Plunger pump cylinder diffusion welding pressurization system and method

Abstract

The invention relates to the technical field of plunger pump cylinder body machining and manufacturing, in particular to a plunger pump cylinder body diffusion welding pressurization system and method. A plunger pump cylinder diffusion welding pressurization system comprises a plurality of pressurization molds, and each pressurization mold comprises a split mold, a taper pin and a cushion block. The plunger pump cylinder body structural part comprises a flange plate and a plurality of bushings, the flange plate is provided with a plurality of plunger holes, the bushings correspond to the plunger holes in a one-to-one mode, in the state that the plunger pump cylinder body structural part and the pressurizing die are positioned, the bushings are inserted into the corresponding plunger holes, and the split die is inserted into the bushings. And the lower pressing die is located above the pressurizing die and the plunger pump cylinder body structural part in the state that the pressurizing die and the plunger pump cylinder body structural part are positioned, the inner diameter of the split die is gradually reduced in the direction away from the lower pressing die, and the hardness of the cushion block is smaller than that of the lower pressing die. Therefore, the problem that the diffusion welding quality of the plunger pump cylinder body is poor is solved.

Description

Technical Field

[0001] The invention relates to the technical field of plunger pump cylinder body processing and manufacturing, and in particular to a plunger pump cylinder body diffusion welding pressurization system and method. Background Art

[0002] Plunger pumps are widely used in various occasions that require high pressure, large flow and flow regulation, such as hydraulic presses, petrochemicals, aircraft, etc. In these occasions, the performance of the plunger pump directly affects the stability and efficiency of the entire system, so the plunger pump plays a key role. The plunger pump includes a cylinder, a plunger, etc. There is a special bimetallic plunger pump cylinder in the plunger pump cylinder. The bimetallic plunger pump cylinder is composed of two metals of different materials welded together. Compared with the ordinary plunger pump cylinder, it improves the stability of flow and pressure output and reduces pulsation. Among them, there are various ways to weld two different metals, such as melt casting and diffusion welding. Among them, the melt casting method is often difficult to obtain high-precision castings due to factors such as the fluidity of liquid metal and shrinkage during cooling. The diffusion welding method is a welding method that combines two or more solid materials by mutual diffusion between atoms at high temperature. In the manufacture of the plunger pump cylinder, diffusion welding technology is used to combine the wear-resistant layer with the cylinder matrix to form a high-strength and high-wear-resistant overall structure. This welding method can significantly improve the overall performance and efficiency of the plunger pump cylinder.

[0003] The cylinder of the plunger pump is mainly composed of two parts: a flange and a bushing. The materials of the two parts are usually dissimilar metals. The two parts are welded by diffusion welding. The quality of the interface connection between the two parts determines the service life of the plunger pump. In the diffusion welding method, diffusion welding requires a higher temperature and a longer insulation time to achieve the mutual diffusion of metal atoms. Therefore, its welding thermal cycle time is long, and the high temperature leads to relatively low production efficiency. For large or complex workpieces, this may become a factor limiting its application. Secondly, when the diffusion welding technology is used to obtain the bimetallic bonding surface, it is difficult to apply pressure on the radial surface, and the process is relatively complicated, so there are higher requirements for pressure control in the diffusion welding link, which will cause the instability of the diffusion welding quality of the plunger pump cylinder. Summary of the invention

[0004] In order to solve the problem of poor quality of diffusion welding of a plunger pump cylinder, the present invention provides a plunger pump cylinder diffusion welding pressurization system and method.

[0005] In a first aspect, the present invention provides a plunger pump cylinder diffusion welding pressurization system, comprising:

[0006] A plurality of pressurizing molds, each of which comprises a split mold, a cone pin and a cushion block, the split mold is cylindrical, the inner hole of the split mold is a cone hole, the split mold comprises a plurality of arc plates, the plurality of arc plates are arranged in a ring shape and fit in sequence, and the cone pin is truncated cone-shaped; when the pressurizing mold is positioned, the cone pin is coaxially arranged with the split mold, the cone pin is inserted in the cone hole of the split mold, the cushion block is located at the top of the cone pin, and the hardness of the cushion block is less than the hardness of the cone pin;

[0007] A plunger pump cylinder structure, the plunger pump cylinder structure comprises a flange and a plurality of bushings, the flange is provided with a plurality of plunger holes, the bushings correspond to the plunger holes one by one; when the plunger pump cylinder structure and the pressure mold are both positioned, the bushings are inserted into the corresponding plunger holes, and the split mold is inserted into the bushings;

[0008] The lower die is located above the pressure die and the plunger pump cylinder structure when the pressure die and the plunger pump cylinder structure are positioned, the inner diameter of the split die gradually decreases in the direction away from the lower die, and the hardness of the pad is less than that of the lower die.

