A self-lubricating screw lifting mechanism

Abstract

This application discloses a self-lubricating screw lifting mechanism, belonging to the field of 3D printing equipment technology. It includes an inner screw (with a first external thread on its outer wall), a drive sleeve (with a first internal thread on its inner wall and a second external thread on its outer wall) fitted around it, a sleeve drive seat with a second internal thread on its inner wall, a transmission component for driving the drive sleeve to rotate, and a sealed cylinder with an oil storage space at the bottom. The inner screw has an axial first oil passage and a transverse second oil passage. The two pairs of threads have opposite directions of rotation. When the drive sleeve rotates, both threads and the inner screw move axially respectively, and their strokes overlap. When the inner screw descends, lubricating oil is inserted into its lower end. The oil flows out through the channels, lubricating the two pairs of threads before returning, achieving circulating lubrication. This eliminates the need for frequent manual oiling, and the mechanism has a compact structure.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing equipment technology, and particularly relates to a self-lubricating screw lifting mechanism. Background Technology

[0002] In 3D printing equipment, existing lead screw lifting mechanisms typically use a motor to drive the internal lead screw to rotate, thereby raising and lowering the printing table by a fixed distance. However, due to the relatively simple internal lead screw transmission structure, sufficient space needs to be reserved for the extension and retraction of the internal lead screw during lifting, making it difficult for the equipment to achieve large-scale lifting movements within a limited height range. To meet the lifting stroke requirements, existing technologies often have to raise the equipment platform or excavate a pit in the ground to accommodate the descent space of the internal lead screw. This not only increases the manufacturing cost and installation difficulty of the equipment, but also increases the complexity of construction and site requirements. In addition, traditional lifting mechanisms require many parts and have a high proportion of customized parts, resulting in longer procurement and production cycles and higher manufacturing costs. At the same time, the simple structure also increases the difficulty of fault repair and prolongs maintenance time, thus affecting the overall efficiency and reliability of the equipment. More importantly, during long-term operation, the lubrication of the threaded joint of existing lead screw lifting mechanisms usually relies on manual periodic addition of lubricating oil or initial filling of grease. With the increase of usage time, the lubrication effect gradually decreases, leading to increased frictional resistance, accelerated wear, and increased heat generation, which not only affects the smoothness and accuracy of lifting movements, but also shortens the service life of the mechanism. Manual lubrication is cumbersome and prone to insufficient lubrication due to negligence, further reducing equipment reliability and production efficiency. Furthermore, manual lubrication can introduce impurities due to operational errors, causing the lead screw to seize. While some mechanisms use external pumps for periodic lubrication, this requires additional pumps, pipelines, and control systems, resulting in complex structures, increased costs, and the inability to recycle lubricating oil. Reliance on manual or timed control makes insufficient or excessive lubrication easy, leading to cumbersome maintenance and poor reliability. These lubrication deficiencies exacerbate equipment friction and wear, increase failure rates, and reduce equipment production efficiency and operational stability. Summary of the Invention

[0003] (a) Purpose of the invention

[0004] To overcome the above shortcomings, the present invention aims to provide a screw lifting self-lubricating mechanism to solve the technical problems of existing screw lifting self-lubricating mechanisms, which are difficult to achieve a wide range of lifting in space-constrained environments due to their simple structure, resulting in high equipment cost, complex installation, and difficult maintenance.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the technical solution provided in this application is as follows:

[0007] A self-lubricating screw lifting mechanism, comprising:

[0008] The internal threaded rod has a first external thread on its outer wall;

[0009] A drive sleeve is open at both ends and fitted around the inner lead screw. Its inner wall is provided with a first internal thread that mates with the first external thread, and its outer wall is provided with a second external thread.

[0010] A sleeve drive seat is fitted over the drive sleeve, and its inner wall is provided with a second internal thread that mates with the second external thread.

[0011] The transmission component is connected to the drive sleeve to drive its rotation.

[0012] The sealing sleeve is connected to the lower part of the sleeve drive seat to accommodate the descending drive sleeve, and its bottom forms an oil storage space.

[0013] The internal lead screw is provided with an axially penetrating first oil passage and multiple transversely penetrating second oil passages on the outer side, and each second oil passage is connected to the first oil passage;

[0014] The rotation directions of the first internal thread and the first external thread are opposite to those of the second internal thread and the second external thread, so that when the drive sleeve rotates, the drive sleeve moves axially relative to the sleeve drive seat, and the internal screw moves axially relative to the drive sleeve.

