Lead screw transmission mechanism for injection molding machine

Abstract

The utility model relates to the technical field of lead screw lubrication, and discloses a lead screw transmission mechanism for an injection molding machine, which comprises a tail plate, a bearing, a nut, a lead screw and a lubrication structure, the lubricating structure comprises an oil injection opening formed in the tail plate, an oil passing channel which is arranged between the tail plate and the nut, communicates with the oil injection opening and the outer surface of the nut and communicates with the bearing, an oil inlet channel penetrating through the inner surface and the outer surface of the nut, and an oil outlet channel formed in the lead screw. A first rotary sealing structure and a second rotary sealing structure which are used for limiting overflow of lubricating oil are arranged between the nut and the tail plate and between the nut and the lead screw correspondingly, and the lubricating oil in the lead screw transmission mechanism enters the space between the lead screw and the nut through the oil injection port and the oil inlet channel to be lubricated and then flows out of the lead screw through the oil outlet channel to be collected. The flowing of the lubricating oil forms a sealed circulation loop, the addition amount of the lubricating oil does not need to be controlled, sufficient lubrication between the lead screw and the nut can be guaranteed after the lubricating oil circulates in the circulation loop for multiple times, and the lubricating oil can be recycled to avoid waste.

Description

Technical Field

[0001] The utility model relates to the technical field of screw lubrication, in particular to a screw transmission mechanism for an injection molding machine. Background Art

[0002] At present, the application of electric injection molding machines is becoming more and more widespread. The mold clamping unit of the electric injection molding machine adopts a ball screw mechanism transmission. Common transmission types include screw rotation and nut rotation types, which make the crankshaft rod on the mold clamping side move back and forth.

[0003] Chinese patent application number 201210567709.0 discloses a clamping mechanism with ball screw pair transmission, including four tie rods, a tail plate, two elbow lever mechanisms, a movable plate, a head plate, a synchronous pulley, a screw bearing seat, a ball screw (screw), a ball nut (nut) and a thrust seat. The synchronous pulley is installed at one end of the ball screw, the ball screw is supported by the screw bearing seat fixed on the tail plate, the ball nut is threadedly connected to the other end of the ball screw, the thrust seat is fixed on the ball nut, and the servo motor is installed on the left side of the tail plate, and the transmission connection is realized with the synchronous pulley through the synchronous belt.

[0004] The above scheme shows the transmission type of screw rotation. When working, the rotation of the servo motor drives the synchronous pulley to rotate through the synchronous belt, and the ball screw rotates together. The rotational motion is then converted into linear motion through the ball nut, driving the thrust seat connected to the ball nut to do back and forth linear motion, thereby realizing mold opening and closing.

[0005] The only difference between the transmission type of nut rotation and the transmission type of lead screw rotation is that the nut is connected to the tail plate through the bearing, the synchronous pulley is installed on the end of the nut away from the tail plate, and the thrust seat is fixed on the end of the lead screw away from the nut. When the transmission type of nut rotation is working, the servo motor drives the synchronous pulley to rotate, and the nut rotates together, and then the lead screw converts the rotational motion into linear motion, driving the thrust seat connected to the lead screw to do back and forth linear motion.

[0006] In the existing ball screw mechanism in which the nut 2 rotates, the lubrication of the mating part of the nut 2 and the screw rod 4 is achieved by opening an oil inlet passage 30 on the screw rod 3, and the lubricating oil is injected from the outside into the threaded mating part of the nut 2 and the screw rod 3 through the oil inlet passage 30 for lubrication. The lubrication of the bearing 8 between the nut 2 and the tail plate 1 requires additional lubricating oil. Figure 1 .

[0007] This lubrication method requires separate operations for lubrication of the mating point between the nut 2 and the screw rod 4 and lubrication of the bearing 8, which results in complicated steps. Utility Model Content

[0008] The utility model aims at the disadvantages in the prior art that lubrication of the matching position between the nut and the screw rod and lubrication of the bearing need to be operated separately, and provides a screw transmission mechanism for an injection molding machine.

[0009] In order to solve the above technical problems, the utility model is solved by the following technical solutions:

[0010] A screw transmission mechanism for an injection molding machine comprises a fixed tail plate, a nut rotatably arranged in the tail plate, a screw rod matched with the screw nut thread and axially reciprocatingly moving with the rotation of the nut, and a lubricating structure for lubricating the matching position of the screw rod and the nut. The lubricating structure comprises an oil filling port opened on the tail plate and connected with the outer surface of the nut, an oil inlet channel which can be connected or staggered with the oil filling port and penetrates the inner and outer surfaces of the nut with the rotation of the nut, and an oil outlet channel arranged on the screw rod and can guide the lubricating oil on the inner surface of the nut from the end of the screw rod. A first rotating sealing structure and a second rotating sealing structure for limiting the overflow of the lubricating oil are respectively arranged between the nut and the tail plate and between the nut and the screw rod.

