Three-dimensional flow large blade pressing tooling and method with guide vane structure for compressor impeller

Abstract

In order to solve the technical problems that when large three-dimensional flow blades are molded at present, the blades are prone to deformation and dislocation, it is not easy to ensure the accuracy of the peripheral profile, the high point position of the molding die is easily damaged during molding, and there is a lack of simple and accurate profile inspection methods, the present invention provides a three-dimensional flow large blade molding tooling and method with a guide vane structure for a compressor impeller. The upper die and the lower die have the same profile as the blade center plane. The blades can be positioned during molding through the positioning pins on the inlet edge, the shroud side and the hub side. The reinforcement platform is used to prevent the molding die from being damaged due to large local pressure during molding. With the tooling of the present invention, the molding of large three-dimensional flow blades with a guide vane structure can be completed, and the accuracy can be ensured at the same time, solving the quality problems of the molding of such blades and ensuring the product manufacturing quality.

Description

Technical Field

[0001] The present invention belongs to a blade pressing tooling and method, and particularly relates to a three-dimensional flow large blade pressing tooling and method for a compressor impeller with a guide vane structure. Background Art

[0002] With the development of equipment towards large-scale, three-dimensional flow compressor impellers with a guide vane structure are widely used in air separation compressors due to their good aerodynamic performance. In the compressor manufacturing industry, blades generally adopt a welded structure, and its manufacturing cost is much lower than that of a milled structure, which is particularly prominent in the manufacturing of large three-dimensional flow impellers. When manufacturing a large three-dimensional flow impeller, if a welded structure is adopted, precise pressing of the blade will become the biggest difficulty, and there are mainly the following problems: 1) The blades of the compressor impeller are made of high-alloy high-strength materials, and the inlet of the blade needs to be designed as a guide vane structure, which belongs to a large three-dimensional twisted thick blade. During pressing, the blade is prone to deformation and dislocation, and it is difficult to ensure the accuracy of the peripheral profile; 2) Due to the large blade twist, the high point position of the pressing die is easily damaged during pressing, resulting in the inability to complete the pressing; 3) The cost of blade profile detection is high, and there is a lack of a simple and accurate profile inspection method. Summary of the Invention

[0003] In order to solve the technical problems that during the pressing of large three-dimensional flow blades at present, the blade is prone to deformation and dislocation, it is difficult to ensure the accuracy of the peripheral profile, the high point position of the pressing die is easily damaged during pressing, and there is a lack of a simple and accurate profile inspection method, the present invention provides a three-dimensional flow large blade pressing tooling and method for a compressor impeller with a guide vane structure.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A three-dimensional flow large blade pressing tooling for a compressor impeller with a guide vane structure, characterized in that it includes an upper die, a lower die, a reinforcement platform and a plurality of positioning pins;

[0006] The profiles of the upper die and the lower die are consistent with the half-thickness position of the blade to be pressed along the X and Y directions of the space rectangular coordinate system, and the Z directions are respectively consistent with the half-thickness position of the blade after being offset along the positive Z-axis direction and the negative Z-axis direction;

[0007] A plurality of the positioning pins are all arranged on the outer edge of the lower die, and are respectively located at the air inlet edge, the shroud side and the hub side of the blade to be pressed. One is arranged at the center of the air inlet edge of the blade to be pressed, and at least two are respectively arranged on the shroud side and the hub side; the height of the positioning pin is higher than the height of the blade to be pressed;

[0008] The reinforcement platform is arranged on the outer edge of the lower die, located at the first stressed position between the upper die and the blade to be pressed, and the reinforcement platform extends along the profile of the blade to be pressed, and the inner side of the reinforcement platform is adapted to the corresponding profile of the blade to be pressed.

[0009] Further, the mold surfaces of the upper mold and the lower mold correspond to the side of the blade wheel to be molded, and a thermal expansion deformation amount of 1-2 mm is increased.

[0010] Further, it also includes guide pillars and guide sleeves; the guide sleeves are arranged on the base of the upper mold, the guide pillars are arranged on the base of the lower mold, and the guide pillars and the guide sleeves are adapted to each other.

[0011] Further, the materials of the upper mold and the lower mold are QT600, and the materials of the positioning pins, guide pillars and guide sleeves are 45# steel.

[0012] Further, lifting holes are provided on the bases of the upper mold and the lower mold, and the lifting holes are respectively located at the central positions of the upper mold and the lower mold.