[0015] When the internal screw descends, its lower end extends into the lubricating oil of the drive sleeve. The lubricating oil flows upward through the first oil passage and flows out through the second oil passage to the meshing area of ​​the first external thread and the first internal thread. Part of the lubricating oil flows into the meshing area of ​​the first external thread and the first internal thread and flows back down into the drive sleeve along the thread gap. The other part overflows from the upper opening of the drive sleeve and flows down along its outer wall, lubricating the second internal thread that is engaged with the second external thread before flowing back to the sealing sleeve.

[0016] The inner screw has a first external thread on its outer wall, and the drive sleeve has a matching first internal thread on its inner wall. The drive sleeve also has a second external thread on its outer wall, and the sleeve drive seat has a matching second internal thread on its inner wall. The two pairs of threads rotate in opposite directions. When the transmission component drives the drive sleeve to rotate, the drive sleeve moves axially relative to the sleeve drive seat, and the inner screw also moves axially relative to the drive sleeve. The strokes are superimposed, achieving a larger lifting range within a limited space. An oil storage space is formed at the bottom of the sealing cylinder. The inner screw has an axial first oil passage and a transverse second oil passage. When the inner screw descends, its lower end extends into the lubricating oil. The oil flows upward through the first oil passage and out through the second oil passage. Part of the oil enters the first threaded pair and flows downward along the thread gap, while the other part overflows from the upper opening of the drive sleeve and flows down its outer wall, lubricating the second threaded pair formed by the second external thread and the second internal thread, as well as the transmission component. Finally, all the oil flows back to the sealing cylinder, forming a cycle. This design utilizes the reverse engagement of the double threads to achieve stroke superposition, eliminating the need to raise the machine platform or excavate a foundation. It has a compact structure and few parts. Simultaneously, the lifting action completes the compression and oil supply. The lubricating oil lubricates both the inner and outer threaded parts and the transmission components, and is completely recycled. After each descent, each friction part can obtain fresh lubrication, significantly reducing friction and wear. Moreover, there is no need for frequent manual oiling, which significantly improves the reliability and automation of operation.

[0017] In some embodiments, the transmission component includes at least one drive sprocket sleeved and fixed to the outside of the drive sleeve.

[0018] This sprocket drive system boasts high load-bearing capacity and transmission efficiency, making it suitable for large worktables with multi-point drive. More importantly, the circulating lubricating oil naturally lubricates the sprockets and chain as it flows through the outer wall of the drive sleeve, eliminating the need for additional grease and reducing maintenance workload. Combined with the stroke stacking and self-lubricating structure, the entire lifting system maintains stable and low-wear operation even under large stroke and heavy-load conditions.

[0019] In some embodiments, a lifting ring is fixedly provided at the upper end of the inner lead screw.

[0020] With the lifting rings installed, the disassembly, assembly, and maintenance of the equipment become more convenient, especially when the mechanism needs to be repaired or parts replaced due to long-term use, the lifting operation is simple and safe.

[0021] In some embodiments, the screw lifting self-lubricating mechanism further includes a bearing, which is sleeved on the outside of the drive sleeve and used to connect with an external mounting plate.

[0022] The bearing is used to connect to the external mounting plate. The bearing allows the mounting plate to rise and fall together with the drive sleeve, while allowing the drive sleeve to rotate independently. It absorbs minor misalignments that may occur during the lifting and lowering of the mounting plate, preventing jamming. The rolling elements inside the bearing also require lubrication during long-term operation, and some of the lubricating oil overflowing from the upper end of the drive sleeve seeps into the bearing area as it flows down the outer wall. Using the bearing improves the smoothness and responsiveness of the lifting and lowering motion, and further reduces frictional resistance under load. The natural impregnation of the bearing by the circulating lubricating oil eliminates the need for separate lubrication, enhancing the overall lifespan and precision of the mechanism.

[0023] In some embodiments, the inner side of the drive sleeve is provided with a notch and a third oil passage with the upper end connected to the notch is provided inside the drive sleeve wall. The inner side of the drive sleeve extends radially to form a stepped surface, and the side of the stepped surface is provided with a first internal thread. The lower end of the third oil passage extends below the stepped surface.

