High-density helical tooth spline transmission device for co-rotating parallel twin-screw extruder

Abstract

The utility model discloses a high-density helical-tooth spline transmission device for a co-rotating parallel twin-screw extruder, which comprises a spline shaft and a threaded block sleeve, and the spline shaft and the threaded block sleeve are in coupling connection through a high-density helical-tooth spline; the tooth number of the high-density helical tooth spline is 18 or 36, the helical angle is 25.75 + / -0.5 degrees, the tooth height is 1.5-4 mm, and the tooth top edge trimming amount is 8-12 microns; the tooth root of the spline shaft is of a double-curvature transition structure, and the double-curvature transition structure comprises a first fillet R1 equal to 0.6 m and a second fillet R2 equal to 1.2 m. According to the high-density helical tooth spline transmission device, the maximum transmission torque reaches 12,000 N.m (the maximum transmission torque in a traditional design is smaller than or equal to 8,000 N.m), and the tooth surface contact stress is smaller than or equal to 900 MPa; the service life of the wear-resistant layer exceeds 8000 hours and is prolonged by 3 times (ASTM G133 wear test) on year-on-year basis. The spline shaft and the threaded block sleeve adopt an H6 / g5 fit clearance, the cold assembly qualification rate is 100%, and the assembly time is shortened by 60%. The synchronous transmission error is smaller than or equal to 0.005 mm, and the vibration noise is smaller than or equal to 72 dB (ISO 10816 standard).

Description

Technical Field

[0001] This disclosure relates to the field of polymer material processing equipment technology, and in particular to a high-density helical spline transmission device for a co-rotating parallel twin-screw extruder. Background Technology

[0002] Co-rotating parallel twin-screw extruders are core equipment for polymer material processing, and the stability of their transmission system directly affects product quality and production efficiency. Traditional extruders generally use involute spline drives, but these have the following drawbacks:

[0003] Severe stress concentration: The stress peak at the tooth root reaches over 800 MPa during high-speed rotation, which can easily lead to fatigue cracks.

[0004] The contradiction between the number of teeth and the tooth height: The tooth height and the number of teeth of the standard involute spline (such as DIN5480) are mutually restrictive. The dense tooth design leads to insufficient tooth height, while the high tooth design reduces the number of teeth and reduces the uniformity of force distribution.

[0005] Poor synchronization: The spline fit clearance is 0.05-0.1mm, which causes vibration noise (≥85dB) and material extrusion fluctuations.

[0006] In existing technologies, some improvements attempt to use helical tooth structures or increase the number of teeth to disperse stress, but these do not solve the problems of radial force interference and process limitations. For example, traditional helical splines have an additional radial component force, which leads to shaft deformation; although cold rolling can form a larger tooth root radius, it will increase the gap between the tooth tip and the tooth root, affecting transmission accuracy. Utility Model Content

[0007] This application provides a high-density helical spline transmission device that achieves stress dispersion, high-torque synchronous transmission, and long-life operation through structural innovation and process optimization.

[0008] This application provides a high-density helical spline transmission device, including a spline shaft and a threaded block sleeve, wherein the spline shaft and the threaded block sleeve are coupled and connected by a high-density helical spline.

[0009] The high-density helical spline has 18 or 36 teeth, a helix angle of 25.75°±0.5°, a tooth height of 1.5 to 4 mm, and a tooth tip trimming amount of 8 to 12 μm.

[0010] The tooth root of the spline shaft adopts a double curvature transition structure, including a first fillet R1 = 0.6m and a second fillet R2 = 1.2m.

[0011] In the high-density helical spline transmission device provided according to at least one embodiment of the present disclosure, the spline shaft adopts asymmetrical helical teeth, and the number of teeth of the spline shaft is increased by 50% compared with standard DIN5480 or ISO4156, and the tooth height is increased by 50%.

[0012] In the high-density helical spline transmission device provided according to at least one embodiment of the present disclosure, the fitting clearance between the spline shaft and the threaded block sleeve is H6 / g5, and the phase difference is controlled as (360° / N)×0.5, where N is the number of teeth.

