A PVC plate extruder main machine reduction gearbox device

Abstract

The utility model discloses a PVC board extruder host computer reduction gearbox device, its characterized in that: including input shaft, output shaft, gear reduction mechanism, lubricating system and box, gear reduction mechanism contains one -level helical gear pair and two -stage planetary gear pair, realizes the speed reduction drive, lubricating system contains oil pool, gear pump and oil injection pipeline, and the oil injection lubrication to the key gear meshing point, the box is split up and down, is equipped with the breather valve on the top, is equipped with the magnetic screw plug on the bottom, the adjusting washer of adjusting the center of the roller bearing, can adjust the axial play, through the utility model PVC board extruder host computer reduction gearbox device, realize " transmission accurate stability, lubrication reliable long -term, maintenance convenient efficient, the function of sufficient connection strength", ensure that the screw rotation speed fluctuation is small, the torque output is stable in the extrusion process of PVC board, reduces the risk of PVC material decomposition, promotes the quality and equipment service life of board forming.

Description

Technical Field

[0001] This utility model belongs to the technical field of polymer material processing equipment, specifically relating to key transmission components for PVC (polyvinyl chloride) polymer material sheet molding, and particularly to a gearbox device specifically used in the main unit of a PVC sheet extruder. Background Technology

[0002] PVC (polyvinyl chloride) is a widely used thermoplastic polymer material with advantages such as high strength, chemical resistance, and low cost. However, its processing characteristics place stringent requirements on extrusion equipment: On the one hand, PVC polymer material has poor thermal stability and a narrow processing temperature range (usually 160℃-190℃). If the screw speed of the extruder fluctuates too much, it is easy to cause local overheating and decomposition of the material, generating HCl gas that corrodes the equipment and affects the appearance of the sheet. On the other hand, the extrusion of PVC sheets (especially rigid PVC sheets) requires high molding pressure, requiring the screw to output sufficient torque to overcome the material flow resistance and avoid defects such as material shortage and surface depressions.

[0003] As the core transmission component of the PVC sheet extruder, the gearbox is crucial for achieving "precise speed control + stable torque increase," but existing technical solutions suffer from significant compatibility issues.

[0004] Insufficient transmission accuracy and stability: Traditional parallel shaft spur gear reducers have large meshing impacts and are prone to speed fluctuations during high-speed operation, resulting in unstable PVC material extrusion and causing deviations in sheet thickness; some planetary gear reducers have large transmission ratios, but poor control of the meshing clearance between the planetary gears and the sun gear. After long-term operation, the clearance increases, further aggravating speed fluctuations and increasing the risk of PVC material decomposition.

[0005] Poor compatibility of the lubrication system: PVC sheet extrusion requires the equipment to run continuously for a long time (usually 16-20 hours a day). Traditional splash lubrication methods are insufficient for lubricating the high gears of the gearbox (such as planetary gear pairs), and the lubricating oil circulation efficiency is low. The lubricating oil is prone to deterioration due to local oil temperature rise. Deteriorated lubricating oil not only reduces the lubrication effect, but its impurities may also enter the extrusion system with the transmission, contaminating the PVC polymer material and affecting the purity of the sheet.

[0006] The contradiction between ease of maintenance and material protection: The integrated gearbox structure is difficult to disassemble and assemble, and maintenance requires a long downtime, which leads to the interruption of PVC sheet production. At the same time, most existing gearboxes do not have an efficient impurity filtration structure. Metal shavings generated by gear wear can easily mix into the lubricating oil, which not only accelerates the wear of transmission components, but may also contaminate the surrounding PVC raw materials during maintenance, increasing material waste costs.

[0007] Insufficient reliability of output shaft connection: The high torque requirements of PVC sheet extrusion place extremely high demands on the connection strength between the output shaft and the screw. Existing gearbox output shafts mostly use ordinary flat keys or short splines for connection. Under long-term high torque, keyway deformation and spline tooth surface wear are prone to occur, leading to loosening of the connection. The sudden change in screw speed caused by loosening will directly cause fluctuations in the extrusion pressure of PVC material, resulting in quality problems such as rough sheet surface and bubbles, and may even cause equipment overload failure.