[0009] In some embodiments, a slot is provided on the end surface of the cone pin with a larger diameter, and when the pressure mold is positioned, the slot is located at the top of the cone pin, and the cushion block is inserted into the slot;

[0010] The bottom of the lower pressing die is provided with a plurality of receiving grooves, and the receiving grooves correspond to the cushion blocks one by one; when the lower pressing die presses the pressurizing die, the top ends of the cushion blocks are inserted into the receiving grooves.

[0011] In some embodiments, the cushion block is cylindrical, truncated cone-shaped, or a cylinder with a spherical end surface, and the slot and the receiving groove are adapted to the shape of the cushion block.

[0012] In some embodiments, the fitting surface between adjacent arc-shaped plates is a plane;

[0013] Alternatively, the fitting surfaces between adjacent arc-shaped plates are spiral surfaces.

[0014] In a second aspect, the present invention provides a plunger pump cylinder diffusion welding pressurization method, the plunger pump cylinder diffusion welding method is applied to a plunger pump cylinder diffusion welding pressurization system in the first aspect, comprising:

[0015] Step S10, based on the completion of positioning of the pressurizing mold and the plunger pump cylinder structure, controlling the lower pressing mold to press down the pressurizing mold;

[0016] Step S20, based on the lower pressing die pressing down the pressurizing die with a first preset pressure and the welding temperature being a first preset temperature, obtaining a first pressing amount of the cone pin within a preset detection time length;

[0017] Step S30, adjusting the pressure of the lower pressing die to a second preset pressure based on the first pressing amount exceeding a preset deviation range;

[0018] Step S40, based on the lower pressing die pressing the pressurizing die with the second preset pressure and the welding temperature being the first preset temperature, obtaining a second pressing amount of the cone pin within the preset detection time length;

[0019] Step S50, based on the second pressing amount being within the preset deviation range and exceeding the preset pressing range, adjusting the pressure of the lower pressing die to a third preset pressure, and adjusting the welding temperature to the second preset temperature; the third preset pressure is calculated according to the following formula:

[0020] (F3-F2) / (F2-F1)=(H3-H2) / (H2-H1);

[0021] Wherein, F3 is the third preset pressure; F2 is the second preset pressure; F1 is the first preset pressure; H3 is the preset downward pressure, and H3 is within the preset downward pressure range; H2 is the second downward pressure; H1 is the first downward pressure;

[0022] Step S60, based on the lower pressing die pressing down the pressurizing die with the third preset pressure, and the welding temperature being the second preset temperature, the temperature and pressure are maintained to a preset welding time.

[0023] In some embodiments, in step S11, based on the completion of positioning of the pressurizing mold and the plunger pump cylinder structure, the lower pressing mold is controlled to press down the pressurizing mold with a preset initial pressure, and the welding temperature is the first preset temperature;

[0024] Step S12, based on the lower die pressing down the pressurizing die with the preset initial pressure and the welding temperature being the first preset temperature, controlling the lower die to increase the pressure of the lower die to the first preset pressure at a preset pressurization speed.

[0025] In some embodiments, in step S31, based on the first pressing amount being less than the minimum value of the preset deviation range, increasing the pressure of the lower pressing die to the second preset pressure;

[0026] Step S32: based on the first pressing amount being greater than the maximum value of the preset deviation range, reducing the pressure of the lower pressing die to the second preset pressure.

[0027] In some embodiments, step S501, based on the second pressing amount being outside the preset deviation range, adjusting the pressing force of the lower pressing die to reset to the first preset pressure;

[0028] Step S502, resetting the lower pressure of the lower pressing die to the first preset pressure, and accumulating the number of resets;

[0029] Step S503: based on the reset times being less than the preset times, calculating the update data of the second preset pressure according to the following formula:

[0030] F2 = F1 ± (F0 + N * ΔF);

[0031] Among them, F0 is the basic voltage regulation amount; N is the number of resets; ΔF is the voltage regulation amplitude;

[0032] Step S504, adjusting the pressure of the lower die from the first preset pressure to the updated second preset pressure based on the acquired update data of the second preset pressure;

[0033] Step S505, repeating the steps S40 to S504 until the second pressing amount is within the preset deviation range and exceeds the preset pressing range.

[0034] In some embodiments, step S51, based on the second pressing amount being within the preset deviation range and less than the minimum value of the preset pressing range, increasing the pressure of the lower pressing die to the third preset pressure, and adjusting the welding temperature to the second preset temperature;

[0035] Step S52, based on the second pressing amount being within the preset deviation range and greater than the maximum value of the preset pressing range, reducing the pressure of the lower pressing die to the third preset pressure, and adjusting the welding temperature to the second preset temperature.

[0036] In some embodiments, in step S70, based on the holding time of the third preset pressure and the second preset temperature reaching the preset welding time, the pressure of the lower die is reduced at a preset pressure relief speed until the pressure of the lower die is zero.

