Reduction gearbox shell and fracturing equipment

Abstract

The invention aims to provide a reduction gearbox shell which is sequentially composed of a cover plate, a first speed reduction structure shell, a second speed reduction structure shell and a connecting flange, and the cover plate, the first speed reduction structure shell and the connecting flange are cast shells formed through a casting forming method and are mutually fixed through connecting parts.

Description

Technical Field

[0001] The invention relates to a reduction gearbox housing and a fracturing device. Background Art

[0002] The reduction gearbox is a key component in the fracturing equipment. It is equipped with various transmission shafts and gears to reduce the rotation speed of the engine output and increase the torque, which is then transmitted to the crankcase in the fracturing equipment. Since the reduction gearbox is a key component of the entire fracturing process, if the reduction gearbox is damaged, it will cause huge economic losses. Therefore, the reduction gearbox needs to have high stability and reliability.

[0003] From this point of view, the development and design of the reduction gearbox plays a vital role in the operation of fracturing equipment and is of great significance to improving the efficiency of oil and gas extraction.

[0004] However, there are many problems in the reduction gearbox used in the prior art.

[0005] First, when the reducer is working, the torque is transmitted between the transmission shafts, which will generate a large reaction force, which will act on the reducer housing. Therefore, the housing is required to have sufficient rigidity and will not be deformed by the reaction force to ensure the accuracy of the relative positions of the transmission shafts.

[0006] In the prior art, the reduction gearbox housing is usually formed by welding. The reduction gearbox housing is a welded housing. However, from the perspective of materials, the welded housing has poor performance in terms of impact resistance, vibration resistance, and noise absorption.

[0007] Moreover, the welded shell has a great disadvantage in terms of service life.

[0008] This is because welding is a local rapid heating and cooling process. The molten metal in the welding area is constrained by the surrounding unmelted metal sheets (metal sheets are also called base materials) and cannot expand and contract freely. During the cooling and shrinking process, it will be subject to the tensile stress of the base material. The metal material (heat-affected zone) that is affected by heat but not melted around the weld will produce uneven tissue distribution under the action of welding thermal cycles. This uneven tissue distribution can easily become a source of fatigue cracks in the shell. Under the action of cyclic alternating stress and impact vibration of the gears inside the reduction gearbox working under long-term high-load conditions, microcracks are easily generated in the heat-affected zone of the weld, and then expand into tensile cracks on the shell, resulting in insufficient overall stiffness and strength of the reduction gearbox and deformation, aggravating the overall vibration of the reduction gearbox, causing structural overall cracking, and ultimately leading to oil leakage in the reduction gearbox and the shell being completely unable to support the gears.

[0009] Therefore, the welded reducer housing is difficult to meet the requirements of long life (>10000h) of the reducer.

[0010] In addition, in terms of manufacturing, the production process of welded gearbox housing is very complicated. Generally speaking, welded housing needs to go through a series of processes such as cutting, assembly, spot welding, preheating, welding, grinding, heat treatment, flaw detection, rough machining, secondary heat treatment, and fine machining. The manufacturing accuracy and quality of each process must be strictly guaranteed, otherwise it is very easy to cause the accumulation and amplification of size and shape errors.

[0011] Moreover, since the welded shell is welded from a large number of parts, the number of welds is as high as hundreds. Even if we do not consider the large amount of manpower and time costs consumed in the welding process, once a certain process in the welding process fails, additional rework time is required. In this way, a lot of time is wasted on process flow, waiting for troubleshooting and rework, etc., which not only makes the entire production cycle long and inefficient, but also increases time, labor and consumables costs, resulting in huge cost consumption.

[0012] Based on this problem, the present invention provides an improved reduction gearbox housing structure, replacing the welded housing in the prior art with an integrally cast reduction gearbox housing.

[0013] Secondly, in the prior art, the reduction gearbox is mainly fixed to the crankcase by connecting flanges, so the weight of the reduction gearbox is almost entirely supported by the structural stiffness of the crankcase and the connecting flanges. However, during the operation of the reduction gearbox, severe vibration may occur, and the vibration sources mainly come from the impact of gear meshing frequency, torsional vibration of the shaft system, changes in tooth surface meshing torque, and vibration of the fracturing pump housing.

[0014] This vibration will lead to insufficient rigidity and stability of the reduction gearbox housing, making the reduction gearbox easily deformed in the direction of its gravity. It may also cause problems such as pitting, bonding and gear breakage of the gears (especially the pinions).

[0015] Based on this problem, the present invention provides a support structure for the reduction box, thereby reducing the load on the connecting flange and the crankcase and increasing the stability of the reduction box operation.

[0016] Third, the reduction box in the prior art is connected to the engine and crankcase through a rigid connection (such as a rigid coupling and a connecting flange). This rigid connection does not have the ability to buffer and absorb shock, which will cause the vibration and impact between the engine, crankcase and reduction box to be transmitted to each other, resulting in the impact and vibration in the gear transmission process being directly transmitted to the crankcase housing, aggravating the fatigue damage of the crankcase housing, generating loud noise, and causing wear and material fatigue of the gears in the reduction box.