[0024] The lubricating oil flowing from the second oil passage is blocked by the stepped surface. Part of it flows into the first threaded pair, and part overflows upwards to lubricate the second threaded pair and transmission components. If a large amount of oil accumulates above the stepped surface, it will reduce the amount of oil flowing to the first threaded pair. The third oil passage provides a direct downward discharge path for the accumulated oil, allowing it to flow quickly below the stepped surface and fully lubricate the first external thread. This results in smoother oil return, avoids insufficient local lubrication, more even oil supply to the internal and external threaded pairs, and fully utilizes the oil squeezing effect during each lifting and lowering process, leading to less thread wear.

[0025] The lubricating oil flowing from the second oil passage is blocked by the stepped surface; some flows into the first threaded joint, while some overflows upwards. The oil accumulating above the stepped surface creates localized pressure, hindering further oil from entering the first threaded joint. The third oil passage provides a pressure relief channel for this portion of oil, allowing the pressure to be released and the oil to flow quickly downwards below the stepped surface, thus smoothly lubricating the first external thread. Reduced return resistance and more balanced oil supply to the internal and external threaded joints ensure effective oil extraction with each lifting and lowering process, resulting in less thread wear.

[0026] In some embodiments, a fourth oil passage is provided through the through sleeve drive seat. The upper opening of the fourth oil passage is used to receive lubricating oil that overflows from the upper opening of the drive sleeve and flows down the outer side of the drive sleeve, and the lower opening is connected to the inside of the sealing sleeve.

[0027] With the fourth oil passage installed, lubricating oil will not accumulate or drip onto the outer wall of the drive sleeve and be wasted. Instead, it will automatically return to the oil sump, keeping the mechanism clean and reducing the frequency of oil replenishment. The lifting and lubrication circulation form a closed loop, further improving the durability and reliability of self-lubrication.

[0028] In some embodiments, a collection groove is provided around the edge of the sleeve drive seat to collect lubricating oil that flows down from the outer side of the drive sleeve but does not enter the fourth oil passage.

[0029] The collection tank, as a supplementary recovery measure, can handle special situations such as large-flow oil spills or tilted installation, ensuring that lubricating oil does not leak outside the mechanism. Together with the fourth oil passage, it forms a double-layer oil recovery system, enabling the self-lubricating mechanism to maintain sufficient oil volume under various operating conditions and extending maintenance intervals.

[0030] In some embodiments, the screw lifting self-lubricating mechanism further includes: a first plug fitted above the first oil passage; and a filter screen disposed within the first oil passage and located below the first plug.

[0031] The first plug fits above the first oil passage, and the filter screen is located inside the first oil passage and below the first plug. The first plug seals the first oil passage, preventing external impurities from entering. Simultaneously, the first plug prevents oil from spraying out from the top. When the lubricating oil is squeezed upwards from below, the filter screen intercepts impurities or wear particles in the oil, preventing them from entering the threaded joint and causing secondary wear. With the addition of the filter screen, the cleanliness of the circulating lubricating oil is ensured, the threaded joint and oil passage are less prone to clogging, and the self-lubricating effect is more durable. The first plug also serves as an inspection port and a filler port, facilitating the addition of lubricating fluid, replacement of the filter screen, and cleaning of the passage, reducing the difficulty of long-term maintenance.

[0032] In some embodiments, the screw lifting self-lubricating mechanism further includes: a second plug, sleeved above the first oil passage and located above the first plug; the inner side of the first oil passage is provided with threads for threaded connection with the lifting eye corresponding to the position of the second plug.

[0033] This structure ensures a secure connection for the lifting ring while enhancing the seal at the top of the first oil passage, preventing oil leakage from the top. The lifting ring, first plug, and second plug work together to achieve multiple functions—lifting, sealing, and filtering—without adding extra parts, resulting in better overall integrity and simpler assembly. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the self-lubricating screw lifting mechanism of the present invention;

[0035] Figure 2 This is a cross-sectional view of the lead screw lifting self-lubricating mechanism of the present invention;

[0036] Figure 3 This is a diagram showing the flow of lubricating oil within the self-lubricating screw lifting mechanism of the present invention.

