclosure, the lubrication oil passages 1500 are all embedded oil passages formed by drilling holes in the housing of the crosshead housing 1000. That is, the embedded lubrication oil passages 1500 of the crosshead housing 1000 according to the embodiments of this disclosure do not require additional oil pipes or other piping components, as well as corresponding connecting components, sealing components, etc. Figure 27In the embodiment shown, both the low-pressure lubrication circuit 1520 and the high-pressure lubrication circuit 1510 include a main circuit and branch circuits. The main circuit, as shown in the figure, extends laterally (i.e., in the direction extending between the two side end faces) along the crosshead housing 1000 and is connected to an oil inlet. Branch circuits branching from the main circuit along the longitudinal direction (i.e., the direction of extension of the crosshead cavity) of the crosshead housing 1000 are used to supply oil from the main circuit to the corresponding lubrication objects. In this embodiment, the lubricating oil in the low-pressure circuit is injected from the low-pressure oil inlet 1512 located on the side of the crosshead housing 1000 (the side near the gearbox 4000 in the figure). A portion of the low-pressure lubricating oil in the embedded circuit flows to the crosshead sleeves 1400 within the five crosshead cavities 1100 to lubricate the sleeves and connecting rod small end bearing assemblies. Figure 27 The low-pressure branch oil pipe flows to the right. Another portion of the low-pressure lubricating oil flows to the rear end face of the crosshead box 1000. Figure 27 The oil flows from the low-pressure branch pipe on the left side to the crankcase oil circuit to lubricate the roller bearings and bearing housings. For this branch circuit, such as... Figure 28 As shown, the position of the oil outlet 1503 at the rear end of the crosshead housing 1000, leading to the outside of the crosshead housing 1000, needs to be aligned with the position of the oil inlet hole of the crankshaft bearing outer ring. For the high-pressure lubrication circuit 1510, as... Figure 27 As shown, oil enters from the high-pressure oil inlet 1511 on the side of the crosshead housing 1000 (the side near the gearbox 4000 in the figure), flows into the crosshead through the oil passage, then through the internal oil passage of the crosshead, and enters the small end of the connecting rod to lubricate the small end bearing as the connecting rod swings. Figure 29 As shown, the lubricating oil in the crosshead box 1000 flows into the bottom of the crosshead box 1000 through the design gaps between the front and rear ends of the sliding sleeve and the rear end plate of the spacer and the front end plate of the crankcase, and then flows into the crankcase oil pan, and finally flows back to the oil tank through the oil return pipe at the bottom of the crankcase.

[0138] like Figure 30 As shown, both the high-pressure oil inlet 1511 and the low-pressure oil inlet 1512, located on the side end plate of the crosshead housing 1000, are provided with boss structures 1504 to provide a flat connecting plane protruding from the side end plate. It should be noted that... Figure 30 For ease of illustration, only the portion of the structure near the oil filling hole on the side of the crosshead housing 1000 is shown. The boss structure 1504 is surrounded by rounded corners to improve the rigidity of the connection. The location and number of oil filling holes are not limited, as long as they correspond to the embedded oil passages and do not affect the function of other structures. Figure 30As shown, the crosshead box 1000 and the external oil pipe are preferably connected by a flange, which facilitates interface replacement and avoids the risk of thread breakage that occurred with the previous internal thread connection, thus ensuring sealing performance. Depending on actual needs, other connection methods such as ordinary threaded connections can also be selected.

[0139] like Figure 27 As shown, both the high-pressure and low-pressure oil circuits are equipped with filters and overflow valves 1501. When the oil pressure in the embedded oil passage of the lubricating oil circuit 1500 is higher than the set pressure, the overflow valve 1501 will overflow a portion of the oil to maintain the lubricating oil pressure at the set pressure. The overflowed lubricating oil is connected to the return oil pipe through an oil pipe and eventually flows together to the oil tank for recovery, filtration, and cooling, thereby achieving the purpose of lubricating oil recycling. For example, the filter and overflow valve 1501 are both located on the opposite end plate 1005 of the crosshead housing 1000, opposite the side end plate 1005 with the oil inlet.

