Non-metal impeller for main cold air blower of locomotive and manufacturing method thereof

Abstract

The application discloses a non-metal impeller for a main cold air blower of a locomotive and a manufacturing method thereof, and relates to the field of lightweight ventilation fan technology. The non-metal impeller comprises, from inside to outside, a wheel core, a wheel disc, a wheel hub and blades, and the wheel core, the wheel disc, the wheel hub and the blades are integrally formed. The manufacturing method of the non-metal impeller comprises pre-impregnated material cutting, mold material laying and overall mold pressing forming. According to the consideration of stress and failure condition, long-fiber filament pre-impregnated material is used as a reinforcing framework layer along the directions of the wheel core, the wheel disc, the wheel hub and the blades, so as to exert the advantages of the long-fiber filament pre-impregnated material in bearing and strengthening. Through the design and the process, the application realizes the optimized distribution of the fiber reinforced material in the complex structure while maintaining the strength and rigidity of the long-fiber filament, and improves the overall strength and durability of the product.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lightening of ventilators, and particularly relates to a non-metal impeller for a main cooling fan of a locomotive and a manufacturing method thereof. BACKGROUND

[0002] At present, an aluminum alloy impeller is mostly used in a main cooling impeller of a locomotive. However, with the increasing demand for lightening, size precision improvement, corrosion resistance, low cost and high production efficiency of a fan impeller, research work on high-efficiency lightening and vibration and noise reduction technology of a track equipment ventilation system is emerging. Under this background, a resin-based non-metal impeller is put forward, and batch use of the impeller in a 160km power concentrated motor train unit main cooling fan has been successfully realized.

[0003] However, the thickness and rotation angle of the impeller blade change in the radial direction, especially at the connecting part of the blade and the disc, where the shape curve changes abruptly.

[0004] Therefore, the application provides a non-metal impeller for a main cooling fan of a locomotive and a manufacturing method thereof to solve the problems in the background technology. SUMMARY

[0005] The application aims to provide a non-metal impeller for a main cooling fan of a locomotive and a manufacturing method thereof to solve at least one aspect of the problems and defects in the background technology.

[0006] According to one aspect of the application, a non-metal impeller for a main cooling fan of a locomotive is provided, which comprises, in sequence from inside to outside, a core, a disc, a hub and a blade, and the core, the disc, the hub and the blade are integrally formed.

[0007] The core is made of metal, and the core comprises a cylindrical barrel, and the cylindrical barrel is circumferentially uniformly provided with at least four protrusions and at least four circular arc grooves.

[0008] The disc is circumferentially uniformly provided with a plurality of reinforcing rib structures.

[0009] The manufacturing raw material of the disc, the hub and the blade comprises prepreg.

[0010] According to another aspect of the application, a manufacturing method of a non-metal impeller for a main cooling fan of a locomotive is provided, which comprises the following steps.

[0011] Prepreg cutting, mold laying and overall mold forming.

[0012] The prepreg cutting comprises short-fiber yarn prepreg cutting and long-fiber yarn prepreg cutting.

[0013] As a further technical solution of the application, the short-fiber yarn prepreg cutting comprises the following steps.

[0014] a. Cutting the short fiber filament pre-impregnated material disc to form the first ply as the main material ply for the wheel disc and hub, ready for use;

[0015] b. Cutting the short fiber filament pre-impregnated material sheet to form the second ply as the main material ply for the wheel disc, hub and blade, ready for use.

[0016] The present application optimizes the mechanical properties, performance and process characteristics of long fiber filaments and short fiber filaments. In order to fully utilize the flowability of short fiber filaments while protecting the fiber bundle direction of long fiber filaments, the present application uses short fiber filament pre-impregnated material with good flowability as the main material ply to fill the variable surface and variable angle structure, which not only meets the requirements of complex structure, but also ensures the wrapping and fixing of long fiber filament pre-impregnated material, effectively preventing cracking and delamination in the fiber bundle direction.

[0017] As a further technical solution of the present application, the long fiber filament pre-impregnated material cutting includes the following steps:

[0018] c. Wrapping the long fiber filament pre-impregnated material along the fiber direction into a circle with a size of 1.5-2 times the diameter of the wheel core to form the third ply as the reinforcing framework ply for the wheel disc, ready for use;

[0019] d. Cutting the long fiber filament pre-impregnated material along the fiber direction to a length of 1.5-2 times the diameter of the impeller to form the fourth ply as the reinforcing framework ply for the wheel disc, hub and blade, ready for use.

