Spinning method and spinning tool for internal tooth-shaped transmission part

Abstract

The invention relates to a spinning method for an internal tooth-shaped transmission part, which comprises the following steps: in finite element software, establishing a model of a plate-shaped blank and a spinning tool which are the same as those of an actually processed transmission part, and carrying out drawing spinning simulation processing on the plate-shaped blank by using the spinning tool to obtain a cylindrical blank subjected to simulation forming; then a model of the spinning tool is used for conducting single-pass spinning simulation machining on the cylindrical blank, and the simulation rolling reduction needed by the tooth height of the inner tooth profile of the transmission part is determined; and drawing spinning and single-pass spinning are adopted, the transmission part is actually machined by using the rolling reduction, and the transmission part with the inner tooth shape is obtained. Compared with a traditional extrusion, broaching and composite forming method, the spinning method for producing the internal tooth-shaped transmission part has the advantages that the fiber flow direction of an original blank is reserved, the surface quality of the part is high, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal plastic forming, and in particular to a method for processing an internal toothed transmission part. Background Art

[0002] my country's auto parts industry has grown rapidly along with the expansion of the vehicle market and global procurement, providing a good foundation for the continued steady development of the automotive manufacturing industry. With the rapid development of the automotive industry, market demand has grown rapidly, and there has been an urgent need for lightweight and low-energy auto parts. Gear parts account for more than 30% of the auto parts market, such as various gears, splines, lead screws, gear rings, etc. These parts have a large application volume and a wide coverage. For transmission parts with internal gears, the traditional processing technology is mainly subtractive manufacturing and plastic forming: (1) Subtractive machining, including gear hobbing, gear shaving, gear shaping, gear grinding, etc., removes excess material by rubbing or cutting the blank with the tool to form parts of the required size. The disadvantages of this method include: a large amount of metal debris will be generated during the processing, and the material utilization rate is low; the original flow line of the material will be destroyed during the forming process; the processing cost of the tool is high; the processing efficiency is low; and the dimensional accuracy is poor.

[0003] (2) Extrusion belongs to the field of plastic forming. The blank is extruded by a punch with an external tooth shape, so that the excess blank flows out of the die cavity, thereby forming a transmission part with an internal tooth shape. The disadvantages of this method are: during the extrusion process, the friction between the blank and the die is large, the die is more easily damaged, resulting in reduced dimensional accuracy of the part; extrusion forming causes large residual stress in the part. Summary of the invention

[0004] The object of the present invention is to avoid the shortcomings of the prior art and provide a spinning method for an internal toothed transmission part of a precision-sized transmission part by spinning a plate-shaped blank.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a spinning method for an internal toothed transmission part, comprising the following steps: Step 1: In the finite element software, a model of a plate blank and a spinning tooling that are the same as the actual processing transmission parts is established, and the spinning tooling is used to simulate the deep drawing and spinning processing of the plate blank to obtain a simulated formed cylindrical blank; Step 2: Use the spinning tool model to perform a single-pass spinning simulation process on the cylindrical blank to determine the simulated reduction required for the internal tooth height of the transmission part; The model of the spinning tooling includes a core mold, a drawing spinning wheel for drawing and spinning simulation processing, and a spinning wheel for single-pass spinning simulation processing. The surface of the core mold is provided with a tooth mold matching the internal tooth shape of the transmission part. At this time, the simulated pressing amount is the pressing amount when the spinning wheel presses the blank of the transmission part tightly into the tooth die on the core die in a single-pass spinning process, so that the inner surface of the transmission part forms the target tooth height of the transmission part; Step 3: Use deep drawing and single-pass spinning, and use the reduction amount to actually process the transmission parts to obtain transmission parts with internal tooth shape.