[0140] In the crosshead housing 1000 according to the embodiments of this disclosure, oil is injected from the side of the crosshead housing 1000, and the main oil passage embedded in the crosshead housing 1000 is designed as multiple branches to supply oil to the crosshead housing 1000 and the crankcase 2000. This reduces the volume occupied by the embedded oil passage in the housing and avoids the thinning of the housing wall due to too many oil passages. Therefore, it can reduce the manufacturing difficulty while ensuring the rigidity of the housing. In addition, by supplying oil with two oil pumps (a high-pressure pump and a low-pressure pump), the oil supply of each oil passage can be better guaranteed, and the lubricating oil can be better distributed. This avoids the problem of uneven distribution of lubricating oil and insufficient lubricating oil at each lubrication point due to too many lubrication branches, improves the lubricating oil utilization rate, reduces abnormalities, and better assists the continuous and stable operation of the high-power plunger pump.

[0141] Furthermore, it should be noted that, besides the methods described above, the lubrication circuit of the crankcase 2000 can also be supplied not from the crosshead housing 1000, but by drilling a separate hole on the crankcase side, forming a self-contained circuit. This method increases the machining process for the borehole, the external piping, and the oil inlet interface, increasing the area occupied by the oil passages inside the crankcase 2000, which will affect the rigidity of the crankcase. In addition, sealing devices need to be added at the interfaces of the internal and external piping to seal the oil pipe connections and prevent oil and gas leakage and contamination. The crankcase oil inlet can be located at the upper or lower part of the crankcase, or on the left or right side of the crankcase. The oil passage can be adjusted laterally or longitudinally accordingly.

[0142] 6. Connection and sealing design

[0143] 6.1 Connection Design

[0144] In the operational state after the fracturing pump is assembled, one end of the crosshead housing 1000 is connected to the crankcase 2000, and the other end is connected to the spacer 3000. For example... Figure 31 and Figure 32 As shown, the connection and fastening between the crosshead housing 1000 and the crankcase 2000, as well as between the crosshead housing 1000 and the spacer 3000, preferably employs a double-bolt method. Specifically, the first bolt is tightened by securing and pre-tightening the first bolt 1611 (a long bolt) as a whole. For example... Figure 33 As shown, the long bolt passes through the first bolt hole 1610 in the crosshead housing 1000 and extends to the crankcase 2000 and the spacer 3000, serving to connect the hydraulic end and the power end of the fracturing pump. The long bolt is designed with a reasonable initial axial force to ensure that the bolt joint surfaces of the hydraulic end and the power end remain connected during the operation of the plunger pump. The second bolt between the crosshead housing 1000 and the crankcase 2000, and the third bolt between the crosshead housing 1000 and the spacer 3000, primarily serve a sealing and fastening function. Therefore, the first bolt 1611 can also be referred to as the fastening bolt or the first bolt, and the second and third bolts can be collectively referred to as the sealing bolt or the second bolt. It is understood that the connection method between the crosshead housing 1000 and the crankcase 2000 or spacer 3000 is not limited to the threaded connection described above. Any connection method that ensures a tight connection between the two without relative displacement can be used. For example, an external clamping structure can be used to clamp and position the two contact surfaces, or electromagnetic attraction, hydraulic connection, automatic connection hook, etc. can be used. Furthermore, the arrangement and number of the first and second bolts are not limited to the preferred embodiments described herein and can be varied according to the needs of fastening and sealing.