[0011] With the above solution, the lubricating oil flows in from the oil filling port, passes through the oil passage and the oil inlet passage, and then enters the fitting place between the screw rod and the nut for lubrication. The lubricating oil lubricates the bearing when passing through the oil passage, and the excess lubricating oil flows out of the screw rod through the oil outlet passage, waiting to be collected. The collected lubricating oil can repeat the above steps again for lubrication. Due to the presence of the first rotary seal structure and the second rotary seal structure, the flow path of the lubricating oil forms a sealed circulation loop, and there is no need to control the amount of lubricating oil added. After multiple cycles of the lubricating oil in the circulation loop, the bearing and the screw rod and the nut can be fully lubricated, and the lubricating oil can be recycled to avoid waste.

[0012] Preferably, the outer ring of the bearing is interference-embedded in the tail plate and the inner ring of the bearing is interference-sleeved outside the nut, and an assembly structure for limiting the bearing and the nut from moving axially along the nut is provided between the nut and the tail plate. The assembly structure includes a retaining ring protruding outwardly on the outer ring wall of the nut and used to limit the axial movement of the inner ring of the bearing, and a pressing component that presses the bearing against the retaining ring and the tail plate when the bearing is installed between the nut and the tail plate, and an oil passage is provided between the retaining ring and the pressing component.

[0013] With the above solution, the bearing ensures the stability of the nut's rotation, the pressing component cooperates with the tail plate to clamp the outer ring of the bearing to prevent the bearing from moving relative to the nut along the axial direction; the pressing component cooperates with the retaining ring to clamp the inner ring of the bearing to prevent the screw rod from moving relative to the bearing along the axial direction of the nut, thereby limiting the movement of the bearing and the nut along the axial direction of the nut. The setting of the oil passage ensures that the lubricating oil can enter the oil inlet channel from the oil filling port through the oil passage, and the lubricating oil can also lubricate the bearing when passing through the oil passage, so that the lubrication of the bearing does not need to be performed additionally, reducing the workload.

[0014] Preferably, two bearings are arranged at intervals, and the two opposite sides of the inner rings of the two bearings are respectively abutted against the retaining ring and the pressure component, and a rotating support ring is arranged between the opposite sides of the inner rings of the two bearings, which is sleeved on the outside of the nut and abutted against the inner rings of the two bearings at both ends; the two opposite sides of the outer rings of the two bearings are respectively abutted against the tail plate and the pressure component, and a fixed support ring is arranged between the opposite sides of the outer rings of the two bearings, which is sleeved on the outside of the rotating support ring and abutted against the outer rings of the two bearings at both ends; a first oil inlet hole connected to the oil filling port is arranged on the fixed support ring, and a second oil inlet hole connected to the oil inlet channel is arranged on the rotating support ring; the oil passage is located between the two bearings and is used to guide the lubricating oil introduced into the first oil inlet hole out of the second oil inlet hole.

[0015] With the above scheme, two bearings are arranged at intervals to ensure the stable rotation of the nut. There is a gap between the two bearings for the passage of lubricating oil. To ensure the limit of the two bearings, a rotating support ring and a fixed support ring are arranged between the two bearings to limit the two bearings to be close to each other. The two bearings and the nut are limited to move along the axial direction of the nut by the extrusion component, the tail plate and the retaining ring. The inner ring of the bearing and the rotating support ring are always synchronized with the nut, and the outer ring of the bearing and the fixed support ring are always relatively stationary with the tail plate. The gap between the outer ring wall of the rotating support ring and the inner ring wall of the fixed support ring is the oil passage. The second oil inlet hole and the first oil inlet hole are respectively arranged on the rotating support ring and the fixed support ring. After the lubricating oil enters from the oil filling port, it passes through the first oil inlet hole, the oil passage and the second oil inlet hole in sequence and enters the oil inlet channel.

[0016] Preferably, the pressing component includes a pressure ring for pressing and limiting the axial displacement of the outer ring of the bearing relative to the tail plate, and a pressing piece for pressing and limiting the axial displacement of the nut relative to the inner ring of the bearing. The pressure ring is sealed and fixed to the tail plate and abuts against the outer ring of the bearing away from the retaining ring. The pressing piece includes a pressing sleeve with a sealing sleeve arranged outside the nut and a pushing nut threadedly engaged on the outer ring wall of the nut for pushing the pressing sleeve.