[0017] At the same time, the rigid connection cannot compensate and adjust the position error. Once the input and output shafts of the reducer have a slight eccentricity or angular error, it will generate additional bending stress on the bearing, causing the bearing to bear excessive axial force and eccentric radial force, aggravating the fatigue failure near the axial limit of the inner and outer rings of the bearing, as well as pitting and eccentric wear of the internal rollers of the bearing.

[0018] In addition, rigid connection will also cause the amplification and accumulation of errors, resulting in changes in the center distance of the meshing gears, causing root cutting or increased side clearance, resulting in meshing impact and vibration, causing adverse consequences such as pitting and bonding of the gear surfaces and gear breakage.

[0019] Based on this problem, the present invention improves the connection mode between the reduction gearbox, the engine and the crankcase, thereby effectively isolating and absorbing the torsional vibration from the input and output ends of the reduction gearbox, and compensating for the axial, radial and angular position deviations between the connecting shafts. Summary of the invention

[0020] In order to solve the above problems, the present invention provides an improved reduction gearbox housing and a fracturing device.

[0021] In a first aspect of the present invention, a reduction gearbox housing is provided, which is composed of a cover plate, a first reduction gear structure housing, a second reduction gear structure housing and a connecting flange in sequence, wherein the cover plate, the first reduction gear structure housing and the connecting flange are cast housings formed using a casting molding method and are fixed to each other by connecting parts.

[0022] According to a further aspect of the present invention, the first reduction structure housing accommodates a parallel-stage reduction structure, and the second reduction structure housing accommodates a planetary-stage reduction structure.

[0023] According to a further aspect of the present invention, a rigid bottom supporting foot is provided at the bottom of the first deceleration structure housing, and the rigid bottom supporting foot is connected and fixed to the bottom skid.

[0024] According to a further aspect of the present invention, the first reduction structure housing accommodates a planetary-stage reduction structure, and the second reduction structure housing accommodates a planetary-stage reduction structure.

[0025] According to a further aspect of the present invention, rigid bottom supporting feet are provided at the bottom of the first deceleration structure housing and the second deceleration structure housing, and the rigid bottom supporting feet are connected and fixed to the bottom skid.

[0026] According to a further aspect of the present invention, the cover plate, the first speed reduction structure housing and the connecting flange are made of ductile iron or vermicular cast iron.

[0027] According to a further aspect of the present invention, the connecting component is a bolt, and the connecting surfaces of the cover plate, the first deceleration structure housing, the second deceleration structure housing and the connecting flange are thickened where the bolt is formed, and a cylinder with an enlarged and thickened diameter is provided within a specific extension range radiating outward from the center of the threaded hole corresponding to the bolt.

[0028] According to a further aspect of the present invention, a first reinforcing rib is provided at a position of the casting shell where rigidity is weak.

[0029] According to a further aspect of the present invention, a second reinforcing rib is provided at a position where the shell contour suddenly changes in the first deceleration structure shell.

[0030] According to a further aspect of the present invention, a transition groove is provided at the root of the first reinforcing rib and / or the second reinforcing rib.

[0031] According to a further aspect of the present invention, a shock absorbing structure is provided at the bottom of the first deceleration structure housing and / or the second deceleration structure housing, and the shock absorbing structure is connected and fixed to the bottom skid.

[0032] According to a further aspect of the present invention, the shock absorbing structure includes a rigid bottom support foot and two shock absorbers.

[0033] According to a further aspect of the present invention, the shock absorber is sequentially composed of a multi-layer metal structure, an elastic structure and a bottom, the multi-layer metal structure is connected to the reduction gearbox housing, and the bottom is connected to the bottom skid.

[0034] Another aspect of the present invention provides a reduction gearbox housing, which includes an upper housing and a lower housing, wherein the upper housing and the lower housing are cast housings formed using a casting molding method, and wherein the upper housing and the lower housing are connected and fixed along the horizontal plane of the axis of the power input shaft and the power output shaft of the reduction gearbox through connecting components.

[0035] According to a further aspect of the present invention, a parallel-stage reduction structure and a planetary-stage reduction structure are accommodated between the upper shell and the lower shell.

[0036] According to a further aspect of the present invention, a rigid bottom support foot is provided at the bottom of the lower shell in which the parallel-stage reduction structure is accommodated, and the rigid bottom support foot is connected and fixed to the bottom skid.

[0037] According to a further aspect of the present invention, more than two planetary stage speed reduction structures are accommodated between the upper shell and the lower shell.

[0038] According to a further aspect of the present invention, a rigid bottom support foot is provided at the bottom of the lower shell in which the planetary-stage deceleration structure is accommodated, and the rigid bottom support foot is connected and fixed to the bottom skid.

[0039] According to a further aspect of the present invention, the upper shell and the lower shell are made of ductile iron or vermicular graphite iron.

[0040] According to a further aspect of the present invention, the connecting component is a bolt, and the connecting surface of the upper shell and the lower shell is thickened where the bolt is formed, and a cylinder with an enlarged and thickened diameter is provided within a specific extension range radiating outward from the center of the threaded hole corresponding to the bolt.

[0041] According to a further aspect of the present invention, a first reinforcing rib is provided at a position of the casting shell where rigidity is weak.