[0145] The location and number of the first bolt hole 1610 (i.e., the long bolt hole) for the first bolt 1611 correspond to the threaded holes in the crankcase 2000. The second bolt hole 1620 for the second bolt and the third bolt hole 1630 for the third bolt should, in principle, be located away from the first bolt hole 1610 and at the thin wall protruding from the crosshead housing 1000. The forming method of the protruding thin wall is not limited, but rounded corners are preferred around the perimeter to facilitate casting and improve root rigidity. This minimizes the impact of the preload force of the first bolt 1611 on the second and third bolts, ensuring a tight seal between them. Figure 31 The diagram illustrates the arrangement of the first bolt holes 1610 and the second bolt holes 1620 on the rear end face of the crosshead box 1000. Figure 32The figure illustrates the arrangement of the first bolt hole 1610 and the third bolt hole 1630 on the front end face of the crosshead housing 1000. As shown, the first bolt hole 1610 is located between two adjacent crosshead cavities 1100 and two adjacent exhaust cavities 1200, and is located outside the multi-functional structural hole 1300. Preferably, the centers of the first bolt hole 1610 and the multi-functional structural hole 1300 are aligned with each other. Furthermore, as shown, in the crosshead housing 1000 according to the embodiments of the present disclosure, the number and arrangement of the second bolt hole 1620 at the rear end and the third bolt hole 1630 at the front end of the crosshead housing 1000 can be different. The side of the crosshead housing 1000 connected to the crankcase 2000 (i.e., the rear end face) is connected by two rows of larger bolts. For example, flanges can be provided on the upper and lower sides of the rear end of the crosshead housing 1000, and the second bolt hole 1620 can be provided in the flanges. Furthermore, a ring of smaller bolts is installed on the side where the crosshead housing 1000 connects to the spacer 3000 (i.e., the front end face) for connection. For example, flanges can be provided on the top, bottom, left, and right sides of the front end of the crosshead housing 1000, with a third bolt hole 1630 in each flange. This is because the reciprocating motion range of the crosshead in the crosshead housing 1000 is more biased towards the crankcase 2000 side, thus the support reaction force of the bolts acting on the crankcase 2000 side is greater, and the moment arm is shorter. In addition, both the crankcase 2000 and the crosshead housing 1000 have high rigidity, and the left and right sides of the connection surface will basically not deform and separate. Therefore, it is sufficient to arrange two rows of larger bolts on the top and bottom to bear the greater axial force. However, the connection end face between the crosshead housing 1000 and the spacer 3000 has lower rigidity, a longer moment arm, and will have some flexural deformation, and the lateral sides of the connection end face may deform and separate. Therefore, bolts are added on the left and right sides to ensure the contact surface fits. It is important to understand that the second bolt hole 1620 and the third bolt hole 1630 do not necessarily need to be located within the flange. They can be positioned outside the first bolt hole 1610, in a location suitable for forming an anti-loosening fastening structure together with the first bolt hole. For example, the second bolt hole 1620 and the third bolt hole 1630 can also be located in recesses on the upper and lower covers of the crosshead housing. Since both the second and third bolt holes are located outside the first bolt hole and have similar functions, the first bolt hole can be referred to as the inner bolt hole, and the second and third bolt holes can be collectively referred to as the outer bolt holes.

[0146] 6.2 Sealing Design

[0147] The front and rear end faces 1002 of the crosshead housing 1000 are connected to the spacer 3000 and the crankcase 2000, respectively. Therefore, a sealing design is required at the front and rear end faces 1002. For example, by setting a sealing structure such as a sealing groove or using a sealing method such as sealant, the inner cavity 1100 of the crosshead housing and the exhaust cavity 1200 are sealed inside to ensure the oil and gas seal between the two sides of the crosshead housing 1000 and the spacer 3000 and the crankcase 2000. Figure 33 as well as Figure 34a and Figure 34b The illustration shows an example of the arrangement of the sealing rings 1701 on the front and rear end faces of the crosshead box 1000. There are no particular restrictions on the positions of the sealing grooves and sealing rings 1701 of the crosshead box 1000, nor on the positions of the sealant and other multiple sealing methods. It is only necessary to ensure that the crosshead inner cavity 1100 and the vent cavity 1200 are included within the sealing area, meeting the sealing requirements of this technical field for oil and gas sealing surfaces without affecting the function of the surrounding structure.

