A screw connection device

Abstract

The application belongs to the technical field of injection molding machines, and particularly relates to a screw connecting device; the device comprises a shell, a glue melting motor, a transmission wheel, a transmission shaft, a belt and a bushing, the glue melting motor is arranged on the shell, the output shaft of the glue melting motor is connected with the transmission wheel through the belt transmission, the transmission shaft is rotatably arranged in the shell, the transmission wheel is transmissionally sleeved with the front end of the transmission shaft, the rear end of the transmission wheel abuts against the front end shaft shoulder of the transmission shaft, the front end of the transmission shaft is provided with a front end butt joint, the rear end is provided with a rear end butt joint, the bushing is slidably arranged in the front end butt joint, the bushing shaft shoulder abuts against the front end of the transmission wheel, the screw is transmissionally connected in the bushing, the bushing and the transmission shaft clamp the transmission wheel and are connected through bolts; the device further comprises a lead screw, a lead screw sleeve and a glue injection motor, the output shaft of the glue injection motor is coaxially connected with the lead screw, the lead screw sleeve is connected with the shell for supporting the shell, the lead screw sleeve is transmissionally sleeved with the lead screw, the front end of the lead screw penetrates through the lead screw sleeve and is rotatably arranged in the rear end butt joint, and the device can avoid the screw from being deviated after long time use.

Description

Technical Field

[0001] This invention belongs to the field of injection molding machine technology, and specifically relates to a screw connection device. Background Technology

[0002] Injection molding machines typically consist of an injection system, a mold clamping system, a hydraulic transmission system, an electrical control system, a heating and cooling system, a lubrication system, and a safety monitoring system. The injection system is one of the most important components, responsible for injecting molten plastic into the mold cavity. The injection system includes a screw and a drive shaft, and the connection between the screw and drive shaft is usually achieved through a specific transmission device or coupling. These connecting components are responsible for effectively transmitting the rotational force of the drive shaft to the screw, thereby driving the screw to rotate within the barrel.

[0003] Injection molding machine screws are generally driven by either belts or directly. In large injection molding machines, belt drives offer some overload protection. When an injection molding machine encounters an overload during operation, the belt may slip, acting as a buffer to protect the screw and other transmission components from damage. Compared to direct motor drives, belt drives can respond and stop more quickly in abnormal situations, such as blockages or overloads, thus reducing the risk of accidents. For example, Chinese patent CN210634101U describes a movable base for injection molding in an injection blow molding machine. This base includes a processing table, a base, and a drive motor. A dual-axis motor is installed inside the processing table, and its output end is connected to a gear. The base is located on top of the processing table, and a limiting seat is fixed to the bottom of the base. The limiting seat is located within a limiting groove, which is located on the upper surface of the processing table. A connecting block is provided at the bottom of the limiting seat. The drive motor is fixed to the top edge of the base, and a barrel is installed on the upper surface of the base. A hopper is connected to the top of the barrel, and a plasticizing screw is installed inside the barrel. A guide rod is shaft-connected to the hopper, and a material distribution plate is fixed on the guide rod. One end of the guide rod passes through the hopper and is connected to the drive motor via a belt. This movable base for injection molding in an injection blow molding machine facilitates the automatic and smooth movement of the injection molding components, while also separating materials and preventing blockage.