[0042] According to a further aspect of the present invention, second reinforcing ribs are provided at locations where the shell contours suddenly change in the upper shell and the lower shell.

[0043] According to a further aspect of the present invention, a transition groove is provided at the root of the first reinforcing rib and / or the second reinforcing rib.

[0044] According to a further aspect of the present invention, a shock absorbing structure is provided at the bottom of the lower shell, and the shock absorbing structure is connected and fixed to the bottom skid.

[0045] According to a further aspect of the present invention, the shock absorbing structure includes a rigid bottom support foot and two shock absorbers.

[0046] Another aspect of the present invention provides a fracturing device, which includes an engine, a reduction gearbox and a crankcase connected in sequence, wherein a flexible support structure is provided at the bottom of the reduction gearbox, wherein the reduction gearbox and the engine are connected via a first coupling, and wherein the reduction gearbox and the crankcase are connected via a second coupling.

[0047] According to a further aspect of the present invention, both the first coupling and the second coupling are flexible couplings.

[0048] According to a further aspect of the present invention, the first coupling is a rigid coupling, and the second coupling is a flexible coupling.

[0049] According to a further aspect of the present invention, the first coupling is a rigid coupling, and the second coupling is a rigid-flexible coupling.

[0050] According to a further aspect of the present invention, the rigid-flexible coupling is a universal joint coupling.

[0051] The flexible coupling is a drum-shaped gear coupling, a serpentine spring coupling or a diaphragm coupling. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1A perspective view showing a reduction gearbox installed in a fracturing device is shown.

[0053] Figure 2 A front view of a first configuration of a reduction gearbox is shown.

[0054] Figure 3 A rear view of a first configuration of the reduction gearbox is shown.

[0055] Figure 4 The composition of the reduction gearbox housing having the first configuration is described.

[0056] Figure 5 The structure in which reinforcing ribs are provided on the cover plate and the parallel stage reduction structure casing is shown by way of example.

[0057] Figure 6 The composition of the reduction gearbox housing having the second configuration is described.

[0058] Figure 7 An example of providing rigid bottom supporting feet when the reduction gearbox is composed of a parallel-stage reduction gear structure and a planetary-stage reduction gear structure is shown.

[0059] Figure 8 An example of providing rigid bottom supporting feet is shown in the case where the reduction gearbox is composed of a two-stage planetary reduction structure.

[0060] Fig. 9 An example of providing a shock-absorbing support structure in a case where the reduction gearbox is composed of a parallel-stage reduction gear structure and a planetary-stage reduction gear structure is shown.

[0061] Fig.10 An example of providing a shock-absorbing support structure in a case where the reduction gearbox is composed of a two-stage planetary reduction structure is shown.

[0062] Fig.11 The structure of the shock absorber is shown.

[0063] Fig.12 A first connection structure of the reduction gearbox is shown.

[0064] Fig.13 A second connection structure of the reduction gearbox is shown. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present disclosure, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. For example, the "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components or structures. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0067] Hereinafter, the reduction gearbox housing and its related features of the present invention are explained in the following order.

[0068] 1. Overview of the principle and structure of the reduction gearbox

[0069] 2. The first structure of the reduction gearbox housing

[0070] 3. Second structure of the reduction gearbox housing

[0071] 4. Support structure of reduction gearbox

[0072] 4.1 Rigid support structure

[0073] 4.2 Shock-absorbing support structure

[0074] 5. Connection structure of reduction gearbox

[0075] 5.1 The first connection structure of the reduction gearbox

[0076] 5.2 Second connection structure of the reduction gearbox

[0077] Hereinafter, the above contents will be explained with reference to the accompanying drawings and the accompanying drawings numerals.

[0078] 1. Overview of the principle and structure of the reduction gearbox

[0079] Figure 1 FIG. 1 shows a stereoscopic view of the reduction gearbox 1 installed in the fracturing equipment. Specifically, Figure 1 As shown, one end of the reduction box 1 is connected to the motor (not shown) through a driving flange and a coupling for transmitting power and twist from the motor, and the other end of the reduction box 1 is connected to the power end crankcase 2 of the fracturing equipment through a spline.

[0080] Figure 2 A front view of a first configuration of the reduction gearbox 1 is shown, and Figure 3 1 shows a rear view of a first configuration of the reduction gearbox 1. Figure 2 and Figure 3As shown, the reduction gearbox 1 with the first structure is composed of a parallel-stage reduction structure and a planetary-stage reduction structure.

[0081] like Figure 2 As shown, the parallel stage reduction structure is connected to the engine (not shown) and consists of parallel transmission shafts and mutually meshing large gears 3 and small gears 4 to form a primary gear transmission (primary reduction). The transmission shaft, large gear 3 and small gear 4 all move in parallel planes. The engine drives the small gear 4, and the small gear 4 transmits power to the large gear 3 by meshing with the large gear 3. Usually, the diameter of the large gear 3 is 2-3 times the diameter of the small gear 4.

[0082] Although in Figure 2 Two gears with a transmission shaft are shown in the figure, but the parallel stage reduction structure can also be composed of more than two parallel transmission shafts and gears to form a multi-stage reduction.