[0037] Figure 4This is an assembly diagram of the self-lubricating screw lifting mechanism of the present invention with an external mounting plate and a base;

[0038] Figure 5 This is a schematic diagram of the internal lead screw in the lead screw lifting self-lubricating mechanism of the present invention;

[0039] Figure 6 This is a schematic diagram of the drive sleeve in the lead screw lifting self-lubricating mechanism of the present invention;

[0040] Figure 7 This is a schematic diagram of the sleeve drive seat in the self-lubricating screw lifting mechanism of the present invention.

[0041] Figure label:

[0042] 1. Inner lead screw; 101. First oil passage; 102. Second oil passage; 2. Drive sleeve; 201. Notch; 202. Stepped surface; 203. Third oil passage; 3. Sleeve drive seat; 301. Fourth oil passage; 302. Collection trough; 4. Transmission component; 5. Sealing sleeve; 6. Lifting ring; 7. Bearing; 8. First plug; 9. Filter screen; 10. Second plug; 11. Mounting plate; 12. Chain; 13. Base. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0044] This invention provides a self-lubricating screw lifting mechanism, comprising an inner screw 1 with a first external thread machined on its outer wall. A drive sleeve 2, open at both ends, is fitted around the inner screw 1. The inner wall of the drive sleeve 2 has a first internal thread that mates with the first external thread, and the outer wall of the drive sleeve 2 also has a second external thread. A sleeve drive seat 3 is fitted around the outer side of the drive sleeve 2, and the inner wall of the sleeve drive seat 3 has a second internal thread that mates with the second external thread. Furthermore, the mechanism includes a transmission component 4, which is connected to the drive sleeve 2 to drive its rotation. A sealing cylinder 5 is connected below the sleeve drive seat 3, and the bottom of the sealing cylinder 5 forms an oil storage space capable of accommodating the lowered drive sleeve 2. The edge of the sealing cylinder 5 is locked and sealed to the sleeve drive seat 3 by screws or other fasteners, and the interior of the sealing cylinder 5 is in communication with the interior of the sleeve drive seat 3. It is worth noting that the internal lead screw 1 has an axially penetrating first oil passage 101 inside, and the upper part of the internal lead screw 1 also has multiple transversely penetrating second oil passages 102, each of which is connected to the first oil passage 101. The rotation direction of the first internal thread and the first external thread is opposite to that of the second internal thread and the second external thread. In this way, when the transmission component 4 drives the drive sleeve 2 to rotate, the drive sleeve 2 will move axially relative to the sleeve drive seat 3, and the internal lead screw 1 will also move axially relative to the drive sleeve 2. The two movements are in the same direction, thus achieving the superposition of strokes.

[0045] During installation, a suitable amount of lubricating oil is pre-injected into the bottom of the sealing sleeve 5. After the drive sleeve 2 is installed, its lower end is immersed in the lubricating oil, which simultaneously fills the interior of the drive sleeve 2. Please refer to [link / reference]. Figure 3 (The arrows indicate the direction of lubricant flow, and the blackened part represents lubricant.) When the internal lead screw 1 descends, its lower end extends into the lubricant inside the drive sleeve 2. As the internal lead screw 1 descends further, its lower end acts like a piston, squeezing the oil below the first oil passage 101. Since the upper end of the first oil passage 101 is blocked, the oil is forced into the first oil passage 101 and flows upward, eventually flowing out from the second oil passage 102 connected to it. The outflowing lubricant is divided into two paths: one part flows into the meshing area of ​​the first external thread and the first internal thread, and slowly flows back down into the drive sleeve 2 along the thread gap; the other part overflows from the upper opening of the drive sleeve 2, and then flows down along the outer wall of the drive sleeve 2. During the flow, it lubricates the second thread pair formed by the second external thread and the second internal thread, and also lubricates the relevant parts of the transmission component 4. Finally, all of this lubricant flows back into the sealing sleeve 5, forming a complete cycle. Preferably, both the inner lead screw 1 and the drive sleeve 2 are made of 40Cr alloy steel and have undergone quenching and tempering treatment to improve their surface hardness and wear resistance. The transmission component 4 can be a gear or sprocket driven by a motor, as long as it can reliably drive the drive sleeve 2 to rotate.