[0013] The present invention also provides a three-dimensional flow large blade molding method for a compressor impeller with a guide vane structure, which is characterized in that the above-mentioned three-dimensional flow large blade molding tooling for a compressor impeller with a guide vane structure is adopted, and it includes the following steps:

[0014] S1, Blade positioning

[0015] After heating the blade to 300-400 °C, remove the positioning pin on the wheel disc side of the lower mold, put the blade into the lower mold, and position the blade through the positioning pins on the wheel cover side and the inlet edge.

[0016] S2, Pre-mold the blade through the upper mold and the lower mold;

[0017] S3, First molding

[0018] Separate the upper mold and the lower mold, install the positioning pin on the wheel disc side of the lower mold, heat the blade to above 800 °C, keep it warm for 1-2 h, and then perform the first molding on the blade through the upper mold and the lower mold.

[0019] S4, Second molding

[0020] Separate the upper mold and the lower mold, take out the blade, cool the three-dimensional flow large blade molding tooling, heat the blade to less than or equal to 620 °C, keep it warm for 1-2 h, and perform the second molding on the blade through the upper mold and the lower mold to complete the three-dimensional flow large blade molding.

[0021] Further, it also includes step S5, blade profile inspection. Under the condition that all the positioning pins are installed, put the blade into the lower mold, and successively use a feeler gauge to inspect whether the gaps between the blade and the lower mold surface and between the blade and each positioning pin meet the preset requirements. If they meet, the blade is qualified; otherwise, repeat steps S4 and S5 until the blade is qualified.

[0022] Further, step S3 specifically includes installing a positioning pin on the disk side of the lower die upper wheel. After heating the blade to a temperature higher than 800 °C and holding for 1 - 2 h, within 30 s, the blade is subjected to the first press forming by the upper die and the lower die, and the press forming time is greater than 30 min and less than 60 min.

[0023] Further, in step S4, the specific press forming time for the blade to be subjected to the second press forming by the upper die and the lower die is greater than 30 min and less than 60 min.

[0024] Further, it further includes step S0 of adjusting the surfaces of the upper die and the lower die, adjusting the blade surface on the three-dimensional model of the blade, and minimizing the lateral movement force of the blade when the blade is placed in the lower die and subjected to press forming by the upper die and the lower die.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. For the three-dimensional flow large blade press forming tooling with a guide vane structure for the compressor impeller of the present invention, the surfaces of the upper die and the lower die are the same as the surface of the blade center plane. The blade can be positioned during press forming through the positioning pins on the inlet edge, shroud side, and disk side. With the tooling of the present invention, the press forming of the three-dimensional flow large blade with a guide vane structure can be completed, and the accuracy can be guaranteed, solving the quality problem of the press forming of this type of blade and ensuring the product manufacturing quality.

[0027] 2. In the press forming tooling of the present invention, on the lower die, a reinforcement platform is added at the point where the upper die and the blade first receive force during press forming, which can effectively protect the high points of the surfaces of the upper die and the lower die, avoid damage to the press forming die due to large local pressure during press forming, and effectively extend the service life of the tooling.

[0028] 3. In the press forming tooling of the present invention, the guide pillars, guide sleeves, positioning pins, upper die, and lower die can all be designed in series, greatly reducing the tooling design cost and manufacturing cycle. The interchangeability of each component in the tooling is conducive to tooling maintenance, and it is especially suitable for the manufacturing of single-piece and small-batch products such as centrifugal compressor impellers.

[0029] 4. In the press forming tooling of the present invention, the guide pillars and guide sleeves are beneficial to ensuring the press forming accuracy of the upper die and the lower die during the press forming process.

[0030] 5. The press forming tooling of the present invention is provided with lifting holes, which facilitate the disassembly and installation of the upper die and the lower die.

[0031] 6. The three-dimensional large blade molding method with guide vane structure for the compressor impeller of the present invention solves the problems in the existing molding technology, such as the low accuracy of the blade profile caused by the misalignment of the blade molding and the damage of the molding die due to the large local pressure at the high points of the molding die. By adopting the hot pressing molding method and innovatively designing the molding process and the blade molding die, the molding accuracy of the pressed sheet is improved. At the same time, the problem of molding die damage is improved, and it can be widely applied to the molding of the blades of this type of compressor impeller.

[0032] 7. In the molding method of the present invention, by adjusting the three-dimensional model of the blade and then adjusting the positions of the upper and lower die surfaces, it can ensure that the lateral moving force of the blade is minimized during molding.

[0033] 8. The molding method of the present invention can also use the molding tooling to inspect the molded blade, further ensuring that the molding quality meets the processing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram when the three-dimensional large blade molding tooling with guide vane structure for the compressor impeller of the present invention molds the blade;

[0035] Figure 2 is Figure 1 the top view of the lower die in the middle.