[0037] In order to solve the problem of poor diffusion welding quality of the plunger pump cylinder, the present invention has the following advantages: when the plunger pump cylinder is diffused and welded, a metal pad with lower hardness is used to correspond to the taper pin one by one, so that when the lower die applies pressure, the metal pad will undergo plastic deformation, thereby ensuring that the upper surfaces of multiple metal pads are located in the same plane, thereby ensuring the uniformity of the pressure under the lower die and improving the diffusion welding quality. The setting of the split die can avoid the obstruction of the diffusion welding pressure by the deformation resistance of the die itself and improve the clamping effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 An exploded view of a plunger pump cylinder diffusion welding system is shown;

[0039] Figure 2 A schematic diagram of the assembly of a plunger pump cylinder diffusion welding pressurization system is shown;

[0040] Figure 3 A cross-sectional view of a plunger pump cylinder diffusion welding pressurization system is shown;

[0041] Figure 4 A schematic diagram of a straight-cylindrical split-flap mold is shown;

[0042] Figure 5 A schematic diagram of a spiral split-petal die is shown;

[0043] Figure 6 A schematic flow chart of a plunger pump cylinder diffusion welding method is shown.

[0044] Reference numerals: pressure die 10 ; split die 11 ; arc plate 111 ; taper pin 12 ; cushion block 13 ; slot 14 ; lower die 20 ; plunger pump cylinder structural member 30 ; flange 31 ; bushing 32 ; plunger hole 33 ; receiving groove 40 . DETAILED DESCRIPTION

[0045] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0046] As used herein, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "based at least in part on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like is based on the orientation or position relationship shown in the accompanying drawings. These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or position relationship, some of the above terms may also be used to indicate other meanings, such as the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "install", "set", "provided with", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0047] In this embodiment, the plunger pump is an important hydraulic power element, which changes the volume of the sealed working chamber through the reciprocating motion of the plunger in the cylinder body, thereby achieving oil suction and discharge. The plunger pump is mainly composed of a cylinder body, a plunger and other components. The plunger pump cylinder body is a key component in the plunger pump. The performance requirements of the cylinder body include high strength, high wear resistance, and good wear resistance. Some plunger pump cylinder bodies use bimetallic composite materials to further improve performance. The bimetallic plunger pump cylinder body is composed of a flange and a bushing containing multiple plunger holes, and the connection method between the two can be diffusion welding. When the bimetallic plunger pump cylinder body is diffusion welded, under the combined action of high temperature and pressure, the contact surface of the plunger hole wall of the flange and the bushing can obtain a bimetallic bonding surface. In this method, since there are multiple plunger holes, when diffusion welding is performed on multiple structural parts at the same time, it is impossible to ensure that each part has uniform pressure, which makes the diffusion welding quality low. In order to solve the above problems, if Figure 1 As shown, this embodiment provides a plunger pump cylinder diffusion welding system, which includes a plurality of pressurizing molds 10 , a plunger pump cylinder structural member 30 and a lower pressing mold 20 .

[0048] A plurality of pressurized molds 10 can be used for diffusion welding of a piston pump cylinder. Each pressurized mold 10 may include a split mold 11, a tapered pin 12 and a cushion block 13. The split mold 11 may be cylindrical, and the inner hole of the split mold 11 may be a tapered hole. The split mold 11 may include a plurality of arc plates 111, and the plurality of arc plates 111 may be arranged in a ring shape and fit in sequence. The tapered pin 12 may be truncated cone-shaped, and the shape of the tapered pin 12 is adapted to the tapered hole of the split mold 11. The cushion block 13 may be made of a softer metal material. When the pressurized mold 10 is positioned, the tapered pin 12 is coaxially arranged with the split mold 11, and the tapered pin 12 is inserted into the tapered hole of the split mold 11, and the split mold 11 fits tightly with the tapered pin 12. The cushion block 13 is located at the top of the tapered pin 12, and the hardness of the cushion block 13 is less than the hardness of the tapered pin 12. By pressing the cushion block 13 downward, the cushion block 13 applies downward pressure to the cone pin 12. By utilizing the structural characteristics of the cone pin 12 and the tapered hole, the downward pressure borne by the cone pin 12 can be transmitted to the radial force on the split mold 11, and the radial force is perpendicular to the downward pressure of the cone pin 12. This makes the multiple arc plates 111 in the split mold 11 tend to move away from each other. The setting of the split mold 11 can avoid the deformation resistance of the mold itself from hindering the diffusion welding pressure and improve the clamping effect. Thus, the pressure requirements of diffusion welding are met.

[0049] The plunger pump cylinder structure 30 may include a flange 31 and a plurality of bushings 32. The flange 31 and the plurality of bushings 32 are components of two different metal materials. The flange 31 may have a plurality of plunger holes 33, and the number of plunger holes 33 and bushings 32 is 3 to 20. The bushings 32 correspond one to one with the plunger holes 33. When the plunger pump cylinder structure 30 and the pressure mold 10 are both positioned, the bushings 32 are inserted into the corresponding plunger holes 33, and the split mold 11 is inserted into the bushings 32. By pressing down the pressure mold 10, the radial force borne by the split mold 11 can be transmitted to the bushings 32, so that the bushings 32 and the wall of the plunger holes 33 in the flange 31 are diffusion welded.