[0020] According to the stress and failure conditions, long fiber filament pre-impregnated material is used as the reinforcing framework ply along the wheel core, wheel disc, hub and blade direction to take advantage of its load bearing and strengthening. Through this design and process, the present application maintains the strength and stiffness of long fiber filaments while achieving optimal distribution of fiber reinforced materials in complex structures, improving the overall strength and durability of the product, and also helping to reduce the cost and complexity of the manufacturing process.

[0021] As a further technical solution of the present application, the pre-impregnated material cutting further includes the following steps:

[0022] e. Taking 1 piece of the fourth ply and clamping it into 2 pieces of the second ply to form the fifth ply as the overall ply for the wheel disc, hub and blade, ready for use;

[0023] f. Taking 1 piece of the third ply and clamping it into 2 pieces of the first ply to form the sixth ply as the overall ply for the wheel disc and hub, ready for use;

[0024] g. Taking 4 pieces of the fifth ply and symmetrically winding them into the sixth ply to form the seventh ply, and taking 5 pieces of the fifth ply and symmetrically winding them into the sixth ply to form the eighth ply.

[0025] As a further technical scheme of the present application, the mold laying includes the following steps:

[0026] h. Put one piece of the seventh layer into the numbered mold pressing mold 1, 5, 9, 13 blade corresponding position respectively;

[0027] i. Put one piece of the seventh layer into the numbered mold pressing mold 2, 6, 10, 14 blade corresponding position respectively;

[0028] j. Put one piece of the seventh layer into the numbered mold pressing mold 3, 7, 11, 16 blade corresponding position respectively;

[0029] k. Put one piece of the eighth layer into the numbered mold pressing mold 4, 8, 12, 15, 17 blade corresponding position respectively.

[0030] As a further technical scheme of the present application, the overall mold pressing forming includes the following steps:

[0031] The upper mold moves to the upper mold core and the material contact surface at a speed of 80-150 mm / s, and when the upper mold contacts the material, the mold is slowly closed, the movement speed of the upper mold is reduced to 10-20 mm / s until the mold is closed, the forming pressure is 7-15 MPa, and the mold is demolded after pressure maintaining for 30-40 min.

[0032] As a further technical scheme of the present application, the length of the short fiber used in the pre-impregnated material cutting is 15 mm-50 mm.

[0033] As a further technical scheme of the present application, the length of the long fiber used in the pre-impregnated material cutting is 1000 mm-2000 mm.

[0034] As a further technical scheme of the present application, the pre-impregnated material is one of epoxy resin, unsaturated polyester resin, polyurethane resin and polyimide resin.

[0035] As a further technical scheme of the present application, the short fiber and the long fiber are one of glass fiber, carbon fiber, carbon glass fiber, aramid fiber, alumina fiber and boron carbide fiber. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to facilitate the understanding of those skilled in the art, the present application will be further described below with reference to the drawings.

[0037] Figure 1 It is a structural schematic diagram of the impeller;

[0038] Figure 2 It is a structural schematic diagram of the wheel core;

[0039] Figure 3Structure schematic diagram of the first ply;

[0040] Figure 4 Structure schematic diagram of the second ply;

[0041] Figure 5 Structure schematic diagram of the third ply;

[0042] Figure 6 Structure schematic diagram of the fourth ply;

[0043] Figure 7 Structure schematic diagram of the fifth ply;

[0044] Figure 8 Structure schematic diagram of the sixth ply;

[0045] Figure 9 Structure schematic diagram of the seventh ply;

[0046] Figure 10 Structure schematic diagram of the eighth ply.

[0047] In the figure: 1, wheel core; 2, wheel disc; 3, wheel hub; 4, blade; 5, protrusion; 6, circular arc groove. DETAILED DESCRIPTION

[0048] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be further specifically explained below by embodiments, and in conjunction with the drawings. In the description, same or similar reference numerals indicate same or similar components. The following description of the embodiments of the present application is intended to explain the general inventive concept of the present application, and should not be understood as limiting the locomotive main cooling fan non-metallic impeller and its manufacturing method of the present application.