[0013] In the high-density helical spline transmission device provided according to at least one embodiment of the present disclosure, the spline shaft is made of powder metallurgy high-speed steel with a tempering hardness of HRC32-38 and a core toughness ≥100J / cm2.

[0014] In the high-density helical spline transmission device provided according to at least one embodiment of the present disclosure, the processing technology of the spline shaft includes cold rolling roughing and CNC precision machining, and the tooth root fillet is formed by cold rolling.

[0015] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0016] 1. The spline shaft uses asymmetrical helical teeth, with the transmission side perpendicular to the circumference and no additional radial force.

[0017] 2. For the same size, the number of teeth is increased by 50% and the tooth height is increased by 50 compared to the standard DIN5480 or ISO4156 (that is, GB3478).

[0018] 3. The spline tooth root adopts a large circumference and a double curvature transition (R1 = 0.6m, R2 = 1.2m). Finite element analysis shows that the maximum stress is reduced by 45% (compared to traditional design).

[0019] 4. The technology of first cold rolling roughing and then CNC precision machining is adopted, which combines the advantages of both. While using large fillet to relieve stress, it will not increase the upper and lower clearance between the tooth tip and the tooth root.

[0020] 5. The initial phase difference of the twin-screw spline is precisely controlled to be (360° / N)×0.5 (N is the number of teeth), ensuring that the meshing overlap is ≥2.5.

[0021] The high-density helical spline transmission device of this application has a maximum transmitted torque of 12000 N·m (traditional design ≤8000 N·m), and a tooth surface contact stress ≤900 MPa; the wear-resistant layer extends the service life to over 8000 hours, a 3-fold increase compared to the previous model (ASTM G133 wear test). The spline shaft and threaded block sleeve use an H6 / g5 fit clearance, achieving a 100% cold assembly pass rate and reducing assembly time by 60%. The synchronous transmission error is ≤0.005 mm, and the vibration noise is ≤72 dB (ISO 10816 standard). Attached Figure Description

[0022] Figure 1This is a schematic diagram of the threaded block sleeve structure in an embodiment of this application;

[0023] Figure 2 This is an enlarged schematic diagram of the structure at point B in the embodiment of this application;

[0024] Figure 3 This is a cross-sectional view of the threaded block sleeve structure in an embodiment of this application. Detailed Implementation

[0025] This application provides a high-density helical spline transmission device that achieves stress dispersion, high-torque synchronous transmission, and long-life operation through structural innovation and process optimization.

[0026] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0027] like Figure 1-3 As shown in the embodiment of this application, the high-density helical spline drive device for a co-rotating parallel twin-screw extruder includes a spline shaft 1 and a threaded block sleeve 2, wherein the spline shaft 1 and the threaded block sleeve 2 are coupled and connected by a high-density helical spline; the high-density helical spline has 18 or 36 teeth, a helix angle of 25.75°±0.5°, a tooth height of 1.5~4mm, and a tooth tip trimming amount of 8~12μm; the tooth root of the spline shaft 1 adopts a double curvature transition structure, including a first fillet R1=0.6m and a second fillet R2=1.2m. In this embodiment, the spline tooth root adopts a large circumference and a double curvature transition (R1=0.6m, R2=1.2m), and finite element analysis shows that the maximum stress decreases by 45% (compared to the traditional design).

[0028] For example, the spline shaft 1 uses asymmetrical helical teeth, and the number of teeth of the spline shaft 1 is increased by 50% compared with the standard DIN5480 or ISO4156, and the tooth height is increased by 50%; the asymmetrical helical teeth are used, the transmission side is perpendicular to the circumference, and there is no additional radial force.

[0029] For example, the fit clearance between the splined shaft 1 and the threaded block sleeve 2 is H6 / g5, and the phase difference is controlled as (360° / N)×0.5, where N is the number of teeth. Assembly time is reduced by 60%, cold assembly qualification rate is 100%, and meshing overlap is ensured to be ≥2.5.

[0030] In this embodiment, the spline shaft 1 is made of powder metallurgy high-speed steel with a tempered hardness of HRC32-38 and a core toughness ≥100J / cm2. Preferably, the processing technology of the spline shaft (1) includes cold rolling roughing and CNC precision machining, and the tooth root fillet is formed by cold rolling. By adopting the technology of first cold rolling roughing and then CNC precision machining, the advantages of both are combined, and while using a large fillet to relieve stress, the upper and lower clearance between the tooth tip and tooth root is not increased.

