A screw conveyor device

Abstract

The present application relates to a kind of screw conveyor, including shell, screw conveying shaft and drive mechanism, the upper portion of the shell is provided with feed inlet, the lower portion of the shell is provided with discharge port;The screw conveying shaft is arranged in the shell, one end is rotatably supported in the front end cover, the other end is rotatably supported in the rear end cover;The drive mechanism is fixed to the outside of the shell, one end of the screw conveying shaft extends out of the front end cover and is connected with the output end of the drive mechanism;The rotating fit part of the front end cover and the screw conveying shaft is provided with multi-stage sealing structure. Wherein the first sealing ring between the front end cover and the shaft sleeve can effectively prevent the screw conveyor from leaking sand;Second sealing assembly and third sealing assembly between shaft sleeve and transmission shaft prevent sand, dust and other into bearing to cause jam, wear, corrosion and other failures, completely eliminate the leakage, accumulation of microfine hard sand material such as precoated sand, quartz sand.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a spiral conveyor for a 3D printer. Background Technology

[0002] Sand mold 3D printing technology is widely used in the foundry industry due to its advantages of high molding precision, short production cycle, and adaptability to complex casting molds. The sand screw conveyor is the core feeding component of a sand mold 3D printer, responsible for quantitatively and evenly conveying powdery, fine-particle sand from the sand storage bin to the sand spreader. Its conveying stability and sealing performance directly affect the printing quality. Currently, the shaft end seals of the screw conveyor devices used in sand mold 3D printers mostly employ single sealing structures such as rubber sealing rings and packing seals. However, this single sealing structure has poor sealing performance and presents many problems in practical use.

[0003] Fine sand particles easily penetrate into the sealing gaps and bearing mating areas. Long-term accumulation can cause the auger shaft to jam, and bearings to wear and corrode. This not only leads to uneven feeding and deviations in the thickness of the printed sand layer, affecting the accuracy of the sand mold, but also significantly shortens the lifespan of the equipment's transmission components, increasing equipment failure rates and maintenance costs. The coated sand and quartz sand used in sand mold printing are both hard, fine powders with high particle hardness and strong flowability. The sealing surface of a single-seal structure is easily eroded and worn by the sand particles carried by the high-speed rotating auger shaft, resulting in increased sealing gaps and seal failure within a short period, leading to frequent sand leakage. Furthermore, sand mold 3D printing equipment often operates in an intermittent start-stop mode. The auger shaft frequently starts and stops, and experiences slight axial movement. Ordinary sealing structures cannot adapt to the dynamic displacement of the shaft, easily leading to loose seals and sand leakage in localized gaps. Summary of the Invention

[0004] Therefore, it is necessary to provide a screw conveyor with a multi-stage sealing structure to address the aforementioned technical problems.

[0005] To solve the above problems, the present invention adopts the following technical solution: This invention discloses a screw conveyor device, including a housing, a screw conveyor shaft, and a drive mechanism. The housing has an inlet at its upper part and an outlet at its lower part. The screw conveyor shaft is disposed within the housing, with one end rotatably supported by a front end cover and the other end rotatably supported by a rear end cover. The drive mechanism is fixed to the outside of the housing, and one end of the screw conveyor shaft extends out of the front end cover and is connected to the output end of the drive mechanism. The rotating joint between the front end cover and the screw conveyor shaft is provided with a multi-stage sealing structure.

[0006] In one embodiment, the rotating mating parts of the front end cover and the screw conveyor shaft are provided with a bearing, a bushing, a first retaining ring, and a second retaining ring. The front end cover has a shaft hole, and the bushing is fixed in the shaft hole by bolts. The drive shaft of the screw conveyor shaft is installed in the bushing and is provided with a mounting boss that matches the bushing. The bearing is located outside the mounting boss. The inner ring of the bearing is interference-fitted with the drive shaft, and the outer ring of the bearing is interference-fitted with the bushing. One side of the inner ring is limited by the mounting boss, and the other side is limited by the first retaining ring. One side of the outer ring is limited by the bushing, and the other side is limited by the second retaining ring.