[0008] In summary, given the processing characteristics of PVC polymer materials, which are "heat-sensitive and require high torque," and the production requirements of PVC sheet extrusion, which are "continuous and high-precision," developing a main reducer device that features precise and stable transmission, reliable and long-lasting lubrication, convenient maintenance, and high connection strength has become the key to solving the pain points of existing technologies and improving the processing quality and production efficiency of PVC sheets. Summary of the Invention

[0009] To address the aforementioned issues, this utility model provides a main gearbox device for a PVC sheet extruder. It overcomes the shortcomings of existing PVC sheet extruder main gearboxes in terms of insufficient adaptability to the processing characteristics of PVC polymer materials, which are characterized by "heat sensitivity and high torque requirements." This new device achieves the functions of "precise and stable transmission, reliable and long-lasting lubrication, convenient and efficient maintenance, and sufficient connection strength," ensuring minimal screw speed fluctuations and stable torque output during PVC sheet extrusion, reducing the risk of PVC material decomposition, and improving sheet forming quality and equipment lifespan.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A PVC sheet extruder main reducer includes an input shaft, an output shaft, a gear reduction mechanism, a lubrication system, a housing, and self-aligning roller bearings.

[0012] The input end of the input shaft is connected to the output end of the extruder motor, and the output end of the output shaft is connected to the extruder screw. The output shaft is a twin-screw structure, including a main output shaft and a driven output shaft. The main output shaft is a power output shaft, and its two ends are rotatably supported in the bearing seats of the housing through self-aligning roller bearings. The driven output shaft is an auxiliary power support shaft, one end of which is rotatably supported in the positioning plate in the middle of the housing through a bearing, and the other end is rotatably supported in the output end bearing seat of the housing through a self-aligning roller bearing, and is used to cooperate with the main output shaft to support the twin screws.

[0013] The gear reduction mechanism is located inside the housing and includes a first-stage helical gear pair and a second-stage planetary gear pair. The first-stage helical gear pair includes a driving gear and a driven gear, which are arranged front and rear. The driving gear is fixed to the input shaft by a key connection, and the driven gear is the sun gear of the second-stage planetary gear pair. The transmission ratio i between the driving gear and the driven gear is greater than or equal to 2.

[0014] The secondary planetary gear pair also includes a gear ring fixed to the positioning plate, three planetary driven gears, and a planet carrier; the positioning plate is integrally formed with the housing, the three planetary driven gears are distributed at equal angles along the circumference of the planet carrier, and the helical teeth have the opposite direction of rotation to the driven gears; the planetary driven gears are rotatably connected to the planet carrier through pins, and simultaneously mesh with the driven gears and the gear ring; the planet carrier and the main output shaft are an integral structure, and power is transmitted to the main output shaft through the planet carrier;

[0015] The output shaft is driven by a bypass drive shaft, which includes a bypass main gear and a bypass output gear fixed coaxially. The bypass main gear meshes with the driving gear of the first-stage helical gear pair, and the bypass output gear meshes with a transmission gear fixed on the outer periphery of the output shaft. The transmission ratio between the bypass main gear and the bypass output gear is equal to the transmission ratio i of the first-stage helical gear pair, which is used to drive the output shaft to rotate synchronously with the main output shaft.

[0016] The lubrication system includes an oil sump located at the bottom of the housing, a gear pump immersed in the oil sump, and oil spray pipes laid along the inner wall of the housing. The oil outlets of the oil spray pipes are respectively aligned with the meshing point of the driving gear-bypass main gear of the first-stage helical gear pair, the meshing point of the driven gear-fed gear of the second-stage planetary gear pair, and the meshing point of the bypass output gear-driven gear of the output shaft, for spraying oil to lubricate all gear meshing areas.

[0017] The top of the box is equipped with a vent valve, and the bottom of the box is equipped with a magnetic plug; the magnetic plug is threadedly connected to the box, and its adsorption end extends to the bottom of the oil sump, for adsorbing metal debris in the lubricating oil.

[0018] Furthermore, the output shaft is a hollow shaft structure with an involute internal spline in its shaft hole, which is used to adapt and connect with the external spline of the drive shaft of the extruder screw. The effective engagement length of the involute internal spline is not less than 50mm.

[0019] Furthermore, the box body adopts an upper and lower split structure, consisting of an upper box body and a lower box body. The joint surfaces of the upper box body and the lower box body are positioned by positioning pins and fastened together by high-strength bolts. The joint surfaces are coated with a sealant layer.

[0020] Furthermore, the gear pump is a cycloidal gear pump, whose drive shaft is connected to an external motor via a flexible coupling. The rated flow rate of the gear pump is 2.5 L / min, and the inner diameter of the fuel injection pipe is 6 mm.

