Electro-hydraulic hybrid injection structure

Abstract

This invention relates to an electro-hydraulic hybrid injection structure, belonging to the field of injection molding technology, including an injection unit; a barrel; a lead screw assembly installed within the injection unit; a screw fixedly connected to the lead screw assembly; one output end of a dual-axis motor is driven by a displacement transmission assembly, which is also driven by the lead screw assembly, the displacement transmission assembly driving axial displacement of the lead screw assembly; the other output end of the dual-axis motor is driven by a rotary transmission assembly; the dual-axis motor has a first operating condition and a second operating condition arranged opposite to each other. In the first operating condition, the dual-axis motor drives the displacement transmission assembly to rotate along a first rotation direction; in the second operating condition, the dual-axis motor drives the displacement transmission assembly to rotate along a second rotation direction; the first rotation direction and the second rotation direction are opposite in direction. This invention improves injection accuracy and dynamic response.

Description

Technical Field

[0001] This invention relates to the field of injection molding technology, and in particular to an electro-hydraulic hybrid injection structure. Background Technology

[0002] Injection molding machines are core equipment in the field of plastic molding and processing. With high-temperature melting, high-pressure injection and cooling and shaping as their core working logic, they can process raw materials such as polypropylene and polyethylene plastic granules of various shapes into various plastic products, which are widely used in the automotive, electronics, home appliance and medical industries.

[0003] In related technologies, the injection and pre-plasticizing functions of injection molding machines often adopt a split drive architecture. One motor drives the screw to rotate through the transmission mechanism to complete the pre-plasticizing process, melting the plastic granules and pushing them to the front end of the barrel. The other motor drives the injection screw or hydraulic cylinder to move the screw forward and realize the high-pressure injection action.

[0004] Regarding the aforementioned technologies, existing injection structures require two motors to perform injection and pre-plasticizing functions respectively. Furthermore, during the injection process, the pre-plasticizing component and its motor move along with the machine, resulting in a large mass and high injection inertia, which leads to low injection accuracy. Summary of the Invention

[0005] To improve the response and accuracy of injection, this invention provides an electro-hydraulic hybrid injection structure.

[0006] This invention provides an electro-hydraulic hybrid injection structure, employing the following technical solution: An electro-hydraulic hybrid injection structure, comprising: Injection port; Barrel; A lead screw assembly, wherein the lead screw assembly is installed within the injection seat; The screw is fixedly connected to the lead screw assembly; The system includes a dual-axis motor, a displacement transmission assembly, and a rotary transmission assembly. One output end of the dual-axis motor is drivenly connected to the displacement transmission assembly, which is drivenly connected to the lead screw assembly. The displacement transmission assembly is used to drive the lead screw assembly to move axially. The other output end of the dual-axis motor is drivenly connected to the rotary transmission assembly, which drives the lead screw assembly to rotate unidirectionally. The dual-output shaft motor has a first working condition and a second working condition arranged opposite to each other. In the first working condition, the dual-output shaft motor drives the displacement transmission assembly to rotate along a first rotation direction, and the displacement transmission assembly drives the lead screw assembly to move axially for injection. In the second working condition, the dual-output shaft motor drives the displacement transmission assembly to rotate along a second rotation direction, and the displacement transmission assembly drives the lead screw assembly to rotate for pre-plasticizing. The rotation directions of the first rotation direction and the second rotation direction are opposite.

[0007] By adopting the above technical solution, the dual-axis motor connects to the displacement transmission component and the rotation transmission component respectively through the two output ends of one motor, realizing the integrated drive of injection and pre-plasticizing functions, replacing the traditional two independent motors.

[0008] Optionally, the lead screw assembly includes a ball spline lead screw, a lead screw nut, and a spline nut, wherein the lead screw nut and the spline nut are both sleeved on the ball spline lead screw and are threadedly engaged with the ball spline lead screw; The displacement transmission assembly has a first one-way transmission member, and the displacement transmission assembly is driven to the lead screw nut through the first one-way transmission member; the displacement transmission assembly also has a second one-way transmission member, and the displacement transmission assembly is driven to the spline nut through the second one-way transmission member.

[0009] By adopting the above technical solution, when the lead screw nut rotates under the drive of the displacement transmission assembly, due to its threaded engagement with the ball spline screw and the axial displacement restricted by the limiting component, the ball spline screw can achieve axial movement, thereby driving the screw to complete the injection action. Similarly, when the spline nut rotates under the drive of the rotary transmission assembly, it also drives the ball spline screw to rotate through its engagement with the ball spline screw, thereby driving the screw to rotate to achieve the pre-plasticizing function.