[0007] In one embodiment, the multi-stage sealing structure includes a first sealing ring, a second sealing assembly, and a third sealing assembly; the first sealing ring is disposed between the front end cover and the bushing; the second sealing assembly and the third sealing assembly are disposed between the bushing and the drive shaft.

[0008] In one embodiment, the second sealing assembly includes a felt ring, a pressure plate, and a screw, wherein the felt ring is fixed to the bushing by the pressure plate and the screw; the inner diameter of the felt ring is smaller than the outer diameter of the drive shaft.

[0009] In one embodiment, the third sealing assembly is a labyrinth sealing assembly, including a first sealing ring and a second sealing ring; the drive shaft is provided with a first slot, the first sealing ring is nested in the first slot and fits and seals against the inner wall of the bushing; the bushing is provided with a second slot, the second sealing ring is nested in the second slot and fits and seals against the inner side of the mounting boss.

[0010] In one embodiment, the first sealing ring and the second sealing ring are made of elastic wear-resistant material.

[0011] In one embodiment, the first sealing ring and the second sealing ring are made of polytetrafluoroethylene (PTFE).

[0012] In one embodiment, the drive mechanism is a rotary motor.

[0013] In one embodiment, a speed reducer is provided between the screw conveyor shaft and the rotating motor.

[0014] In one embodiment, the mating portion of the rear end cover and the spiral conveyor shaft is provided with a sealing structure.

[0015] The technical solution adopted in this invention can achieve the following beneficial effects: The spiral conveyor disclosed in this invention features a multi-stage sealing structure at the mating point between the front cover and the drive shaft of the spiral conveyor shaft. The first sealing ring between the front cover and the bushing effectively prevents sand leakage. The multi-layered sealing measures, achieved through the cooperation of the second and third sealing components between the bushing and the drive shaft, comprehensively eliminate the leakage and accumulation of fine, hard sand materials such as coated sand and quartz sand. This solves the defects of traditional sealing structures, which are prone to sand leakage and dust accumulation, ensuring the clean operation of the feeding system in a sand mold 3D printer. The core sealing surface is made of highly wear-resistant polytetrafluoroethylene (PTFE), which can resist long-term erosion and wear from hard sand particles, preventing shaft jamming, bearing wear, and corrosion caused by sand powder accumulation. This significantly reduces the equipment failure rate, extends the service life of the spiral conveyor shaft, bearings, and seals, and reduces the frequency of equipment maintenance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the screw conveyor disclosed in an embodiment of the present invention; Figure 2 This is a cross-sectional view of the screw conveyor device disclosed in an embodiment of the present invention; Figure 3 for Figure 2 Enlarged view of part A in the middle; 100 - Housing; 110 - Front cover; 120 - Rear cover; 200 - Screw conveyor shaft; 210 - Drive shaft; 300 - Drive mechanism; 410 - Bearing, 420 - Bushing, 430 - First retaining ring, 440 - Second retaining ring, 450 - Bolt; 510 - First sealing ring; 521 - Felt ring; 522 - Pressure plate; 523 - Screw; 531 - First sealing ring; 532 - Second sealing ring. Detailed Implementation

[0017] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0018] It should be noted that when a component is referred to as being "set on" another component, it can be directly on the other component or there may be an intervening component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," "top," "bottom," "end," "top," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations. The connections described herein can be integral connections or fixed connections using screws, bolts, welding, etc. Similar expressions are for illustrative purposes only and do not represent the only possible implementations.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] This invention discloses a screw conveyor device, such as... Figure 1 As shown, the disclosed screw conveyor includes a housing 100, a screw conveyor shaft 200, and a drive mechanism 300. A front cover 110, a rear cover 120, and two side walls are welded together to form the housing 100 of the screw conveyor. The housing 100 has an inlet at the top and an outlet at the bottom. The drive mechanism 300 is mounted on the outside of the housing 100. One end of the screw conveyor shaft 200 is rotatably mounted to the rear cover 120, and the other end is rotatably mounted to the front cover 110 and driven by the drive mechanism 300. The rotating joint between the front cover 110 and the screw conveyor shaft 200 is equipped with a multi-stage sealing structure.