[0083] like Figure 3 As shown, the planetary stage reduction structure is connected in series with the parallel stage reduction structure, and is composed of a sun gear 51, four planetary gears 52, an inner gear ring 53 of a planetary gear transmission box, and a planet carrier 54. Among them, the large gear of the parallel stage reduction structure is coaxially connected with the core shaft of the sun gear 51 of the planetary stage reduction structure, and the sun gear 51 is meshed with the four planetary gears 52 at the same time. In addition, the four planetary gears 52 are installed in the planet carrier 54 and rotate around the planet carrier, and are meshed with the inner gear ring 53 of the planetary gear transmission box. The output end of the planet carrier 54 is coaxially arranged with the core shaft of the sun gear 51, and is drivingly connected with the input shaft of the crankcase of the fracturing equipment.

[0084] In this way, the planetary stage reduction structure performs secondary reduction on the power transmitted from the large gear 3 in the parallel stage reduction box.

[0085] In addition, depending on the size and direction of the shaft force, different types of bearings such as thrust spherical roller bearings and cylindrical roller bearings are used to support the rotation of the gear shaft. In the case of larger shaft forces, roller bearings with line contact and small deformation are used, and in the case of lighter or medium shaft forces, ball bearings with point contact are used.

[0086] in addition, Figure 1-3 The figure shows a reduction gearbox composed of a parallel-stage reduction gearbox and a planetary-stage reduction gearbox. Alternatively, the reduction gearbox may also be composed of a two-stage planetary-stage reduction gearbox. Figure 1-3 The parallel-stage reduction structure in the shown construction is replaced by a planetary-stage reduction structure, thereby forming a reduction box by two planetary-stage reduction structures connected in parallel.

[0087] The reduction gearbox formed by a two-stage planetary reduction structure can achieve the same reduction ratio with a smaller size.

[0088] Below, the first and second structures of the reduction gearbox housing are described by taking the reduction gearbox composed of a parallel-stage reduction gearbox structure and a planetary-stage reduction gearbox structure as an example. However, it should be noted that the reduction gearbox composed of a two-stage planetary-stage reduction gearbox structure can also adopt the first and second structures of the reduction gearbox housing.

[0089] As mentioned in the background of the present invention, the gearbox housing provides support for the gear train and the transmission shaft system, etc., and may undergo elastic deformation when subjected to force, and transmit vibrations to and from the transmission shaft. In this case, if the gearbox housing vibrates due to material molding process, material, etc., it will aggravate the vibration of the gears in the housing and the crankshaft connected to the gears, thus becoming a source of vibration and noise, and making it impossible for the entire fracturing pump to operate smoothly.

[0090] In the prior art, the reduction gearbox housing is formed by welding, which is difficult to withstand the above-mentioned vibration and other problems, and thus has the disadvantages of short service life and high cost. To overcome the above-mentioned defects, the present invention uses a reduction gearbox housing with the following structure.

[0091] 2. The first structure of the reduction gearbox housing

[0092] Figure 4 The components of the reduction gearbox housing having the first structure are described. Figure 4 As shown, the reduction box housing is formed by a cover plate 6, a parallel-stage reduction structure housing 7, a planetary-stage reduction mechanism gear ring 8 (ie, a planetary-stage reduction mechanism housing) and a connecting flange 9 in sequence.

[0093] In the above-mentioned first structure, the cover plate 6, the parallel stage reduction structure housing 7 and the connecting flange 9 are respectively formed by a casting molding manufacturing method (hereinafter collectively referred to as "cast housing"), and cast steel or cast iron can be selected according to needs, preferably ductile iron or vermicular cast iron.

[0094] In addition, the reduction gearbox housing having the above-mentioned first structure may be formed by combining steel plate welding and casting.

[0095] The reduction gearbox housing formed in the above manner can meet the support requirements for the gear train and the transmission shaft system, and can buffer and absorb vibrations.

[0096] Compared with the steel plate welded reduction gearbox housing formed by welding using steel plate materials in the prior art, the reduction gearbox housing formed by integral casting is simpler and does not require a series of processes such as cutting, assembling, spot welding, preheating, welding, grinding, heat treatment, flaw detection, rough machining, secondary heat treatment, and fine machining as in the steel plate welding process. In addition, since the cast housing of the present invention is not formed by cutting steel plate materials, the cost loss of raw materials is also lower.

[0097] In addition, when the cover plate 6 is formed by integral casting, for example, there is no need to weld a large number of parts together, so there is no need to waste a lot of time in quality inspection of many processes such as cutting and welding, which can shorten the entire production cycle and improve efficiency.

[0098] Moreover, there are hundreds of welds on the steel plate welded reducer housing in the prior art, and each weld may crack due to stress during the operation of the reducer. Once cracked, the operation needs to be stopped and all welds need to be repaired and inspected, resulting in extremely high labor costs.

[0099] In comparison, since the integrally cast reduction gearbox housing in the present invention does not have welds subject to stress, the above-mentioned problems in the prior art do not exist, thereby having better impact resistance, vibration resistance and longer service life.