[0049] In addition, in the following detailed description, many specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent, however, that one or more embodiments can be practiced without these specific details. In other instances, well-known structures and devices are illustrated in block diagram form in order to simplify the figures.

[0050] Embodiment 1

[0051] As shown in Figures 1-3 , a locomotive main cooling fan non-metallic impeller comprises, from inside to outside, a wheel core 1, a wheel disc 2, a wheel hub 3 and a blade 4, and the wheel core 1, the wheel disc 2, the wheel hub 3 and the blade 4 are integrally formed; the wheel core 1 is made of metal, and the wheel core 1 comprises a cylindrical barrel, and the cylindrical barrel is circumferentially uniformly distributed with four protrusions 5 and four circular arc grooves 6; the wheel disc 2 is circumferentially uniformly distributed with a plurality of reinforcing rib structures.

[0052] As shown in Figures 4-10The application provides a manufacturing method of a non-metal impeller for a locomotive main cold air blower.

[0053] Prepreg cutting

[0054] a. Cutting the short-fiber filament prepreg disc to form a first ply as a main material ply for the wheel disc 2 and the wheel hub 3, and reserving the first ply for use.

[0055] b. Cutting the short-fiber filament prepreg sheet to form a second ply as a main material ply for the wheel disc 2, the wheel hub 3 and the blade 4, and reserving the second ply for use.

[0056] c. Winding the long-fiber filament prepreg along the fiber direction to form a third ply as a reinforcing framework ply for the wheel disc 2, and reserving the third ply for use.

[0057] d. Cutting the long-fiber filament prepreg along the fiber direction to form a fourth ply as a reinforcing framework ply for the wheel disc 2, the wheel hub 3 and the blade 4, and reserving the fourth ply for use.

[0058] e. Taking one piece of the fourth ply and clamping it into two pieces of the second ply to form a fifth ply as an overall ply for the wheel disc 2, the wheel hub 3 and the blade 4, and reserving the fifth ply for use.

[0059] f. Taking one piece of the third ply and clamping it into two pieces of the first ply to form a sixth ply as an overall ply for the wheel disc 2 and the wheel hub 3, and reserving the sixth ply for use.

[0060] g. Taking four pieces of the fifth ply and symmetrically winding them into the sixth ply to form a seventh ply, and taking five pieces of the fifth ply and symmetrically winding them into the sixth ply to form an eighth ply.

[0061] Mold laying

[0062] h. Placing one piece of the seventh ply into the numbered mold pressing mold 1, 5, 9 and 13 corresponding to the blade 4 respectively.

[0063] i. Placing one piece of the seventh ply into the numbered mold pressing mold 2, 6, 10 and 14 corresponding to the blade 4 respectively.

[0064] j. Placing one piece of the seventh ply into the numbered mold pressing mold 3, 7, 11 and 16 corresponding to the blade 4 respectively.

[0065] k. Placing one piece of the eighth ply into the numbered mold pressing mold 4, 8, 12, 15 and 17 corresponding to the blade 4 respectively.

[0066] Overall mold pressing forming

[0067] The upper die moves at a speed of 80 mm / s to the upper die core and the material contact surface, and when the upper die contacts the material, the die is slowly closed, the movement speed of the upper die is reduced to 10 mm / s until the die is closed, the forming pressure is 7 MPa, the pressure is maintained for 30 min, and then the die is opened, and the non-metal impeller is completed.

[0068] In this embodiment, the length of the short fiber used in the preform cutting is 15 mm, and the length of the long fiber used in the preform cutting is 1000 mm.

[0069] In this embodiment, the preform is an epoxy resin, and the preform fiber is a glass fiber.

[0070] Accelerated fatigue test

[0071] The non-metal impeller is covered with a sealed cover and runs in a closed space; the non-metal impeller is started from a static state to the highest allowable speed of the impeller within 10 s and continuously runs for 10 s; then it is stopped from the highest allowable speed to a static state within 20 s as a cycle, and the total cycle number is 1.04*105 times, without abnormal conditions during the test. After the test, the impeller should be checked for no cracks and looseness.