[0046] Furthermore, the transmission component 4 includes at least one drive sprocket sleeved and fixed to the outside of the drive sleeve 2. The sprocket is typically fixed to the drive sleeve 2 via a key connection to ensure reliable transmission. In practical applications, when multiple screw-lifting self-lubricating mechanisms need to be driven synchronously, the same chain 12 can be used to simultaneously pass over multiple sets of drive sprockets, driven by a single motor, thereby achieving synchronous lifting of multiple lifting points. Preferably, the drive sprocket is made of 45# steel and has undergone quenching treatment to give its tooth surface high wear resistance. As an alternative, the transmission component 4 can also use a synchronous pulley in conjunction with a synchronous belt, which can also achieve synchronous drive of multiple mechanisms.

[0047] Furthermore, a lifting ring 6 is fixedly installed at the upper end of the inner lead screw 1. The lifting ring 6 is typically screwed into the threaded hole at the top of the inner lead screw 1 using a threaded connection, and a lock nut can be installed to prevent loosening. This lifting ring 6 provides a convenient lifting point for the hoisting and handling of the entire mechanism. During equipment installation or maintenance, a crane or manual hoist can be used to hook the lifting ring 6 for lifting, greatly reducing the intensity of manual labor. On the other hand, when the mechanism rises to its designated position, the lifting ring 6 will contact the upper limiting component, thereby preventing the inner lead screw 1 from rising excessively and coming off. Preferably, the lifting ring 6 is forged and galvanized to enhance its corrosion resistance.

[0048] Furthermore, the screw lifting self-lubricating mechanism also includes a bearing 7, which is sleeved on the outside of the drive sleeve 2 for connection with the external mounting plate 11. Specifically, the inner ring of the bearing 7 is interference-fitted with the drive sleeve 2, while the outer ring of the bearing 7 is fixedly connected to the mounting plate 11. This allows the mounting plate 11 to rise and fall together with the drive sleeve 2, while the drive sleeve 2 can still rotate independently under the drive of the transmission component 4. This design effectively absorbs the slight misalignment of the mounting plate 11 caused by uneven force during lifting, preventing jamming. It is worth noting that when the lubricating oil overflowing from the upper end of the drive sleeve 2 flows down the outer wall, some of it naturally seeps into the interior of the bearing 7, thus lubricating the balls and raceways of the bearing 7. Therefore, the bearing 7 does not require separate grease application. Preferably, the bearing 7 is a deep groove ball bearing, which has good load-bearing capacity and low frictional resistance.

[0049] When assembled into a complete lifting device, the sleeve drive base 3 is fixedly installed on the base 13 of the device using bolts and other fasteners, providing a stable support foundation for the entire mechanism. The drive motor and its connected chain 12 are simultaneously installed on the mounting plate 11. The chain 12 meshes with a drive sprocket (usually located above the bearing 7) sleeved outside the drive sleeve 2, thereby transmitting the motor's rotational power to the drive sleeve 2. The upper end of the inner lead screw 1 (or via the lifting ring 6) is connected to a support platform, which can be used to install a printing worktable or other components requiring lifting. When the motor starts, the chain 12 drives the sprocket to rotate, and the drive sleeve 2 rotates accordingly, thus achieving smooth lifting of the inner lead screw 1 and the mounting plate 11. The fixing method of the base 13 ensures that the entire mechanism will not shift or shake under load, further improving the accuracy and reliability of the lifting motion.

[0050] Furthermore, a notch 201 is provided on the inner side of the drive sleeve 2, and a third oil passage 203 with its upper end connected to the notch 201 is provided inside the cylinder wall of the drive sleeve 2. The inner side of the drive sleeve 2 extends radially to form a stepped surface 202, and a first internal thread is provided on the side of the stepped surface 202; wherein, the lower end of the third oil passage 203 extends below the stepped surface 202. Its function will be explained in detail below:

[0051] The lubricating oil flowing out from the second oil passage 102 first reaches the stepped surface 202 area on the inner side of the drive sleeve 2. Due to the radially protruding structure of the stepped surface 202, the lubricating oil is significantly blocked and stagnant here. Part of the lubricating oil directly enters the meshing area of ​​the first internal thread and the first external thread (i.e., the first thread pair) along the side wall of the stepped surface 202, playing a lubricating role; the other part of the lubricating oil gradually accumulates above the stepped surface 202 due to continuous inflow. Without the third oil passage 203, the accumulated oil will form local hydraulic pressure, which will in turn hinder the subsequent flow of lubricating oil from the second oil passage 102. At the same time, because less lubricating oil flows down from the first thread pair, the threads at the lower part of the first external thread (the part that does not contact the first internal thread) will not be adequately lubricated. In addition, the accumulated oil may also be forced upward and overflow in large quantities from the upper opening of the drive sleeve 2, causing instantaneous over-lubrication of the second thread pair and the transmission component 4, while the first thread pair is insufficiently lubricated, disrupting the balance of the entire lubrication cycle.