[0148] At the junction of the lubrication oil passages on the contact surface between the crosshead housing 1000 and the crankcase 2000, a local seal 1702 can be added. Figure 35 The diagram illustrates a sealing ring 1702, positioned around the oil outlet 1503 in the lubrication circuit, serving as a partial seal. The sealing range of the partial seal 1702 is not limited, as long as it meets the sealing requirements at the oil outlet. The form of the seal is also not particularly restricted, such as a sealing ring (shape not limited), sealant, etc.

[0149] In addition, such as Figure 36 As shown, a pair of locating pin holes 1703 are provided on both end faces of the crosshead housing 1000, for connecting the locating pins when assembling the crosshead housing 1000 with the spacer 3000 and crankcase 2000, so as to achieve mutual alignment and positioning among the three. Figure 36 (Only one end face is shown in the figure). Corresponding pin holes are also formed on the crankcase 2000 and the spacer 3000. The size and shape of the locating pin hole 1703 correspond to the locating pin used. The location of the locating pin hole 1703 is not limited, as long as it meets the positioning requirements and does not affect the function of the surrounding structure. It is preferred to set it at the diagonal of the end face to facilitate positioning.

[0150] 7. Other structural components of the crosshead box

[0151] 7.1 Process holes and / or observation windows

[0152] The crosshead housing 1000 also has several process holes and / or observation windows 1810. Since these process holes and observation windows are formed through the housing of the crosshead housing 1000 and have similar functions and structures, they can be collectively referred to as process holes herein. For example, the upper mask 1003 and / or lower mask 1004 may be provided with process holes and / or observation windows 1810 for machining internal oil passages or other processes after the housing is cast, as well as for maintenance and repair during later use. Referring to the accompanying drawings, the process holes and / or observation windows 1810 are preferably formed on the upper mask 1003 and / or lower mask 1004 at positions corresponding to the crosshead cavity 1100, to facilitate future maintenance and repair. Furthermore, as mentioned above, the process holes and / or observation windows 1810 are preferably formed near the embedded oil passage 1500, which facilitates the machining and maintenance of the oil passage. In the crosshead housing 1000 according to an embodiment of the present disclosure, since lubricating oil flowing to the crankcase 2000 for recycling occurs at the bottom of the crosshead housing 1000, therefore, as Figure 37 As shown, the process holes and / or observation windows 1810 of the lower cover plate 1004 of the crosshead box 1000 have upward-protruding structures 1811, such as bosses, that protrude into the box. By providing these upward-protruding structures, lubricating oil at the bottom of the crosshead box 1000 can be prevented from flowing out of the holes and causing environmental pollution. These upward-protruding structures 1811 also increase the engagement length of the fixing bolts, enhancing the tightness at this location. Furthermore, the upper process window of the upper cover plate 1003 of the crosshead box 1000 uses a downward-protruding structure 1812 that protrudes into the box to increase the engagement length of the fixing bolts and enhance the tightness at this location. Since workers will stand above the crosshead box 1000 during equipment maintenance, considering operational safety and reducing the possibility of workers tripping, upward-protruding structures are not selected here. Figure 38 The illustration shows a schematic structure of the boss forming the upper convex structure 1811 or lower convex structure 1812 for the process hole and / or observation window 1810. For clarity, other components are omitted from the illustration. If other methods of collecting lubricating oil are used, the bottom process hole / observation window can be designed with other structures. The number of process holes / observation windows is unlimited, and their shape is not limited to circular; their placement should not obstruct subsequent processing. Furthermore, depending on actual needs, process holes / observation windows can be manufactured using other methods, or they may not be provided at all.

[0153] 7.2 Mounting boss and related design

[0154] On both sides of the crosshead box 1000, mounting surfaces for arranging lifting lugs and supporting lugs are provided on the side end plates 1005. For example, as Figure 39As shown, such a mounting surface can be in the form of a mounting boss 1820. The mounting boss 1820 is integrally formed with the main body of the crosshead box 1000, and has rounded or beveled transitions around its perimeter to increase root rigidity. The position, number, and cross-sectional shape of the mounting boss 1820 are determined according to the requirements of the lifting lugs and support lugs. In addition to the mounting boss 1820 (outer convex plane), a mounting surface (inner concave plane) can also be created by thinning at the lifting point, depending on the actual situation.

