Single-cylinder injection structure of injection molding machine

Abstract

The invention discloses a single-cylinder injection structure of an injection molding machine. The single-cylinder injection structure comprises a screw rod, a front cylinder cover, a mandrel, a rotary supporting piece, an outer cylinder barrel, a piston barrel, an inner cylinder barrel, a transmission shaft, a rear cylinder cover and a motor, the front end of the mandrel is connected with the screw, a connecting cavity is formed in the rear end of the mandrel, the front end of the transmission shaft is inserted into the connecting cavity, the mandrel is sleeved with the inner cylinder barrel, the inner cylinder barrel is sleeved with the piston barrel, the rotary supporting piece is arranged between the piston barrel and the mandrel, and the piston barrel is located in the outer cylinder barrel and can axially move relative to the outer cylinder barrel. An ejection retreating cavity is formed between the outer cylinder barrel and the piston barrel, the front cylinder cover is fixed to the front end of the outer cylinder barrel, the rear cylinder cover is fixed to the rear end of the outer cylinder barrel and connected with the inner cylinder barrel, an injection cavity is formed between the rear cylinder cover and the piston barrel and communicated with an inner cavity of the inner cylinder barrel and the connecting cavity through a flow channel, and the transmission shaft is in transmission connection with the motor. According to the single-cylinder injection structure, the requirement for the sealing ring is lowered, and the size of the oil cylinder can be smaller on the premise that the injection force is met.

Description

Technical Field

[0001] This invention belongs to the field of injection molding machine technology, and specifically relates to a single-cylinder injection structure for an injection molding machine. Background Technology

[0002] In the single-cylinder injection structure of an injection molding machine, the injection cylinder, as the core power component of the injection molding machine, not only needs to provide axial thrust to the screw, that is, to push the screw to inject molten plastic into the mold cavity at high speed and high pressure during the injection process; but the piston rod of the injection cylinder also needs to transmit the plasticizing motion, that is, to transmit the rotational motion of the plasticizing motor during the material storage process, drive the screw to rotate, and combine with the back pressure control of the cylinder to complete the plasticizing and melting of the plastic raw material.

[0003] In existing single-cylinder injection structures, such as Figure 1 As shown, the front end of the piston cylinder 6 is fixedly connected to the screw 1, and the rear end of the piston cylinder 6 is sleeved on the front end of the drive shaft 8. The piston cylinder 6 and the drive shaft 8 are connected by a spline. The rear end of the drive shaft 8 is connected to the motor 10. The outer cylinder 5 is sleeved on the outside of the piston cylinder 6. The piston cylinder 6 can move axially and rotate circumferentially within the outer cylinder 5. The front end of the outer cylinder 5 is fixed with a front cylinder cover 2. A first sealing ring 11 is provided between the front cylinder cover 2 and the piston cylinder 6. A second sealing ring 12 is provided between the rear end of the piston cylinder 6 and the outer cylinder 5. When the equipment is storing material, the motor 10 drives the drive shaft 8 to rotate. The drive shaft 8 drives the piston cylinder 6 to rotate through the spline. The piston cylinder 6 drives the screw 1 to rotate. The screw 1 retracts under the push of the front melt, so that the piston cylinder 6 rotates and retracts at the same time. When the equipment is injecting, pressurized oil is injected through the oil port to push the piston cylinder 6 forward, which in turn pushes the screw 1 forward, injecting molten plastic into the mold. Throughout the injection process, the first sealing ring 11 and the second sealing ring 12 must ensure both rotational sealing and axial sliding sealing. This results in extremely high requirements for the sealing rings. However, there are very few brands of large-sized rotary reciprocating sealing rings available on the market for large single cylinders, the ordering cycle is very long, and the price is very expensive. In addition, the sealing rings in this single-cylinder injection structure are prone to damage and failure, which can cause internal and external leakage in the cylinder. Internal leakage will greatly reduce the injection and pressure holding accuracy, while external leakage will waste hydraulic oil, pollute the environment, and require a lot of manpower and resources for maintenance. Summary of the Invention

[0004] To address the aforementioned problems, this invention discloses a single-cylinder injection structure for an injection molding machine, which overcomes or at least partially solves the problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention discloses a single-cylinder injection structure for an injection molding machine, including a screw, a front cylinder head, a mandrel, a rotating support, an outer cylinder, a piston cylinder, an inner cylinder, a drive shaft, a rear cylinder head, and a motor; The front end of the mandrel is fixedly connected to the screw. The rear end of the mandrel has an axially formed connecting cavity. The front end of the drive shaft is inserted into the connecting cavity and connected to the mandrel via a spline. The inner cylinder is sleeved on the mandrel, and the piston cylinder is sleeved on the inner cylinder. The rotating support is disposed between the front part of the piston cylinder and the mandrel, allowing the mandrel to rotate within the piston cylinder. A first sealing ring is provided between the front end of the piston cylinder and the mandrel. The piston cylinder is located within the outer cylinder and can move axially relative to the outer cylinder. The rear end of the piston cylinder and the... A second sealing ring is provided between the outer cylinder and the piston cylinder, and an injection chamber is formed between the outer cylinder and the piston cylinder. The front cylinder head is fixed to the front end of the outer cylinder, and a third sealing ring is provided between the front cylinder head and the piston cylinder. The rear cylinder head is fixed to the rear end of the outer cylinder and is fixedly connected to the rear end of the inner cylinder. An injection chamber is formed between the rear cylinder head and the piston cylinder. The injection chamber communicates with the inner cavity of the inner cylinder and the connecting cavity through a flow channel. The rear end of the drive shaft passes through the rear cylinder head and is connected to the motor for transmission. A fourth sealing ring is provided between the rear cylinder head and the drive shaft.