[0017] With the above solution, after the pressure ring is fixed on the tail plate, it cooperates with the tail plate to clamp the two bearing outer rings and the fixed support ring, limiting the axial displacement of the bearing outer ring relative to the tail plate. The jacking nut pushes into the jacking sleeve, and the two bearing inner rings and the rotating support ring are pressed against the retaining ring through the jacking sleeve, limiting the axial displacement of the nut relative to the bearing inner ring. The pressure ring and the tail plate are sealed, and the jacking sleeve and the nut are sealed to prevent the lubricating oil from overflowing from between the tail plate and the pressure ring, and between the jacking sleeve and the nut.

[0018] Preferably, the first rotating sealing structure includes a first sealing ring which is sleeved outside the nut and has its two ends respectively in contact with the retaining ring and the tail plate, and a compensating sealing structure which is arranged between the pressure ring, the tail plate, the top pressure sleeve and the nut and realizes a rotating seal among the four while compensating for the axial installation error of the bearing.

[0019] By adopting the above solution, the first sealing ring prevents the lubricating oil from overflowing from between the retaining ring and the tail plate, and the compensating sealing structure ensures that the nut and the top pressing sleeve can rotate relative to the pressing ring while preventing the lubricating oil from overflowing from between the top pressing sleeve and the pressing ring.

[0020] Preferably, the compensating sealing structure includes a sealing sleeve arranged on a movable ring on the outer ring wall of the top pressure sleeve, and an elastic member at both ends respectively fixed to the top pressure sleeve and the movable ring and driving the movable ring to elastically seal against the pressure ring. Several elastic members are evenly spaced around the outer circumference of the top pressure sleeve.

[0021] With the above scheme, there will be precision errors in the production of parts such as the pressure ring, top pressure sleeve and movable ring. Therefore, an elastic member is arranged between the movable ring and the top pressure sleeve to ensure that the movable ring is always elastically in contact with the inner wall of the pressure ring, and the elasticity of the elastic member compensates for the error during installation. Several elastic members connect the movable ring and the top pressure sleeve. When the top pressure sleeve rotates with the nut, the movable ring rotates at the same time and rotates relative to the pressure ring. The elastic member and the lubricating oil medium pressure generate a clamping force on the movable ring and the pressure ring, so that the end faces of the movable ring and the pressure ring fit together to form an extremely thin oil film to prevent the lubricating oil from overflowing from between the movable ring and the pressure ring, thereby realizing the sealed rotation between the movable ring and the pressure ring; the movable ring sealing sleeve is arranged on the outer ring wall of the top pressure sleeve to prevent the lubricating oil from overflowing from between the top pressure sleeve and the movable ring.

[0022] Preferably, a static ring with a flat end portion for sealing against the dynamic ring is embedded in the side of the pressure ring facing the dynamic ring, and an anti-rotation pin is inserted between the pressure ring and the static ring to limit their relative deflection.

[0023] With the above solution, in the actual production and installation process, the abutment surface between the dynamic ring and the pressure ring is generally not very smooth, resulting in a decrease in sealing ability. Therefore, a static ring is provided, and the static ring is relatively still with the pressure ring through an anti-rotation pin, and the static ring seal is embedded in the pressure ring to prevent the lubricating oil from overflowing from between the static ring and the dynamic ring. The dynamic ring elastically abuts against the static ring, and the elastic member and the lubricating oil medium pressure generate a clamping force on the dynamic ring and the static ring, so that the end faces of the dynamic ring and the static ring fit together to form an extremely thin oil film, which prevents the lubricating oil from overflowing from between the dynamic ring and the static ring, and realizes the sealed rotation between the dynamic ring and the static ring.

[0024] Preferably, a filter screen is arranged in the first oil inlet hole and / or the second oil inlet hole.

[0025] By adopting the above scheme, when the lubricating oil is circulated, the filter can effectively prevent impurities from entering between the nut and the screw rod, and when the filter is arranged on the first oil inlet hole, it can also prevent impurities from entering the oil passage, thereby protecting the bearing.

[0026] Preferably, the second rotary sealing structure includes oil seals respectively arranged at both ends of the mating point between the nut and the screw rod.

[0027] By adopting the above solution, the lubricating oil is prevented from overflowing from between the nut and the screw rod by means of the oil seals arranged in two sections.

[0028] Preferably, the oil filling port is located below the nut, an exhaust port connected to the outside is provided on the tail plate between the first sealing ring and the pressing component, the exhaust port is located above the nut, and a screw plug is provided on the exhaust port to open or close the exhaust port.

[0029] With the above solution, the lubricating oil enters from the bottom of the nut, increasing the time the lubricating oil stays and fully lubricating it. The exhaust port is set above the nut to reduce the possibility of lubricating oil overflowing. When the internal pressure of the lubricating structure increases, the exhaust port can be opened for exhaust, and then sealed and closed after exhaust.