[0050] like Figure 2As shown, when the pressure mold 10 and the plunger pump cylinder structure 30 are positioned, the lower die 20 is located above the pressure mold 10 and the plunger pump cylinder structure 30, so that the lower die 20 can apply downward pressure to the top of the pressure mold 10 when it moves downward. The inner diameter of the split mold 11 gradually decreases in the direction away from the lower die 20, and the hardness of the pad 13 is less than the hardness of the lower die 20. When the lower die 20 presses the pressure mold 10, the metal pad 13 with lower hardness undergoes plastic deformation, thereby ensuring that the upper surfaces of multiple metal pads 13 are located in the same plane, thereby ensuring the uniformity of the downward pressure of the lower die 20 and improving the quality of diffusion welding. Since the pad 13 undergoes plastic deformation when subjected to downward pressure, it ensures that the force transmission of multiple pressure molds 10 is relatively uniform, so that the extrusion force between multiple bushings 32 and the corresponding plunger hole 33 walls is relatively uniform and stable, thereby improving the diffusion welding quality of the plunger pump cylinder.

[0051] In this embodiment, if Figure 3 As shown, a slot 14 may be provided on the end surface of the cone pin 12 with a larger diameter in the pressure mold 10, and the slot 14 matches the shape of the cushion block 13. When the pressure mold 10 is positioned, the cone pin 12 is coaxially arranged with the split mold 11, the cone pin 12 is inserted in the tapered hole of the split mold 11, the slot 14 is located at the top of the cone pin 12, and the cushion block 13 may be inserted in the slot 14. In this way, the cushion block 13 and the cone pin 12 can be connected to each other through the slot 14, thereby improving the accuracy of positioning the cushion block 13.

[0052] The bottom of the lower die 20 may be provided with a plurality of receiving grooves 40, and the receiving grooves 40 may correspond to the pads 13 one by one. The receiving grooves 40 match the shapes of the pads 13. When the lower die 20 presses down the pressurizing die 10, the top of the pad 13 is inserted into the receiving groove 40. When the lower die 20 is pressed down, the downward pressure will cause the pad 13 to undergo plastic deformation, and at this time, the pad 13 can be fixed in the receiving groove 40, which can further improve the accuracy of positioning the pad 13. Preferably, the diameter of the receiving groove 40 may be larger than the diameter of the pad 13, so that there is enough space for the pad 13 to undergo plastic deformation in the receiving groove 40.

[0053] like Figure 1 As shown, the cushion block 13 can be cylindrical, truncated cone or a cylinder with a spherical end face, and the hardness of the cushion block 13 is less than the hardness of the taper pin 12 and the lower die 20. The slot 14 and the receiving groove 40 are adapted to the shape of the cushion block 13. Considering the convenience of processing and the stability of force, the cylindrical cushion block 13 is preferred. Other embodiments can be used as alternative embodiments.

[0054] In this embodiment, if Figure 4As shown, in the split mold 11, the contact surface between adjacent arc plates 111 is a plane. The adjacent arc plates 111 are split along the circumferential direction to form a combined structure. The arc plates 111 have a simple shape so as to facilitate processing and assembly.

[0055] In some embodiments, Figure 5 As shown, the fitting surface between adjacent arc plates 111 is a spiral surface. When the downward pressure of the cone pin 12 is transmitted to the radial force of the split mold 11, the arc plates 111 will produce corresponding gaps along the circumferential petal due to the radial force. The gaps are spirally distributed evenly around the split mold 11, so that the diffusion welding quality of the bushing 32 is evenly distributed along its own circumferential direction. The isotropy of the final diffusion welding product is improved.

[0056] The number of plunger holes 33 and bushings 32 on the flange 31 can be 3 to 20, and the surface of the flange 31 and bushing 32 containing several plunger holes 33 can be polished smooth so that the roughness is ≤0.6μm. Ensure the welding surface size, shape and position tolerance and roughness requirements. The plunger hole 33 corresponds to the bushing 32 one by one. The inclination angle of the tapered hole of the split mold 11 can be 1 to 3°, and the gap between each adjacent arc plate 111 in the split mold 11 can be 0.2 to 1mm. The height of the pad 13 can be 9 to 20mm. The welding temperature can be set to 0.4Tm to 0.8Tm, Tm is the melting point of the parts to be welded (the diffusion welding temperature is set according to the conditions of the two metals), the welding insulation time is 30min to 240min, the heating rate is 1 to 10℃ / min, the welding pressure is 1MPa to 150MPa50MPa, and the pressurization begins after the temperature is raised to the first preset temperature. Within such a parameter range, the joint surface between the plunger hole 33 of the flange 31 and the bushing 32 can produce a joint with relatively high strength.