[0004] However, when the screw is driven by a belt, the driving position is generally at the end of the screw. A molten plastic cylinder is set on the outside of the screw, and the injection port of the molten plastic cylinder at the front end of the screw is far from the end of the screw. Vibration during the operation of a large injection molding machine is unavoidable. When the end of the belt-driven screw experiences a small vibration and a small displacement, the injection port at the front end of the screw will have a large offset. This will reduce the docking accuracy between the injection port of the molten plastic cylinder and the injection port of the mold, and easily lead to poor product quality. Based on this, in order to avoid the problem of screw displacement caused by belt driving, a screw connection device is proposed. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention provides a screw connection device.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A screw connection device includes a screw, a rotating assembly, and a pushing assembly. The rotating assembly includes a housing, a melt-melting motor, a transmission wheel, a transmission shaft, a belt, and a bushing. The melt-melting motor is mounted on the housing. The output shaft of the melt-melting motor is connected to the transmission wheel via the belt. The transmission shaft is rotatably disposed within the housing. The transmission wheel is driven and sleeved on the front end of the transmission shaft, and the rear end of the transmission wheel abuts against the front shoulder of the transmission shaft. The front end of the transmission shaft has a front end interface, and the rear end has a rear end interface. The bushing is slidably disposed within the front end interface, and the bushing shoulder abuts against the front end of the transmission wheel. The screw is driven and connected within the bushing. The bushing shoulder and the front shoulder of the transmission shaft clamp the transmission wheel and are connected by bolts.

[0008] The pushing assembly includes a lead screw, a sleeve, and a glue injection motor. The output shaft of the glue injection motor is coaxially connected to the lead screw. The sleeve is connected to the housing and is used for rear-end support of the housing. The sleeve is driven onto the lead screw. The front end of the lead screw passes through the sleeve and is rotatably disposed within the rear-end interface.

[0009] Furthermore, a first bearing is abutted against the front end of the housing, the rear shoulder of the drive shaft abuts against the first bearing, a second bearing is abutted against the rear end of the housing, and a retaining ring is detachably installed on the drive shaft, the retaining ring abutting against the other end of the second bearing, the retaining ring being used to limit the movement of the drive shaft.

[0010] Furthermore, the first bearing is an axial contact ball bearing, and the second bearing is a tapered roller bearing.

[0011] Furthermore, it also includes two crescent rings, and the rear end of the screw has a shoulder. The two crescent rings abut against the shoulder at the rear end of the screw and are detachably connected to the bushing for axial positioning of the screw.

[0012] Furthermore, the two crescent rings interlock to form a fastening ring. The inner wall of the fastening ring is provided with an internal thread, and the annular groove of the screw is provided with an external thread. The side wall of the fastening ring is provided with a plurality of bolt holes at equal intervals, and the side wall of the large column section of the pad is provided with a plurality of bolt holes correspondingly. The fastening ring is used to adjust the tightness between the screw and the pad. The bolt holes on the pad and the fastening ring are connected by bolts to fix the adjusted fastening ring.

[0013] Furthermore, a washer is provided at the bottom of the circular groove of the drive shaft. The outer wall of the washer is an inclined surface. The outer wall of the washer abuts against the bottom of the sleeve, and the end face of the washer abuts against the end face of the screw.

[0014] Furthermore, the drive shaft and the drive wheel are connected by a key, and the screw and the bushing are connected by a spline.

[0015] The beneficial effects of this invention are as follows:

[0016] (1) By making the lead screw drive the sleeve and the rotating assembly reciprocate, on the one hand, the sleeve is connected to the housing, so that the injection motor, lead screw and sleeve can serve as the support point at the rear end of the rotating assembly. By increasing the support point, the screw offset caused by vibration is reduced. On the other hand, the lead screw can always slide and rotate in the rear end interface, so that the lead screw, the transmission shaft and the screw always remain coaxial, improving the stability of the screw and the rotating assembly during injection, and thus improving the docking accuracy between the injection port of the melt cylinder and the injection port of the mold.

[0017] (2) By using a bushing as an intermediate layer, the load and stress between the screw and the drive shaft can be distributed. When the screw is subjected to loads from plastic melting, conveying, and injection, these loads are first applied to the bushing and then transferred to the drive shaft. This avoids direct contact and hard-on-hard contact between the screw and the drive shaft, thereby reducing wear. The addition of the bushing also allows for more flexible adjustment of the fit clearance between the screw and the drive shaft. Even if wear occurs, it is mainly the bushing that wears, rather than the screw or drive shaft. By reducing wear, the bushing indirectly extends the service life of the screw and the drive shaft. When the bushing wears to a certain extent, it can be easily removed and replaced with a new one without requiring large-scale disassembly and maintenance of the entire transmission system.