[0030] The utility model has significant technical effects due to the adoption of the above technical scheme: the lubricating oil passes through the oil filling port, the oil passage and the oil inlet channel, enters between the screw rod and the nut for lubrication, and then flows out of the screw rod through the oil outlet channel for collection. The collected lubricating oil can repeat the above steps again. The flow path of the lubricating oil forms a sealed circulation loop, and there is no need to control the amount of lubricating oil added. After the lubricating oil circulates in the circulation loop for multiple times, sufficient lubrication between the screw rod and the nut can be guaranteed, and the lubricating oil can be recycled to avoid waste. In addition, the lubricating oil can also lubricate the bearings when passing through the oil passage, so that the lubrication of the bearings does not need to be performed additionally, thereby simplifying the operating steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a half-section schematic diagram of the lubrication method between the nut and the screw rod in the prior art;

[0032] Figure 2 is a partial cross-sectional view of a screw transmission mechanism for an injection molding machine in an embodiment;

[0033] Figure 3 yes Figure 2 A in the enlarged view;

[0034] Figure 4 yes Figure 3 The enlarged view of point B in the figure;

[0035] Figure 5 This is a partial exploded view of a screw transmission mechanism for an injection molding machine in an embodiment;

[0036] Figure 6 It is a partial schematic diagram of a side away from a thrust seat in a screw transmission mechanism for an injection molding machine in an embodiment;

[0037] Figure 7 yes Figure 6 A partial schematic diagram when no synchronous pulley is provided.

[0038] The names of the parts indicated by the numerical labels in the above drawings are as follows: 1. tail plate; 2. nut; 3. screw rod; 4. thrust seat; 5. oil filling port; 6. oil inlet channel; 7. oil outlet channel; 8. bearing; 9. retaining ring; 10. rotating support ring; 11. fixed support ring; 12. first oil inlet hole; 13. second oil inlet hole; 14. oil passage; 15. pressure ring; 1501, second sealing ring; 16. top pressure sleeve; 1601, third sealing ring; 17. top nut; 18. first sealing ring; 19. dynamic ring; 1901, fourth sealing ring; 20. elastic member; 21. static ring; 2101, fifth sealing ring; 22. anti-rotation pin; 23. filter screen; 24. oil seal; 25. exhaust port; 26. through groove; 27. first groove; 28. second groove; 29. ​​temperature sensor; 30. oil inlet pipeline; 31. synchronous pulley. DETAILED DESCRIPTION

[0039] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0040] Example

[0041] A screw drive mechanism for an injection molding machine, referring to Figures 2 to 7 , including a fixed tail plate 1, a nut 2 with one end inserted into the tail plate 1 and rotatably connected to the tail plate 1 and the other end located outside the tail plate 1, a screw rod 3 threadedly matched with the inner thread wall of the screw rod 2 and axially reciprocatingly moving with the rotation of the screw rod 2, and a lubricating structure for lubricating the screw rod 3 and the screw rod 2. One end of the screw rod 3 is fixedly connected to the thrust seat 4, and the end of the screw rod 3 away from the thrust seat 4 is provided with a stopper to prevent the screw rod 3 from being separated from the screw rod 2. A synchronous pulley 31 is coaxially fixedly sleeved on the outer ring wall of the end of the screw nut 2 located outside the tail plate 1. The rotation of the synchronous pulley 31 drives the screw nut 2 to rotate synchronously, driving the screw rod 3 to reciprocate linearly along its axial direction, thereby driving the thrust seat 4 to move linearly close to or away from the tail plate 1. The driving method for driving the synchronous pulley 31 to rotate is an existing technology. The common driving method is to achieve a transmission connection through the cooperation between the motor, the synchronous belt and the synchronous pulley 31. When the motor rotates, the synchronous belt drives the synchronous pulley 31 to rotate. The above-mentioned driving method is a prior art, which is not shown in the figure and will not be described in detail here.

[0042] The nut 2 and the tail plate 1 are rotatably connected via a bearing 8. A first groove 27 is concavely provided on the tail plate 1. A second groove 28 is concavely provided at the bottom of the first groove 27. The first groove 27 and the second groove 28 are both coaxially arranged with the nut 2 and the diameter of the second groove 28 is smaller than the diameter of the first groove 27. The end of the nut 2 away from the synchronous pulley 31 passes through the first groove 27 and is located in the second groove 28. The bearing 8 is arranged in the first groove 27, the outer ring of the bearing 8 is interference-embedded in the first groove 27 of the tail plate 1, and the inner ring of the bearing 8 is interference-sleeved outside the nut 2. In this embodiment, the bearing 8 is a ball bearing, including an outer ring of the bearing 8, an inner ring of the bearing 8, and a retainer and a ball disposed between the outer ring of the bearing 8 and the inner ring of the bearing 8, so as to realize the rotational cooperation between the inner ring of the bearing 8 and the outer ring of the bearing 8. The ball bearing is a prior art, so it is simply illustrated in the figure and will not be described in detail here.