[0036] Wherein: 1 - reinforcement platform, 2 - blade, 3 - positioning pin, 4 - guide post, 5 - guide sleeve, 6 - upper die, 7 - lower die. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0038] The present invention provides a three-dimensional large blade molding method with guide vane structure for a compressor impeller. This method mainly includes the manufacturing of the molding die, the blanking and processing of the blade 2 → removing the pin on the wheel disc side → pre-molding → installing all the positioning pins 3 → heating the workpiece → hot pressing → holding pressure → heating the workpiece → secondary hot pressing → holding pressure → checking the surface. The specific steps are as follows:

[0039] Step 1, Molding Die Design

[0040] The design data of the upper die 6 and the lower die 7 surfaces of the molding die are derived from the three-dimensional modeling of the blade 2. The molding die of the blade 2 includes the upper die 6, the lower die 7, the guide post 4, the guide sleeve 5, the positioning pin 3, etc. The design of the molding die is specifically divided into the following steps:

[0041] Step 1.1: Design of the surface data of the upper die 6 and the lower die 7 of the three-dimensional flow pressure die:

[0042] Add a thermal expansion deformation of 1 - 2 mm to the three-dimensional model of the blade 2. The thermal expansion deformation can only be added on the disk side of the blade 2. Based on the surface data at the 1 / 2 thickness of the blade 2, determine the X and Y data of the surfaces of the upper die 6 and the lower die 7. After offsetting according to the design requirements, obtain the Z value of the surface of the upper die 6 and the Z value of the surface of the lower die 7 respectively.

[0043] Step 1.2: Design of the positions of the surfaces of the upper die 6 and the lower die 7 of the three-dimensional flow pressure die

[0044] Adjust the three-dimensional model of the blade 2 so that the heights of the two diagonals of the blade 2 are the same. Refer to the mass center of the three-dimensional model of the blade 2 and make a minor adjustment to the final three-dimensional model of the blade 2, mainly to avoid excessive distortion of the blade 2 at the inlet and outlet, which affects the pressing. The position of the adjusted blade 2 model is the position of the pressing model surface. The data can be obtained through UG in three-dimensional modeling. The surfaces of the upper die 6 and the lower die 7 can be adjusted according to the surface of the blade 2, so that when the blade 2 is placed in the lower die 7, it can remain stable, without displacement, and when pressing, the lateral force on the side of the blade 2 by a certain positioning pin 3 will not be too large, minimizing the lateral movement force of the blade 2.

[0045] Step 1.3: Design of the surface reinforcement platform 1

[0046] According to the surface data designed in Step 1.1 and Step 1.2, add a reinforcement platform 1 at the first stress point positions of the upper die 6 and the lower die 7. The width dimension of the reinforcement platform 1 is 15 - 25 mm. It must follow the contour of the blade 2 surface and be 2 - 3 mm lower than the surface. Due to different blade profiles, generally, the positions of the reinforcement platform 1 are at the inlet and outlet positions.

[0047] Step 1.4: Determination of the positions of the positioning pins 3

[0048] The positioning pins 3 are tangent to the lower die 7 and the die surface. The positioning pins 3 are arranged on the three perimeters of the inlet edge, shroud side, and disk side of the blade 2 respectively. One positioning pin 3 is set at the inlet edge, and its position is generally at the center of the inlet edge. At least two positioning pins 3 are set on the shroud side, and generally 2 - 3 positioning pins 3 are set on the disk side. The positioning pins 3 are avoided to be set at the lowest and highest points of the surface. The positions of the positioning pins 3 on the shroud and disk sides are designed as triangles with similar angles as much as possible and are evenly distributed around the perimeter of the shroud disk. The specific number of the positioning pins 3 can be adjusted according to the size of the blade 2. The depth of the installation hole of the positioning pin 3 is greater than or equal to 1.5 times the diameter of the positioning pin 3.

[0049] Step 1.5: Design of the positioning pins 3

[0050] The top 20 mm of the locating pin 3 is designed with a tapered dimension according to 1 / 2 of its diameter, which is beneficial to the hot pressing deformation of the blade 2 and prevents damage to the edge of the blade 2. The diameter and height of the locating pin 3 can be made into universal parts according to a series based on the thickness of the blade 2 and the size of the die for profiling, reducing the die manufacturing cost. The height of the locating pin 3 is higher than the height of the blade 2 to be profiled. The height of the locating pin 3 is approximately the highest point of the profiling die surface + the thickness of the blade 2 + 30 mm.