[0006] Furthermore, it also includes a front cover and a rear cover; The front end cover is fixed to the front end of the piston cylinder, and the first sealing ring is disposed between the front end cover and the spindle; the rear end cover is fixed to the rear cylinder cover, and the fourth sealing ring is disposed between the rear end cover and the drive shaft.

[0007] Furthermore, a first boss is formed on the inner circumference of the front part of the piston cylinder, and a second boss is formed on the outer circumference of the front part of the spindle, with the second boss located in front of the first boss. The rotating support includes a first sliding plate and a second sliding plate; the first sliding plate is located between the first boss and the second boss, and the second sliding plate is located between the front end cover and the second boss.

[0008] Furthermore, it also includes guide rings; The guide ring is fixed to the inner circumference of the inner cylinder and sleeved on the outside of the mandrel, serving as a guide for the mandrel when it moves axially relative to the inner cylinder.

[0009] Furthermore, it also includes a connecting ring sleeve, two semi-circular pressure plates, two threaded sleeves, two bushings, and two screws; An annular groove is formed on the screw, and two semi-annular pressure plates can be inserted into the annular groove. A through hole is radially formed at the center of each of the two semi-annular pressure plates. Two bushings are located within the two through holes. A connecting ring is sleeved on the outside of the two semi-annular pressure plates. The connecting ring has two threaded holes corresponding to the positions of the two through holes. Each screw sleeve passes through the corresponding threaded hole from the outside of the connecting ring and is fixedly connected to a screw that passes through the bushing and the through hole from the inside of the semi-annular pressure plate. A first external thread is formed on the outer circumference of the screw sleeve to mate with the threaded hole. A second external thread is formed on the outer circumference of the front end of the mandrel. An internal thread is formed on the connecting ring sleeve to mate with the second external thread. When the connecting ring sleeve is rotated and fixed on the mandrel, both semi-annular pressure plates abut against the front end face of the mandrel.

[0010] Furthermore, it also includes an annular pressure plate and a buffer structure; wherein the annular pressure plate is formed by splicing two semi-annular pressure plates; The front end of the mandrel has a receiving groove, the rear end of the screw is inserted into the receiving groove, the annular pressure plate is sleeved on the shoulder of the screw and fixedly connected to the mandrel; the buffer structure is located in the receiving groove and includes a support column, an elastic element and a fixing block; the fixing block is fixed to the bottom of the receiving groove, the support column abuts between the rear end of the screw and the fixing block, and the elastic element is disposed between the support column and the fixing block and has a compression preload.

[0011] Furthermore, a third boss is formed on the outer circumference of the front end of the piston cylinder, and the second sealing ring is disposed between the third boss and the outer cylinder.

[0012] Furthermore, it also includes an injection port; The injection seat is fixed to the front end of the outer cylinder, the front cylinder cover is fixed to the injection seat, and a crash plate is fixed to the rear end face of the injection seat. The crash plate is located in the ejection cavity and corresponds to the position of the third protrusion.

[0013] Furthermore, it also includes the middle end cap; The middle end cap is fixed to the front end of the inner cylinder, and a fifth sealing ring is provided between the middle end cap and the mandrel.

[0014] Furthermore, the outer cylinder is provided with a first exhaust channel, and the ejection chamber is connected to the external environment through the first exhaust channel. The rear cylinder head is provided with a second exhaust channel, and the injection chamber is connected to the external environment through the second exhaust channel.

[0015] Furthermore, the rear end of the drive shaft is connected to the motor via a spline.

[0016] The advantages and beneficial effects of this invention are: In the single-cylinder injection structure of this invention, the axial movement and circumferential rotation of the screw are decomposed into the axial movement of the piston cylinder relative to the outer cylinder and the circumferential rotation of the mandrel relative to the piston cylinder. This allows the first sealing ring between the mandrel and the piston cylinder to only perform rotational sealing, and the second and third sealing rings between the piston cylinder and the outer cylinder and the front cylinder head to only perform axial sliding sealing. This reduces the requirements for the sealing rings and decreases the risk of damage to them, thereby reducing the failure rate and subsequent maintenance costs. Furthermore, by connecting the injection chamber to the inner cavity of the inner cylinder and the connecting cavity through the flow channel, hydraulic oil can enter the interior of the inner cylinder and the connecting cavity during injection, expanding the compression area of ​​the hydraulic oil. This allows the screw to output a larger injection force, and the cylinder volume can be reduced while still meeting the injection force requirements. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is an axial cross-sectional view of an existing single-cylinder injection structure; Figure 2 This is an axial cross-sectional view of a single-cylinder injection structure in one embodiment of the present invention; Figure 3 This is a top view of a single-cylinder injection structure in one embodiment of the present invention; Figure 4 for Figure 3 Cross-sectional view at the EE section; Figure 5 for Figure 3 Cross-sectional view at the middle FF section; Figure 6 This is a radial cross-sectional view of the connection between the screw and the spindle in one embodiment of the present invention; Figure 7 This is an axial cross-sectional view of the connection between the screw and the mandrel in another embodiment of the present invention.

[0018] In the diagram: 1. Screw; 2. Front cylinder head; 3. Spindle; 4. Rotary support; 4-1. First sliding plate; 4-2. Second sliding plate; 5. Outer cylinder; 6. Piston cylinder; 7. Inner cylinder; 8. Drive shaft; 9. Rear cylinder head; 10. Motor; 11. First sealing ring; 12. Second sealing ring; 13. Third sealing ring; 14. Fourth sealing ring; 15. Front end cover; 16. Rear end cover; 17. First boss; 18. Second boss; 19. Guide ring; 20. Connecting ring sleeve; 21. 21. Semi-ring pressure plate; 22. Screw sleeve; 23. Screw; 24. Receiving slot; 25. Support column; 26. Elastic element; 27. Fixing block; 28. Fixing bolt; 29. ​​Third boss; 30. Injection seat; 31. Anti-collision plate; 32. Middle end cap; 33. Fifth sealing ring; 34. First exhaust channel; 35. Second exhaust channel; 36. First oil passage; 37. Second oil passage; 38. Bearing; 39. Pressure testing and exhaust connector; 40. Bushing; 41. Front pressure plate; 42. Rear pressure plate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] The terms "first" and "second" in the specification and claims of this invention may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] To facilitate understanding and description of the technical solution of this invention, it is hereby ordered that... Figure 2 The left side is the front side, let Figure 2 The right side is the rear side.