[0006] Furthermore, in the step 2, a model using multiple spinning wheels is established and simulated, and the multiple spinning wheels include at least one circular arc wheel and at least two double cone wheels, and the multiple spinning wheels are evenly distributed around the core mold; At this time, the spinning wheel is used to simulate the staggered spinning of the cylindrical blank, so as to determine the simulated total reduction required for the internal tooth height of the transmission part; Then, the simulated total reduction is distributed to multiple spinning wheels in different proportions, and staggered spinning simulation processing with different radial staggered amounts is performed. The simulated reduction of each spinning wheel corresponding to the spinning pressure difference of multiple spinning wheels is selected to be less than 3-5%. The simulated reduction of each spinning wheel is the reduction amount when each spinning wheel presses the blank of the transmission part tightly into the tooth die on the core die in the staggered spinning process so that the inner surface of the blank of the transmission part forms the target tooth height of the transmission part. The sum of the reduction amounts of each spinning wheel is the total reduction, and the total reduction amount is equal to the simulated total reduction. At the same time, the axial spacing between the multiple spinning wheels is determined under the premise of preventing interference between the multiple spinning wheels; In step three, multiple spinning wheels are used to perform staggered spinning processing, and the pressing amount of each spinning wheel is used to actually process the transmission part to obtain a transmission part with an internal tooth shape.

[0007] Furthermore, in step 2, during the single-pass deep drawing and spinning simulation processing, the gap between the deep drawing and spinning wheel and the core mold is 6-20mm, the rotation speed of the core mold is 300-2000rpm, the axial feed speed of the deep drawing and spinning wheel is 0.5-1.5mm / r, and the single-pass deep drawing and spinning simulation processing is the same as the actual single-pass deep drawing and spinning processing.

[0008] Furthermore, the plate-shaped blank is a circular plate-shaped blank with a diameter of 150-400 mm and a thickness of 6-15 mm.

[0009] Furthermore, the single-pass spinning simulation process in step 2 is the same as the actual single-pass spinning process, the target tooth height of the transmission part is h=2-4mm, and the pressing amount of the spinning wheel is 2.8-6mm.

[0010] Furthermore, the staggered spinning simulation process is the same as the actual staggered spinning process, the target tooth height of the transmission part is h=2-4mm, the model of the spinning wheel includes a circular arc spinning wheel and two double cone spinning wheels, and the total reduction of the three spinning wheels is 2.8-6mm; The pressing amount t of the three spinning rollers 1 ,t 2 ,t 3 45-55%, 25-35%, and 15-25% of the total reduction, respectively; At this time, the radial distance between the first spinning wheel and the second spinning wheel is equal to t 2 , the radial distance between the second spinning wheel and the third spinning wheel is equal to t 3 ; At the same time, in order to prevent interference between the spinning wheels, the axial spacing S between the first spinning wheel and the second spinning wheel is determined. 12 The axial distance S between the second spinning wheel and the third spinning wheel is 15-20mm. 23 It is 10-15mm.

[0011] Furthermore, the material of the plate-shaped blank described in step three is carbon or alloy structural steel, and is subjected to annealing treatment before deep drawing and spinning processing to reduce hardness, improve plasticity and eliminate internal stress of the blank.

[0012] Furthermore, the specific annealing steps are: placing the plate-shaped blank into an annealing furnace, heating the annealing furnace temperature to 650-850°C, performing a heat preservation treatment for 10-15 hours, cooling it to 400-500°C with the furnace, and then taking out the plate-shaped blank and air-cooling it to room temperature to complete the annealing treatment of the plate-shaped blank.

[0013] The present invention also provides a spinning tool for the spinning method of the internal gear transmission part as described above, comprising a tail top, a core mold installed on a base, the tail top and the core mold cooperate to press the plate blank together, the tail top, the core mold and the base are coaxially arranged, and are all driven to rotate by the main shaft of the spinning machine; It also includes a drawing and spinning roller and three spinning rollers mounted on a roller frame, and the roller frame is used to drive the three rollers to move axially and radially; Among them, the drawing and spinning wheel is used during deep drawing and spinning; the spinning wheel is used during single-pass spinning or staggered spinning. The spinning wheel includes an arc wheel and two double-conical wheels. The drawing and spinning wheel and the arc wheel have the same structure.