[0018] (3) Two crescent rings can form a complete fastening ring. The fixed section in the middle of the crescent rings has connecting sections at both ends. One crescent ring has a protruding male connector on the inner side of its connecting section, while the other crescent ring has a recessed female connector on its connecting section. The male and female connectors are connected to form a complete fastening ring. The inner side of the fastening ring is threaded. In use, the two crescent rings are attached to the annular groove from both sides, and then the two crescent rings are interlocked to form a fastening ring. The fastening ring is then tightened towards the washer side to make the connection between the screw and the washer tighter. After long-term use, when the connection between the screw and the washer wears down, the fastening ring can be used to reinforce the connection and prevent loosening. At the same time, the tighter connection between the screw, the washer, and the drive shaft can also reduce wear, thereby reducing the frequency of maintenance and replacement and increasing service life. Attached Figure Description

[0019] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the internal structure of the present invention;

[0021] Figure 2 This is a partial side view of the structure of the present invention;

[0022] Figure 3 This is a partial three-dimensional structural diagram of the present invention;

[0023] Figure 4 This is a schematic diagram of the semi-lunar ring structure of the present invention.

[0024] Legend: 1. Screw; 11. Half-moon ring; 12. Washer; 2. Melt glue motor; 3. Drive shaft; 4. Drive wheel; 5. Injection motor; 6. Lead screw; 7. Lead sleeve; 8. Housing; 81. First bearing; 82. Second bearing; 83. Snap ring. Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0026] like Figure 1-4 As shown, a screw connection device of the present invention includes a screw 1, a rotating assembly and a pushing assembly. The rotating assembly includes a housing 8, a melt motor 2, a transmission wheel 4, a transmission shaft 3, a belt and a bushing. The melt motor 2 is mounted on the housing 8. The output shaft of the melt motor 2 is connected to the transmission wheel 4 via a belt drive. The transmission shaft 3 is rotatably mounted inside the housing 8. The transmission wheel 4 is driven and sleeved on the front end of the transmission shaft 3, and the rear end of the transmission wheel 4 abuts against the front shoulder of the transmission shaft 3. The front end of the transmission shaft 3 has a front end interface, and the rear end has a rear end interface. The bushing is slidably mounted inside the front end interface, and the bushing shoulder abuts against the front end of the transmission wheel 4. The screw 1 is driven and connected inside the bushing. The bushing shoulder and the front shoulder of the transmission shaft 3 clamp the transmission wheel 4 and are connected by bolts.

[0027] The driving assembly includes a lead screw 6, a sleeve 7, and a glue injection motor 5. The output shaft of the glue injection motor 5 is coaxially connected to the lead screw 6. The sleeve 7 is connected to the housing 8 and is used for the rear end support of the housing 8. The sleeve 7 is driven and sleeved on the lead screw 6. The front end of the lead screw 6 passes through the sleeve 7 and is rotatably set in the rear end interface.

[0028] Working principle of screw 1, rotating assembly and pushing assembly: The output shaft of the melt glue motor 2 drives the transmission wheel 4 through a belt. The belt is a toothed belt, and the rim surface of the transmission wheel 4 is provided with teeth. The teeth of the belt mesh with the teeth of the transmission wheel 4 to drive it. Since the transmission wheel 4 is connected to the transmission shaft 3, the screw 1 is connected to the front end interface of the transmission shaft 3 through the washer. Therefore, when the transmission wheel 4 rotates, the transmission shaft 3 and the screw 1 rotate synchronously. The output shaft of the glue injection motor 5 of the pushing assembly drives the lead screw 6 to rotate, so that the lead screw 6 pushes the threaded sleeve 7 to reciprocate, thereby driving the rotating assembly and the screw 1 to reciprocate. During the process of driving the threaded sleeve 7 to reciprocate, the lead screw 6 can always slide and rotate within the rear end interface because the transmission shaft 3 has a rear end interface.