[0024] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] One embodiment of the present invention provides a single-cylinder injection structure for an injection molding machine, such as... Figures 2 to 5 As shown, the single-cylinder injection structure includes a screw 1, a front cylinder head 2, a spindle 3, a rotating support 4, an outer cylinder 5, a piston cylinder 6, an inner cylinder 7, a drive shaft 8, a rear cylinder head 9, and a motor 10.

[0026] Specifically, the front end of the mandrel 3 is fixedly connected to the screw 1, and the rear end of the mandrel 3 has a connecting cavity formed axially. The front end of the drive shaft 8 is inserted into the connecting cavity and connected to the mandrel 3 via a spline, allowing the drive shaft 8 to move axially within the connecting cavity, i.e., the mandrel 3 can move axially relative to the drive shaft 8. The inner cylinder 7 is sleeved on the mandrel 3, only covering a portion of the mandrel 3 (i.e., the inner cylinder 7 only covers the middle and rear parts of the mandrel 3). The mandrel 3 can move axially and rotate circumferentially relative to the inner cylinder 7. The piston cylinder 6 is sleeved on the inner cylinder 7, and the piston cylinder 6 can move axially relative to the inner cylinder 7. The piston cylinder 6 can cover the front part of the mandrel 3. The rotating support 4 is disposed between the front part of the piston cylinder 6 and the mandrel 3, allowing the mandrel 3 to rotate within the piston cylinder 6. That is, the rotating support 4 acts as a rotating support between the piston cylinder 6 and the mandrel 3. The piston cylinder 6 serves as a pivot support. A first sealing ring 11 is provided between the front end of the piston cylinder 6 and the spindle 3. The piston cylinder 6 is located inside the outer cylinder 5 and can move axially relative to the outer cylinder 5. A second sealing ring 12 is provided between the rear end of the piston cylinder 6 and the outer cylinder 5. A ejection chamber is formed between the outer cylinder 5 and the piston cylinder 6. Hydraulic oil can be injected into the ejection chamber through the first oil passage 36 and hydraulic oil can be drawn out of the ejection chamber through the first oil passage 36. The front cylinder head 2 is fixed to the front end of the outer cylinder 5. A sealing ring 11 is provided between the front cylinder head 2 and the piston cylinder 6. The third sealing ring 13 seals the rear side of the ejection chamber through the second sealing ring 12 and the front side of the ejection chamber through the third sealing ring 13. The rear cylinder cover 9 is fixed to the rear end of the outer cylinder 5 and is fixedly connected to the rear end of the inner cylinder 7. An injection chamber is formed between the rear cylinder cover 9 and the piston cylinder 6. The injection chamber is specifically composed of the rear end face of the piston cylinder 6, the outer side face of the inner cylinder 7, the front end face of the rear cylinder cover 9, and the inner side face of the outer cylinder 5. Hydraulic oil can be injected into the injection chamber through the second oil passage 37 and through the second oil passage 38. 7. Hydraulic oil is drawn from the injection chamber. The injection chamber is connected to the inner cavity of the inner cylinder 7 and the connecting cavity through a flow channel (not shown in the figure), allowing the hydraulic oil in the injection chamber to enter the inner cavity of the inner cylinder 7 and the connecting cavity through the flow channel. The flow channel can be specifically set on the rear cylinder cover 9. The rear end of the drive shaft 8 passes through the rear cylinder cover 9 and is connected to the motor 10 for transmission. The motor 10 provides rotational driving force to the drive shaft 8. A bearing 38 is provided between the drive shaft 8 and the rear cylinder cover 9 to provide rotational support for the drive shaft 8. A fourth sealing ring 14 is provided between the rear cylinder cover 9 and the drive shaft 8. The first sealing ring 11 achieves sealing on the front side of the injection chamber, and the fourth sealing ring 14 achieves sealing on the rear side of the injection chamber.

[0027] The single-cylinder injection structure works as follows: During the injection process, hydraulic oil is injected into the injection chamber through the second oil passage 37. The oil pressure generated by the hydraulic oil in the injection chamber exerts a forward thrust on the rear end face of the piston cylinder 6, pushing the piston cylinder 6 forward. At the same time, the hydraulic oil in the injection chamber enters the inner cavity of the inner cylinder 7 and the connecting cavity through the flow channel, so that the oil pressure of the hydraulic oil exerts a forward thrust on the rear end face of the mandrel 3 and the bottom of the connecting cavity (i.e., Figure 2 The left side of the connecting cavity generates a forward thrust, pushing the mandrel 3 forward, which in turn drives the screw 1 forward, generating injection force. During this process, there is no relative movement between the mandrel 3 and the piston cylinder 6; only the piston cylinder 6 moves axially relative to the outer cylinder 5. The second sealing ring 12 and the third sealing ring 13 only provide axial sliding seals. Furthermore, since the hydraulic oil in the injection cavity can enter the interior of the inner cylinder 7 and the connecting cavity through the flow channel, the compression area of ​​the hydraulic oil is expanded, thereby enabling the screw 1 to output a larger injection force. Under the premise of meeting the injection force requirements, the cylinder can be made smaller and more compact, reducing the weight of the moving parts during injection, thereby reducing the injection inertia, improving the injection accuracy and response speed of the equipment, and reducing the energy consumption of the equipment.