[0057] In some implementations, the cylinder metal of the flange 31 is 25Cr3MoA structural steel, the metal of the bushing 32 is ZQSn10-2-3 tin bronze, and the material of the gasket 13 can be selected as T2 copper. The flange 31 contains 9 plunger holes 33. In the pressure mold 10, the inclination angle of the tapered hole of the split mold 11 is 1°, and the gap between each adjacent arc plate 111 in the split mold 11 is 0.3mm. The shape of the metal gasket 13 is selected to be cylindrical, and the axial height of the metal gasket 13 is 10mm. The cavity of the diffusion furnace is evacuated to 1×10-3Pa, thereby axially pressurizing and diffusion welding is performed. The welding temperature can be set to 830°C, the welding insulation time is 60min, the heating rate is 2°C / min, and the welding pressure is 5MPa.

[0058] In other embodiments, the cylinder metal of the flange 31 is Q235 steel, the metal of the bushing 32 is T2 copper, the material of the gasket 13 is 6061 aluminum alloy, and the flange 31 contains 12 plunger holes 33. In the pressure mold 10, the inclination angle of the tapered hole of the split mold 11 is 2°, and the gap between each adjacent arc plate 111 in the split mold 11 is 0.5mm. The shape of the metal gasket 13 is selected to be truncated cone. And the axial height of the metal gasket 13 is 12mm. The diffusion furnace cavity is evacuated to 1×10-3Pa, thereby axially pressurizing and diffusion welding is performed. The welding temperature can be set to 880°C, the welding insulation time is 30min, the heating rate is 5°C / min, and the welding pressure is 15MPa.

[0059] In other embodiments, the cylinder metal of the flange 31 is Ti6Al4V titanium alloy, the metal of the bushing 32 is ZQSn10-10 copper, the material of the gasket 13 is 6063 aluminum alloy, and the flange 31 contains 15 plunger holes 33. In the pressure mold 10, the inclination angle of the tapered hole of the split mold 11 is 3°, and the gap between each adjacent arc plate 111 in the split mold 11 is 0.5mm. The shape of the metal gasket 13 is selected to be an inverted truncated cone. And the axial height of the metal gasket 13 is 15mm. The diffusion furnace cavity is evacuated to 1×10-3Pa, thereby axially pressurizing and diffusion welding is performed. The welding temperature can be set to 830°C, the welding insulation time is 30min, the heating rate is 5°C / min, and the welding pressure is 10MPa.

[0060] In other embodiments, the cylinder metal of the flange 31 is 316L stainless steel, the metal of the bushing 32 is T2 copper, and the material of the pad 13 is ZCuAl10Fe3 aluminum bronze. The surface of the flange 31 and the bushing 32 containing 10 plunger holes 33 is polished smooth so that the roughness is ≤0.6μm. The plunger hole 33 corresponds to the bushing one by one. In the pressure mold 10, the inclination angle of the conical hole of the split mold 11 is 1°, and the gap between each adjacent arc plate 111 in the split mold 11 is 0.8mm. The shape of the metal pad 13 is selected to be hemispherical. And the axial height of the metal pad 13 is 10mm. The diffusion furnace cavity is evacuated to 1×10-3Pa, thereby axially pressurizing and diffusion welding is performed. The welding temperature can be set to 950℃, the welding insulation time is 120min, the heating rate is 5℃ / min, and the welding pressure is 30MPa.

[0061] Before diffusion welding, the parts to be welded need to be degreased, pickled, rinsed with water, cleaned with acetone, cleaned with anhydrous ethanol, wiped, and blown dry in sequence. Ultrasonic cleaning is used in the cleaning process to increase the cleaning efficiency, so that the surface pollutants that hinder diffusion are decomposed, and the effective bonding of diffusion welding metal is guaranteed from all material ends. Before assembling the pressure mold 10, it is also necessary to spray boron nitride release agent between the split mold 11 and the cone pin 12, between the bushing 32 and the split mold 11, and on the lower surface of the lower die 20 and the upper surface of the flange 31, so that the lower die 20 and the pressure mold can be separated from the plunger pump cylinder structure 30 after the diffusion welding is completed.

[0062] After the pressure mold 10 and the plunger pump cylinder structural member 30 are positioned, when the lower die 20 applies pressure, since the hardness of the pad 13 is less than the hardness of the lower die 20, and the hardness of the pad 13 is less than the hardness of the taper pin 12. By using the above-mentioned material, the pad 13 has good toughness and plasticity, and different pads 13 can undergo different plastic deformations, and then different amounts of downward pressure will be provided to different pads 13, so that the downward pressure generated by multiple pressure molds 10 on their corresponding bushings 32 is relatively uniform. Therefore, it is ensured that the diffusion pressure in each plunger hole 33 is also uniform. That is, the pressure distributed on each welding surface is uniform. Finally, the ideal effect of the diffusion welding quality of the plunger pump cylinder can be achieved.