[0043] An assembly structure for limiting the axial movement of the bearing 8 and the nut 2 along the nut 2 is provided between the nut 2 and the tail plate 1. The assembly structure includes a retaining ring 9 protruding outwardly on the outer ring wall of the nut 2 in the second groove 28. An extrusion component is also provided between the nut 2 and the tail plate 1. After the bearing 8 is installed in the first groove 27, the extrusion component presses the outer ring of the bearing 8 against the bottom of the first groove 27, that is, the outer ring of the bearing 8 is clamped between the bottom of the first groove 27 and the extrusion component, limiting the axial movement between the outer ring of the bearing 8 and the tail plate 1; the extrusion component presses the inner ring of the bearing 8 against the retaining ring 9, that is, the inner ring of the bearing 8 is clamped between the retaining ring 9 and the extrusion component, limiting the axial movement between the nut 2 and the inner ring of the bearing 8. Thus, the axial movement of the bearing 8 and the nut 2 along the axial direction of the nut 2 is limited.

[0044] Two bearings 8 are arranged at intervals, and the two opposite sides of the inner rings of the two bearings 8 are respectively in contact with the retaining ring 9 and the pressing component, and a rotating support ring 10 is provided between the opposite sides of the inner rings of the two bearings 8, which is sleeved on the outside of the nut 2 and abutted with the inner rings of the two bearings 8 at both ends. The two opposite sides of the outer rings of the two bearings 8 are respectively in contact with the bottom of the first groove 27 of the tail plate 1 and the pressing component, and a fixed support ring 11 is provided between the opposite sides of the outer rings of the two bearings 8, which is sleeved on the outside of the rotating support ring 10 and abutted with the outer rings of the two bearings 8 at both ends.

[0045] The pressing component includes a pressure ring 15, which is sealed and fixed with the tail plate 1 and abuts against the outer ring of the bearing 8 far away from the retaining ring 9. At this time, the outer ring of the bearing 8 close to the retaining ring 9 abuts against the bottom of the first groove 27, and the pressure ring 15 and the bottom of the first groove 27 cooperate to limit the axial displacement of the outer ring of the bearing 8 relative to the tail plate 1. It also includes a top pressing sleeve 16 with a sealing sleeve arranged outside the nut 2 and a jacking nut 17 threadedly engaged with the outer ring wall of the nut 2 for pushing the top pressing sleeve 16, one end of the top pressing sleeve 16 away from the jacking nut 17 abuts against the inner ring of the bearing 8 far away from the retaining ring 9, and the inner ring of the bearing 8 close to the retaining ring 9 abuts against the retaining ring 9. The top pressing sleeve 16 cooperates with the retaining ring 9 to limit the axial displacement of the nut 2 relative to the inner ring of the bearing 8 under the limitation of the jacking nut 17. The pressure ring 15 and the tail plate 1 are fixedly connected by a bolt structure, which includes a threaded hole provided on the tail plate 1, a through hole provided on the pressure ring 15, and a bolt that passes through the through hole and is threadedly matched with the threaded hole. The method used for fixing with the bolt structure is the existing technology, which is not marked in the figure and will not be described here.

[0046] The lubrication structure includes an oil filling port 5 opened on the tail plate 1, an oil inlet channel 6 which can be connected or staggered with the oil filling port 5 as the nut 2 rotates and penetrates the inner and outer surfaces of the nut 2, and an oil outlet channel 7 provided on the screw rod 3 and can guide the lubricating oil on the inner surface of the nut 2 from the end of the screw rod 3. The oil outlet channel 7 includes a first flow channel coaxially recessed with the screw rod 3 on the end surface of one end of the screw rod 3 and a second flow channel provided perpendicular to the first flow channel in the screw rod 3 so as to communicate with the matching position of the screw rod 3 and the nut 2, and at least one second flow channel is provided at intervals along the axial direction of the screw rod 3. The oil filling port 5 is located below the nut 2.

[0047] The distance between the outer ring wall of the rotating support ring 10 and the inner ring wall of the fixed support ring 11 is the oil passage 14. The fixed support ring 11 is provided with a first oil inlet hole 12 for connecting the oil filling port 5 with the oil passage 14. The rotating support ring 10 is provided with a second oil inlet hole 13 for connecting the oil passage 14 with the oil inlet channel 6. A filter screen 23 is provided in the first oil inlet hole 12 and / or the second oil inlet hole 13. In this embodiment, the filter screen 23 is provided in the second oil inlet hole 13.