[0029] Since vibration is unavoidable during the operation of large injection molding machines, when the end of the belt-driven screw 1 experiences small vibrations and small displacements, the injection nozzle at the front end of the screw 1 will have a large offset. This will reduce the docking accuracy between the injection nozzle of the melt cylinder and the injection port of the mold, and easily lead to poor product quality.

[0030] Therefore, in the process of driving the lead screw 6 to reciprocate through the sleeve 7 and the rotating assembly, on the one hand, the sleeve 7 is connected to the housing 8, so that the injection motor 5, lead screw 6 and sleeve 7 can serve as support points at the rear end of the rotating assembly. By increasing the support points, the offset of the screw 1 caused by vibration is reduced. On the other hand, the lead screw 6 can always slide and rotate back and forth within the rear end interface, so that the lead screw 6, the transmission shaft 3 and the screw 1 always remain coaxial, improving the stability of the screw 1 and the rotating assembly during injection, and thus improving the docking accuracy between the injection port of the melt cylinder and the injection port of the mold.

[0031] Simultaneously, the bushing acts as an intermediate layer, distributing the load and stress between the screw 1 and the drive shaft 3. When the screw 1 is subjected to loads from plastic melting, conveying, and injection, these loads first act on the bushing and are then transferred to the drive shaft 3. This avoids direct contact and hard-on-hard contact between the screw 1 and the drive shaft 3, thus reducing wear. The addition of the bushing also allows for more flexible adjustment of the fit clearance between the screw 1 and the drive shaft 3. By selecting appropriate bushing thickness and material, it can be ensured that the clearance between the screw 1 and the drive shaft 3 is neither too large nor too small, thereby reducing wear while maintaining transmission efficiency. The presence of the bushing reduces the direct contact area between the screw 1 and the drive shaft 3, thereby reducing the risk of wear. Even if wear occurs, it is primarily the bushing that wears, not the screw 1 or the drive shaft 3. By reducing wear, the bushing indirectly extends the service life of the screw 1 and the drive shaft 3. This not only reduces equipment maintenance costs but also improves equipment reliability and stability. The material and thickness of the bushing can be selected according to different operating conditions and requirements. For example, injection molding machines operating in high-temperature, high-pressure, or corrosive environments can choose high-temperature and corrosion-resistant bushing materials to ensure normal equipment operation and reduce wear. As consumable parts, bushings are relatively simple and quick to replace. When a bushing wears to a certain extent, it can be easily removed and replaced with a new one without requiring extensive disassembly and repair of the entire transmission system.

[0032] Because the reciprocating motion of the housing 8 is driven by the lead screw 6 and the lead sleeve 7, and the large injection molding machine is heavy, there is a large inertia during the start and stop of the reciprocating motion. In order to make the drive shaft 3 rotate more smoothly inside the housing 8, in one embodiment, the front end of the housing 8 is abutted against the first bearing 81, the rear shoulder of the drive shaft 3 abuts against the first bearing 81, and the rear end of the housing 8 is abutted against the second bearing 82. A retaining ring 83 is detachably installed on the drive shaft 3, and the retaining ring 83 abuts against the other end of the second bearing 82. The retaining ring 83 is used to limit the movement of the drive shaft 3. The first bearing 81 is an axial contact ball bearing, and the second bearing 82 is a tapered roller bearing.