[0028] During the material storage operation, motor 10 drives transmission shaft 8 to rotate, and transmission shaft 8 drives spindle 3 to rotate via splines. Sparrow 3 further drives screw 1 to rotate. At this time, relative rotation occurs between spindle 3 and piston cylinder 6, so that the first sealing ring 11 between spindle 3 and piston cylinder 6 only provides rotational sealing. Screw 1 retracts under the push of the front melt, and screw 1 drives spindle 3 and piston cylinder 6 to retract synchronously (i.e., towards) Figure 2 (Moving to the right), at this time, there is no relative rotation between the spindle 3 and the piston cylinder 6, and axial movement occurs between the piston cylinder 6 and the outer cylinder 5, so that the second sealing ring 12 and the third sealing ring 13 between the piston cylinder 6 and the outer cylinder 5 and the front cylinder head 2 only bear axial sliding seal. It can be understood that by decomposing the axial movement and circumferential rotation of the screw 1 into the axial movement of the piston cylinder 6 relative to the outer cylinder 5 and the circumferential rotation of the spindle 3 relative to the piston cylinder 6, the first sealing ring 11 between the spindle 3 and the piston cylinder 6 only bears rotational seal, and the second sealing ring 12 and the third sealing ring 13 between the piston cylinder 6 and the outer cylinder 5 and the front cylinder head 2 only bear axial sliding seal, the requirements for the sealing rings are reduced, and the risk of damage to the sealing rings is reduced, thereby reducing the failure rate and subsequent maintenance costs.

[0029] During the glue extraction action, hydraulic oil is injected into the ejection chamber through the first oil passage 36. The oil pressure generated by the hydraulic oil in the ejection chamber exerts a backward thrust on the piston cylinder 6, pushing the piston cylinder 6 to move backward. The piston cylinder 6 drives the screw 1 to move backward through the spindle 3. At this time, there is no relative movement between the spindle 3 and the piston cylinder 6. The piston cylinder 6 only moves axially relative to the outer cylinder 5.

[0030] In this embodiment, as Figure 2 As shown, the single-cylinder injection structure also includes a front cover 15, a front pressure plate 41, a rear pressure plate 42, and a rear cover 16.

[0031] Specifically, the front end cover 15 is fixed to the front end of the piston cylinder 6, and the first sealing ring 11 is disposed between the front end cover 15 and the spindle 3, thereby achieving a seal between the front end of the piston cylinder 6 and the spindle 3. The front pressure plate 41 is fixed to the rear side of the front end cover 15, and the first sealing ring 11 is clamped and fixed by the front end cover 15 and the front pressure plate 41, which facilitates the installation of the first sealing ring 11. The rear end cover 16 is fixed to the rear cylinder head 9, and the fourth sealing ring 14 is disposed between the rear end cover 16 and the drive shaft 8, thereby achieving a seal between the rear cylinder head 9 and the drive shaft 8. The rear pressure plate 42 is fixed to the front side of the rear end cover 16, and the fourth sealing ring 14 is clamped and fixed by the rear pressure plate 42 and the rear end cover 16, which facilitates the installation of the fourth sealing ring 14.

[0032] And, as Figure 2 As shown, a first boss 17 is formed on the inner circumference of the front part of the piston cylinder 6, and a second boss 18 is formed on the outer circumference of the front part of the spindle 3. The second boss 18 is located in front of the first boss 17 and overlaps with it in the axial direction.

[0033] The rotating support 4 includes a first sliding plate 4-1 and a second sliding plate 4-2. The first sliding plate 4-1 is fitted onto the spindle 3 between the first boss 17 and the second boss 18, with its two end faces abutting against the first boss 17 and the second boss 18, respectively. The second sliding plate 4-2 is fitted onto the spindle 3 between the front cover 15 (front pressure plate 41) and the second boss 18, with its two end faces abutting against the front cover 15 (front pressure plate 41) and the second boss 18, respectively. The first sliding plate 4-1 can be an aluminum-copper alloy sliding plate, and the second sliding plate 4-2 can be a copper alloy sliding plate. Of course, the first sliding plate 4-1 and the second sliding plate 4-2 can also be sliding plates made of other materials, which are also within the scope of protection of this invention.

[0034] Understandably, the first sliding plate 4-1 and the second sliding plate 4-2 provide radial support for the mandrel 3, allowing it to rotate within the piston cylinder 6. Furthermore, when transmitting injection force, the piston cylinder 6 axially presses the first sliding plate 4-1 via the first boss 17, and the first sliding plate 4-1 then axially presses the second boss 18, pushing the mandrel 3 forward. Because the first sliding plate 4-1 and the second sliding plate 4-2 are compact and can withstand high pressure, the size of the injection cylinder is reduced compared to using a thrust bearing, resulting in a more compact cylinder structure and effectively lower equipment costs. In addition, the hydraulic oil inside the cylinder can flow through the gap between the piston cylinder 6 and the mandrel 3 to the first sliding plate 4-1 and the second sliding plate 4-2, achieving lubrication of both.

[0035] Taking the SP55000 injection molding machine as an example, the injection cylinder with a single-cylinder design has a diameter of 660mm. If a thrust bearing is used, according to the static load safety factor of the thrust bearing, the outer ring size of the thrust bearing will reach 640mm, and the calculated diameter of the injection cylinder will reach about 850mm. Compared with the cylinder that achieves rotational support through a sliding plate, the mass of the injection cylinder will increase by about 25%.

[0036] In this embodiment, as Figure 2 As shown, a third boss 29 is formed on the outer circumference of the front end of the piston cylinder 6, and a second sealing ring 12 is disposed between the third boss 29 and the outer cylinder 5. On the one hand, when hydraulic oil is injected into the ejection chamber, the front end face of the third boss 29 can provide a force-bearing surface for the oil pressure, so that the oil pressure pushes the piston cylinder 6 to move backward relative to the outer cylinder 5 by squeezing the front end face of the third boss 29; on the other hand, the third boss 29 can provide a limit for the axial movement of the piston cylinder 6 in the outer cylinder 5, preventing the piston cylinder 6 from disengaging from the outer cylinder 5 during axial movement.