[0021] like Figure 2 , Figure 3 As shown, the rotating joint between the front cover 110 and the screw conveyor shaft 200 is equipped with a bearing 410, a bushing 420, a first retaining ring 430, a second retaining ring 440, and a multi-stage sealing structure. The drive shaft 210 at the end of the screw conveyor shaft 200 is rotatably mounted inside the front cover 110 via the bearing 410 and bushing 420. The first retaining ring 430 and the second retaining ring 440, in conjunction with the bushing 420, limit the bearing 410. The drive shaft 210 extends out of the front cover 110 and is driven by the drive mechanism 300. The drive mechanism 300 can be a rotary motor and a reducer. The drive motor, reducer, and drive shaft 210 are connected. The output of the drive motor is reduced in speed by the reducer and then drives the drive shaft 210 to rotate.

[0022] like Figure 3As shown, the front cover 110 has a shaft hole, and the bushing 420 is fixed in the shaft hole by bolts 450. The drive shaft 210 is installed in the bushing 420, and a bearing 410 is provided between the drive shaft 210 and the bushing 420. Specifically, the drive shaft 210 may be provided with a mounting boss, and the bushing 420 is provided with a first mounting platform and a second mounting platform. The mounting boss is provided in the first mounting platform, and the bearing 410 is provided in the second mounting platform. A first retaining ring 430 and a second retaining ring 440 are installed on the outer end of the bearing 410. The inner ring of the bearing 410 is interference-fitted with the drive shaft 210, and the outer ring is interference-fitted with the bushing 420. One side of the outer ring of the bearing 410 is limited by the second mounting platform, and the other side is limited by the second retaining ring 440. One side of the inner ring of the bearing 410 is limited by the mounting boss of the drive shaft 210, and the other side is limited by the first retaining ring 430.

[0023] In the embodiments disclosed in this invention, the multi-stage sealing structure is a three-stage sealing structure, which may include a first sealing ring 510, a second sealing assembly, and a third sealing assembly. The first sealing ring 510 is an elastic sealing material and can be disposed between the outer side of the front end cover 110 and the bushing 420 to prevent sand particles, dust, etc., inside the housing 100 from leaking out through the gap between the bushing 420 and the shaft hole. The second and third sealing assemblies can be disposed between the bushing 420 and the drive shaft 210 to prevent sand particles, dust, etc., inside the housing 100 from entering the bearing 410 and causing malfunctions such as jamming, wear, and corrosion.

[0024] Specifically, the second sealing assembly may include a felt ring 521, a pressure plate 522, and a screw 523. The felt ring 521 is disposed on the inner end face of the bushing 420, and its inner diameter is smaller than the outer diameter of the drive shaft 210. The pressure plate 522 presses against the side of the felt ring 521 away from the bushing 420 and is fixed by the screw 523. The felt ring 521 can prevent sand, dust, etc. from entering the gap between the bushing 420 and the drive shaft 210.

[0025] The third sealing assembly can be a labyrinth-type sealing assembly, which may include a first sealing ring 531 and a second sealing ring 532. A first groove is provided on the right side of the mounting boss of the drive shaft 210, and the first sealing ring 531 is nested in the first groove and fits tightly against the inner wall of the bushing 420 for sealing. The bushing 420 is provided with a second groove, and the second sealing ring 532 is nested in the second groove and fits tightly against the side of the mounting boss of the drive shaft 210 for sealing. The third sealing assembly, in conjunction with the second sealing assembly, can effectively prevent sand particles, dust, etc., from entering the bearing 410 and causing malfunctions such as jamming, wear, and corrosion. The first sealing ring 531 and the second sealing ring 532 can be made of elastic wear-resistant material, preferably polytetrafluoroethylene (PTFE), which has high wear resistance and is suitable for sealing and isolating hard particles such as sand.