[0063] The diffusion welding process has specific pressure and temperature parameter requirements for different materials, and the downward pressure is an important parameter. The same set of downward pressure parameters is used to perform diffusion welding on various combinations of heterogeneous materials (material selection of flange 31 and bushing 32), so the quality of diffusion welding cannot be accurately controlled. To solve the above problem, this embodiment provides a plunger pump cylinder diffusion welding method, such as Figure 6 As shown:

[0064] In step S10 , when the pressure mold 10 and the plunger pump cylinder structure 30 are positioned, the lower pressing mold 20 is controlled to press the pressure mold 10 downward.

[0065] Step S20, due to the change of dissimilar metal materials, the lower pressing die 20 presses the pressurizing die 10 with a first preset pressure, and the welding temperature is the first preset temperature. At this time, the first pressing amount of the taper pin 12 within the preset detection time can be obtained. For the material selection of the flange 31 and the bushing 32, the value of the set first preset pressure can be the same or different as needed. For the material selection of the flange 31 and the bushing 32, the value of the set first preset temperature can be the same or different as needed. Here, the bushing 32 can be pressure tested with a pre-set first preset pressure. If the first pressing amount exceeds the preset deviation range, it means that the first preset pressure and the first preset temperature deviate too much from the ideal value, and the first preset pressure needs to be adjusted in two stages. The use of two adjustment methods can accurately adjust the pressure and temperature parameters to avoid the pressure adjustment being too large at one time, resulting in inaccurate pressure adjustment.

[0066] Step S30, when it is detected within the preset detection time that the first pressing amount exceeds the preset deviation range, a first adjustment is required to adjust the pressure of the lower pressing mold 20 to a second preset pressure.

[0067] Step S40, based on the lower pressing die 20 pressing down the pressurizing die 10 at the second preset pressure, and the welding temperature being the first preset temperature, obtain the second pressing amount of the cone pin 12 within the preset detection time. During the first adjustment, the temperature does not need to be adjusted, and only the pressure needs to be adjusted to observe the diffusion effect.

[0068] Step S50, based on the second pressure amount detected within the preset detection time being within the preset deviation range and exceeding the preset pressure range, a second level of adjustment is required, that is, the second preset pressure and the first preset temperature are adjusted. Adjust the pressure of the lower pressure mold 20 to the third preset pressure, and adjust the welding temperature to the second preset temperature. Among them, the higher the temperature, the higher the degree of diffusion, but the temperature also has a suitable range, which cannot be too high or too low. The temperature is generally related to the properties of the material, and generally cannot exceed the phase change point of the material, otherwise the internal phase change of the material will be uncontrollable during diffusion. Temperature adjustment can be determined according to the characteristics of the material. The third preset pressure is calculated according to the following formula:

[0069] (F3-F2) / (F2-F1)=(H3-H2) / (H2-H1);

[0070] Among them, F3 is the third preset pressure; F2 is the second preset pressure; F1 is the first preset pressure; H3 is the preset downward pressure amount, and H3 is within the preset downward pressure range; H2 is the second downward pressure amount; H1 is the first downward pressure amount.

[0071] Since the pressing amount and the pressing force are affected by the actual processing conditions and are not in a strictly linear relationship, the third preset pressure under the ideal state is calculated using the formula in step S50. The third preset pressure and the second preset temperature can meet the ideal pressure parameters required for diffusion welding. Therefore, there is no need to test the third preset pressing amount in the future, thereby improving the adjustment efficiency.

[0072] Step S60, based on the lower pressing die 20 pressing down the pressurizing die 10 with a third preset pressure, and the welding temperature is the second preset temperature, the temperature and pressure are maintained to the preset welding time, and the diffusion welding is completed, which can finally achieve the effect of improving the diffusion welding quality.

[0073] In the above-mentioned multiple embodiments, according to the selection of different structural materials such as the flange 31 and the bushing 32, the welding temperature given is the second preset temperature in step S60, and the welding pressure is the third preset pressure in step S60.

[0074] In this embodiment, step S10 may further include:

[0075] Step S11, when diffusion welding is performed on the piston pump cylinder of different materials, based on the completion of positioning of the pressure mold 10 and the piston pump cylinder structure 30, the lower pressure mold 20 is controlled to press the pressure mold 10 with a preset initial pressure to perform diffusion welding. The welding temperature is a first preset temperature.

[0076] Step S12, based on the lower die 20 pressing down the pressurizing die 10 at a preset initial pressure, and the welding temperature being the first preset temperature, the lower die 20 is controlled to increase the pressure of the lower die 20 to the first preset pressure at a preset pressurization speed due to the different material selections of the flange 31 and the bushing 32. By adjusting the preset initial pressure to the first preset pressure and pressing down the lower die 20, damage to the pressurizing die 10 caused by a sudden change in pressure can be avoided as much as possible.

[0077] In this embodiment, step S30 may further include:

[0078] Step S31, when the first pressing amount of the cone pin 12 is less than the minimum value of the preset deviation range, the pressure of the lower pressing die 20 is increased to a second preset pressure. When the result of the first pressing amount is too small, the first preset pressure is adaptively increased and adjusted.