[0021] Furthermore, the self-aligning roller bearing is of type 22218, and a replaceable adjusting shim is provided between the mating surface of its outer ring and the bearing housing. The thickness of the adjusting shim is 0.2mm to 1.0mm, which is used to adjust the axial clearance of the self-aligning roller bearing.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The device adopts an integrated transmission structure of "first-stage helical gear pair + second-stage planetary gear pair". The driven wheel of the first-stage helical gear pair directly serves as the sun gear of the second-stage planetary gear pair, reducing intermediate connecting parts and transmission clearance. The transmission ratio between the driving wheel and the driven wheel is stable at ≥2, which can accurately convert the high-speed power of the extruder motor into low-speed, high-torque output. Combined with the integrated structure of the planetary carrier and the main output shaft, the connection clearance is eliminated, which can effectively control the main output shaft speed fluctuation to ≤1%. This avoids local overheating and decomposition of PVC material (narrow thermal stability range, 160℃-190℃) due to sudden speed changes, reducing defects such as yellowing and bubbles on the sheet surface. At the same time, it ensures stable screw output torque, overcomes the high flow resistance during the extrusion of rigid PVC sheets, and reduces molding problems such as material shortage and dents.

[0024] The oil injection lubrication system precisely covers the core transmission meshing points, adapting to the long-term continuous operation of PVC sheet extrusion, reducing the wear rate of gears and bearings, and extending the service life of the gearbox; at the same time, the magnetic plugs adsorb metal debris, further reducing secondary wear of transmission components and ensuring stable equipment operation. Attached Figure Description

[0025] For ease of explanation, this utility model is described in detail below with reference to the specific embodiments and accompanying drawings.

[0026] Figure 1 : Overall structural assembly drawing of the device;

[0027] Figure 2 Assembly drawing after removing the upper housing;

[0028] Figure 3 : Figure 2 Top view;

[0029] Figure 4 : Figure 2 A schematic diagram of the side tilt angle;

[0030] In the diagram: 1-Input shaft; 2-Output shaft; 21-Main output shaft; 22-Slave output shaft; 3-Gear reduction mechanism; 31-First-stage helical gear pair; 32-Second-stage planetary gear pair; 4-Lubrication system; 41-Oil sump; 42-Gear pump; 43-Injection pipeline; 5-Box housing; 5a-Upper box housing; 5b-Lower box housing; 51-Breath valve; 52-Positioning pin; 6-Self-aligning roller bearing. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] like Figures 1-4 As shown, a PVC sheet extruder main reducer includes an input shaft 1, an output shaft 2, a gear reduction mechanism 3, a lubrication system 4, a housing 5, and a self-aligning roller bearing 6.

[0033] Input shaft 1 is connected to the extruder motor, and output shaft 2 is connected to the extruder screw. One end of input shaft 1 is connected to the output end of the extruder motor via a flexible coupling, and the other end is fixed to the power input end of the gear reduction mechanism 3. One end of output shaft 2 is connected to the power output end of the gear reduction mechanism 3, and the other end is adapted to the extruder screw drive shaft via a spline. Input shaft 1 serves as the core of power input, receiving the high-speed power output from the motor and transmitting it to the gear reduction mechanism 3. Output shaft 2 serves as the power output carrier, transmitting the low-speed, high-torque power processed by the gear reduction mechanism 3 to the screw, ensuring that the screw obtains the speed and torque required for PVC sheet extrusion, and realizing stable conveying and molding of PVC material.

[0034] The gear reduction mechanism 3 is located inside the housing 5 and includes a first-stage helical gear pair 31 and a second-stage planetary gear pair 32. The driving gear of the first-stage helical gear pair 31 is fixed to the input shaft 1, and the driven gear is the sun gear of the second-stage planetary gear pair 32. The gear ring of the second-stage planetary gear pair 32 is fixed to the positioning plate, which is integrally formed with the housing 5. The planet carrier of the second-stage planetary gear pair 32 is integrally formed with the main output shaft 21. As the core component for speed reduction and torque enhancement, the high-speed, low-torque power transmitted by the input shaft 1 is converted into low-speed, high-torque power through the combined transmission of the "first-stage helical gear pair + second-stage planetary gear pair". The first-stage helical gear pair 31 utilizes the characteristics of small impact from helical gear meshing and smooth transmission to initially reduce the speed and buffer the power impact, avoiding the decomposition of PVC material due to speed fluctuations. The second-stage planetary gear pair 32 relies on the advantages of compact planetary transmission structure and large transmission ratio to further enhance the torque. The planet carrier and the main output shaft 21 are integrally designed to eliminate connection gaps, ensuring lossless power transmission and meeting the high torque requirements of the screw to overcome material flow resistance during PVC sheet extrusion.