[0048] After the lubricating oil enters the oil filling port 5, it passes through the first oil inlet hole 12, the oil passage 14, the second oil inlet hole 13 and the oil inlet passage 6 in sequence, and finally flows out through the oil outlet passage 7 to wait for collection. The collected lubricating oil can repeat the above steps again for lubrication. In the prior art, the oil can be pumped to the oil filling port 5 by an oil pump, and the lubricating oil flowing out through the oil outlet passage 7 can also flow into the collection box through a connecting pipe for collection. The other end of the oil pump is connected to the collection box. The oil pump, the connecting pipe and the collection box are all prior art, which are not shown in the figure and will not be described here.

[0049] A first rotary sealing structure for limiting the overflow of lubricating oil is provided between the nut 2 and the tail plate 1. The first rotary sealing structure comprises a first sealing ring 18 sleeved outside the nut 2 and having two ends respectively in contact with the retaining ring 9 and the tail plate 1. In this embodiment, the first sealing ring 18 is fixedly provided on the inner ring wall of the second groove 28, and the inner ring wall of the first sealing ring 18 close to the retaining plate is elastically abutted against the outer ring wall of the retaining ring 9, and the retaining ring 9 can rotate relative to the first sealing ring 18 in a sealed manner.

[0050] A stationary ring 21 is sealed and embedded in the pressure ring 15, and an anti-rotation pin 22 is inserted between the pressure ring 15 and the stationary ring 21 to limit the relative deflection of the two. A dynamic ring 19 is provided on the sealing sleeve on the outer ring wall of the top pressure sleeve 16, and an elastic member 20 is arranged between the dynamic ring 19 and the top pressure sleeve 16 along the axial direction of the screw rod 3. The two ends of the elastic member 20 are respectively fixed to the top pressure sleeve 16 and the dynamic ring 19 and drive the dynamic ring 19 to elastically seal against the stationary ring 21. Several elastic members 20 are evenly spaced around the outer circumference of the top pressure sleeve 16. In this embodiment, the elastic member 20 is a spring. The nut 2 rotates, driving the top pressure sleeve 16 and the dynamic ring 19 to rotate, and the stationary ring 21 and the pressure ring 15 are stationary on the tail plate 1, so the dynamic ring 19 rotates relative to the static ring 21 and prevents the lubricating oil from overflowing from the abutment surface of the dynamic ring 19 and the stationary ring 21 in the first groove 27.

[0051] A second sealing ring 1501 is provided between the compression ring 15 and the tail plate 1. The second sealing ring 1501 is fixed on the compression ring 15 and is circumferentially arranged around the first groove 27. The side of the second sealing ring 1501 away from the compression ring 15 is in sealing contact with the tail plate 1 to prevent lubricating oil from escaping from the first groove 27 from the fitting surface of the compression ring 15 and the tail plate 1. In order to ensure the sealing effect of the second sealing ring 1501, the second sealing ring 1501 needs to be provided between the first groove 27 and the bolt structure that fixes the compression ring 15 and the tail plate 1.

[0052] A third sealing ring 1601 is arranged between the nut 2 and the top pressing sleeve 16. The third sealing ring 1601 is fixed on the inner ring wall of the top pressing sleeve 16, and the inner ring wall of the third sealing ring 1601 is sealed against the outer ring wall of the nut 2 to prevent the lubricating oil from overflowing from the fitting surface of the nut 2 and the top pressing sleeve 16 from the first groove 27.

[0053] A fourth sealing ring 1901 is arranged between the dynamic ring 19 and the top pressure sleeve 16. The fourth sealing ring 1901 is fixed on the inner ring wall of the dynamic ring 19, and the inner ring wall of the fourth sealing ring 1901 is sealed against the outer ring wall of the top pressure sleeve 16 to prevent the lubricating oil from overflowing from the fitting surface of the dynamic ring 19 and the top pressure sleeve 16 from the first groove 27.

[0054] A fifth sealing ring 2101 is arranged between the stationary ring 21 and the pressure ring 15. The fifth sealing ring 2101 is fixed on the inner wall of the pressure ring 15, and the side of the fifth sealing ring 2101 away from the pressure ring 15 is sealed against the side wall of the stationary ring 21 away from the dynamic ring 19 to prevent the lubricating oil from overflowing from between the stationary ring 21 and the pressure ring 15 from the first groove 27.

[0055] A second rotary sealing structure for limiting the lubricating oil overflow is provided between the nut 2 and the screw rod 3. The second rotary sealing structure includes oil seals 24 respectively provided at both ends of the mating part of the nut 2 and the screw rod 3, and the inner ring wall of the oil seal 24 is elastically embedded and rotatably matched with the threaded outer surface of the screw rod 3 to prevent the lubricating oil from overflowing from between the nut 2 and the screw rod 3.