[0037] And, as Figures 2 to 5 As shown, the single-cylinder injection structure also includes an injection seat 30.

[0038] Specifically, the injection seat 30 is fixed to the front end of the outer cylinder 5, the front cylinder head 2 is fixed to the injection seat 30, and a crash plate 31 is fixed to the rear end face of the injection seat 30. The crash plate 31 is located in the ejection cavity and corresponds to the position of the third protrusion 29. The crash plate is made of high manganese steel, high carbon chromium bearing steel, tungsten carbide-based cemented carbide, or titanium carbide-based cemented carbide, giving it high hardness and wear resistance, ensuring excellent wear resistance and impact resistance.

[0039] Understandably, by fixing the anti-collision plate 31 to the rear end face of the injection seat 30, when the hydraulic oil in the injection chamber squeezes the piston cylinder 6 and causes the piston cylinder 6 to move forward, the front end face of the third protrusion 29 will impact the anti-collision plate 31, rather than the injection seat 30. Since the injection seat 30 is usually made of ordinary medium carbon steel and has a low surface hardness, the anti-collision plate 31 can protect the injection seat 30 and prevent the injection seat 30 from being worn or deformed during the impact.

[0040] In addition, such as Figure 2As shown, the outer cylinder 5 is provided with a first exhaust channel 34, through which the ejection chamber communicates with the external environment. The first exhaust channel 34 can be specifically located on the outer cylinder 5 or the injection seat 30, or both the outer cylinder 5 and the injection seat 30 may have a first exhaust channel 34. A pressure testing and exhaust connector 39 is provided at the outlet of the first exhaust channel 34. The rear cylinder cover 9 is provided with a second exhaust channel 35, through which the injection chamber communicates with the external environment. The second exhaust channel 35 can be specifically located on the outer cylinder 5 or the rear cylinder cover 9, or both the outer cylinder 5 and the rear cylinder cover 9 may have a second exhaust channel 35. A pressure testing and exhaust connector 39 is also provided at the outlet of the second exhaust channel 35. When hydraulic oil is injected into the cylinder for the first time during use, the gas inside the cylinder can be discharged through the first exhaust channel 34 and the second exhaust channel 35. During subsequent use of the cylinder, the oil pressure in the ejection chamber and the injection chamber can be detected through the first exhaust channel 34, the second exhaust channel 35, and the pressure testing and exhaust connector 39.

[0041] In addition, such as Figures 3 to 5 As shown, the first oil passage 36, which communicates with the ejection chamber, is disposed on the injection seat 30, and the second oil passage 37, which communicates with the injection chamber, is disposed on the rear cylinder head 9. Of course, in other embodiments, the first oil passage 36 and the second oil passage 37 may also be disposed on the outer cylinder 5, which is also within the protection scope of this invention.

[0042] In this embodiment, as Figure 2 As shown, the single-cylinder injection structure also includes a guide ring 19.

[0043] The guide ring 19 is fixed on the inner circumference of the inner cylinder 7 and sleeved on the outside of the spindle 3, and is used to guide the spindle 3 when it moves axially relative to the inner cylinder 7.

[0044] Understandably, the guide ring 19 can provide guidance and support for the spindle 3, improving the coaxiality of the spindle 3 and the inner cylinder 7, and making the circumferential rotation and axial movement of the spindle 3 relative to the inner cylinder 7 smoother.

[0045] Furthermore, the rear end of the drive shaft 8 is connected to the motor 10 via a spline, which not only facilitates the assembly and disassembly of the drive shaft 8 and the motor 10, but also reduces the assembly precision requirements of the motor 10.

[0046] In addition, such as Figure 2 As shown, the single-cylinder injection structure also includes a middle end cap 32.

[0047] The middle end cap 32 is fixed to the front end of the inner cylinder 7, and a fifth sealing ring 33 is provided between the middle end cap 32 and the mandrel 3. The function of the fifth sealing ring 33 is to seal the injection chamber (made by...) between the outer side of the mandrel 3 and the inner side of the outer cylinder 5. Figure 3 The second oil passage 37 in the lower middle part (oil inlet) and the injection chamber 2 inside the mandrel 3 (by...Figure 3 The second oil passage 37 in the upper middle part is separated from the injection chamber. During the injection action: injection chamber one and injection chamber two receive oil simultaneously to provide injection force; during the material storage action, the material storage back pressure only controls the return oil back pressure of injection chamber two, while the oil circuit of injection chamber one is directly connected to the return oil tank. It is understandable that if injection chamber one and injection chamber two provide back pressure simultaneously, due to the very large cylinder area and the often small plasticizing back pressure, the actual cylinder return oil back pressure would be very small. Furthermore, even a slight adjustment to the return oil back pressure valve would cause a significant change in the actual back pressure, making it difficult to guarantee control accuracy. However, by using only injection chamber two for return oil back pressure control, the cylinder area is smaller, the adjustment range of the return oil back pressure valve is larger, and the control accuracy is higher. Injection chamber one and injection chamber two constitute the injection chamber.

[0048] In this embodiment, as Figure 2 and Figure 6 As shown, the single-cylinder injection structure also includes a connecting ring sleeve 20, two semi-ring pressure plates 21, two threaded sleeves 22, two bushings 40, and two screws 23.