[0014] Furthermore, the diameters D of the drawing and spinning roller, the arc roller and the double-cone roller are all: D=(1.2-2)d, d is the diameter of the core mold; If the diameter D is too small, the metal tangential flow will increase and the workpiece precision will decrease; if it is too large, the spinning pressure will increase; During the drawing and spinning, in order to increase the contact area between the drawing and spinning roller and the blank and improve the quality of the cylindrical blank, the arc radius R of the drawing and spinning roller is 30-40 mm. During the single-pass spinning or staggered spinning, when the cone angle radius r of the double-cone spinning wheel is large, the contact area between the double-cone spinning wheel and the blank is increased, the blank of the transmission part is fully extruded, and the surface quality of the formed part is high, but the spinning force is increased, which can easily cause the blank to wrinkle and become unstable, which is not conducive to the forming of the spun part; when the r value is small, the spinning force is reduced, and the forming process is more stable, but the surface quality of the blank is poor, and too small a contact area will also lead to stress concentration, cracks or tears; Therefore, the value of the cone radius r is: r=(1-3)t, t is the thickness of the plate blank; At the same time, if the working angle α of the double-conical wheel is too large, the height of the material bulge in front of the wheel will increase, making the fluidity of the material worse, and even causing instability or wrinkling. If it is too small, the contact area between the wheel and the blank will increase, thereby increasing the spinning pressure and bringing adverse effects to spinning. Therefore, the working angle α is taken as 15-30°.

[0015] The beneficial effects of the present invention are: the present invention produces internal tooth transmission parts through a spinning method. Compared with traditional extrusion, broaching, and composite forming methods, the fiber flow direction of the original blank is retained, the surface quality of the parts is high, and it is a forming method with little or even no cutting, which effectively improves the utilization rate of materials.

[0016] The present invention can spin a circular plate blank through the die provided by the present invention in a spinning machine in two passes to form a transmission part with an internal tooth shape, thereby greatly improving production efficiency.

[0017] The present invention fills the tooth shape successively through the three-wheel staggered spinning method, which can improve the forming accuracy of transmission parts with internal tooth shape, and the internal tooth accuracy can reach level 6. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a schematic diagram of a spinning tooling model for deep drawing and spinning simulation processing of the present invention; Figure 2 It is a schematic diagram of a spinning tooling model for staggered spinning simulation processing of the present invention; Figure 3 It is a schematic diagram of radial offset processing of the second rotating wheel of the present invention; Figure 4 It is a schematic diagram of the axial offset processing of the second rotating wheel of the present invention; Figure 5 It is a schematic diagram of the structure of the circular arc rotor in the second rotor of the present invention; Figure 6 It is a schematic diagram of the structure of the double-conical rotating wheel in the second rotating wheel of the present invention; Figure 7 It is a structural schematic diagram of tightly pressing the blank of the transmission part into the tooth mold on the core mold in the staggered spinning process of the present invention; Figure 8 It is a process flow diagram of a specific example of the present invention; Fig. 9 It is a schematic diagram of an internal tooth forming part of a specific example of the present invention.

[0019] The numbers in the figure are: 1, core mold; 11, tooth mold; 2, tail top; 3, plate-shaped blank; 41, drawing and spinning roller; 42, spinning roller; 421, arc roller; 422, double-conical roller; 7, roller frame; 8, base; 9, cylindrical blank. DETAILED DESCRIPTION

[0020] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0021] In order to achieve the above object, the present invention provides the following specific implementation methods: Example 1: Figure 1 As shown, a spinning method for an internal toothed transmission part comprises the following steps: Step 1: In the finite element software, a model of a plate blank 3 and a spinning tooling that are the same as the actual processing transmission parts is established, and the spinning tooling is used to simulate the deep drawing and spinning of the plate blank 3 to obtain a simulated formed cylindrical blank 9, such as Figure 1 As shown; The plate-shaped blank 3 is a circular plate-shaped blank with a diameter of 150-400 mm and a thickness of 6-15 mm.