[0010] Optionally, the displacement transmission assembly further includes: A first synchronous belt structure is disposed between the dual-output shaft motor and the lead screw nut. The first synchronous belt structure is driven and connected to one output end of the dual-output shaft motor through the first one-way transmission component. The second synchronous belt structure is disposed between the dual-output shaft motor and the spline nut, and the second synchronous belt structure is driven to the other output end of the dual-output shaft motor through the second unidirectional transmission component.

[0011] By adopting the above technical solution, the first synchronous belt structure and the second synchronous belt structure respectively transmit the power from the two output ends of the dual-shaft motor to the lead screw nut and the spline nut. The synchronous belt drive has the advantages of smooth transmission, low noise, high transmission efficiency and low maintenance cost, which can ensure the accuracy and reliability of power transmission.

[0012] Optionally, the first one-way transmission component includes a first one-way bearing that rotates in one direction, and the second one-way transmission component includes a second one-way bearing that rotates in one direction, wherein the first one-way bearing and the second one-way bearing rotate in opposite directions.

[0013] By adopting the above technical solution, the function can be switched under different rotation directions through two unidirectional bearings in opposite directions. The two processes of injection and pre-plasticizing are realized by a single dual-output shaft motor, which reduces the weight of the follower parts, reduces the injection inertia, and thus improves the injection accuracy and dynamic response speed.

[0014] Optionally, it also includes a pre-plasticized screw seat installed in the injection unit, wherein a limiting element is provided in the pre-plasticized screw seat to limit the axial displacement of the spline nut relative to the pre-plasticized screw seat.

[0015] By adopting the above technical solution, the limiting component restricts the axial position of the spline nut within the pre-plasticized screw seat, so that the spline nut can only rotate relative to the pre-plasticized screw seat and will not undergo axial displacement. This ensures that when the screw nut rotates, the ball spline screw can move smoothly along the axial direction without being disturbed by the axial movement of the spline nut, thereby improving the stability of the injection action and ensuring injection accuracy.

[0016] Optionally, it also includes an injection screw seat; the injection screw seat and the pre-plasticized screw seat are fixedly installed together in the injection seat; the spline nut is rotatably installed in the pre-plasticized screw seat, and the screw nut is rotatably installed in the injection screw seat.

[0017] By adopting the above technical solution, the injection screw seat and the pre-plasticized screw seat independently install and position the screw nut and the spline nut, respectively. The installation positions of the two do not interfere with each other, which can effectively improve the coaxiality of the two nuts when rotating, reduce eccentric wear during rotation, extend the service life of the overall structure, and also facilitate the separate maintenance and disassembly of the two nuts.

[0018] Optionally, the spline nut and the lead screw nut are fixedly connected by a connector.

[0019] By adopting the above technical solution, the spline nut and the lead screw nut can rotate synchronously. When one nut is driven to rotate by power, the other nut will rotate synchronously, reducing additional power loss, simplifying the overall transmission structure, and reducing the overall design complexity.

[0020] Optionally, it further includes a hydraulic cylinder assembly disposed on the injection seat and used to drive the lead screw assembly to retract from the barrel after injection is completed; a lead screw bearing seat is connected between the hydraulic cylinder assembly and the lead screw assembly, the lead screw bearing seat being slidably mounted on the injection seat and through which the lead screw assembly passes.

[0021] By adopting the above technical solution, the hydraulic cylinder assembly can drive the screw bearing housing to move the ball spline screw linearly along the barrel after injection, thereby realizing the retraction action of the screw relative to the barrel. At the same time, the sliding installation method of the screw bearing housing provides guidance and support for the axial movement of the screw assembly, ensuring the smoothness of the withdrawal process.

[0022] Optionally, the cylinder assembly includes a cylinder piston rod and a cylinder body, and the lead screw bearing seat is fixedly connected to the cylinder body so that during the pre-plasticizing action, the lead screw bearing seat and the cylinder body move synchronously along the axial direction of the lead screw assembly away from the material cylinder.

[0023] By adopting the above technical solution, during the pre-plasticizing process, the cylinder body drives the lead screw bearing seat to retract along the cylinder piston rod, providing sufficient axial space for the rotational pre-plasticizing action of the lead screw assembly. At the same time, the driving force of the cylinder is used to ensure precise control of the retraction action, thus ensuring the stability of the pre-plasticizing process.

[0024] Optionally, the lead screw assembly further includes a screw connecting sleeve, which connects the ball spline lead screw and the screw; the lead screw bearing housing is sleeved on the outside of the screw connecting sleeve to allow the two to rotate relative to each other, and a bearing is provided between the lead screw bearing housing and the screw connecting sleeve.