[0100] In addition, in the present invention, ductile iron and vermicular iron are used to integrally cast components such as the cover plate 6. The concept of "integral casting" means that, for example, the cover plate 6 is cast in an integrally formed manner, so as to distinguish it from the welding manufacturing method in the prior art in which steel plate materials are processed to form parts and then the parts are welded to each other.

[0101] Since the carbon content of ductile iron and vermicular cast iron is high, some carbon will precipitate after casting and solidification, becoming free cementite or graphite, which is equivalent to forming multiple "cavities" in metal structures such as cast iron. The vibration and sound waves in the gearbox housing are waveform energy, which propagate discontinuously in the cavity, so the energy of the vibration and sound waves will be greatly reduced.

[0102] Therefore, the reduction gearbox housing formed by casting in the present invention can suppress the transmission of vibration and noise. However, the organizational structure of the steel plate material used in the prior art cannot achieve this effect due to the lack of free cementite or graphite.

[0103] In addition, to facilitate the installation of gears and bearings, the cover plate 6, the parallel stage reduction structure housing 7, the planetary stage reduction mechanism gear ring 8 and the connecting flange 9 are connected by bolts 10. The connection surface of the casting housing where the bolts are formed is thickened, and a cylinder with an enlarged diameter and thickening is arranged within a specific extension range radiating outward from the center of the threaded hole. The thickness of the cylinder is related to the size of the bolt and the bolt engagement depth.

[0104] According to the above structure, by increasing the length and area of ​​the threaded connection area of ​​the bolt connected to the casting shell, a reliable connection between the casting shells can be ensured. The cross section of the column material radiating outward from the center of the threaded hole is not limited to a circle, and it is sufficient to ensure that the thread has sufficient connection effect on the casting shell.

[0105] In order to further enhance the strength of the casting shell, reinforcing ribs may be provided on each casting shell. Figure 5 The structure in which the reinforcing ribs 12 are provided on the cover plate 6 and the parallel-stage reduction structure housing 7 is shown by way of example.

[0106] For example, reinforcing ribs 12 are provided between the bearing seat 30 and the surrounding vertical plate 11 of the casting shell, at the corners of the vertical plate 11, at the shell connection between the two-stage transmission gearboxes, etc., where the rigidity is weak due to the additional bending moment. The reinforcing ribs 12 may be array reinforcing ribs, for example.

[0107] The reinforcing ribs 12 are used to increase the supporting strength and rigidity of the bearing seat 30, inhibit deformation of the casting shell such as the cover plate 6, and avoid abnormal wear and damage to the bearings and gears caused by deformation of the casting shell.

[0108] In the parallel stage reduction structure, due to the large difference in diameter between the large gear and the small gear, Figure 5 The parallel stage reduction structure housing 7 shown has a sudden change in housing profile at the connection between the two gears. Providing transverse reinforcing ribs 12 at the sudden change in housing profile not only improves the support stiffness of the parallel stage reduction structure housing 7, but also converts the tangential force generated by the impact of the meshing of the large gear teeth and the small gear into a radial force, thereby reducing the impact vibration of the large gear and the small gear caused by excessive tangential force.

[0109] The cross-sectional shape of the reinforcing rib 12 may be rectangular. Compared with a solid cross-section (such as a circle or a square) with the same area and regular shape, a rectangular cross-section with a long axis has a larger moment of inertia, which can ensure that the reinforcing rib 12 has sufficient bending stiffness. However, the reinforcing rib 12 may also have any cross-sectional shape that can meet the support requirements and the casting process as required.

[0110] In addition, a transition groove is provided at the root of the reinforcing rib 12. A large transition fillet is provided between the transition groove and the vertical plate 11 of the casting shell to improve the bending rigidity at the root of the reinforcing rib 12.

[0111] The transition groove can be set to an oblique angle or an arc shape (with constant curvature or variable curvature) according to needs, but the transition groove of the present invention is not limited thereto.

[0112] The design of transition grooves and fillets is advantageous in the casting process. This is because, in the casting process, when molten iron is poured and flows through a sudden corner at high speed, interception and aggregation will occur, thus affecting the uniformity of the material. Setting transition grooves and fillets can achieve a gradual transition of the corner, thereby improving the efficiency of molten iron punching and avoiding defects such as shrinkage and cold cracking of casting components due to metal structure accumulation and stress concentration. In addition, it can also prevent erosion and damage to the corner of the sand mold caused by eddy currents and bubbles generated by the high-speed impact of molten iron on the sudden corner.

[0113] In contrast, since the welding manufacturing process of the prior art forms parts by cutting plate-like materials, it is difficult to form the above-mentioned transition grooves and fillets on the housing due to production cost and time considerations. In addition, since the problems caused by molten iron pouring are not considered in the welding manufacturing process, it is not thought of to set transition grooves and fillets on the reduction gearbox housing formed by the welding manufacturing process.

[0114] 3. Second structure of the reduction gearbox housing

[0115] Figure 6 The components of the reduction gearbox housing having the second structure are described. For ease of understanding, Figure 6 Zhongyu Figure 4 The same parts are used Figure 4 The same reference numerals are used in the drawings.