[0052] After the third oil passage 203 is opened, it provides a direct downward pressure relief and flow path for the accumulated oil above the stepped surface 202. The oil can quickly enter the third oil passage 203 through the notch 201, and then flow out from below the stepped surface 202, directly wetting the lower part of the first external thread. In this way, the pressure above the stepped surface 202 is released in time, and the lubricating oil flowing out from the second oil passage 102 can continuously and smoothly enter the first threaded pair without being stagnant due to back pressure. At the same time, the oil flowing out from the third oil passage 203 can also supplement the lubrication needs of the lower part of the first threaded pair, so that the entire first threaded pair can be uniformly covered with oil film from top to bottom. The return oil resistance is significantly reduced, the oil supply of the inner and outer threaded pairs is more balanced, the lubricating oil squeezed up during each lifting and lowering process can be effectively utilized, the wear of the threads is significantly reduced, and the friction and heat generation of the lifting and lowering motion are further reduced. Preferably, multiple third oil passages 203 can be provided and evenly distributed along the circumference of the drive sleeve 2, so that the pressure relief and oil return effects will be more uniform and reliable.

[0053] Furthermore, a fourth oil passage 301 is provided through the sleeve drive base 3. The upper opening of the fourth oil passage 301 is located below the upper opening of the drive sleeve 2, and is used to receive the lubricating oil that overflows from the upper end of the drive sleeve 2 and flows down along the outer wall. The lower opening of the fourth oil passage 301 is directly connected to the interior of the sealing cylinder 5. With this passage, the lubricating oil flowing down the outer wall of the drive sleeve 2 will not accumulate on the end face of the sleeve drive base 3 or drip to the outside, but will be mostly guided directly back to the sealing cylinder 5, thereby keeping the exterior of the mechanism clean and reducing lubricating oil consumption. In this way, the entire lubrication cycle forms a relatively closed loop, and the durability and reliability of self-lubrication are improved.

[0054] Furthermore, a collection groove 302 is also provided around the edge of the sleeve drive seat 3 to collect the portion of lubricating oil that flows down from the outer side of the drive sleeve 2 but fails to enter the fourth oil passage 301. For example, when the lubricating oil flow is large or the equipment is installed at a slight inclination, some oil may overflow the upper opening of the fourth oil passage 301. In this case, the collection groove 302 can catch this oil, ensuring that the lubricating oil does not drip directly onto the ground. A return hole (not shown in the figure) can be provided at the bottom of the collection groove 302 to communicate with the sealing cylinder 5, or it can be manually cleaned and recycled periodically, further improving the lubricating oil recovery rate and reducing waste.

[0055] Furthermore, the screw lifting self-lubricating mechanism also includes a first plug 8 and a filter screen 9. The first plug 8 fits above the first oil passage 101, acting as a seal to prevent oil from spraying out from the top and also to prevent external dust and impurities from falling directly into the oil passage. The filter screen 9 is located inside the first oil passage 101, below the first plug 8. The filter screen 9 can be installed into the first oil passage 101 in various ways, for example: the first oil passage 101 has an annular step, the filter screen 9 is placed on the step and pressed and fixed by the first plug 8 above; or the first oil passage 101 has an annular groove, the filter screen 9 is placed in place and fixed by the elastic retaining ring embedded in the groove.

[0056] Specifically, when the lubricating oil is squeezed upwards from below, the filter screen 9 can intercept any metal shavings or other solid impurities that may be present in the oil, preventing these impurities from entering the threaded joint and causing secondary wear. When it is necessary to add lubricating oil, replace the filter screen 9, or clean impurities, simply unscrew the first plug 8; this is very convenient. Preferably, the filter screen 9 is made of stainless steel wire mesh with a mesh diameter of approximately 0.2 mm, which effectively filters the oil without excessively obstructing its flow.