[0022] Step 2: Use the spinning tool model to perform a single-pass spinning simulation process on the cylindrical blank 9 to determine the simulated reduction required for the internal tooth height of the transmission part; The model of the spinning tooling includes a core mold 1, a drawing spinning wheel 41 for drawing spinning simulation processing, and a spinning wheel 42 for single-pass spinning simulation processing. The surface of the core mold 1 is provided with a tooth mold 11 matching the internal tooth shape of the transmission part; At this time, the simulated pressing amount is the pressing amount by which the spinning roller 42 presses the blank of the transmission part tightly into the tooth mold 11 on the core mold 1 in a single-pass spinning process, so that the inner surface of the transmission part forms the target tooth height of the transmission part; Among them, during the single-pass deep drawing and spinning simulation processing, the gap between the deep drawing and spinning wheel 41 and the core mold 1 is 6-20mm, the rotation speed of the core mold 1 is 300-2000rpm, the axial feed speed of the deep drawing and spinning wheel 41 is 0.5-1.5mm / r, and the single-pass deep drawing and spinning simulation processing is the same as the actual single-pass deep drawing and spinning processing.

[0023] The single-pass spinning simulation process is the same as the actual single-pass spinning process, the target tooth height of the transmission part is h=2-4 mm, and the pressing amount of the spinning roller 42 is 2.8-6 mm.

[0024] Step 3: Use deep drawing and single-pass spinning, and use the reduction amount to actually process the transmission parts to obtain transmission parts with internal tooth shape.

[0025] Example 2: Figure 2 , Figure 7 As shown, it is the same as Example 1, except that: in step 2, a model using multiple spinning wheels 42 is established and simulated, and the multiple spinning wheels 42 include at least one arc spinning wheel 421 and at least two double-conical spinning wheels 422, and the multiple spinning wheels 42 are evenly distributed around the core mold 1. Figure 2 As shown; At this time, the spinning wheel 42 is used to simulate the staggered spinning of the cylindrical blank, thereby determining the simulated total reduction required for the internal tooth height of the transmission part; Then, the total simulated reduction is distributed to the multiple spinning wheels 42 in different proportions, and staggered spinning simulation processing with different radial staggered amounts is performed. The simulated reduction of each spinning wheel 42 corresponding to the spinning pressure difference of the multiple spinning wheels 42 is selected to be less than 3-5%. The simulated reduction of each spinning wheel 42 is the simulated reduction of the spinning wheel 42 in the staggered spinning process. Figure 7 As shown, each spinning roller 42 presses the blank of the transmission part tightly into the tooth mold 11 on the core mold 1, so that the inner surface of the blank of the transmission part forms a reduction amount of the target tooth height of the transmission part. The sum of the reduction amounts of each spinning roller 42 is the total reduction amount, and the total reduction amount is equal to the simulated total reduction amount; At the same time, the axial spacing between the multiple spinning wheels 42 is determined under the premise of preventing interference between the multiple spinning wheels 42; In step three, multiple spinning wheels 42 are used to perform staggered spinning processing, and the pressing amount of each spinning wheel 42 is used to actually process the transmission part to obtain a transmission part with an internal tooth shape.