[0049] Specifically, an annular groove is formed on the screw 1. Two semi-annular pressure plates 21 can be spliced ​​and wrapped around the screw 1 and inserted into the annular groove. The middle of the two semi-annular pressure plates 21 has through holes in the radial direction. Two bushings 40 are located in the two through holes respectively. The connecting ring sleeve 20 is sleeved on the outside of the two semi-annular pressure plates 21. The connecting ring sleeve 20 has two threaded holes corresponding to the positions of the two through holes respectively. Each screw sleeve 22 is inserted into the corresponding threaded hole from the outside of the connecting ring sleeve 20 and is fixedly connected to the screw 23 inserted into the bushing 40 and the through hole from the inside of the semi-annular pressure plate 21, so that the semi-annular pressure plate 21 is fixed to the front end of the screw sleeve 22. When the screw sleeve 22 moves axially, the semi-annular pressure plate 21 connected to the screw sleeve 22 will also move accordingly. When the threaded sleeve 22 is rotated, the screw 23 will rotate relative to the bushing 40, that is, the screw 23 can rotate relative to the semi-annular pressure plate 21. The outer circumference of the threaded sleeve 22 is formed with a first external thread that mates with the threaded hole. By rotating the threaded sleeve 22, the depth of the threaded sleeve 22 screwed into the threaded hole can be adjusted, thereby realizing the adjustment of the radial position of the semi-annular pressure plate 21 along the connecting ring sleeve 20. The outer circumference of the front end of the mandrel 3 is formed with a second external thread, and the connecting ring sleeve 20 is formed with an internal thread that mates with the second external thread, so that the connecting ring sleeve 20 is rotated and fixed on the mandrel 3 through the second external thread and the internal thread. When the connecting ring sleeve 20 is rotated and fixed on the mandrel 3, both semi-annular pressure plates 21 abut against the front end face of the mandrel 3.

[0050] Understandably, when assembling the screw 1 and the mandrel 3, firstly, the depth of the threaded sleeve 22 into the threaded hole is adjusted to maximize the distance between the two semi-annular pressure plates 21; secondly, the connecting ring sleeve 20 and the semi-annular pressure plates 21 are fitted onto the screw 1, and the depth of the threaded sleeve 22 into the threaded hole is adjusted again so that the threaded sleeve 22 pushes the semi-annular pressure plates 21 into the annular groove on the screw 1, achieving axial and radial fixation of the connecting ring sleeve 20 and the screw 1; then, the rear end of the screw 1 is inserted into the receiving groove 24 on the mandrel 3; finally, the connecting ring sleeve 20 is rotated and fixed to the front end of the mandrel 3, achieving a fixed connection between the screw 1 and the mandrel 3. The disassembly steps of the screw 1 and the mandrel 3 are the reverse of the assembly steps described above, and will not be repeated here. It can be seen that the connection structure of the screw 1 and the mandrel 3 in this embodiment is easy to disassemble and assemble.

[0051] Furthermore, an annular flange extends radially along the inner circumference of the connecting ring sleeve 20. The annular flange is located in front of the threaded hole. The inner diameter of the annular flange is smaller than the outer diameter of the semi-annular pressure plate 21. When the semi-annular pressure plate 21 is assembled on the connecting ring sleeve 20, the front end face of the semi-annular pressure plate 21 abuts against the rear end face of the annular flange. As a result, the force on the semi-annular pressure plate 21 can be transmitted more evenly to the connecting ring sleeve 20 and transmitted to the mandrel 3 through the inner ring thread on the connecting ring sleeve 20.

[0052] It is evident that the axial force on the semi-ring pressure plate 21 is more uniform, which solves the problems of uneven force on the semi-ring pressure plate 21 and easy breakage of the semi-ring fixing screws in the traditional connection structure, thereby improving the stability of the equipment and reducing the risk and cost of subsequent equipment downtime maintenance.

[0053] In addition, such as Figure 2 As shown, a fixing block 27 is fixed to the bottom of the receiving groove 24. Specifically, the fixing block 27 is located between the rear end of the screw 1 and the bottom of the receiving groove 24, and is fixed to the mandrel 3 by screws or bolts. The fixing block 27 is made of high-manganese steel, high-carbon chromium bearing steel, tungsten carbide-based cemented carbide, or titanium carbide-based cemented carbide. Understandably, when the injection molding machine switches from the drawing action to the injection action, the screw 1 will generate an axial impact on the mandrel 3. At this time, the fixing block 27 acts as an intermediate transition, providing some protection for the mandrel 3 and preventing damage or replacement. When the fixing block 27 wears out, only the fixing block 27 needs to be replaced, reducing the operating cost of the injection molding machine.

[0054] In another embodiment of the invention, such as Figure 7 As shown, the single-cylinder injection structure also includes an annular pressure plate and a buffer structure; wherein, the annular pressure plate is formed by splicing two semi-annular pressure plates 21.

[0055] Specifically, the front end of the mandrel 3 has a receiving groove 24, and the rear end of the screw 1 is inserted into the receiving groove 24. An annular pressure plate is fitted onto the shoulder of the screw 1 and is fixedly connected to the mandrel 3 (i.e., the two semi-annular pressure plates 21 are respectively fixedly connected to the mandrel 3), so that the end of the screw 1 is pressed and fixed in the receiving groove 24, thereby realizing the fixed connection between the screw 1 and the mandrel 3. The buffer structure is located in the receiving groove 24 and between the end face of the screw 1 and the end face of the mandrel 3. The buffer structure includes a support column 25, an elastic element 26, and a fixing block 27. The fixing block 27 is fixed to the bottom of the receiving groove 24 by fixing bolts 28. The support column 25 abuts against the end of the screw 1 and the fixing block 27. That is, the support column 25 and the fixing block 27 are provided between the end of the screw 1 and the bottom of the receiving groove 24, which avoids direct contact between the end face of the screw 1 and the end face of the mandrel 3, thereby preventing contact wear between the screw 1 and the mandrel 3. The elastic element 26 is disposed between the support column 25 and the fixing block 27, and has a compression preload, so that the support column 25 is always pressed against the end of the screw 1. In this embodiment, during installation, the fixing block 27 is first placed in the receiving hole groove 24 on the mandrel 3 and fixed to the bottom of the receiving hole groove 24; then the elastic element 26 and the support column 25 are placed in the receiving hole groove 24 in sequence, so that the elastic element 26 is located between the support column 25 and the fixing block 27; finally, the screw 1 is inserted into the receiving hole groove 24 and pressed and fixed on the mandrel 3 by the annular pressure plate.