[0116] like Figure 6 As shown, the entire housing of the reduction gearbox is formed in an integral casting manner, and along the horizontal plane of the axis of the input shaft and the output shaft, the reduction gearbox housing is divided into an upper housing 13 and a lower housing 14. In this second construction, the gear is vertically placed in the upper housing 13 and the lower housing 14 along the longitudinal direction.

[0117] In the structure in which the reduction gearbox housing is divided into an upper housing 13 and a lower housing 14, a sliding bearing can be used as a rolling bearing of the gear shaft, thereby facilitating the installation of the bearing and reducing the volume and loading amount of the reduction gearbox.

[0118] In addition, whether the bearing bushing 15 can bear the axial load is selected according to whether there is an axial force during gear transmission. Specifically, rolling bearings such as tapered roller bearings, angular contact ball bearings, and thrust ball bearings can bear the axial load.

[0119] Compared with conventional rolling bearings, the bearing shell 15 with a thrust limit structure can prevent the gear from shifting in the axial direction, can withstand greater axial loads, and can withstand greater impact and vibration, and is more stable during operation. Therefore, when there is axial force during gear transmission, it is preferred to use the bearing shell 15 with a thrust limit structure.

[0120] The upper shell 13 and the lower shell 14 are clamped by bolts. In order to improve the support strength of the bearing seat surface, a reinforcing rib 12 is arranged in a direction perpendicular to the joint surface of the upper shell 13 and the lower shell 14, and the root of the reinforcing rib 12 is formed with a groove transition and / or a fillet.

[0121] Regarding the related features of bolt fixing, setting of reinforcing ribs, groove transition and / or rounded corners, the features applied in the above-mentioned first structure are also applicable to the second structure, so they are not repeated here.

[0122] 4. Support structure of reduction gearbox

[0123] In the prior art reduction gearbox structure, the reduction gearbox cooperates with the splines in the crankcase at the power end through rigid splines to transmit torque and ensure that the external splines of the reduction gearbox output shaft are coaxial with the internal splines of the crankcase, but lacks additional support and positioning. That is, the reduction gearbox is not connected to any other components in a supported manner except for being connected to the crankcase.

[0124] However, under this structure, the support stiffness of the reduction gearbox can only be ensured by the input drive flange and the output drive flange, and the overall stiffness is insufficient.

[0125] In response to the above problems, the applicant proposed the following design solutions:

[0126] 4.1 Rigid support structure

[0127] In addition to the spline and the external flange in the prior art, the present invention further provides a rigid bottom support foot on the bottom skid on which the fracturing equipment is installed, and the reduction gearbox is installed on the rigid bottom support foot.

[0128] Figure 7 The example of setting the rigid bottom support feet when the reduction gearbox is composed of a parallel-stage reduction gearbox and a planetary-stage reduction gearbox is shown. Figure 7 As shown, the rigid bottom support foot 16 is arranged with one end thereof supporting the reduction box at the bottom of the parallel-stage reduction structure housing 7 in the reduction box, and the other end thereof being connected and fixed to the bottom skid.

[0129] Through the above structure, the rigidity of the parallel-stage reduction gearbox structure can be improved, the load on the connecting flange 17 and the crankcase can be reduced, and the stability of the reduction gearbox operation can be increased.

[0130] The shape, quantity and position of the bottom support legs 16 are not limited and can be determined according to actual vibration conditions and structural environment.

[0131] in addition, Figure 8 An example of providing a rigid bottom support foot when the reduction gearbox is composed of a two-stage planetary reduction structure is shown. Figure 8 The bottom support feet are made of Figure 7 Same reference numerals.

[0132] like Figure 8 As shown, a plurality of rigid bottom support legs 16 are provided at the bottom of the planetary-stage deceleration structure housing 8, and the other ends of the rigid bottom support legs 16 are connected and fixed to the bottom skid.

[0133] The shape, number and position of the bottom support legs 16 are not limited and can be determined according to the actual vibration conditions and structural environment, as long as they can ensure stable support for the reduction gearbox.

[0134] 4.2 Shock-absorbing support structure

[0135] In order to further absorb the vibration inside and outside the reduction gearbox, a shock-absorbing support structure (hereinafter also referred to as a flexible support structure) may be provided between the reduction gearbox housing and the bottom skid. The shock-absorbing support structure specifically includes the above-mentioned rigid bottom support foot 16 and a shock absorber 18, wherein the bottom support foot 16 is provided between the shock absorber 18 and the bottom of the reduction gearbox housing, and the shock absorber 18 is provided on the bottom skid.

[0136] With this structure, adverse consequences caused by resonance, such as gear breakage and / or damage, and failure due to bearing fatigue, can be effectively avoided.

[0137] Fig. 9 The figure shows the case where a damping support structure is provided when the reduction gearbox is composed of a parallel-stage reduction gear structure and a planetary-stage reduction gear structure. Fig. 9 As shown, the bottom supporting foot 16 in the shock-absorbing support structure is arranged at the bottom of the parallel-stage reduction structure housing 7 in the reduction box, specifically, at the bottom of the housing accommodating the large gear in the parallel-stage reduction structure housing 7 connected to the connecting flange 17, and two shock absorbers 18 are arranged at the bottom of the bottom supporting foot 16, and the shock absorbers 18 are connected and fixed to the bottom skid.