[0025] By adopting the above technical solution, the screw connecting sleeve realizes the detachable connection between the ball spline screw and the screw, which facilitates the separate maintenance or replacement of both. At the same time, the screw bearing housing is located on the outside of the screw connecting sleeve and allows relative rotation, which provides radial support for the screw connecting sleeve without affecting the ball spline screw to drive the screw to perform rotational pre-plasticizing action, ensuring the independence of transmission, and reducing the friction when the two rotate relative to each other through the bearing.

[0026] In summary, the present invention has at least one of the following beneficial technical effects: By using a single dual-output shaft motor in conjunction with two sets of one-way bearings and transmission components, the injection and pre-plasticizing actions are driven in a time-sharing manner, which significantly reduces the inertia of moving parts and improves the injection accuracy of the overall structure. The use of a lead screw assembly, constrained by an independent bearing housing structure, ensures the independence and precision of movement during injection and pre-plasticization, thereby improving the working stability and reliability of the equipment. By integrating an electro-hydraulic hybrid drive system, the equipment utilizes a dual-output shaft motor for precise injection and pre-plasticizing control, while employing a hydraulic system to achieve efficient injection retraction. This approach combines the advantages of both electric control and hydraulic drive, thus broadening the equipment's process adaptability. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of an electro-hydraulic hybrid injection structure in an embodiment of this application.

[0028] The parts referred to by the numbers in the above attached figures are as follows: 1. Injection seat; 11. Injection screw seat; 12. Pre-plasticizing screw seat; 13. Hydraulic cylinder assembly; 14. Limit bearing; 15. Hydraulic cylinder piston rod; 16. Hydraulic cylinder body; 17. Screw bearing seat; 171. Bearing; 2. Barrel; 3. Screw assembly; 31. Ball spline screw; 32. Screw nut; 33. Spline nut; 4. Screw; 41. Screw connecting sleeve; 5. Dual-shaft motor; 6. First one-way bearing; 7. Displacement transmission assembly; 71. First synchronous belt structure; 8. Second one-way bearing; 9. Rotary transmission assembly; 91. Second synchronous belt structure; 10. Motor bracket. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0030] This invention discloses an electro-hydraulic hybrid injection structure.

[0031] Example 1:

[0032] Reference Figure 1An electro-hydraulic hybrid injection structure includes an injection base 1, a barrel 2, a lead screw assembly 3, a screw 4, a dual-shaft motor 5, a first one-way bearing 6, a displacement transmission assembly 7, a second one-way bearing 8, a rotary transmission assembly 9, and a motor bracket 10. The lead screw assembly 3 includes a ball spline lead screw 31, a lead screw nut 32, and a spline nut 33. The displacement transmission assembly 7 includes the first one-way bearing 6 and a first synchronous belt structure 71. The rotary transmission assembly 9 includes the second one-way bearing 8 and the second synchronous belt structure 91. The barrel 2 is fixedly connected to the injection base 1, and the lead screw assembly 3 is installed inside the injection base 1. The screw 4 is connected to the ball spline lead screw 31 to complete the injection and pre-plasticizing actions. The dual-shaft motor 5 is fixedly connected to the motor bracket 10. The first one-way bearing 6 and the second one-way bearing 8 are respectively installed at both ends of the dual-shaft motor 5, and the permissible rotation directions of the first one-way bearing 6 and the second one-way bearing 8 are opposite. The displacement transmission assembly 7 connects the first one-way bearing 6 to the lead screw assembly 3, and the rotary transmission assembly 9 connects the second one-way bearing 8 to the lead screw assembly 3. The displacement transmission assembly 7 is driven by the first one-way transmission member and the lead screw nut 32, and the rotary transmission assembly 9 is driven by the second one-way transmission member and the spline nut 33. The first one-way transmission member and the second one-way transmission member can also be a backstop bearing or a clutch.

[0033] Reference Figure 1 When the dual-axis motor 5 rotates and drives the displacement transmission assembly 7 to rotate via the first one-way bearing 6, the displacement transmission assembly 7 drives the lead screw assembly 3 to perform linear reciprocating motion, thereby driving the screw 4 to complete the injection action. When the dual-axis motor 5 reverses and drives the rotary transmission assembly 9 to rotate via the second one-way bearing 8, the rotary transmission assembly 9 drives the lead screw assembly 3 to perform rotational motion, thereby driving the screw 4 to complete the pre-plasticizing action.