[0072] Vibration and impact test during operation

[0073] The vibration and impact test is carried out according to the requirements of Class I B of GB / T 21563-2018 "Railway Rolling Stock Equipment Impact and Vibration Test".

[0074] The frequency range of the long-life simulation test is 5 Hz to 150 Hz, and each direction lasts for 5 h.

[0075] The r.m.s magnitude of the long-life simulation test is:

[0076] Vertical: 7.9 (m / s2):

[0077] Lateral: 3.5 (m / s2):

[0078] Longitudinal: 5.5 (m / s2)

[0079] Direction: three mutually perpendicular axis directions.

[0080] The impact test is carried out in the vertical, lateral and longitudinal directions respectively with pulse acceleration of 30 m2 / s, 30 m2 / s and 50 m2 / s respectively, and the pulse is 30 ms.

[0081] The operating frequency of the main cold air fan is 35 Hz, 40 Hz and 45 Hz, and the operating time of each frequency accounts for 1 / 3, a total of 5 cycle tests, and the impeller is checked after each cycle test is completed.

[0082] After the test, the non-metal impeller has no damage, fracture, structural deformation and other phenomena.

[0083] Limit overspeed explosion

[0084] The limit overspeed test is carried out on the non-metal impeller, the rated speed is 1440r / min, the fan is operated at the rated voltage and frequency, the speed is gradually increased, the test speed is increased by 10% each time, when the speed is 120%, 130%, 140% and 150%, the non-metal impeller is detected according to the test requirement of overspeed 110% respectively.

[0085] At the rated speed of 220%, the actual highest speed is 3113r / min, and the non-metal impeller appears collapse.

[0086] Repeated start test

[0087] The non-metal impeller is subjected to cycle start test at the rated voltage and frequency, the start operation time is 2min, then it is stopped for 3min, and the cycle is repeated in turn, the total operation times are 4000 times.

[0088] After the test, the non-metal impeller is visually inspected without deformation, cracking, and the assembled bolts are not loose or broken.

[0089] In summary, the non-metal impeller made in example 1 has good overall performance, and is significantly better than the cast aluminum alloy impeller in bearing life, quality, residual unbalance and strength.

[0090] Example 2

[0091] As shown in Figures 1-3 , a non-metal impeller for main cold air fan of locomotive comprises, from inside to outside, a wheel core 1, a wheel disc 2, a hub wheel and a blade 4, and the wheel core 1, the wheel disc 2, the hub wheel and the blade 4 are integrally formed; the wheel core 1 is made of metal, and comprises a cylindrical barrel body, four protrusions 5 and four circular arc grooves 6 are uniformly distributed around the cylindrical barrel body; the wheel disc 2 is uniformly distributed with a plurality of reinforcing rib structures.

[0092] As shown in Figures 4-10 , a method for manufacturing a non-metal impeller for main cold air fan of locomotive is provided, comprising the following steps:

[0093] Prepreg cutting

[0094] a. Cut the short fiber filament prepreg disc to form a first lay-up as a wheel disc 2 and a hub wheel 3 main material lay-up for standby, with the diameter of the wheel core 1 as the inner diameter and 2 times the diameter of the wheel core 1 as the outer diameter;

[0095] b. Cut the short fiber filament prepreg sheet to form a second lay-up as a wheel disc 2, a hub wheel 3 and a blade 4 main material lay-up for standby, with the diameter of the impeller as the length and the width of the blade 4 as the width.

[0096] c. The long fiber filament prepreg is wound along the fiber direction to form a third layer, which is 2 times the diameter of the core 1, and is used as a reinforcing framework layer for the wheel disc 2;

[0097] d. The long fiber filament prepreg is cut along the fiber direction to form a fourth layer, which is 2 times the diameter of the impeller, and is used as a reinforcing framework layer for the wheel disc 2, the hub 3 and the blade 4.

[0098] e. One piece of the fourth layer is taken and clamped into two pieces of the second layer to form a fifth layer, which is used as a whole layer for the wheel disc 2, the hub 3 and the blade 4;

[0099] f. One piece of the third layer is taken and clamped into two pieces of the first layer to form a sixth layer, which is used as a whole layer for the wheel disc 2 and the hub 3;

[0100] g. Four pieces of the fifth layer are symmetrically wound into the sixth layer to form a seventh layer, and five pieces of the fifth layer are symmetrically wound into the sixth layer to form an eighth layer.