[0035] The output shaft 2 is supported at both ends of the housing 5 by self-aligning roller bearings 6. The inner ring of the self-aligning roller bearing 6 is interference-fitted with the output shaft 2, and the outer ring is clearance-fitted with the bearing seat of the housing 5. The self-aligning roller bearing 6 provides bidirectional stable support for the output shaft 2, and can simultaneously withstand the radial load (material flow resistance) and axial load (screw axial thrust) transmitted by the screw during PVC extrusion, preventing the output shaft 2 from shaking during operation. At the same time, the bearing has a self-aligning function, which can compensate for installation deviations, ensure the coaxiality of the output shaft 2 and the screw, ensure the uniform thickness of the PVC sheet, and improve molding accuracy.

[0036] The lubrication system 4 includes an oil sump 41 located at the bottom of the housing 5, a gear pump 42 immersed in the oil sump, and oil spray pipes 43 distributed on the inner wall of the housing 5. The oil outlet of the oil spray pipes 43 is aligned with the meshing point of the driving gear and bypass main gear of the first-stage helical gear pair 31, the meshing point of the driven gear and driven gear of the second-stage planetary gear pair 32, and the meshing point of the bypass output gear and the gear driven by the output shaft. The oil sump 41 stores lubricating oil to provide an oil source for the lubrication system. After the gear pump 42 is immersed in the oil sump, it is driven by an external motor to pressurize and deliver the lubricating oil to the oil spray pipes 43. The oil spray pipes 43 accurately spray lubricating oil at the gear meshing point, which reduces gear meshing friction loss and extends component life. On the other hand, it removes the heat generated by meshing, avoids excessive oil temperature leading to lubricating oil deterioration, and prevents high gear temperature from affecting the processing stability of PVC materials.

[0037] The top of the housing 5 is equipped with a vent valve 51, and the bottom is equipped with a magnetic plug. The magnetic plug is threaded to the housing 5 and its end extends into the oil sump 41. The housing 5 serves as the overall protection and installation carrier, providing stable support and a sealed environment for all internal components, isolating external dust, and preventing lubricating oil contamination and leakage. The vent valve 51 balances the air pressure inside and outside the housing, preventing the housing seal from failing due to thermal expansion of the lubricating oil, and ensuring the normal operation of the lubrication system. The magnetic plug extends into the oil sump 41 to absorb metal debris generated by gear and bearing wear in the lubricating oil, preventing debris from entering the transmission components and aggravating wear, while also preventing debris from contaminating the PVC material and ensuring the purity of the board.

[0038] Working principle:

[0039] When the extruder motor starts, it drives the input shaft 1 to rotate via a flexible coupling (a conventional operation in the field). The driving wheel of the first-stage helical gear pair 31 drives the driven wheel to rotate, initially reducing the speed. The sun gear drives the three planetary driven wheels of the second-stage planetary gear pair 32 to revolve around the sun gear. The planet carrier rotates synchronously with the planetary driven wheels, transmitting power to the main output shaft 21 to complete the secondary speed reduction and torque increase.

[0040] When the input shaft 1 drives the primary helical gear pair drive wheel to rotate, it synchronously drives the bypass main gear of the bypass transmission shaft. The bypass main gear drives the transmission gear of the output shaft 22 to rotate through the bypass output gear. Since the bypass transmission ratio is equal to the transmission ratio of the primary helical gear pair, the output shaft 22 and the main output shaft 21 rotate in perfect synchronization, achieving stable support and synchronous drive for the twin screw.

[0041] The gear pump 42 is driven by an external motor. The output shaft of the external motor is connected to the drive shaft of the gear pump 42 through a keyway and a flexible coupling. The external motor pressurizes the lubricating oil in the oil sump 41 and delivers it to the oil injection pipeline 43, reducing friction loss and carrying away meshing heat. The magnetic plug adsorbs metal debris in the lubricating oil, and the vent valve 51 balances the air pressure inside and outside the housing, ensuring long-term stable operation of the device.

[0042] The main output shaft 21 and the slave output shaft 22 drive the twin screw of the extruder to rotate through the involute internal spline, so as to stably convey, plasticize and extrude PVC material to obtain PVC sheets with high flatness and no defects.

[0043] The entire device achieves the adaptation and conversion of motor power to screw through a closed-loop process of "power transmission from input shaft → speed reduction and torque increase from gear reduction mechanism → screw drive from output shaft → lubrication and housing to ensure stability". This not only meets the low speed and high torque requirements of PVC sheet extrusion, but also reduces the risk of PVC material decomposition through smooth transmission, precise lubrication and structural protection, ensuring long-term reliable operation of the equipment.

[0044] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design concept of the present invention should fall within the protection scope of the present invention. The technical content for which protection is sought in the present invention has been fully described in the claims.