[0155] 7.3 Support Ear Plate

[0156] According to an embodiment of this disclosure, the crosshead box 1000 is further provided with a support lug 1830. For example... Figure 39 As shown, according to this embodiment, the support ear plate 1830 is mounted on the mounting boss 1820 and is located at the rear end of the crosshead housing 1000 near the gearbox, for connecting the gearbox's screw support assembly. A well-placed support ear plate 1830 can effectively reduce the deformation of the gearbox towards the power transmission shaft and the direction of gravity, improving the gearbox's rigidity. The position, number, and cross-sectional shape of the support ear plate 1830 are not limited, as long as it matches the screw support assembly.

[0157] 7.4 Lifting Ear Plates

[0158] According to an embodiment of this disclosure, the crosshead box 1000 is further provided with a lifting lug 1840. For example... Figure 39 As shown, according to this embodiment, the lifting lug 1840 is mounted on the mounting boss 1820 located on the upper part of the housing. When the hydraulic end is disassembled, the lifting lug 1840 can be used for lifting operations of the crosshead housing 1000 and the crankcase assembly or the crosshead housing 1000 itself. The shape, position, and number of the lifting lug 1840 are not limited. The key is to ensure uniform force distribution during lifting and prevent the crosshead housing 1000 from tilting. The forming method of the lifting lug 1840 is not limited; it can be integrally formed by casting or machining. Figure 39 In the embodiment shown, the lifting lug 1840 and the support lug 1830 are integrally formed on the mounting boss located on the upper part of the crosshead box. This structure reduces the area occupied by the mounting boss 1820 and the processing steps, saving costs. It should be understood that, according to design requirements, the support lug 1830 and the lifting lug 1840 can also be formed on the mounting boss 1820 at different locations respectively.

[0159] The preferred embodiments of the integrally molded crosshead box according to the present invention have been described in detail above with reference to the accompanying drawings. It should be understood that the integrally molded crosshead box according to the present invention does not necessarily need to have all the technical features shown in the drawings, but can combine these technical features as needed. For example, in the various preferred structures of the integrally molded crosshead box according to the present invention described above, structures such as venting chambers, embedded oil passages, and multi-functional structural holes can be selectively provided according to specific needs. They are not essential structures for realizing the basic functions of the integrally molded crosshead box according to the present invention. For example, the integrally molded crosshead box according to the present invention may also not employ embedded oil passages, but instead use external oil pipes as in the prior art.

[0160] For example, according to one embodiment of the present invention, the crosshead box is a generally rectangular box formed by an integral molding process, and has a front end face, a rear end face, an upper end face, a lower end face, and a side end face. The crosshead box is provided with a plurality of crosshead cavities, each of which extends longitudinally along the crosshead box and penetrates the box body, and the plurality of crosshead cavities are arranged transversely along the crosshead box. The crosshead box is also provided with a plurality of exhaust chambers, each of which penetrates the crosshead box longitudinally and communicates with the corresponding crosshead cavity.

[0161] For example, according to another embodiment of the present invention, the crosshead box is a generally rectangular box formed by an integral molding process, and has a front end face, a rear end face, an upper end face, a lower end face, and a side end face. The crosshead box is provided with a plurality of crosshead cavities, each of which extends longitudinally along the crosshead box and penetrates the box body, and the plurality of crosshead cavities are arranged transversely along the crosshead box. The crosshead box is also provided with a plurality of multifunctional structural holes, each of which extends longitudinally along the crosshead box and penetrates the box body.

[0162] For example, according to another embodiment of the present invention, the crosshead box is a generally rectangular box formed by an integral molding process, and has a front end face, a rear end face, an upper end face, a lower end face, and a side end face. The crosshead box is provided with a plurality of crosshead cavities, each of which extends longitudinally along the crosshead box and penetrates the box body, and the plurality of crosshead cavities are arranged transversely along the crosshead box. The crosshead box is also provided with an embedded lubricating oil passage, which is an interconnected oil hole and oil channel formed in the box body of the crosshead box, and the embedded lubricating oil passage includes a main oil passage and branch oil passages.