[0056] It should be noted that during the process of pressing and fixing the end of the screw 1 into the receiving groove 24 by the annular pressure plate, the elastic element 26 will be compressed until the end face of the support column 25 and the end face of the fixing block 27 are completely in contact. That is, the screw 1 and the support column 25 need to be tightly abutted, and the support column 25 and the fixing block 27 need to be tightly abutted to ensure that there is no gap between the screw 1, the support column 25 and the fixing block 27 when the injection molding machine is not working, so as to prevent the screw 1 from shaking in the receiving groove 24.

[0057] The working process of the connection structure in this embodiment is as follows: When the injection molding machine begins the injection molding process, the mandrel 3 moves backward relative to the screw 1 (towards) Figure 7 (Moves to the right), a gap is generated between the mandrel 3 and the screw 1. At this time, under the elastic force of the elastic element 26, the support column 25 automatically compensates for the gap generated by the relative movement of the mandrel 3, so that the end face of the support column 25 and the end face of the screw 1 always remain in contact, while the end face of the support column 25 and the end face of the fixing block 27 are separated, which fundamentally avoids the wear of the end face of the screw 1, and indirectly ensures the reliability of the screw 1 fixing of the injection molding machine, as well as the stability of the injection of the injection molding machine, and reduces the later manual maintenance cost.

[0058] When the injection molding machine begins the injection process, the mandrel 3, under the action of the injection force, moves forward relative to the screw 1 (towards...). Figure 7The screw 1 moves to the left, compressing the elastic element 26 until the end face of the support column 25 and the end face of the fixing block 27 are pressed together. During this process, the elastic force of the elastic element 26 buffers the impact between the support column 25 and the fixing block 27, reducing wear between them and preventing the screw 1 from loosening. This ensures the stability of the injection molding machine. Furthermore, the fixing block 27 acts as a transition element, providing some protection for the mandrel 3 and preventing damage or replacement. When the fixing block 27 wears out, it can be replaced, reducing the operating cost of the injection molding machine. The fixing block 27 also serves as a limiter, ensuring consistent positional accuracy during each injection.

[0059] In detail, the elastic element 26 consists of multiple disc springs arranged in series. These disc springs are sleeved on the support column 25, with one end abutting against the support column 25 and the other end abutting against the fixing block 27. The support column 25 provides radial limiting for the disc springs, ensuring that each disc spring is coaxial and thus guaranteeing stable operation. For example, a trapezoidal platform is formed on the circumference of the end of the support column 25 near the screw 1. One end of the multiple disc springs arranged in series abuts against the trapezoidal platform, and the other end abuts against the end face of the fixing block 27.

[0060] Among them, the disc spring can withstand a large load in a small space, has a large deformation energy per unit volume, can withstand heavy load pressure, and has good buffering and shock absorption capabilities. In particular, when it is combined in a stacked (series) manner, the effect of absorbing impact and dissipating energy is more significant due to the surface friction resistance, making the buffering and shock absorption effect between the support column 25 and the fixed block 27 better.

[0061] In addition, the support column 25 and the fixing block 27 are made of high manganese steel, high carbon chromium bearing steel, tungsten carbide-based hard alloy or titanium carbide-based hard alloy, which gives the support column 25 and the fixing block 27 high hardness and wear resistance, ensuring that they have excellent wear resistance and impact resistance, reducing mutual wear between the two, preventing the screw 1 from loosening, and making the injection molding machine run more stably.

[0062] In the single-cylinder injection structure of this invention, the axial movement and circumferential rotation of the screw are decomposed into the axial movement of the piston cylinder relative to the outer cylinder and the circumferential rotation of the mandrel relative to the piston cylinder. This allows the first sealing ring between the mandrel and the piston cylinder to only perform rotational sealing, and the second and third sealing rings between the piston cylinder and the outer cylinder and the front cylinder head to only perform axial sliding sealing. This reduces the requirements for the sealing rings and decreases the risk of damage to them, thereby reducing the failure rate and subsequent maintenance costs. Furthermore, by connecting the injection chamber to the inner cavity of the inner cylinder and the connecting cavity through the flow channel, hydraulic oil can enter the interior of the inner cylinder and the connecting cavity during injection, expanding the compression area of ​​the hydraulic oil. This allows the screw to output a larger injection force, and the cylinder volume can be reduced while still meeting the injection force requirements.

[0063] The above description is merely a specific embodiment of the present invention. Under the teachings of the present invention, those skilled in the art can make other improvements or modifications based on the above embodiments. Those skilled in the art should understand that the above specific description is only to better explain the purpose of the present invention, and the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A single cylinder injection structure of an injection molding machine, characterized by comprising: The screw rod, the front cylinder cover, the mandrel, the rotary support, the outer cylinder, the piston cylinder, the inner cylinder, the transmission shaft, the rear cylinder cover and the motor are included. The front end of the mandrel is fixedly connected with the screw rod, the rear end of the mandrel is formed with a connecting cavity in the axial direction, the front end of the transmission shaft is inserted into the connecting cavity and connected with the mandrel through a spline, the inner cylinder is sleeved on the mandrel, the piston cylinder is sleeved on the inner cylinder, the rotary support is arranged between the front part of the piston cylinder and the mandrel, so that the mandrel can rotate in the piston cylinder, a first sealing ring is arranged between the front end of the piston cylinder and the mandrel, the piston cylinder is located in the outer cylinder and can move axially relative to the outer cylinder, a second sealing ring is arranged between the rear end of the piston cylinder and the outer cylinder, a retreat cavity is formed between the outer cylinder and the piston cylinder, the front cylinder cover is fixed to the front end of the outer cylinder, a third sealing ring is arranged between the front cylinder cover and the piston cylinder, the rear cylinder cover is fixed to the rear end of the outer cylinder and fixedly connected with the rear end of the inner cylinder, an injection cavity is formed between the rear cylinder cover and the piston cylinder, the injection cavity is communicated with the inner cavity of the inner cylinder and the connecting cavity through flow channels, the rear end of the transmission shaft is in transmission connection with the motor through the rear cylinder cover, and a fourth sealing ring is arranged between the rear cylinder cover and the transmission shaft.