[0051] Step 1.6: Design of the guide pillar 4 and guide sleeve 5

[0052] The functions of the guide pillar 4 and guide sleeve 5 are to ensure the alignment of the upper die 6 and the lower die 7 and the consistency of the blade profile of the blade 2 during profiling. The guide pillar 4 and guide sleeve 5 are respectively designed at the diagonals of the profiling die, which can ensure the stability of the die during the profiling of the blade 2. Among them, the guide sleeve 5 is installed on the upper die 6 in an interference fit manner, and the guide pillar 4 is installed on the lower die 7 in an interference fit manner. The length of the guide pillar 4 should be lower than the total height of the die.

[0053] Step 1.7: Determination of the material of the profiling die

[0054] To ensure that the surface of the blade 2 is not damaged during the profiling process, the material of the profiling die surface part is selected as QT600, and the materials of the locating pin 3, guide pillar 4 and guide sleeve 5 can be selected as 45 steel.

[0055] Step 1.8: Design of the lifting holes and lifting bolts

[0056] The lifting holes can be designed at the two sides of the profiling die at positions that are beneficial to lifting and die installation. The positions of the lifting holes on the upper die 6 and the lower die 7 are generally less than 60 mm away from the bottom surface of the die and are located at the center of the die to ensure stable lifting and installation of the die.

[0057] Step 2: Manufacturing of the blanks of the three-dimensional flow blades 2

[0058] Take the blade profile at 1 / 2 thickness of the three-dimensional modeling of the blade 2, flatten the three-dimensional twisted blade profile with UG software to obtain the discrete blade peripheral curves, cut and process according to the curves. Double-sided symmetrical bevels must be opened at the periphery of the blade 2, and the thickness of the root face ≤ 2 mm.

[0059] Step 3: Pre-profiling

[0060] Remove the locating pin 3 on the wheel disc side of the blade 2 profiling die, use the locating pins 3 on the wheel cover side and the inlet edge side for positioning, heat the blade 2 to 300 - 400 °C and then place it in the lower die 7. After adjusting the positioning, perform pre-profiling without pressure holding.

[0061] Step 4: Hot pressing of the blade 2

[0062] Before profiling, all the positioning pins 3 on the lower die 7 of the blade 2 need to be installed. Place the blade 2 in the furnace for heating, with the heating temperature ≥ 800 °C, and keep it warm for 1 - 2 hours. The specific temperature needs to be determined according to the material of the blade 2. After the blade 2 is taken out of the furnace, profiling should start within 30 seconds. The holding time for profiling is calculated based on the material and heating temperature, generally more than 30 minutes and less than 60 minutes.

[0063] Step 5: Second hot pressing and pressure holding

[0064] Before the second hot pressing, the mold must be cooled. Place the blade 2 in the furnace for heating, with the temperature generally not higher than 620 °C. The heating time of the blade 2 needs to be determined according to the tempering temperature of the blade 2, and keep it warm for 1 - 2 hours; then perform the second profiling, and the pressure holding time is generally more than 30 minutes and less than 60 minutes.

[0065] Step 6: Profile inspection of the blade 2

[0066] Place the blade 2 after the second profiling into the lower die 7, and use a feeler gauge to check the gap between the blade 2 and the lower die 7. The gap of the feeler gauge ≤ 0.5 mm. Check the gap between the blade 2 and the positioning pin 3, and check the consistency between the blade 2 and the profiling model surface, then it can be determined whether the profile of the blade 2 is qualified for profiling. If the blade 2 is unqualified, repeat the second hot pressing and pressure holding according to Step 5.

[0067] The present invention has been actually verified. By comparing with the existing profiling methods, first of all, other profiling dies with the same precision are not suitable for profiling the ternary twisted high-strength steel blade 2 for compressors. Even if used, the profiling method of the present invention has higher precision and longer service life of the profiling die. The profiling tooling and profiling method of the present invention can complete the profiling of the three-dimensional flow blade 2 with a guide vane structure, and can meet the product design requirements. The profiling tooling can effectively reduce the damage of the tooling and improve the service life of the tooling.

[0068] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A three-dimensional flow large blade pressing tooling with a guide vane structure for a compressor impeller, characterized in that: it includes an upper die (6), a lower die (7), a reinforcement platform (1) and a plurality of positioning pins (3); the profiles of the upper die (6) and the lower die (7) are consistent with the half-thickness of the blade (2) to be pressed along the X and Y directions of the space rectangular coordinate system, and are consistent after being offset along the positive Z-axis and the negative Z-axis directions respectively from the half-thickness of the blade (2) to be pressed in the Z direction; the profiles of the upper die (6) and the lower die (7) corresponding to the disk side of the blade (2) to be pressed are increased by 1-2 mm of thermal expansion deformation; a plurality of the positioning pins (3) are all arranged on the outer edge of the lower die (7), and are respectively located at the inlet edge, the shroud side and the disk side of the blade (2) to be pressed. One is arranged at the center of the inlet edge of the blade (2) to be pressed, and at least two are arranged on the shroud side and the disk side respectively; the height of the positioning pin (3) is higher than the height of the blade (2) to be pressed; the reinforcement platform (1) is arranged on the outer edge of the lower die (7), and is located at the first stressed position between the upper die (6) and the blade (2) to be pressed. The reinforcement platform (1) extends along the profile of the blade (2) to be pressed and is 2-3 mm lower than the profile; the inner side of the reinforcement platform (1) is adapted to the profile line at the corresponding position of the blade (2) to be pressed.