[0079] Step S32, when the first pressing amount of the cone pin 12 is greater than the maximum value of the preset deviation range, the pressure of the lower pressing die 20 is reduced to a second preset pressure. When the first pressing amount is too large, the first preset pressure is adaptively reduced.

[0080] In this embodiment, the following steps may be further included between step S40 and step S50:

[0081] Step S501, after the lower die 20 presses the pressurizing die 10 with the second preset pressure, when the second pressing amount of the cone pin 12 obtained is outside the preset deviation range, it is necessary to adjust the pressing force of the lower die 20 to reset to the first preset pressure.

[0082] Step S502, based on the lower pressure of the lower pressing die 20 being reset to the first preset pressure, the first pressing amount of the cone pin 12 is obtained again, and the welding temperature is the first preset temperature. Based on the first pressing amount of the cone pin 12 exceeding the preset deviation range, the pressure of the lower pressing die 20 is adjusted to the second preset pressure and the welding temperature is the first preset temperature, and then the second pressing amount is obtained, so as to determine whether the second pressing amount is within the preset deviation range and exceeds the preset pressing range. If the second pressing amount exceeds the preset deviation range, the lower pressure of the lower pressing die 20 is reset to the first preset pressure and the number of resets is accumulated.

[0083] Step S503: Based on the reset times being less than the preset times, the second preset pressure is adjusted. The updated data of the second preset pressure is calculated according to the following formula:

[0084] F2 = F1 ± (F0 + N * ΔF);

[0085] Among them, F0 is the basic voltage regulation amount; N is the number of resets; ΔF is the voltage regulation amplitude. F0 can be the same or different for different material selections. ΔF can be the same or different for different material selections.

[0086] Step S504: Based on the acquired update data of the second preset pressure, the pressure of the lower die 20 is adjusted from the first preset pressure to the updated second preset pressure.

[0087] Step S505, repeating steps S40 to S504 until the second downward pressure amount is within the preset deviation range and exceeds the preset downward pressure range. This can avoid the problem that the second downward pressure amount is frequently measured with discontinuities, low reliability, and large errors when the downward pressure is adjusted step by step, i.e., each adjustment is based on the pressure value after the last adjustment.

[0088] In this embodiment, step S50 may further include:

[0089] Step S51, after the lower pressing die 20 presses the pressurizing die 10 by the second preset pressure, if the second pressing amount obtained is within the preset deviation range and is less than the minimum value of the preset pressing range, the pressure of the lower pressing die 20 is increased to the third preset pressure, and the welding temperature is adjusted to the second preset temperature. When the result of the second pressing amount is too small, the second preset pressure is adaptively increased.

[0090] Step S52, after the lower pressing die 20 presses the pressurizing die 10 with the second preset pressure, the second pressing amount obtained is within the preset deviation range and is greater than the maximum value of the preset pressing range, the pressure of the lower pressing die 20 is reduced to the third preset pressure, and the welding temperature is adjusted to the second preset temperature. When the result of the second pressing amount is too small, the second preset pressure is adaptively reduced.

[0091] In this embodiment, in step S70, the lower die 20 presses the pressurizing die 10 based on the third preset pressure, and after the holding time of the pressure and the second preset temperature reaches the preset welding time condition, the pressure of the lower die 20 is reduced at a preset pressure relief speed until the pressure of the lower die 20 is zero, so as to prevent the pressure relief speed from being too fast and causing damage to the material. Finally, the diffusion welding of the piston pump cylinder of different materials is completed.

[0092] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made thereto in form and detail without departing from the scope of the present disclosure.

Claims

1. A plunger pump cylinder diffusion welding system, characterized in that: include: A plurality of pressurizing molds, each of which comprises a split mold, a cone pin and a cushion block, the split mold is cylindrical, the inner hole of the split mold is a cone hole, the split mold comprises a plurality of arc plates, the plurality of arc plates are arranged in a ring shape and fit in sequence, and the cone pin is truncated cone-shaped; when the pressurizing mold is positioned, the cone pin is coaxially arranged with the split mold, the cone pin is inserted in the cone hole of the split mold, the cushion block is located at the top of the cone pin, and the hardness of the cushion block is less than the hardness of the cone pin; A plunger pump cylinder structure, the plunger pump cylinder structure comprises a flange and a plurality of bushings, the flange is provided with a plurality of plunger holes, the bushings correspond to the plunger holes one by one; when the plunger pump cylinder structure and the pressure mold are both positioned, the bushings are inserted into the corresponding plunger holes, and the split mold is inserted into the bushings; The lower die is located above the pressure die and the plunger pump cylinder structure when the pressure die and the plunger pump cylinder structure are positioned, the inner diameter of the split die gradually decreases in the direction away from the lower die, and the hardness of the pad is less than that of the lower die.

2. A plunger pump cylinder diffusion welding system according to claim 1, characterized in that: A slot is provided on the end surface of the cone pin with a larger diameter. When the pressure die is positioned, the slot is located at the top of the cone pin, and the cushion block is inserted into the slot. The bottom of the lower pressing die is provided with a plurality of receiving grooves, and the receiving grooves correspond to the cushion blocks one by one; when the lower pressing die presses the pressurizing die, the top ends of the cushion blocks are inserted into the receiving grooves.