[0034] Reference Figure 1 A screw connecting sleeve 41 is installed on the screw 4, and the screw 4 is fixedly connected to the ball spline screw 31 through the screw connecting sleeve 41. When the screw assembly 3 moves, the screw 4 is driven to move through the screw connecting sleeve 41. The screw connecting sleeve 41 provides a stable connection between the screw 4 and the ball spline screw 31, ensuring that power is transmitted from the screw assembly 3 to the screw 4.

[0035] Reference Figure 1 The injection seat 1 is also equipped with an injection screw seat 11, a pre-plasticized screw seat 12, a hydraulic cylinder assembly 13, and a limit bearing 14. The screw assembly 3 includes a ball spline screw 31, a screw nut 32, and a spline nut 33. The screw nut 32 is installed in the inner cavity of the injection screw seat 11. The spline nut 33 is installed in the inner cavity of the pre-plasticized screw seat 12 by a limit member, which is preferably a limit bearing 14.

[0036] Reference Figure 1When the dual-output shaft motor 5 drives the first one-way bearing 6 to rotate, the first synchronous belt structure 71 rotates synchronously, and the first synchronous belt structure 71 drives the lead screw nut 32 to rotate, and through the lead screw nut 32 drives the ball spline lead screw 31 to perform linear reciprocating motion to complete the injection action.

[0037] Reference Figure 1 When the dual-output shaft motor 5 drives the second one-way bearing 8 to rotate, the second synchronous belt structure 91 rotates synchronously, and the second synchronous belt structure 91 drives the spline nut 33 to rotate, which in turn drives the ball spline screw 31 to rotate to complete the pre-plasticizing action. The axial direction of the spline nut 33 is constrained by the limit bearing 14, ensuring that the movements of the spline nut 33 and the screw nut 32 do not interfere with each other. Even when switching between injection and pre-plasticizing actions, both can maintain their respective motion accuracy. The difference between the spline nut 33 and the screw nut 32 is that the screw nut 32 drives the ball spline screw 31 to perform linear reciprocating motion through the threaded section to complete the injection action, while the spline nut 33 drives the ball spline screw 31 to perform rotational motion through the spline section to complete the pre-plasticizing action.

[0038] Reference Figure 1 The hydraulic cylinder assembly 13 also includes a hydraulic cylinder piston rod 15, a hydraulic cylinder body 16, and a lead screw bearing seat 17. The two ends of the hydraulic cylinder piston rod 15 are fixed to the injection seat 1. The hydraulic cylinder body 16 can slide along the hydraulic cylinder piston rod 15, and the lead screw bearing seat 17 is fixedly connected to the hydraulic cylinder body 16. A bearing 171 is installed inside the lead screw bearing seat 17 to support the ball spline lead screw 31 and to reciprocate with it. When retraction is required, pressurized oil enters the hydraulic cylinder body 16, causing the hydraulic cylinder body 16 and the lead screw bearing seat 17 to retract along the hydraulic cylinder piston rod 15. The bearing 171 then drives the ball spline lead screw 31 and the screw 4 to retract, completing the retraction function.

[0039] The implementation principle of an electro-hydraulic hybrid injection structure according to an embodiment of the present invention is as follows: When the dual-output shaft motor 5 drives the first one-way bearing 6 to rotate, the first synchronous belt structure 71 drives the lead screw nut 32 to rotate, thereby driving the ball spline lead screw 31 to reciprocate to complete the injection action. When the dual-output shaft motor 5 drives the second one-way bearing 8 to rotate, the second synchronous belt structure 91 drives the spline nut 33 to rotate, thereby driving the ball spline lead screw 31 to rotate to complete the pre-plasticizing action. The cylinder body 16 drives the lead screw bearing seat 17 to drive the ball spline lead screw 31 to retract, thereby realizing the injection retraction function.

[0040] Example 2:

[0041] The difference from Embodiment 1 lies in the installation method of the spline nut 33 and the lead screw nut 32. In this embodiment, the spline nut 33 and the lead screw nut 32 are fixedly connected by a connector, thereby enabling the spline nut and the lead screw nut to rotate synchronously and ensuring the coaxiality of the spline nut 33 and the lead screw nut 32 during rotation. Here, the connector can preferably be a connecting flange.