[0026] In the embodiments disclosed in this invention, the rear end cover 120 and the screw conveyor shaft 200 can also be rotatably installed using a bearing and bushing. The rotatable mating part between the rear end cover 120 and the screw conveyor shaft 200 can also be provided with a sealing structure. This sealing structure can be a single-stage sealing ring or a multi-stage sealing structure similar to the above embodiments. This invention will not elaborate further on this aspect.

[0027] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A screw conveyor device, characterized in that, It includes a housing (100), a screw conveyor shaft (200), and a drive mechanism (300). The upper part of the housing (100) is provided with a feed inlet, and the lower part of the housing (100) is provided with a discharge outlet; the screw conveyor shaft (200) is disposed inside the housing (100), one end of which is rotatably supported on the front end cover (110), and the other end of which is rotatably supported on the rear end cover (120). The drive mechanism (300) is fixed to the outside of the housing (100), and one end of the spiral conveying shaft (200) extends out of the front end cover (110) and is connected to the output end of the drive mechanism (300); The rotating parts of the front cover (110) and the spiral conveying shaft (200) are provided with a multi-stage sealing structure.

2. The screw conveyor according to claim 1, characterized in that, The rotating mating parts of the front end cover (110) and the screw conveyor shaft (200) are provided with a bearing (410), a bushing (420), a first retaining ring (430), and a second retaining ring (440). The front end cover (110) has a shaft hole, and the bushing (420) is fixed in the shaft hole by bolts (450). The drive shaft (210) of the screw conveyor shaft (200) is installed in the bushing (420) and is provided with a mounting boss that matches the bushing (420). The bearing (410) is located on the outside of the mounting boss. The inner ring of the bearing (410) is interference-fitted with the transmission shaft (210), and the outer ring of the bearing (410) is interference-fitted with the bushing (420); one side of the inner ring is limited by the mounting boss, and the other side is limited by the first retaining ring (430); one side of the outer ring is limited by the bushing (420), and the other side is limited by the second retaining ring (440).

3. The screw conveyor according to claim 2, characterized in that, The multi-stage sealing structure includes a first sealing ring (510), a second sealing assembly, and a third sealing assembly; The first sealing ring (510) is disposed between the front end cover (110) and the bushing (420); The second sealing assembly and the third sealing assembly are disposed between the bushing (420) and the drive shaft (210).

4. The screw conveyor according to claim 3, characterized in that, The second sealing assembly includes a felt ring (521), a pressure plate (522), and a screw (523), wherein the felt ring (521) is fixed to the bushing (420) by the pressure plate (522) and the screw (523); The inner diameter of the felt ring (521) is smaller than the outer diameter of the drive shaft (210).

5. The screw conveyor according to claim 3, characterized in that, The third sealing assembly is a labyrinth sealing assembly, including a first sealing ring (531) and a second sealing ring (532). The drive shaft (210) is provided with a first slot, and the first sealing ring (531) is nested in the first slot and fits and seals against the inner wall of the bushing (420); the bushing (420) is provided with a second slot, and the second sealing ring (532) is nested in the second slot and fits and seals against the side of the mounting boss.

6. The screw conveyor according to claim 5, characterized in that, The first sealing ring (531) and the second sealing ring (532) are made of elastic wear-resistant material.

7. The screw conveyor according to claim 5, characterized in that, The first sealing ring (531) and the second sealing ring (532) are made of polytetrafluoroethylene.

8. The screw conveyor according to claim 1, characterized in that, The drive mechanism (300) is a rotary motor.

9. The screw conveyor according to claim 1, characterized in that, A speed reducer is provided between the screw conveyor shaft (200) and the rotating motor.

10. The screw conveyor according to any one of claims 1 to 9, characterized in that, The mating parts of the rear end cover (120) and the spiral conveyor shaft (200) are provided with a sealing structure.

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