Claims

1. A gearbox device for a PVC sheet extruder main unit, characterized in that: It includes an input shaft (1), an output shaft (2), a gear reduction mechanism (3), a lubrication system (4), a housing (5), and a self-aligning roller bearing (6); The input end of the input shaft (1) is connected to the output end of the extruder motor, and the output end of the output shaft (2) is connected to the extruder screw. The output shaft (2) is a twin-screw structure, including a main output shaft (21) and a slave output shaft (22). The main output shaft (21) is a power output shaft, and its two ends are rotatably supported in the bearing seats of the housing (5) through self-aligning roller bearings (6). The slave output shaft (22) is an auxiliary power support shaft, one end of which is rotatably supported in the positioning plate in the middle of the housing (5) through a bearing, and the other end is rotatably supported in the output end bearing seat of the housing (5) through a self-aligning roller bearing (6), which is used to cooperate with the main output shaft (21) to support the twin screw. The gear reduction mechanism (3) is located inside the housing (5) and includes a first-stage helical gear pair (31) and a second-stage planetary gear pair (32). The first-stage helical gear pair (31) includes a driving gear and a driven gear, which are arranged front and rear. The driving gear is fixed to the input shaft (1) by a key connection. The driven gear is the sun gear of the second-stage planetary gear pair (32). The transmission ratio i between the driving gear and the driven gear is greater than or equal to 2. The secondary planetary gear pair (32) also includes a gear ring fixed to the positioning plate, three planetary driven gears and a planet carrier; the positioning plate is integrally formed with the housing (5), the three planetary driven gears are distributed at equal angles along the circumference of the planet carrier, and the helical gears are opposite to the driven gears; the planetary driven gears are rotatably connected to the planet carrier through pins, and simultaneously mesh with the driven gears and the gear ring; the planet carrier and the main output shaft (21) are an integral structure, and the power is transmitted to the main output shaft (21) through the planet carrier; The output shaft (22) is driven by a bypass drive shaft, which includes a bypass main gear and a bypass output gear fixed on the same axis. The bypass main gear meshes with the driving gear of the first-stage helical gear pair (31), and the bypass output gear meshes with the transmission gear fixed from the outer periphery of the output shaft (22); Furthermore, the transmission ratio between the bypass main gear and the bypass output gear is equal to the transmission ratio i of the first-stage helical gear pair (31), which is used to drive the output shaft (22) and the main output shaft (21) to rotate synchronously. The lubrication system (4) includes an oil sump (41) located at the bottom of the housing (5), a gear pump (42) immersed in the oil sump (41), and an oil spray pipe (43) arranged along the inner wall of the housing (5); the oil outlet of the oil spray pipe (43) is respectively aligned with the meshing point of the driving gear-bypass main gear of the first-stage helical gear pair (31), the meshing point of the driven gear-driven gear of the second-stage planetary gear pair (32), and the meshing point of the bypass output gear-driven gear of the output shaft, for oil spraying lubrication of all gear meshing areas; The top of the box (5) is provided with a vent valve (51), and the bottom of the box (5) is provided with a magnetic plug; the magnetic plug is threadedly connected to the box (5), and its adsorption end extends to the bottom of the oil sump (41) for adsorbing metal debris in the lubricating oil.

2. The main reducer device for a PVC sheet extruder according to claim 1, characterized in that: The output shaft (2) is a hollow shaft structure with an involute internal spline in its shaft hole, which is used to adapt and connect with the external spline of the drive shaft of the extruder screw. The effective engagement length of the involute internal spline is not less than 50mm.

3. The main reducer device for a PVC sheet extruder according to claim 1, characterized in that: The box (5) adopts a split structure, consisting of an upper box (5a) and a lower box (5b). The joint surfaces of the upper box (5a) and the lower box (5b) are positioned by positioning pins (52) and fastened by high-strength bolts. The joint surfaces are coated with a sealant layer.

4. The main reducer device for a PVC sheet extruder according to claim 1, characterized in that: The gear pump (42) is a cycloidal gear pump, and its drive shaft is connected to the external motor keyway through a flexible coupling. The rated flow rate of the gear pump (42) is 2.5L / min, and the inner diameter of the oil injection pipe (43) is 6mm.

5. The main reducer device for a PVC sheet extruder according to claim 1, characterized in that: The self-aligning roller bearing (6) is of type 22218. A replaceable adjusting shim is provided between the outer ring and the mating surface of the bearing housing (5). The thickness of the adjusting shim is 0.2mm to 1.0mm, which is used to adjust the axial clearance of the self-aligning roller bearing (6).

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