[0042] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An electro-hydraulic hybrid injection structure, characterized in that: The electro-hydraulic hybrid injection structure includes: Injection port (1); Cylinder (2); A lead screw assembly (3) is installed inside the injection seat (1); Screw (4), which is fixedly connected to the lead screw assembly (3); The system comprises a dual-axis motor (5), a displacement transmission assembly (7), and a rotary transmission assembly (9). One output end of the dual-axis motor (5) is driven to the displacement transmission assembly (7), which is driven to the lead screw assembly (3). The displacement transmission assembly (7) is used to drive the lead screw assembly (3) to move axially. The other output end of the dual-axis motor (5) is driven to the rotary transmission assembly (9), which drives the lead screw assembly (3) to rotate unidirectionally. The dual-output shaft motor (5) has a first working condition and a second working condition that are arranged opposite to each other. In the first working condition, the dual-output shaft motor (5) drives the displacement transmission assembly (7) to rotate along the first rotation direction, and the displacement transmission assembly (7) drives the lead screw assembly (3) to rotate axially for injection. In the second working condition, the dual-output shaft motor (5) drives the displacement transmission assembly (7) to rotate along the second rotation direction, and the displacement transmission assembly (7) drives the lead screw assembly (3) to rotate for pre-plasticizing. The rotation directions of the first rotation direction and the second rotation direction are opposite.

2. The electro-hydraulic hybrid injection structure according to claim 1, characterized in that: The lead screw assembly (3) includes a ball spline lead screw (31), a lead screw nut (32) and a spline nut (33). The lead screw nut (32) and the spline nut (33) are both sleeved on the ball spline lead screw (31) and are threaded to the ball spline lead screw (31). The displacement transmission assembly (7) has a first one-way transmission member, and the displacement transmission assembly (7) is driven to the lead screw nut (32) through the first one-way transmission member; the displacement transmission assembly (7) has a second one-way transmission member, and the displacement transmission assembly (7) is driven to the spline nut (33) through the second one-way transmission member.

3. The electro-hydraulic hybrid injection structure according to claim 2, characterized in that: The displacement transmission assembly (7) further includes: The first synchronous belt structure (71) is disposed between the dual-output shaft motor (5) and the lead screw nut (32). The first synchronous belt structure (71) is driven to one output end of the dual-output shaft motor (5) through the first unidirectional transmission member. The second synchronous belt structure (91) is disposed between the dual-output shaft motor (5) and the spline nut (33). The second synchronous belt structure (91) is driven to the other output end of the dual-output shaft motor (5) through the second unidirectional transmission member.

4. The electro-hydraulic hybrid injection structure according to claim 3, characterized in that: The first one-way transmission component includes a first one-way bearing (6) that rotates in one direction, and the second one-way transmission component includes a second one-way bearing (8) that rotates in one direction. The first one-way bearing (6) and the second one-way bearing (8) rotate in opposite directions.

5. The electro-hydraulic hybrid injection structure according to claim 2, characterized in that: It also includes a pre-plasticized screw seat (12) installed in the injection seat (1), and a limiting element is provided in the pre-plasticized screw seat (12) to limit the axial displacement of the spline nut (33) relative to the pre-plasticized screw seat (12).

6. The electro-hydraulic hybrid injection structure according to claim 5, characterized in that: It also includes an injection screw seat (11); the injection screw seat (11) and the pre-plasticized screw seat (12) are fixedly installed together in the injection seat (1); the spline nut (33) is rotatably installed in the pre-plasticized screw seat (12), and the screw nut (32) is rotatably installed in the injection screw seat (11).

7. The electro-hydraulic hybrid injection structure according to claim 6, characterized in that: The spline nut (33) and the lead screw nut (32) are fixedly connected by a connector.

8. The electro-hydraulic hybrid injection structure according to claim 2, characterized in that: It also includes a hydraulic cylinder assembly (13) disposed on the injection seat (1) and used to drive the lead screw assembly (3) to exit from the barrel (2) after injection is completed; a lead screw bearing seat (17) is connected between the hydraulic cylinder assembly (13) and the lead screw assembly (3), the lead screw bearing seat (17) is slidably installed on the injection seat (1) and the lead screw assembly (3) passes through it.

9. The electro-hydraulic hybrid injection structure according to claim 8, characterized in that: The cylinder assembly (13) includes a cylinder piston rod (15) and a cylinder body (16). The lead screw bearing seat (17) is fixedly connected to the cylinder body (16) so that during the pre-plasticizing action, the lead screw bearing seat (17) and the cylinder body (16) move synchronously along the axial direction of the lead screw assembly (3) away from the material cylinder (2).

10. The electro-hydraulic hybrid injection structure according to claim 8, characterized in that: The lead screw assembly (3) further includes a screw connecting sleeve (41), which connects the ball spline lead screw (31) and the screw (4); the lead screw bearing seat (17) is sleeved on the outside of the screw connecting sleeve (41) for relative rotation between the two, and a bearing (171) is provided between the lead screw bearing seat (17) and the screw connecting sleeve (41).

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