[0057] Furthermore, the screw lifting self-lubricating mechanism also includes a second plug 10. The second plug 10 is fitted above the first oil passage 101 and located above the first plug 8. The inner surface of the first oil passage 101 is machined with threads corresponding to the position of the second plug 10. These threads are also used for threaded connection with the lifting ring 6. That is, the mounting threads of the lifting ring 6 and the mounting threads of the second plug 10 are in the same location. During installation, the second plug 10 is first removed, and then the lifting ring 6 is screwed in to lock them together. Without adding any extra parts, the three functions of lifting, sealing, and filtering are simultaneously achieved, resulting in better overall integrity and simpler assembly.

[0058] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A self-lubricating mechanism of a lead screw lift characterized by, include: The inner threaded rod (1) has a first external thread on its outer wall; The drive sleeve (2) is open at both ends and sleeved on the outside of the inner screw (1). Its inner wall is provided with a first internal thread that mates with the first external thread, and its outer wall is provided with a second external thread. The sleeve drive seat (3) is fitted outside the drive sleeve (2), and its inner wall is provided with a second internal thread that mates with the second external thread; The transmission component (4) is connected to the drive sleeve (2) to drive its rotation; The sealing sleeve (5) is connected to the lower part of the sleeve drive seat (3) to accommodate the descending drive sleeve (2), and its bottom forms an oil storage space; The inner lead screw (1) is provided with an axially penetrating first oil passage (101) and multiple transversely penetrating second oil passages (102) on the outer side, and each second oil passage (102) is connected to the first oil passage (101); The direction of rotation of the first internal thread and the first external thread is opposite to that of the second internal thread and the second external thread, so that when the drive sleeve (2) rotates, the drive sleeve (2) moves axially relative to the sleeve drive seat (3), and the inner screw (1) moves axially relative to the drive sleeve (2). When the internal screw (1) descends, its lower end extends into the lubricating oil in the drive sleeve (2). The lubricating oil flows upward through the first oil passage (101) and flows out through the second oil passage (102). Part of it flows into the meshing area of ​​the first external thread and the first internal thread and flows back down into the drive sleeve (2) along the thread gap. The other part overflows from the upper opening of the drive sleeve (2) and flows down along its outer wall, lubricating the second internal thread that is engaged with the second external thread, and then flows back to the sealing sleeve (5).

2. The self-lubricating mechanism of claim 1, wherein, The transmission component (4) includes at least one drive sprocket that is sleeved and fixed to the outside of the drive sleeve (2).

3. The self-lubricating mechanism of claim 1, wherein, A lifting ring (6) is fixedly installed at the upper end of the inner screw (1).

4. The self-lubricating mechanism of claim 1, wherein, Also includes: The bearing (7) is sleeved on the outside of the drive sleeve (2) and is used to connect with the external mounting plate.

5. The self-lubricating mechanism of claim 1, wherein, The inner side of the drive sleeve (2) is provided with a notch (201) and a third oil passage (203) with its upper end connected to the notch (201) is provided inside the cylinder wall of the drive sleeve (2). The inner side of the drive sleeve (2) extends radially to form a stepped surface (202), and the side of the stepped surface (202) is provided with the first internal thread; wherein, the lower end of the third oil passage (203) extends below the stepped surface (202).

6. The self-lubricating mechanism of claim 1, wherein, A fourth oil passage (301) is provided through the sleeve drive seat (3). The upper opening of the fourth oil passage (301) is used to receive lubricating oil that overflows from the upper opening of the drive sleeve (2) and flows down along the outer side of the drive sleeve (2). The lower opening is connected to the inside of the sealing cylinder (5).

7. The self-lubricating mechanism of claim 6, wherein, The sleeve drive seat (3) has a collection groove (302) around its edge for collecting lubricating oil that flows down from the outer side of the drive sleeve (2) and does not enter the fourth oil passage (301).

8. The self-lubricating mechanism of claim 3, wherein, Also includes: The first plug (8) is fitted above the first oil passage (101); and the filter screen (9) is disposed inside the first oil passage (101) and located below the first plug (8).

9. The self-lubricating screw lifting mechanism according to claim 8, characterized in that, Also includes: The second plug (10) is sleeved above the first oil passage (101) and located above the first plug (8); the inner side of the first oil passage (101) is provided with threads for threaded connection with the lifting ring (6) at the position corresponding to the second plug (10).

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