[0163] The crosshead box disclosed herein, through integrated casting and platform design, improves the versatility and adaptability of parts, significantly reducing the variety of accessories used in different fracturing pump models and saving substantial costs associated with purchasing spare parts and maintenance. Traditional welded power end housings require complete rework or even scrapping if partially cracked, impacting fracturing efficiency and increasing maintenance costs. Furthermore, the integrated crosshead box not only improves the strength and rigidity of the power end housing, extending its lifespan and maintenance cycle, but also allows for individual maintenance and replacement of parts of the housing, reducing repair difficulty and rework costs.

[0164] Furthermore, the one-piece molded crosshead box according to embodiments of this disclosure can be provided with multi-functional structural holes and other structures, thereby ensuring structural rigidity while reducing the weight of the box. The one-piece molded crosshead box according to embodiments of this disclosure can provide a good fluid circulation path inside the box by setting a dedicated exhaust chamber and fluid channel, thereby ensuring that the air pressure inside the box remains balanced during operation, thus improving the operational stability and service life of the equipment. The lubrication circuit of the crosshead box according to embodiments of this disclosure can adopt an embedded structure to replace the traditional external oil pipe arrangement, thereby eliminating a large number of flexible hoses and pipe joints, greatly reducing oil pressure leakage problems caused by potential risks such as pipe oxidation and corrosion, and loose pipe joints. Therefore, it can effectively extend the maintenance cycle of the lubrication system and facilitate fault diagnosis and repair.

[0165] The crosshead box disclosed herein is designed with lifting points on both sides for easy individual and combined lifting. The cylindrical crosshead cavity of the crosshead box allows the use of a cylindrical crosshead sleeve to replace the two-piece bearing, reducing installation steps and facilitating bearing inspection and replacement. The crosshead box is also equipped with sensors to monitor equipment vibration, housing temperature, and lubricating oil temperature and flow rate in real time, enabling on-site personnel to promptly detect and respond to equipment malfunctions in their initial stages, such as stopping the machine for inspection or replacing components.

[0166] Although the integrally molded crosshead box according to this disclosure has been described above with reference to the accompanying drawings, the invention is not limited to the embodiments described above. Furthermore, those skilled in the art will understand that various changes, combinations, sub-combinations, and modifications can be made without departing from the spirit or scope defined by the appended claims. In addition, the beneficial effects of this disclosure are not limited to those mentioned above, but may include other effects that can be conceived upon reading this disclosure.