[0056] An exhaust port 25 connected to the outside is provided between the first sealing ring 18 and the pressing component on the tail plate 1. The exhaust port 25 is located above the nut 2. A screw plug that can open or close it is provided on the exhaust port 25. The screw plug is a prior art, not shown in the figure, and will not be described in detail here. In this embodiment, three groups of exhaust ports 25 and screw plugs are provided. The three exhaust ports 25 are respectively provided between the first sealing ring 18 and the bearing 8 close to the retaining ring 9, between the two bearings 8, and between the bearing 8 far from the retaining ring 9 and the pressure ring 15. A through groove 26 is provided on the fixed support ring 11 to connect the exhaust port 25 above it with the oil passage 14.

[0057] A temperature sensor 29 for real-time temperature monitoring is provided at the end of the nut 2. The temperature sensor 29 signal is electrically connected to the control module, and the control module is electrically connected to the oil pump signal. When the temperature reaches or exceeds the preset value, the control module controls the oil pump to inject oil into the oil injection port 5; conversely, when the temperature is lower than the preset value, the control module controls the oil pump to stop injecting oil into the oil injection port 5. The connection method and control method between the control module, the temperature sensor 29 and the oil pump are all prior art, which are not shown in the figure and will not be described here.

[0058] A bearing 8, a fixed support ring 11, a rotating support ring 10 and another bearing 8 are sequentially installed in the first groove 27, and then the top pressing sleeve 16 is sealed and sleeved on the nut 2, and the pressure ring 15 is sleeved on the top pressing sleeve 16, and the top pressing sleeve 16 is abutted against the inner ring of the bearing 8 away from the retaining ring 9 through the nut, and finally the pressure ring 15 is sealed and fixed on the tail plate 1, so that the pressure ring 15 abuts against the outer ring of the bearing 8 away from the retaining ring 9. That is, the outer rings of the two bearings 8 and the fixed support ring 11 are pressed between the bottom of the first groove 27 and the pressure ring 15, limiting the relative movement between the outer rings of the bearing 8 and the tail plate 1; the inner rings of the two bearings 8 and the rotating support ring 10 are pressed between the retaining ring 9 and the top pressing sleeve 16, limiting the relative movement between the inner ring of the bearing 8 and the nut 2, thereby limiting the axial movement of the bearing 8 and the nut 2. The outer ring of the bearing 8 is inserted into the first groove 27 and the inner ring of the bearing 8 is sleeved outside the nut 2, ensuring that the outer ring of the bearing 8 and the fixed support frame are stationary relative to the tail plate 1, and the inner ring of the bearing 8 and the rotating support frame are stationary relative to the nut 2. After assembly, the first oil inlet hole 12 is opposite to the oil filling port 5, and the second oil inlet hole 13 is opposite to the oil inlet channel 6. In addition, the stationary ring 21 on the pressure ring and the dynamic ring 19 on the jacking sleeve are elastically abutted. After the lubricating oil enters the oil filling port 5, it passes through the first oil inlet hole 12, the oil passage 14, the second oil inlet hole 13 and the oil inlet passage 6 in sequence, and finally flows out through the oil outlet passage 7. During this flow process, the two bearings 8 and the fitting parts of the nut 2 and the screw rod 3 can be lubricated. In addition, due to the presence of the first sealing ring 18, the second sealing ring 1501, the third sealing ring 1601, the fourth sealing ring 1901, the fifth sealing ring 2101, the oil seal 24 and the elastically abutted dynamic ring 19 and the static ring 21, the leakage of the lubricating oil during flow is prevented.

[0059] The above is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A screw transmission mechanism for an injection molding machine, comprising a fixed tail plate (1), a nut (2) rotatably connected to the tail plate (1) through a bearing (8), and a screw rod (3) threadably matched with the nut (2) and axially reciprocating with the rotation of the nut (2), characterized in that: A lubrication structure capable of simultaneously lubricating the bearing (8) and the fitting position between the screw rod (3) and the screw rod (2) is arranged between the tail plate (1), the nut (2) and the screw rod (3). The lubrication structure comprises an oil filling port (5) provided on the tail plate (1), an oil passage (14) provided between the tail plate (1) and the screw rod (2) and communicating with the oil filling port (5) and the outer surface of the screw rod (2) and communicating with the bearing (8), an oil inlet channel (6) which can be connected or staggered with the oil passage channel (14) as the screw rod (2) rotates and passes through the inner and outer surfaces of the screw rod (2), and an oil outlet channel (7) provided on the screw rod (3) and capable of guiding the lubricating oil on the inner surface of the screw rod (2) from the end of the screw rod (3). A first rotary sealing structure and a second rotary sealing structure for limiting the overflow of the lubricating oil are provided between the screw rod (2) and the tail plate (1) and between the screw rod (2) and the screw rod (3), respectively.