[0026] Example 3: Figure 3 , Figure 4As shown, it is the same as Example 2, except that the staggered spinning simulation process is the same as the actual staggered spinning process, the target tooth height of the transmission part is h=2-4mm, the model of the spinning wheel 42 includes a circular arc spinning wheel 421 and two double cone spinning wheels 422, and the total reduction of the three spinning wheels 42 is 2.8-6mm. Figure 3 As shown; The pressing amount t of the three spinning rollers 42 1 ,t 2 ,t 3 45-55%, 25-35%, and 15-25% of the total reduction, respectively; At this time, the radial distance between the first spinning wheel 42 and the second spinning wheel 42 is equal to t 2 The radial distance between the second spinning wheel 42 and the third spinning wheel 42 is equal to t 3 ; At the same time, in order to prevent interference between the spinning wheels 42, the axial distance S between the first spinning wheel 42 and the second spinning wheel 42 is determined. 12 The axial distance S between the second spinning wheel 42 and the third spinning wheel 42 is 15-20 mm. 23 10-15mm, such as Figure 4 shown.

[0027] Example 4: The same as Example 1, except that the material of the plate-like blank 3 is carbon or alloy structural steel, and is annealed before the drawing and spinning process to reduce the hardness, improve the plasticity and eliminate the internal stress of the blank.

[0028] The specific annealing steps are: put the plate blank 3 into the annealing furnace, heat the annealing furnace temperature to 650-850℃, carry out insulation treatment for 10-15h, cool it to 400-500℃ with the furnace, then take out the plate blank and air cool it to room temperature to complete the annealing treatment of the plate blank.

[0029] Example 5: Figure 1 , Figure 5 , Figure 6 As shown, the present invention also provides a spinning tool for the spinning method of the internal gear transmission part as above, such as Figure 1 As shown, it includes a tail top 2, a core mold 1 is installed on a base 8, the tail top 2 and the core mold 1 cooperate to press the plate-shaped blank 3, the tail top 2, the core mold 1 and the base 8 are coaxially arranged, and are all driven to rotate by the main shaft of the spinning machine; It also includes a drawing and spinning roller 41 and three spinning rollers 42 mounted on a roller frame 7. The roller frame 7 is used to drive the three rollers to move axially and radially. Among them, the drawing and spinning wheel 41 is used during drawing and spinning; the spinning wheel 42 is used during single-pass spinning or staggered spinning. The spinning wheel 42 includes an arc wheel 421 and two double-conical wheels 422. The drawing and spinning wheel 41 and the arc wheel 421 have the same structure.

[0030] The diameters D of the drawing and spinning roller 41, the arc roller 421 and the double-cone roller 422 are all: D=(1.2-2)d, d is the diameter of the core mold 1; If the diameter D is too small, the metal tangential flow will increase and the workpiece precision will decrease; if it is too large, the spinning pressure will increase; During the deep drawing and spinning, in order to increase the contact area between the deep drawing and spinning roller 41 and the blank, the quality of the cylindrical blank 9 is improved. Figure 5 As shown, the arc radius R of the drawing and spinning roller 41 is 30-40 mm; In single-pass spinning or staggered spinning, such as Figure 6 As shown in the figure, when the cone angle radius r of the double-cone rotating wheel 422 is large, the contact area between the double-cone rotating wheel 422 and the blank is increased, the blank of the transmission part is fully extruded, and the surface quality of the formed part is high, but the spinning pressure is increased, which easily causes the blank to wrinkle and become unstable, which is not conducive to the forming of the spun part; when the r value is small, the spinning pressure is reduced, and the forming process is relatively stable, but the surface quality of the blank is poor, and too small a contact area will also lead to stress concentration, cracks or tearing; Therefore, the value of the cone radius r is: r=(1-3)t, t is the thickness of the plate blank 3; At the same time, if the working angle α of the double-conical wheel 422 is too large, the height of the material bulge in front of the wheel will increase, making the fluidity of the material worse, or even causing instability or wrinkling. If it is too small, the contact area between the wheel and the blank will increase, thereby increasing the spinning pressure and bringing adverse effects to the spinning. Therefore, the working angle α is set to 15-30°.