2. The single cylinder injection structure of an injection molding machine according to claim 1, wherein The front end cover and the rear end cover are further included. The front end cover is fixed to the front end of the piston cylinder, and the first sealing ring is arranged between the front end cover and the mandrel; the rear end cover is fixed to the rear cylinder cover, and the fourth sealing ring is arranged between the rear end cover and the transmission shaft.

3. The single cylinder injection structure of an injection molding machine according to claim 2, wherein A first boss is formed on the inner circumferential surface of the front part of the piston cylinder, a second boss is formed on the outer circumferential surface of the front part of the mandrel, and the second boss is located on the front side of the first boss. The rotary support includes a first sliding plate and a second sliding plate; the first sliding plate is located between the first boss and the second boss, and the second sliding plate is located between the front end cover and the second boss.

4. The single cylinder injection structure of an injection molding machine according to claim 1, wherein The guide ring is further included. The guide ring is fixed to the inner circumferential surface of the inner cylinder and sleeved on the outer side of the mandrel, so as to guide the axial movement of the mandrel relative to the inner cylinder.

5. The single cylinder injection structure of an injection molding machine according to claim 1, wherein The connecting ring sleeve, the two half-ring pressing plates, the two screw sleeves, the two bushings and the two screws are further included. The screw is provided with an annular groove, two half-ring pressing plates can be inserted into the annular groove, the middle part of the two half-ring pressing plates is respectively provided with a through hole in the radial direction, two bushings are respectively located in the two through holes, the connecting ring is sleeved on the outer side of the two half-ring pressing plates, the connecting ring is provided with two threaded holes corresponding to the positions of the two through holes, each screw sleeve is respectively inserted into the corresponding threaded hole from the outer side of the connecting ring and is fixedly connected with the screw inserted into the bushing and the through hole from the inner side of the half-ring pressing plate, the outer circumference of the screw sleeve is provided with a first external thread matched with the threaded hole, the front end of the mandrel is provided with a second external thread, the connecting ring is provided with an internal thread matched with the second external thread, so that when the connecting ring is rotationally fixed on the mandrel, the two half-ring pressing plates are in abutment with the front end face of the mandrel.

6. The single cylinder injection structure of an injection molding machine according to claim 1, wherein Further comprising a ring-shaped pressing plate and a buffer structure; wherein the ring-shaped pressing plate is formed by splicing two half-ring pressing plates; The front end of the mandrel is provided with a receiving hole groove, the rear end of the screw is inserted into the receiving hole groove, the ring-shaped pressing plate is sleeved on the shaft shoulder of the screw and is fixedly connected with the mandrel; the buffer structure is located in the receiving hole groove and comprises a supporting column, an elastic member and a fixed block; the fixed block is fixed to the groove bottom of the receiving hole groove, the supporting column is in abutment between the rear end of the screw and the fixed block, and the elastic member is arranged between the supporting column and the fixed block and has a compression pre-tightening force.

7. The single cylinder injection structure of an injection molding machine according to claim 1, wherein The outer circumference of the front end of the piston cylinder is provided with a third boss, and the second sealing ring is arranged between the third boss and the outer cylinder.

8. The single cylinder injection structure of an injection molding machine according to claim 7, wherein Further comprising an injection seat; The injection seat is fixed to the front end of the outer cylinder, the front cylinder cover is fixed to the injection seat, the rear end face of the injection seat is fixed with a bumper plate, the bumper plate is located in the ejection cavity and corresponds to the position of the third boss.

9. The single cylinder injection structure of an injection molding machine according to claim 1, wherein Further comprising a middle end cover; The middle end cover is fixed to the front end of the inner cylinder, and a fifth sealing ring is arranged between the middle end cover and the mandrel.

10. The single cylinder injection structure of an injection molding machine according to claim 1, wherein The outer cylinder is provided with a first exhaust passage, the ejection cavity is communicated with the external environment through the first exhaust passage, the rear cylinder cover is provided with a second exhaust passage, and the injection cavity is communicated with the external environment through the second exhaust passage.

11. The single cylinder injection structure of an injection molding machine according to any one of claims 1 to 10, characterized in that, The rear end of the transmission shaft is in transmission connection with the motor through a spline. The screw is provided with an annular groove, two half-ring pressing plates can be inserted into the annular groove, the middle part of the two half-ring pressing plates is respectively provided with a through hole in the radial direction, two bushings are respectively located in the two through holes, the connecting ring is sleeved on the outer side of the two half-ring pressing plates, the connecting ring is provided with two threaded holes corresponding to the positions of the two through holes, each screw sleeve is respectively inserted into the corresponding threaded hole from the outer side of the connecting ring and is fixedly connected with the screw inserted into the bushing and the through hole from the inner side of the half-ring pressing plate, the outer circumference of the screw sleeve is provided with a first external thread matched with the threaded hole, the front end of the mandrel is provided with a second external thread, the connecting ring is provided with an internal thread matched with the second external thread, so that when the connecting ring is rotationally fixed on the mandrel, the two half-ring pressing plates are in abutment with the front end face of the mandrel.

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