2. A screw transmission mechanism for an injection molding machine according to claim 1, characterized in that: The outer ring of the bearing (8) is interference-embedded in the tail plate (1) and the inner ring of the bearing (8) is interference-sleeved outside the nut (2). An assembly structure for limiting the bearing (8) and the nut (2) from axial movement along the nut (2) is provided between the nut (2) and the tail plate (1). The assembly structure comprises a retaining ring (9) protruding outwardly on the outer ring wall of the nut (2) for limiting the axial movement of the inner ring of the bearing (8) and a pressing component for pressing the bearing (8) against the retaining ring (9) and the tail plate (1) when the bearing (8) is installed between the nut (2) and the tail plate (1). An oil passage (14) is provided between the retaining ring (9) and the pressing component.

3. A screw transmission mechanism for an injection molding machine according to claim 2, characterized in that: Two bearings (8) are arranged at intervals, and the inner rings of the two bearings (8) are respectively in contact with the retaining ring (9) and the pressing component on the opposite sides thereof, and a rotating support ring (10) is arranged between the opposite sides of the inner rings of the two bearings (8), which is sleeved on the outside of the nut (2) and in contact with the inner rings of the two bearings (8) at both ends; the outer rings of the two bearings (8) are respectively in contact with the tail plate (1) and the pressing component on the opposite sides thereof, and a fixed support ring (11) is arranged between the opposite sides of the outer rings of the two bearings (8), which is sleeved on the outside of the rotating support ring (10) and in contact with the outer rings of the two bearings (8) at both ends; a first oil inlet hole (12) communicating with the oil filling port (5) is arranged on the fixed support ring (11), and a second oil inlet hole (13) communicating with the oil inlet channel (6) is arranged on the rotating support ring (10); an oil passage (14) is located between the two bearings (8) and is used to guide the lubricating oil introduced into the first oil inlet hole (12) out of the second oil inlet hole (13).

4. A screw transmission mechanism for an injection molding machine according to claim 3, characterized in that: The pressing component comprises a pressure ring (15) for pressing and limiting the axial displacement of the outer ring of the bearing (8) relative to the tail plate (1) and a pressing piece for pressing and limiting the axial displacement of the nut (2) relative to the inner ring of the bearing (8). The pressure ring (15) is sealed and fixed to the tail plate (1) and abuts against the outer ring of the bearing (8) away from the retaining ring (9). The pressing piece comprises a pressing sleeve (16) with a sealing sleeve arranged outside the nut (2) and a pushing nut (17) threadedly engaged on the outer ring wall of the nut (2) for pushing the pressing sleeve (16).

5. A screw transmission mechanism for an injection molding machine according to claim 4, characterized in that: The first rotary seal structure comprises a first seal ring (18) which is sleeved outside the nut (2) and has two ends respectively fitted with a retaining ring (9) and a tail plate (1), and a compensating seal structure which is arranged between the pressure ring (15), the tail plate (1), the top pressure sleeve (16) and the nut (2) and realizes a rotary seal among the four while compensating for an axial installation error of the bearing (8).

6. A screw transmission mechanism for an injection molding machine according to claim 5, characterized in that: The compensating seal structure comprises a seal sleeve arranged on a movable ring (19) on the outer ring wall of a top pressure sleeve (16), and an elastic member (20) whose two ends are respectively fixed to the top pressure sleeve (16) and the movable ring (19) and drives the movable ring (19) to elastically seal against the pressure ring (15), and a plurality of elastic members (20) are evenly spaced around the outer circumference of the top pressure sleeve (16).

7. A screw transmission mechanism for an injection molding machine according to claim 6, characterized in that: A static ring (21) having a flat end and used for sealingly contacting the dynamic ring (19) is embedded in the pressure ring (15) on one side facing the dynamic ring (19) and an anti-rotation pin (22) is inserted between the pressure ring (15) and the static ring (21) to limit the relative deflection of the two.

8. The screw transmission mechanism for an injection molding machine according to claim 3, characterized in that: A filter screen (23) is arranged in the first oil inlet hole (12) and / or the second oil inlet hole (13).

9. The screw transmission mechanism for an injection molding machine according to claim 1, characterized in that: The second rotary sealing structure comprises oil seals (24) respectively arranged at both ends of the matching position of the nut (2) and the screw rod (3).

10. The screw transmission mechanism for an injection molding machine according to claim 5, characterized in that: The oil filling port (5) is located below the nut (2); an exhaust port (25) communicating with the outside is provided on the tail plate (1) between the first sealing ring (18) and the pressing component; the exhaust port (25) is located above the nut (2); and a screw plug capable of opening or closing the exhaust port (25) is provided on the exhaust port (25).

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