[0031] like Figure 2 , Figure 3 , Figure 4 , Figure 8 , Fig. 9 To further illustrate the technical solution and technical effects of the present invention, the present invention provides the following specific examples: Specific example 1: Figure 8 As shown, The process described in this example is Figure 8In the processing flow chart, in the step (e) of internal gear spinning, the plate-shaped blank 3 is a plate-shaped blank with a mounting shaft hole in the middle. Its size is determined to belong to step (a) of blanking. After steps (b), (c), and (d), the blank shown in (d) is obtained. The internal gear spinning (e) involved in the present invention is performed on the blank of the shape shown in (d). At this time, the part of the blank involved in the deep drawing spinning and the offset spinning is the outer side of the circumference. The central shaft hole structure of the blank does not affect the process described in this example. The specific processing steps are as follows: Step 1: According to the size and volume of the internal tooth transmission part to be formed, determine the plate blank 3, which is a circular plate blank with a diameter of 250 mm, a thickness of 8 mm, and a material of SAPH440.

[0032] Step 2: Place the plate-shaped blank 3 into an annealing furnace, heat the annealing furnace to 750°C, then perform a heat preservation treatment for 10 hours, cool it to 450°C with the furnace, and finally take out the plate-shaped blank 3 and air-cool it to room temperature to complete the annealing treatment of the initial blank.

[0033] Step 3: Single-pass deep drawing and spinning. Use the drawing and spinning wheel 41 to perform single-pass deep drawing and spinning on the plate-like blank 3. The gap between the drawing and spinning wheel 41 and the core mold 1 is 7mm, the spindle speed is 600rpm, and the axial feed speed of the wheel is 1mm / r, so that the plate-like blank 3 is formed into a cylindrical blank 9 through deep drawing and spinning.

[0034] The diameter of the drawing and spinning wheel 41 is D=300 mm, the arc radius is R=40 mm, the arc wheel (421) is consistent with the drawing and spinning wheel 41, the diameter of the double-conical wheel 422 is D=300 mm, the working angle α=30°, the cone angle radius r=10 mm, and the tooth mold 11 on the core mold 1 matches the internal tooth shape of the target part; Step 4: In the finite element software ABAQUS, a single-pass spinning simulation is performed to determine the amount of reduction required to form the target tooth height. The internal tooth height of the target internal tooth transmission part is 2.25 mm. According to the simulation results, it is determined that the total reduction of the spinning wheel 42 needs to reach 3 mm.

[0035] Step 5: Figure 2 , Figure 3 , Figure 4 As shown, staggered spinning simulation is carried out in the finite element software ABAQUS. The specific scheme is shown in Table 1. The radial spacing is distributed according to the equal spinning pressure and is determined according to the simulation results: The radial distance between the first spinning wheel 42 and the second spinning wheel 42 is equal to t 2 The radial distance between the second spinning wheel 42 and the third spinning wheel 42 is equal to t 3 , t 1 =1.5mm, t2 =0.9mm, t 3 =0.6mm, at this time the radial distance between the first and second spinning wheels 42 is Δ 12 = t 2 =0.9mm, the radial spacing Δ between the second and third spinning wheels 42 23 = t 3 =0.6mm.

[0036] To prevent interference between the spinning wheels, the axial spacing S between the first and second spinning wheels 42 is determined as 12 =15mm, the axial distance S between the second and third spinning wheels 42 23 =10mm.