[0138] exist Fig. 9 An example of a set of shock absorbing structures consisting of a bottom support leg 16 and two shock absorbers 18 is shown in FIG. However, the present invention is not limited thereto, and multiple sets of shock absorbing structures can also be selected according to requirements, each set of shock absorbing structures consisting of a bottom support leg 16 and two shock absorbers 18.

[0139] In addition, the shape of the bottom support foot 16 is not limited to Fig. 9 The shape shown in can be any shape as long as it can be set between the reduction box and the shock absorber to support the reduction box.

[0140] Fig.10 An example of setting a shock-absorbing support structure when the reduction box is composed of a two-stage planetary reduction structure is shown. Fig.10 The bottom support feet and shock absorbers are made of the same Fig. 9 Same reference numerals.

[0141] In such Fig.10 In the structure shown, a plurality of shock absorbing structures are arranged at the bottom of the two-stage planetary reduction structure, and each set of shock absorbing structures is composed of a bottom support foot 16 and two shock absorbers 18. For example, multiple sets of shock absorbing structures can be arranged on the front and rear sides of the reduction box housing to maintain stable support.

[0142] In addition, the shape of the bottom support foot 16 is not limited to Fig. 9 The shape shown in can be any shape as long as it can be set between the reduction box and the shock absorber to support the reduction box.

[0143] The number and position of the shock absorbing structures are not limited to the above description, and the number of bottom support legs 16 and shock absorbers 18 included in a set of shock absorbing structures is also not limited thereto, as long as the equipment requirements are met.

[0144] Although the above description and drawings record a structure in which the bottom supporting foot 16 is directly connected to the shock absorber 18 in the shock absorbing structure, other structures may also be used, such as adding a platform and threaded holes at the bottom of the bottom supporting foot and then connecting it to the shock absorber 18.

[0145] Fig.11 The structure of the shock absorber is shown. The multi-layer metal structure 19 can bear the weight of the reduction box, the middle elastic structure 20 can absorb and buffer the noise and vibration generated by the reduction box, and the bottom 21 is connected and fixed to the bottom skid. The middle elastic structure can be a rubber structure, for example.

[0146] The shock absorber can be simply and conveniently installed between the bottom support foot 16 and the bottom skid.

[0147] However, the present invention may also use other shock-absorbing support methods, such as a composite shock-absorbing method combining a spring and a rubber structure, or the helical gears used in the reduction box may be replaced with staggered herringbone gears to achieve a smooth transmission effect.

[0148] 5. Connection structure of reduction gearbox

[0149] When the reduction gearbox and the skid are connected through a supporting structure, it is difficult to ensure that the output shaft of the reduction gearbox and the input shaft of the crankcase are strictly connected in a centering manner with the axes set on the same line, considering the existence of processing and installation errors. However, the rigid connection relying on the connecting flange cannot compensate for this error, so over-positioning may occur when installing the reduction gearbox, resulting in excessive restriction of the displacement freedom of the reduction gearbox, which may cause problems such as inability to install or eccentric wear and abnormal stress concentration after installation.

[0150] To solve the above problems, the present invention is based on Figure 12-13 The fracturing equipment shown is used to illustrate the improvement in the connection between the reduction gearbox and the engine and crankcase.

[0151] To simplify the explanation, Fig.12 and 13 The fracturing equipment in FIG. 1 only shows the engine, reduction box and crankcase it includes, while other components are omitted.

[0152] 5.1 The first connection structure of the reduction gearbox

[0153] Fig.12 1 shows a first connection structure of the reduction gearbox 1. Fig.12As shown, a flexible support structure 26 is provided at the bottom of the reduction box 1 (i.e., between the reduction box 1 and the bottom skid), and a flexible connection is achieved between the reduction box 1 and the engine 27 via a flexible coupling 23, i.e., the power input shaft 24 of the engine 27 drives the driving flange 22 of the reduction box via the flexible coupling 23.

[0154] Then, the reduction box 1 reduces the high speed from the engine 27 to a low speed through gear transmission, and increases the transmission torque of the output shaft (ie, the planetary carrier) of the reduction box.

[0155] In addition, the output shaft of the reduction gearbox 1 is connected to the spline 25 of the crankcase 28 through the flexible coupling 23, thereby driving the crankshaft of the crankcase to rotate.

[0156] exist Fig.12 In the first connection structure of the reduction gearbox 1 shown, the engine 27 is a diesel engine or a turbine engine.

[0157] 5.2 Second connection structure of the reduction gearbox

[0158] Fig.13 The second connection structure of the reduction gearbox 1 is shown. Fig.13 The same parts in Fig.12 The same reference numerals are used for corresponding parts.

[0159] like Fig.13 As shown, a flexible support structure 16 is provided at the bottom of the reduction box 1 (i.e., between the reduction box 1 and the bottom skid), and the reduction box 1 and the engine 27 are connected via a rigid coupling 29, i.e., the power input shaft 24 of the engine 27 drives the driving flange 22 of the reduction box via the rigid coupling 29.