[0031] Example 1

[0032] like Figure 1 and Figure 2 As shown, the parameter design is as follows: 36 teeth, 1.75 effective tooth height (the effective overlap of the inner and outer splines is 1.75, and the overall tooth height of the splines is 2.25), helix angle 25.75°, tooth height 2.25 mm, and tooth tip trimming amount 10 μm.

[0033] Material selection: OS17 powder metallurgy high-speed steel, with a hardness of HRC35 after quenching and tempering.

[0034] Processing steps: cold rolling rough machining to form tooth shape and R0.5mm pre-rounded corner; CNC precision machining to correct the double curvature rounded corners of tooth tip and tooth root (R1=1.05mm, R2=2.1mm); surface quenching treatment to form a 0.3mm wear-resistant layer.

[0035] In comparison, using a DIN5480 spline, with a 1-module configuration, a 36mm outer diameter has 34 teeth, fewer than a close-tooth spline. Furthermore, with a 1-module configuration, the effective overlap is only 0.9mm. To achieve the same tooth height as a high-density spline, a 2-module spline is required, but this only results in 17 teeth, leading to uneven spline distribution and uneven circumferential stress.

[0036] According to the 5480 standard, the root fillet radius in turning is only 0.16 times the module. Even at a module of 2, the fillet radius is 0.32, which is smaller than the R0.5 fillet radius of high-density helical teeth. A larger fillet radius can better distribute stress and protect the spline teeth. In traditional processes, when cold rolling is used, the fillet radius is 0.54 times the module. However, cold rolling causes the overall tooth size to increase, and the gaps at the top and bottom of the tooth increase, which is not conducive to stress distribution.

[0037] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages:

[0038] The high-density helical spline transmission device of this application has a maximum transmitted torque of 12000 N·m (traditional design ≤8000 N·m), and a tooth surface contact stress ≤900 MPa; the wear-resistant layer extends the service life to over 8000 hours, a 3-fold increase compared to the previous model (ASTM G133 wear test). The spline shaft and threaded block sleeve use an H6 / g5 fit clearance, achieving a 100% cold assembly pass rate and reducing assembly time by 60%. The synchronous transmission error is ≤0.005 mm, and the vibration noise is ≤72 dB (ISO 10816 standard).

[0039] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0040] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from the spirit and scope of the invention. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A high-density helical spline transmission device for co-rotating parallel twin-screw extruders, comprising a spline shaft (1) and a threaded block sleeve (2), characterized in that: the spline shaft (1) and the threaded block sleeve (2) are coupled and connected by a high-density helical spline; the high-density helical spline has 18 or 36 teeth, a helix angle of 25.75°±0.5°, a tooth height of 1.5-4 mm, and a tooth crest chamfering amount of 8-12 μm; the spline shaft (1) has a double-curvature transition structure including a first round corner R1=0.6 m and a second round corner R2=1.2 m; the spline shaft (1) has an asymmetric helical tooth, and the number of teeth of the spline shaft (1) is increased by 50% and the tooth height is increased by 50% compared with the standard DIN5480 or ISO4156; the fitting clearance of the spline shaft (1) and the threaded block sleeve (2) is H6 / g5, and the phase difference control is (360° / N)×0.5, wherein N is the number of teeth; the spline shaft (1) is made of powder metallurgy high-speed steel, has a quenched and tempered hardness of HRC32-38, and a core toughness of ≥100 J / cm²; and the machining process of the spline shaft (1) includes cold rolling rough machining and numerical control finishing, and the tooth root round corner is formed by a cold rolling process. ​ ​ ​ 2. The high density helical tooth spline drive of claim 1 wherein, ​ 3. The high density helical tooth spline drive of claim 1 wherein, ​ 4. A high density helical tooth spline drive as claimed in any one of claims 1 to 3 wherein, ​ 5. A high density helical tooth spline drive as claimed in claim 4, wherein, ​

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