[0037] Table 1

[0038] Wherein, the difference in spinning pressure of the plurality of spinning wheels 42 is less than 3-5%; Step six: Perform actual staggered spinning on the spinning machine. The positions of the three spinning wheels 42 are determined according to the above-mentioned radial and axial spacings, and are evenly distributed around the core mold for staggered spinning. The spindle speed is 600 rpm, and the axial feed speed of the spinning wheel is 1 mm / r, so as to obtain a transmission part with internal teeth that meets the dimensional accuracy requirements.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A spinning method for an internal toothed transmission part, characterized in that: The following steps are involved: Step 1: In finite element software, a model of a plate-shaped blank (3) and a spinning tooling that are the same as those of the actual transmission parts to be processed is established, and the spinning tooling is used to simulate deep drawing and spinning processing on the plate-shaped blank (3) to obtain a simulated formed cylindrical blank (9); Step 2: Use the spinning tool model to perform a single-pass spinning simulation process on the cylindrical blank (9) to determine the simulated reduction required for the internal tooth height of the transmission part; The model of the spinning tooling comprises a core mold (1), a drawing spinning wheel (41) for drawing spinning simulation processing, and a spinning wheel (42) for single-pass spinning simulation processing, and the surface of the core mold (1) is provided with a tooth mold (11) matching the internal tooth shape of the transmission part; At this time, the simulated pressing amount is the pressing amount when the spinning wheel (42) tightly presses the blank of the transmission part into the tooth mold (11) on the core mold (1) in a single-pass spinning process, so that the inner surface of the transmission part forms a target tooth height of the transmission part; Step 3: Use deep drawing and single-pass spinning, and use the reduction amount to actually process the transmission parts to obtain transmission parts with internal tooth shape.

2. The spinning method of the internal tooth transmission part according to claim 1, characterized in that: In the step 2, a model using a plurality of spinning wheels (42) is established and simulated, wherein the plurality of spinning wheels (42) include at least one circular arc spinning wheel (421) and at least two double-conical spinning wheels (422), and the plurality of spinning wheels (42) are evenly distributed around the core mold (1); At this time, the spinning wheel (42) is used to simulate the staggered spinning process of the cylindrical blank, thereby determining the simulated total reduction required for the internal tooth height of the transmission part; Furthermore, the simulated total reduction amount is distributed to a plurality of spinning wheels (42) in different proportions, and staggered spinning simulation processing with different radial staggered amounts is performed. The simulated reduction amount of each spinning wheel (42) corresponding to the spinning pressure difference of the plurality of spinning wheels (42) is selected to be less than 3-5%. The simulated reduction amount of each spinning wheel (42) is the reduction amount when, in the staggered spinning processing, each spinning wheel (42) tightly presses the blank of the transmission part into the tooth die (11) on the core die (1) so that the inner surface of the blank of the transmission part forms a target tooth height of the transmission part. The sum of the reduction amounts of each spinning wheel (42) is the total reduction amount, and the total reduction amount is equal to the simulated total reduction amount. At the same time, the axial spacing between the plurality of spinning wheels (42) is determined under the premise of preventing interference between the plurality of spinning wheels (42); In step three, a plurality of spinning wheels (42) are used to perform staggered spinning processing, and the pressing amount of each spinning wheel (42) is used to actually process the transmission part, thereby obtaining a transmission part with an internal tooth shape.

3. The spinning method of the internal tooth transmission part according to claim 1, characterized in that: In step 2, during the single-pass deep drawing and spinning simulation processing, the gap between the deep drawing and spinning wheel (41) and the core mold (1) is 6-20 mm, the rotation speed of the core mold (1) is 300-2000 rpm, the axial feed speed of the deep drawing and spinning wheel (41) is 0.5-1.5 mm / r, and the single-pass deep drawing and spinning simulation processing is the same as the actual single-pass deep drawing and spinning processing.

4. The spinning method of the internal tooth transmission part according to claim 1, characterized in that: The plate-shaped blank (3) is a circular plate-shaped blank with a diameter of 150-400 mm and a thickness of 6-15 mm.

5. The spinning method of the internal tooth transmission part according to claim 1, characterized in that: The single-pass spinning simulation process in step 2 is the same as the actual single-pass spinning process, the target tooth height of the transmission part is h=2-4 mm, and the pressing amount of the spinning wheel (42) is 2.8-6 mm.