[0160] The rigid coupling 29 may also be a rigid-flexible coupling with a position offset compensation function, such as a universal joint coupling.

[0161] Then, the reduction box 1 reduces the high speed from the engine 27 to a low speed through gear transmission, and increases the transmission distortion of the output shaft (ie, the planetary carrier) of the reduction box.

[0162] In addition, the output shaft of the reduction gearbox 1 is connected to the spline 25 of the crankcase 28 through the flexible coupling 23, thereby driving the crankshaft of the crankcase 28 to rotate.

[0163] exist Fig.13 In the second connection structure of the reduction gearbox 1 shown, the engine 27 is an electric motor.

[0164] exist Fig.12 The first connection structure shown and Fig.13The second connection structure shown uses a flexible coupling. According to the transmission characteristics and working conditions of the fracturing equipment, the type of flexible coupling can be selected based on the following requirements:

[0165] The coupling can transmit large torque, where large torque means the nominal torque is greater than 300kN·m;

[0166] It can compensate for the axial, radial and angular displacement of two shafts connected by a flexible coupling and is easy to install.

[0167] Since the working environment of the fracturing equipment has a wide temperature range, the flexible coupling can adapt to both cold and hot weather;

[0168] Resistant to corrosion, dust particles and other airborne impurities; and

[0169] Easy maintenance and long continuous service life.

[0170] The flexible coupling in the present invention can be a coupling with an elastic element or a coupling without an elastic element, such as (but not limited to) a drum gear coupling, a serpentine spring coupling, a diaphragm coupling, etc., as long as the coupling used can meet the requirements of transmitting power, compensating errors and / or absorbing and buffering vibrations.

[0171] As described above, by changing the connection between the reduction gearbox and the engine and / or crankcase from a rigid connection to a flexible connection and providing a flexible support structure between the reduction gearbox and the skid, the axial, radial and angular position deviations between the connecting shafts can be compensated.

[0172] At the same time, compared with the adverse effects that the low-frequency torsional vibration of the rigidly connected shaft system (the input shaft of the motor and the output end of the crankcase) may bring to the overall reduction gearbox, the flexible connection used in the present invention can effectively isolate and absorb the torsional vibration from the input shaft and output shaft of the reduction gearbox, thereby preventing gear tooth damage due to resonance or even shaft breakage.

[0173] Note that those skilled in the art can clearly understand the concept of the present invention based on the disclosure of the present invention, and can understand that the embodiments according to the present technology are not limited to the above-described embodiments and can be variously modified within the scope of the present technology.

Claims

1. A reduction gearbox housing, which is composed of a cover plate, a first reduction gear structure housing, a second reduction gear structure housing and a connecting flange in sequence, in, The cover plate, the first deceleration structure housing and the connecting flange are cast housings formed by a casting method and are fixed to each other by connecting components.

2. The reduction gearbox housing according to claim 1, wherein: The first reduction structure housing accommodates a parallel-stage reduction structure or a planetary-stage reduction structure, and the second reduction structure housing accommodates a planetary-stage reduction structure. Rigid bottom support feet are arranged at the bottom of the first reduction structure housing and / or the second reduction structure housing, and the rigid bottom support feet are connected and fixed to the bottom skid.

3. The reduction gearbox housing according to claim 1 or 2, wherein: Reinforcing ribs are arranged in the casting shell.

4. The reduction gearbox housing according to claim 1 or 2, wherein: A shock absorbing structure is arranged at the bottom of the first deceleration structure housing and / or the second deceleration structure housing, and the shock absorbing structure is connected and fixed to the bottom skid.

5. A reduction gearbox housing, comprising an upper housing and a lower housing, in, The upper shell and the lower shell are cast shells formed using a casting molding method, and Wherein, the upper housing and the lower housing are connected and fixed along the horizontal plane of the axis of the power input shaft and the power output shaft of the reduction box through the connecting components.

6. The reduction gearbox housing according to claim 5, wherein: A parallel-stage reduction structure and a planetary-stage reduction structure, or a two-stage planetary-stage reduction structure, are accommodated between the upper shell and the lower shell, and a rigid bottom support foot is arranged at the bottom of the lower shell, and the rigid bottom support foot is connected and fixed to the bottom skid.

7. The reduction gearbox housing according to claim 5 or 6, wherein: Reinforcing ribs are arranged in the casting shell.

8. The reduction gearbox housing according to claim 5 or 6, wherein: A shock absorbing structure is arranged at the bottom of the lower shell, and the shock absorbing structure is connected and fixed to the bottom skid.

9. A fracturing device comprising an engine, a reduction gearbox and a crankcase connected in sequence, in, The reduction gearbox comprises a reduction gearbox housing as claimed in any one of claims 1 to 8, wherein a flexible support structure is provided at the bottom of the reduction gearbox housing. Wherein, the reduction gearbox and the engine are connected via a first coupling, and Wherein, the reduction gear box and the crankcase are connected via a second coupling.

10. The fracturing device according to claim 9, wherein: The first coupling is a flexible coupling or a rigid coupling, and the second coupling is a flexible coupling or a rigid-flexible coupling.

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