[0101] Mold laying

[0102] h. One piece of the seventh layer is placed in the corresponding position of the numbered mold pressing mold 1, 5, 9, 13 blade 4 respectively;

[0103] i. One piece of the seventh layer is placed in the corresponding position of the numbered mold pressing mold 2, 6, 10, 14 blade 4 respectively;

[0104] j. One piece of the seventh layer is placed in the corresponding position of the numbered mold pressing mold 3, 7, 11, 16 blade 4 respectively;

[0105] k. One piece of the eighth layer is placed in the corresponding position of the numbered mold pressing mold 4, 8, 12, 15, 17 blade 4 respectively.

[0106] Integral mold forming;

[0107] The upper mold moves to the upper mold core and the material contact surface at a speed of 150 mm / s, and after the upper mold contacts the material, the mold is slowly closed, the movement speed of the upper mold is reduced to 20 mm / s until the mold is closed, the forming pressure is 15 MPa, and the mold is demolded after pressure maintaining for 40 min.

[0108] In this embodiment, the length of the short fiber filament used in the prepreg cutting is 50 mm, and the length of the long fiber filament used in the prepreg cutting is 2000 mm.

[0109] In this embodiment, the prepreg is an unsaturated polyester resin, and the prepreg fiber filament is carbon fiber.

[0110] Accelerated fatigue test

[0111] The non-metal impeller is covered with a closed cover and runs in a closed space; the non-metal impeller is started from a static state to the highest allowable speed of the impeller within 10s and runs continuously for 10s; then it is stopped from the highest allowable speed to a static state within 20s as a cycle, and the total cycle number is 1.04*105 times, without abnormal conditions during the test. After the test, the impeller should be checked for no cracks and looseness.

[0112] Vibration and impact test

[0113] The vibration and impact test is carried out according to the requirements of Class I B of GB / T 21563-2018 “Railway Rolling Stock Equipment Impact and Vibration Test”.

[0114] Simulation long life test frequency range: 5Hz-150Hz, each direction for 5h.

[0115] Simulation long life test r.m.s magnitude:

[0116] Vertical: 7.9(m / s2):

[0117] Lateral: 3.5(m / s2):

[0118] Longitudinal: 5.5(m / s2)

[0119] Direction: three mutually perpendicular axis directions.

[0120] Impact test in vertical, lateral and longitudinal directions respectively with pulse acceleration of 30m2 / s, 30m2 / s and 50m2 / s respectively, pulse 30ms.

[0121] The operating frequency of the main cooling fan is 35Hz, 40Hz and 45z, and the operating time of each frequency accounts for 1 / 3, a total of 5 cycle tests, and the impeller is checked after each cycle test is completed.

[0122] After the test, the non-metal impeller has no damage, fracture, structural deformation and other phenomena.

[0123] Limit overspeed explosion

[0124] The non-metal impeller is subjected to limit overspeed test, the rated speed is 1440r / min, the fan is operated at rated voltage and frequency, the speed is gradually increased, the test speed is increased by 10% each time, when the speed is 120%, 130%, 140% and 150%, the non-metal impeller is detected according to the test requirements of overspeed 110%.

[0125] At the rated speed of 220%, the actual highest speed is 3113r / min, and the non-metal impeller appears to be broken.

[0126] Repeated start test

[0127] The non-metal impeller is subjected to cyclic starting test under the rated voltage and frequency, the starting operation time is 2 min, then stopped for 3 min, and the total operation times are 4000 times.

[0128] After the test, the non-metal impeller is visually inspected to be free of deformation, cracking, and the assembled bolts are free of loosening or breaking.

[0129] In summary, the non-metal impeller prepared in Example 2 has better overall performance, and is significantly superior to the cast aluminum alloy impeller in bearing life, mass, residual unbalance and strength.

[0130] The non-metal impellers prepared in Examples 1 and 2 are also subjected to a plurality of performance tests, and the test results of Examples 1 and 2 are shown in Table 1.

[0131] Table 1: Test results of Examples 1 and 2 of the present application

[0132]

[0133]

[0134] In summary, the non-metal impeller has higher static pressure, smaller residual unbalance, lighter impeller, higher bearing life, better overspeed effect, lower density and higher strength compared with the cast aluminum impeller.