6. The spinning method of the internal tooth transmission part according to claim 2, characterized in that: The staggered spinning simulation process is the same as the actual staggered spinning process, the target tooth height of the transmission part is h=2-4 mm, the model of the spinning wheel (42) includes a circular arc spinning wheel (421) and two double cone spinning wheels (422), and the total reduction of the three spinning wheels (42) is 2.8-6 mm; The pressing amounts t1, t2 and t3 of the three spinning rollers (42) are 45-55%, 25-35% and 15-25% of the total pressing amount respectively; At this time, the radial distance between the first spinning wheel (42) and the second spinning wheel (42) is equal to t2, and the radial distance between the second spinning wheel (42) and the third spinning wheel (42) is equal to t3; At the same time, in order to prevent interference between the spinning wheels (42), the axial spacing S between the first spinning wheel (42) and the second spinning wheel (42) is determined. 12 The axial spacing S between the second spinning wheel (42) and the third spinning wheel (42) is 15-20 mm. 23 It is 10-15mm.

7. The spinning method of an internal toothed transmission part according to any one of claims 1 to 6, characterized in that: The material of the plate-shaped blank (3) in step 3 is carbon or alloy structural steel, and is subjected to annealing treatment before deep drawing and spinning processing to reduce hardness, improve plasticity and eliminate internal stress of the blank.

8. The spinning method of the internal gear transmission part according to claim 7, characterized in that: The specific annealing steps are as follows: placing the plate-shaped blank (3) into an annealing furnace, heating the annealing furnace to 650-850°C, performing a heat preservation treatment for 10-15 hours, cooling the plate-shaped blank to 400-500°C in the furnace, and then taking the plate-shaped blank out and air cooling it to room temperature, thereby completing the annealing treatment of the plate-shaped blank.

9. A spinning tool for the spinning method of internal gear transmission parts as claimed in claims 1 to 8, characterized in that: It comprises a tail top (2), a core mold (1) mounted on a base (8), the tail top (2) and the core mold (1) cooperate to press the plate-shaped blank (3), the tail top (2), the core mold (1) and the base (8) are coaxially arranged and are all driven to rotate by a main shaft of a spinning machine; It also includes a drawing and spinning roller (41) and three spinning rollers (42) mounted on a roller frame (7), wherein the roller frame (7) is used to drive the three rollers to move axially and radially; The drawing and spinning wheel (41) is used during drawing and spinning; the spinning wheel (42) is used during single-pass spinning or staggered spinning. The spinning wheel (42) comprises an arc wheel (421) and two double-cone wheels (422). The drawing and spinning wheel (41) and the arc wheel (421) have the same structure.

10. The spinning tool according to claim 9, characterized in that: The diameters D of the drawing and spinning wheel (41), the arc wheel (421) and the double-cone wheel (422) are all: D = (1.2-2) d, d is the diameter of the core mold (1); If the diameter D is too small, the metal tangential flow will increase and the workpiece precision will decrease; if it is too large, the spinning pressure will increase; During the drawing and spinning, in order to increase the contact area between the drawing and spinning roller (41) and the blank and improve the quality of the cylindrical blank (9), the arc radius R of the drawing and spinning roller (41) is 30-40 mm; During the single-pass spinning or staggered spinning, when the cone angle radius r of the double-cone spinning wheel (422) is large, the contact area between the double-cone spinning wheel (422) and the blank increases, the blank of the transmission part is fully extruded, and the surface quality of the formed part is high, but the spinning pressure increases, which easily causes the blank to wrinkle and become unstable, which is not conducive to the forming of the spun part; when the r value is small, the spinning pressure decreases, and the forming process is more stable, but the surface quality of the blank is poor, and too small a contact area will also lead to stress concentration, resulting in cracks or tearing; Therefore, the value of the cone radius r is: r = (1-3) t, t is the thickness of the plate blank (3); At the same time, if the working angle α of the double-conical spinning wheel (422) is too large, the height of the material bulge in front of the spinning wheel will increase, making the fluidity of the material worse, and even causing instability or wrinkling. If it is too small, the contact area between the spinning wheel and the blank will increase, thereby increasing the spinning pressure and bringing adverse effects on spinning. Therefore, the value of the working angle α is 15-30°.

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