[0167] List of reference numerals

[0168] 1000 crosshead boxes

[0169] 2000 crankcase

[0170] 3000 spacers

[0171] 4000 Gearbox

[0172] 1001 Front Face

[0173] 1002 Back end face

[0174] 1003 Upper mask, upper end face

[0175] 1004 Lower mask plate, lower end face

[0176] 1005 Side end plate, side end face

[0177] 1006 Limiting Groove

[0178] 1100 Crosshead Inner Cavity

[0179] 1200 Exhaust Chamber

[0180] 1300 Multifunctional Structural Hole

[0181] 1101 Spacer

[0182] 1102 Spacer

[0183] 1400 Crosshead Slipper

[0184] 1401 Sleeve Oil Hole

[0185] 1402 Sliding sleeve locating pin hole

[0186] 1403 Sleeve Protrusion

[0187] 1404 Recessed part of sliding sleeve

[0188] 1201 Fluid Channel

[0189] 1210 Reinforced Beam

[0190] 1211 Transition Structure

[0191] 1500 Lubrication Circuit

[0192] 1510 High-pressure lubrication circuit

[0193] 1520 Low-pressure lubrication circuit

[0194] 1511 High-pressure oil inlet

[0195] 1512 Low-pressure oil inlet

[0196] 1501 Relief Valve

[0197] 1502 Oil tank end

[0198] 1503 Oil outlet

[0199] 1504 boss structure

[0200] 1610 First bolt hole

[0201] 1620 Second bolt hole

[0202] 1630 Third bolt hole

[0203] 1611 First Bolt

[0204] 1701 Sealing Ring

[0205] 1702 Partial Seal

[0206] 1703 Locating pin hole

[0207] 1810 Process Hole / Observation Window

[0208] 1811 Convex Structure

[0209] 1812 Convex Structure

[0210] 1820 Install boss

[0211] 1830 Support Ear Plate

[0212] 1840 Lifting Ear Plate

[0213] 2001 Linkage-operated movable window

Claims

1. A crosshead housing, which is a substantially rectangular housing formed by an integrated molding process and has a front end surface, a rear end surface, an upper end surface, a lower end surface, and side end surfaces, a fluid passage being provided at the front end surface, the crosshead housing being provided with: a plurality of crosshead bores each extending in a longitudinal direction of the crosshead housing and penetrating the housing, the plurality of crosshead bores being arranged in a lateral direction of the crosshead housing, an exhaust chamber being provided above and / or below the crosshead bores; the crosshead housing being further provided with an in-mold lubrication passage, which is oil holes and oil passages formed in the housing of the crosshead housing and communicating with each other, and which includes a main oil passage and branch oil passages; the crosshead housing further including a crosshead shoe, a front end of the crosshead shoe being provided with at least one inwardly recessed portion recessed inwardly in a longitudinal direction of the crosshead shoe, a rear end of the crosshead shoe being provided with at least one outwardly protruding portion protruding outwardly in the longitudinal direction of the crosshead shoe; the crosshead bores being in fluid communication with the exhaust chamber via the recessed portion and the fluid passage; the protruding portion and an oil groove of a crosshead bottom portion forming a seal; a transition area between the protruding portion and a non-protruding portion of the rear end surface of the crosshead shoe being formed with a transition round corner. The main oil passage extends in the lateral direction of the crosshead housing, and the branch oil passages extend in the longitudinal direction of the crosshead housing. characterized in that The in-mold lubrication passage includes a high-pressure lubrication passage. The high-pressure lubrication passage lubricates crosshead bearing shells and connecting rod bearing shells operating in the crosshead housing. The high-pressure lubrication passage includes a high-pressure oil inlet provided on the side end surface of the crosshead housing.

2. The crosshead housing of claim 1, wherein, The high-pressure oil inlet is provided on a flat connection plane formed on the side end surface.

3. The crosshead housing of claim 1, wherein, The high-pressure lubrication passage has a filter and an overflow valve.

4. The crosshead as defined in claim 3, wherein, The in-mold lubrication passage includes a low-pressure lubrication passage.

5. The crosshead as defined in claim 3, wherein, The low-pressure lubrication passage lubricates the crosshead shoe.

6. The crosshead as defined in claim 5, wherein, The low-pressure lubrication passage includes a low-pressure oil inlet provided on the side end surface of the crosshead housing.

7. The crosshead as defined in claim 3, wherein, The low-pressure oil inlet is provided on a flat connection plane formed on the side end surface.

8. The crosshead as defined in claim 1, wherein, The low-pressure lubrication passage has a filter and an overflow valve.

9. The crosshead as defined in claim 8, wherein, The in-mold lubrication passage is provided with the branch oil passages for supplying oil to a crankcase, and the branch oil passages for supplying oil to the crankcase have an oil outlet opening to the crankcase at the rear end surface of the crosshead housing.

10. The crosshead as defined in claim 8, wherein, An outer periphery of the oil outlet is provided with a seal ring as a partial seal.

11. The crosshead as defined in claim 10, wherein, Each of the crosshead bores is approximately cylindrical in shape.

12. The crosshead as defined in claim 8, wherein, The crosshead shoe has a shape matching the crosshead bores and is capable of being fitted in the crosshead bores.

13. The crosshead as defined in claim 1, wherein, The crosshead shoe is provided with an oil hole penetrating a shoe wall, the oil hole being part of the branch oil passages.