[0033] The two outer rings of the axial contact ball bearing abut against the rear shoulder of the drive shaft 3 and the front end of the housing 8, respectively, which can reduce the friction between the drive shaft 3 and the housing 8 under axial impact. The tapered roller bearing can withstand larger radial and axial loads, making it particularly suitable for applications requiring simultaneous radial and axial loads. This line contact design reduces the contact stress between the rollers and raceways, thereby improving load-bearing capacity and extending service life. Tapered roller bearings have high rigidity and can withstand large impact and vibration loads, making them suitable for large injection molding machines. To prevent relative displacement between the tapered roller bearing and the housing 8, the front end of the housing 8 is limited by the first bearing 81 abutting against the rear shoulder of the drive shaft 3. Then, the second bearing 82 is sleeved onto the drive shaft 3 and abuts against the rear end of the housing 8. Finally, it is fixed to the drive shaft 3 by a retaining ring 83, which also abuts against the second bearing 82, preventing relative displacement of the drive shaft 3 within the housing 8.

[0034] It also includes two crescent rings 11. The rear end of the screw 1 has a shoulder. The two crescent rings 11 abut against the shoulder at the rear end of the screw 1 and are detachably connected to the bushing for axial positioning of the screw 1.

[0035] Due to wear between the screw 1 and the bushing after prolonged use, a gap may appear at their connection. Injection molding machines have high requirements for the connection between the screw 1 and the drive shaft 3 to avoid vibration during use. Replacing the bushing with wear on the screw 1 not only causes inconvenience but also increases operating costs. Therefore, to reduce maintenance and replacement costs, in one embodiment, two crescent rings 11 are interlocked to form a fastening ring. The inner wall of the fastening ring has an internal thread, and the annular groove of the screw 1 has an external thread. The side wall of the fastening ring has several bolt holes equidistantly arranged, and the side wall of the bushing's large column section has corresponding bolt holes. The fastening ring is used to adjust the tightness between the screw 1 and the bushing. The bolt holes on the bushing and the fastening ring are connected by bolts to fix the adjusted fastening ring.

[0036] Furthermore, each of the two crescent rings 11 includes a fixed section and connecting sections at both ends of the fixed section. One of the connecting sections of the crescent ring 11 is provided with a male interface, and the other half of the crescent ring 11 is provided with a female interface. The male and female interfaces are interlocked to connect the two crescent rings 11 to form a fastening ring. The thickness of the fixed section is twice the thickness of the connecting section.

[0037] Specifically, the two crescent rings 11 can form a complete fastening ring. The fixed section in the middle of each crescent ring 11 has connecting sections at both ends. One crescent ring 11 has a protruding male connector on its inner side of the connecting section, while the other crescent ring 11 has a recessed female connector on its connecting section. The male and female connectors connect to form a complete fastening ring, and the inner surface of the fastening ring is threaded. In use, the two crescent rings 11 are fitted onto the annular groove from both sides, then interlocked to form the fastening ring. The fastening ring is then tightened towards the washer side, making the connection between the screw 1 and the washer more secure. After prolonged use causing wear at the connection between the screw 1 and the washer, the fastening ring provides further reinforcement to prevent loosening. Simultaneously, the tighter connection between the screw 1, the washer, and the drive shaft 3 reduces wear, thereby decreasing the frequency of maintenance and replacement and extending service life.

[0038] To facilitate installation after connecting the two crescent rings 11 to form a fastening ring, an annular groove needs to be formed at the front end of the shoulder of the screw 1. The diameter of this groove is smaller than that of other parts of the screw 1, and it is used to install the two crescent rings 11. The annular groove includes a threaded section and a smooth section. During installation, the fastening ring is positioned on the smooth section. After connecting the two crescent rings 11 to form the fastening ring, it is then tightened towards the washer. Furthermore, if the screw 1 and the washer become loose after prolonged use, it is not necessary to disassemble the entire device; simply tighten the fastening ring directly.