3. A plunger pump cylinder diffusion welding system according to claim 2, characterized in that: The cushion block is cylindrical, truncated cone-shaped or a column with a spherical end surface, and the slot and the receiving groove are adapted to the shape of the cushion block.

4. A plunger pump cylinder diffusion welding system according to claim 1, characterized in that: The fitting surfaces between the adjacent arc-shaped plates are planes; Alternatively, the fitting surfaces between adjacent arc-shaped plates are spiral surfaces.

5. A plunger pump cylinder diffusion welding method, using the plunger pump cylinder diffusion welding system according to any one of claims 1 to 4, characterized in that: The plunger pump cylinder diffusion welding method comprises: Step S10, based on the completion of positioning of the pressurizing mold and the plunger pump cylinder structure, controlling the lower pressing mold to press down the pressurizing mold; Step S20, based on the lower pressing die pressing down the pressurizing die with a first preset pressure and the welding temperature being a first preset temperature, obtaining a first pressing amount of the cone pin within a preset detection time length; Step S30, adjusting the pressure of the lower pressing die to a second preset pressure based on the first pressing amount exceeding a preset deviation range; Step S40, based on the lower pressing die pressing the pressurizing die with the second preset pressure and the welding temperature being the first preset temperature, obtaining a second pressing amount of the cone pin within the preset detection time length; Step S50, based on the second pressing amount being within the preset deviation range and exceeding the preset pressing range, adjusting the pressure of the lower pressing die to a third preset pressure, and adjusting the welding temperature to the second preset temperature; the third preset pressure is calculated according to the following formula: (F3-F2) / (F2-F1)=(H3-H2) / (H2-H1); Wherein, F3 is the third preset pressure; F2 is the second preset pressure; F1 is the first preset pressure; H3 is the preset downward pressure, and H3 is within the preset downward pressure range; H2 is the second downward pressure; H1 is the first downward pressure; Step S60, based on the lower pressing die pressing down the pressurizing die with the third preset pressure, and the welding temperature being the second preset temperature, the temperature and pressure are maintained to a preset welding time.

6. A plunger pump cylinder diffusion welding method according to claim 5, characterized in that: The step S10 comprises: Step S11, based on the completion of positioning of the pressurizing mold and the plunger pump cylinder structure, controlling the lower pressing mold to press down the pressurizing mold with a preset initial pressure, and the welding temperature is the first preset temperature; Step S12, based on the lower die pressing down the pressurizing die with the preset initial pressure and the welding temperature being the first preset temperature, controlling the lower die to increase the pressure of the lower die to the first preset pressure at a preset pressurization speed.

7. A plunger pump cylinder diffusion welding method according to claim 5, characterized in that: The step S30 comprises: Step S31, based on the first pressing amount being less than the minimum value of the preset deviation range, increasing the pressure of the lower pressing die to the second preset pressure; Step S32: based on the first pressing amount being greater than the maximum value of the preset deviation range, reducing the pressure of the lower pressing die to the second preset pressure.

8. The method for diffusion welding a plunger pump cylinder according to claim 5, characterized in that: Between step S40 and step S50, the plunger pump cylinder diffusion welding method further includes: Step S501, based on the second pressing amount being outside the preset deviation range, adjusting the pressing force of the lower pressing die to be reset to the first preset pressure; Step S502, resetting the lower pressure of the lower pressing die to the first preset pressure, and accumulating the number of resets; Step S503: based on the reset times being less than the preset times, calculating the update data of the second preset pressure according to the following formula: F2 = F1 ± (F0 + N * ΔF); Among them, F0 is the basic voltage regulation amount; N is the number of resets; ΔF is the voltage regulation amplitude; Step S504, adjusting the pressure of the lower die from the first preset pressure to the updated second preset pressure based on the acquired update data of the second preset pressure; Step S505, repeating the steps S40 to S504 until the second pressing amount is within the preset deviation range and exceeds the preset pressing range.

9. A plunger pump cylinder diffusion welding method according to claim 5, characterized in that: The step S50 comprises: Step S51, based on the second pressing amount being within the preset deviation range and less than the minimum value of the preset pressing range, increasing the pressure of the lower pressing die to the third preset pressure, and adjusting the welding temperature to the second preset temperature; Step S52, based on the second pressing amount being within the preset deviation range and greater than the maximum value of the preset pressing range, reducing the pressure of the lower pressing die to the third preset pressure, and adjusting the welding temperature to the second preset temperature.

10. The method for diffusion welding a plunger pump cylinder according to claim 5, characterized in that: The plunger pump cylinder diffusion welding method also includes: Step S70, based on the holding time of the third preset pressure and the second preset temperature reaching the preset welding time, reducing the pressure of the lower die at a preset pressure relief speed until the pressure of the lower die is zero.

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