14. The crosshead as claimed in claim 13, wherein, The recessed portion is two, and 15. The crosshead as claimed in any one of claims 1 to 14, wherein, In a state where the crosshead shoe is fitted in the crosshead bores, the two recessed portions are located at the top and bottom of the crosshead bores.

16. The crosshead as claimed in any one of claims 1 to 14, wherein, The protruding portion is two, and 17. The crosshead as claimed in claim 16, wherein, ​ 18. The crosshead as defined in claim 16, wherein, ​ ​ 19. The crosshead as defined in claim 16, wherein, ​ In the state that the cross head slide is installed in the cross head inner cavity, the two protruding parts are located at the top and bottom of the cross head inner cavity.

20. The crosshead as defined in claim 16, wherein, The inner recess and the protruding part are both two, and In the state that the cross head slide is installed in the cross head inner cavity, the two inner recesses are located at the top and bottom of the cross head inner cavity, and the two protruding parts are also located at the top and bottom of the cross head inner cavity.

21. The crosshead as defined in claim 16, wherein, The front end face of the cross head inner cavity is provided with a limiting slot, and the end head part of the cross head slide located at one end of the front end face is provided with a positioning pin hole, the positioning pin hole and the limiting slot are matched and connected through a pin shaft inserted into the pin hole, so as to axially position the cross head slide in the cross head inner cavity.

22. The crosshead as claimed in any one of claims 1 to 14, wherein, The cross head box is also provided with at least one first bolt hole, each of the first bolt holes is located above and below the plurality of cross head inner cavities and extends along the longitudinal direction of the cross head box and penetrates the box body.

23. The crosshead as claimed in claim 22, wherein, The cross head box is also provided with at least one second bolt hole, each of the second bolt holes extends along the longitudinal direction of the cross head box and penetrates the box body, and on the front end face and the rear end face, the second bolt hole is located outside the first bolt hole.

24. The crosshead as defined in claim 23, wherein, On the front end face of the cross head box, the edge part located at both sides of the cross head body is also provided with the second bolt hole.

25. The crosshead as defined in claim 23, wherein, On the front end face of the cross head box, a flange part is provided on the outer periphery of the cross head box, and the second bolt hole is provided on the flange part.

26. The crosshead as defined in claim 23, wherein, On the rear end face of the cross head box, a flange part is provided on the upper edge and the lower edge of the cross head box, and the second bolt hole is provided on the flange part.

27. The crosshead as claimed in any one of claims 1 to 14, wherein, Sealing grooves are respectively provided on the front end face and the rear end face of the cross head box, and the sealing area surrounded by the sealing grooves at least includes the cross head inner cavity and the exhaust cavity.

28. The crosshead as claimed in any one of claims 1 to 14, wherein, The cross head box also includes a process hole penetrating the box body of the cross head box.

29. The crosshead as claimed in claim 28, wherein, The process hole is formed at a position corresponding to the cross head inner cavity.

30. The cross head housing of claim 28, wherein, The process hole is at least provided at a position close to the embedded lubricating oil path.

31. The cross head housing of claim 28 wherein, The process hole formed on the top of the cross head box is formed with a lower convex structure protruding towards the cross head inner cavity.

32. The cross head housing of claim 28 wherein, The process hole formed on the bottom of the cross head box is formed with an upper convex structure protruding towards the cross head inner cavity.

33. The crosshead as claimed in any one of claims 1 to 14, wherein, The cross head box is also provided with a mounting boss formed on the side end face.

34. A plunger pump comprising a crankcase, a cross head box according to any one of claims 1 to 33, and a spacer.

35. The piston pump of claim 34, wherein, Positioning pin holes are provided on the joint end faces between the crankcase, the cross head box and the spacer, for alignment positioning of the crankcase, the cross head box and the spacer.

36. The piston pump of claim 34 or 35, wherein, The plunger pump also comprises a reduction box, and A support lug is provided on the mounting boss formed on the side end face of the cross head box, and the support lug is connected to the support assembly of the reduction box.

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