[0135] The above-described specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above-described specific embodiments are merely examples of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for manufacturing a non-metal impeller for a locomotive main cold air blower, the non-metal impeller comprising, in order from the inside to the outside, a core, a disc, a hub and blades, and the core, the disc, the hub and the blades being integrally formed; the core is made of metal, the core comprises a cylindrical barrel, and the cylindrical barrel is circumferentially uniformly distributed with at least four protrusions and at least four circular arc grooves; the disc is circumferentially uniformly distributed with a plurality of reinforcing rib structures; and the disc, the hub and the blades are made of prepreg. characterized in that The method comprises the following steps: cutting and laying the prepreg, and integrally molding the disc, the hub and the blades; the cutting of the prepreg comprises cutting short fiber prepreg and cutting long fiber prepreg; the cutting of the short fiber prepreg comprises the following steps: a. cutting a short fiber prepreg disc with a diameter of 1.5-2 times the diameter of the core as the first layer, which is used as the main material layer of the disc and the hub; b. cutting a short fiber prepreg sheet with a length of the diameter of the impeller and a width of the width of the blades as the second layer, which is used as the main material layer of the disc, the hub and the blades; the cutting of the long fiber prepreg comprises the following steps: c. winding the long fiber prepreg along the fiber direction to form a circle with a diameter of 1.5-2 times the diameter of the core as the third layer, which is used as the reinforcing framework layer of the disc; d. cutting the long fiber prepreg along the fiber direction to form a circle with a length of 1.5-2 times the diameter of the impeller as the fourth layer, which is used as the reinforcing framework layer of the disc, the hub and the blades; the cutting of the prepreg further comprises the following steps: e. taking one piece of the fourth layer and clamping it between two pieces of the second layer to form the fifth layer, which is used as the overall layer of the disc, the hub and the blades; f. taking one piece of the third layer and clamping it between two pieces of the first layer to form the sixth layer, which is used as the overall layer of the disc and the hub; g. taking four pieces of the fifth layer and symmetrically winding them into the sixth layer to form the seventh layer, and taking five pieces of the fifth layer and symmetrically winding them into the sixth layer to form the eighth layer; the laying of the mold comprises the following steps: h. placing one piece of the seventh layer into the corresponding position of the blade of the numbered mold pressing mold 1, 5, 9 and 13 respectively; i. placing one piece of the seventh layer into the corresponding position of the blade of the numbered mold pressing mold 2, 6, 10 and 14 respectively; j. placing one piece of the seventh layer into the corresponding position of the blade of the numbered mold pressing mold 3, 7, 11 and 16 respectively; k. placing one piece of the eighth layer into the corresponding position of the blade of the numbered mold pressing mold 4, 8, 12, 15 and 17 respectively.

2. The method for manufacturing a non-metallic impeller for a locomotive main air cooler according to claim 1, characterized in that, the integrally molding of the disc, the hub and the blades comprises the following steps: the upper mold moves to the contact surface of the upper mold core and the material at a speed of 80-150 mm / s, and after the upper mold contacts the material, the mold is slowly closed, the movement speed of the upper mold is reduced to 10-20 mm / s until the mold is closed, the molding pressure is 7-15 MPa, and the mold is demolded after pressure maintaining for 30-40 min.

3. The method for manufacturing a non-metallic impeller for a locomotive main air cooler according to claim 1, characterized in that, The length of the short fiber used in the cutting of the prepreg is 15-50 mm.

4. The method of claim 1, wherein the non-metallic impeller is made of a material selected from the group consisting of a resin, a plastic, a ceramic, a glass, a composite material, and a combination thereof. The length of the long fiber used in the cutting of the prepreg is 1000-2000 mm.

5. The method of claim 1, wherein the non-metallic impeller is made of a material selected from the group consisting of a resin, a plastic, a ceramic, a glass, a composite material, and a combination thereof. The prepreg is one of epoxy resin, unsaturated polyester resin, polyurethane resin and polyimide resin.

6. A non-metallic impeller for a main cold air blower of a locomotive, characterized by comprising: The production method according to any one of claims 1 to 5. The production method according to any one of claims 1 to 5.

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