2. The three-dimensional flow large blade pressing tooling with a guide vane structure for a compressor impeller according to claim 1, characterized in that: it further includes a guide post (4) and a guide sleeve (5); the guide sleeve (5) is arranged on the base of the upper die (6), the guide post (4) is arranged on the base of the lower die (7), and the guide post (4) and the guide sleeve (5) are adapted to each other.

3. The three-dimensional flow large blade pressing tooling with a guide vane structure for a compressor impeller according to claim 2, characterized in that: the materials of the upper die (6) and the lower die (7) are QT600, and the materials of the positioning pin (3), the guide post (4) and the guide sleeve (5) are 45 steel.

4. The three-dimensional flow large blade pressing tooling with a guide vane structure for a compressor impeller according to claim 2, characterized in that: lifting holes are respectively arranged on the bases of the upper die (6) and the lower die (7), and the lifting holes are respectively located at the central positions of the upper die (6) and the lower die (7).

5. A three-dimensional flow large blade pressing method for a compressor impeller with a guide vane structure, characterized in that: using the three-dimensional flow large blade pressing tooling with a guide vane structure for a compressor impeller according to any one of claims 1 to 4, including the following steps: S1, positioning of the blade (2) to be pressed After heating the blade (2) to be pressed to 300-400 °C, remove the positioning pin (3) on the disk side of the lower die (7), put the blade (2) to be pressed into the lower die (7), and position the blade (2) to be pressed through the positioning pins (3) on the shroud side and the inlet edge; S2, pre-pressing the blade (2) to be pressed through the upper die (6) and the lower die (7); S3, the first pressing Separate the upper die (6) and the lower die (7), install the positioning pin (3) on the disk side of the lower die (7), heat the blade (2) to above 800 °C, keep it warm for 1-2 h, and then press the blade (2) through the upper die (6) and the lower die (7) for the first time; S4, the second pressing Separate the upper die (6) from the lower die (7), take out the blade (2), cool the three-dimensional flow large blade pressing tooling, heat the blade (2) to less than or equal to 620 °C, hold for 1 - 2 h, and perform the second pressing of the blade (2) through the upper die (6) and the lower die (7) to complete the pressing of the three-dimensional flow large blade.

6. The method for pressing a three-dimensional flow large blade with a guide vane structure for a compressor impeller as described in claim 5, characterized in that: It further includes step S5, blade (2) profile inspection. Under the condition that all the positioning pins (3) are installed, place the blade (2) into the lower die (7), and successively use a feeler gauge to inspect the gap between the blade (2) and the profile surface of the lower die (7), and whether the gap between the blade (2) and each positioning pin (3) meets the preset requirements. If it meets, the blade (2) is qualified; otherwise, repeat steps S4 and S5 until the blade (2) is qualified.

7. The method for pressing a three-dimensional flow large blade with a guide vane structure for a compressor impeller as described in claim 6, characterized in that: Step S3 is specifically as follows: Install the positioning pins (3) on the disk side of the lower die (7), heat the blade (2) to above 800 °C, hold for 1 - 2 h, and within 30 s, perform the first pressing of the blade (2) through the upper die (6) and the lower die (7), and the pressing time is greater than 30 min and less than 60 min.

8. The method for pressing a three-dimensional flow large blade with a guide vane structure for a compressor impeller as described in claim 7, characterized in that: In step S4, the specific pressing time for performing the second pressing of the blade (2) through the upper die (6) and the lower die (7) is greater than 30 min and less than 60 min.

9. The method for pressing a three-dimensional flow large blade with a guide vane structure for a compressor impeller as described in claim 8, characterized in that: It further includes step S0, adjusting the profile surfaces of the upper die (6) and the lower die (7). Adjust the profile surface of the blade (2) on the three-dimensional model of the blade (2) so that when the blade (2) is placed in the lower die (7) and pressed through the upper die (6) and the lower die (7), the lateral moving force of the blade (2) is minimized.

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