[0039] Meanwhile, when the screw 1 is fixed to the bushing using the fastening ring, only one side is secured by the fastening ring, preventing the screw 1 from moving in that direction. However, since the screw 1 facing the drive shaft 3 is not limited at this point, it can still move. Therefore, it is necessary to connect the side wall of the bushing to the side wall of the drive shaft 3, so that the end of the screw 1 abuts against the inner side wall of the circular groove of the drive shaft 3, thus limiting the screw 1. The fastening ring is then adjusted and tightened sequentially according to the wear condition of the screw 1 and the bushing. In actual use, the screw 1 can be extended to a smaller length, and the fastening ring can be adjusted according to the actual distance between the screw 1 and the drive shaft 3 after connecting the bushing to the drive shaft 3.

[0040] Since it is necessary to form a contact force between the end of the screw 1 and the end of the drive shaft 3 to tighten the screw 1 and prevent loosening, in one embodiment, a washer 12 is provided at the bottom of the circular groove of the drive shaft 3. The outer wall of the washer 12 is an inclined surface, the outer wall of the washer 12 abuts against the bottom of the sleeve, and the end face of the washer 12 abuts against the end face of the screw 1.

[0041] Furthermore, the drive shaft 3 and the drive wheel 4 are connected by a key, and the screw 1 and the bushing are connected by a spline.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A screw connection device, characterized in that: The device includes a screw, a rotating assembly, and a pushing assembly. The rotating assembly includes a housing, a melt-melting motor, a transmission wheel, a transmission shaft, a belt, and a bushing. The melt-melting motor is mounted on the housing. The output shaft of the melt-melting motor is connected to the transmission wheel via the belt. The transmission shaft is rotatably mounted inside the housing. The transmission wheel is driven and sleeved on the front end of the transmission shaft, and the rear end of the transmission wheel abuts against the front shoulder of the transmission shaft. The front end of the transmission shaft has a front-end interface, and the rear end has a rear-end interface. The bushing is slidably mounted inside the front-end interface, and the bushing shoulder abuts against the front end of the transmission wheel. The screw is driven and connected inside the bushing. The bushing shoulder and the front shoulder of the transmission shaft clamp the transmission wheel and are connected by bolts. The pushing assembly includes a lead screw, a sleeve, and a glue injection motor. The output shaft of the glue injection motor is coaxially connected to the lead screw. The sleeve is connected to the housing and is used for rear-end support of the housing. The sleeve is driven and sleeved on the lead screw. The front end of the lead screw passes through the sleeve and is rotatably disposed in the rear-end interface. It also includes two crescent rings, and the rear end of the screw has a shoulder. The two crescent rings abut against the shoulder at the rear end of the screw and are detachably connected to the bushing for axial positioning of the screw. The two crescent rings interlock to form a fastening ring. The inner wall of the fastening ring is provided with an internal thread, and the annular groove of the screw is provided with an external thread. The side wall of the fastening ring is provided with a plurality of bolt holes at equal intervals, and the side wall of the large column section of the pad is provided with a plurality of bolt holes correspondingly. The fastening ring is used to adjust the tightness between the screw and the pad. The bolt holes on the pad and the fastening ring are connected by bolts to fix the fastening ring after adjustment.

2. The screw connection device according to claim 1, characterized in that: The front end of the housing abuts against a first bearing, the rear shoulder of the drive shaft abuts against the first bearing, the rear end of the housing abuts against a second bearing, and a retaining ring is detachably installed on the drive shaft, the retaining ring abuts against the other end of the second bearing, the retaining ring being used to limit the movement of the drive shaft.

3. The screw connection device according to claim 2, characterized in that: The first bearing is an axial contact ball bearing, and the second bearing is a tapered roller bearing.

4. The screw connection device according to claim 1, characterized in that: A washer is provided at the bottom of the circular groove of the drive shaft. The outer wall of the washer is an inclined surface. The outer wall of the washer abuts against the bottom of the sleeve. The end face of the washer abuts against the end face of the screw.

5. The screw connection device according to claim 1, characterized in that: The drive shaft and the drive wheel are connected by a key, and the screw and the bushing are connected by a spline.

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