Rubber injection molding machine and method

Abstract

The invention relates to a rubber injection molding machine and method, which comprises a frame assembly, a mold clamping cylinder is vertically arranged on the frame assembly, a sliding lower hot plate which is lifted and lowered on the frame assembly is arranged on the mold clamping cylinder, a fixed upper hot plate is arranged above the sliding lower hot plate, a mold whose upper surface is used for pressure contact with the lower surface of the fixed upper hot plate is pre-set on the upper surface of the sliding lower hot plate, an injection cylinder is arranged on the frame assembly, a hydraulic motor is lifted and lowered on the injection cylinder, an injection rod is transmission-connected to the lower end of the hydraulic motor, and an injection barrel is arranged on the fixed upper hot plate. The invention has reasonable design, compact structure and convenient use.

Description

Technical Field

[0001] The present invention relates to a rubber injection molding machine and method. Background Art

[0002] At present, rubber injection molding machine is a technology for the production of rubber molded products. Injection machine for short, it is the main molding equipment that uses a molding mold to make rubber into various shapes of rubber products. Injection molding is achieved through injection machines and molds. The working principle of the injection machine is to inject the plasticized (i.e. viscous flow state) rubber into the closed mold cavity with the help of the thrust of the injection rod, and obtain the product after vulcanization and finalization. Injection molding is a cyclic process, and each cycle mainly includes: melt plasticization-quantitative feeding-pressure injection-mold filling vulcanization-mold opening and taking out the workpiece. After taking out the workpiece, the mold is closed again and the next cycle is carried out. Quantitative feeding-melt plasticization: the screw of the feeder rotates, so that the rubber fills the entire injection cavity under the rotation of the screw of the feeder, and the rubber completes the mixing and plasticization and quantitative feeding. Pressure injection: the injection rod is pushed by the hydraulic cylinder, and the molten rubber is injected into the mold cavity through the injection rod at a certain pressure and speed. Vulcanization: After the injection is completed, the molten material injected into the mold cavity is kept in a fixed state of vulcanization. After the vulcanization time is up, the mold is removed and the part is taken out.

[0003] like Figure 1 In the prior art, the feeder stops working after quantitative feeding. During injection, the injection rod only moves axially to push the material and exert pressure on the rubber. The disadvantages are as follows:

[0004] 1. Since there is a mutual moving assembly gap between the outer diameter of the injection rod and the inner diameter of the barrel, when the injection rod pushes the material forward, part of the material will flow back from the gap due to the resistance such as the reduction of the nozzle diameter and the friction between the material and the inner wall of the barrel.

[0005] 2. In addition, the reflux of the rubber may lead to insufficient injection volume, resulting in poor density of the workpiece after vulcanization, and defects such as pores.

[0006] 3. The injection rod pushes the injection in a straight line, which not only has to overcome the resistance of the rubber, but also the friction between the screw and the barrel. Long-term high pressure will cause certain damage to the hydraulic system.

[0007] 4. Since the injection rod has a large aspect ratio, when the injection rod pushes the material forward, it will swing. In addition, the reaction force of the material will cause gnawing between the injection rod and the barrel, resulting in damage to the barrel or the injection rod. Summary of the invention

[0008] The technical problem to be solved by the present invention is generally to provide a rubber injection molding machine and method. The innovation of the present invention is to change the injection rod smooth (or with multiple annular grooves) head structure into a structure with a reverse thread groove; the helix angle of the reverse thread groove is 8°∽12°; the traditional single linear propulsion motion of the injection rod is added with a rotational motion, and the injection rod implements both linear propulsion and rotational motion at the same time.

[0009] To solve the above problems, the technical solution adopted by the present invention is:

[0010] A rubber injection molding machine comprises a frame assembly, on which a mold clamping cylinder is vertically arranged, on which a sliding lower hot plate which is lifted and lowered on the frame assembly is arranged, on which a fixed upper hot plate is arranged above the sliding lower hot plate, on the upper surface of the sliding lower hot plate a mold whose upper surface is used for pressure contact with the lower surface of the fixed upper hot plate is pre-set, on which an injection cylinder is arranged on the frame assembly, on which a hydraulic motor is lifted and lowered, an injection rod is transmission-connected at the lower end of the hydraulic motor, an injection barrel is arranged on the fixed upper hot plate, the injection rod performs lifting and rotating motions in the vertical injection channel of the injection barrel, and on which an injection fixing sleeve is arranged, the upper end of the injection fixing sleeve is connected to the injection channel, and the lower end of the injection fixing sleeve is provided with an injection head for injecting rubber into an inner cavity of the mold.

[0011] As a further improvement of the above technical solution:

[0012] A feeder is arranged on the frame assembly.

[0013] The feeder comprises a feeding barrel arranged obliquely; a feeding channel inclined in the feeding barrel and having a lower end output port connected to the injection channel and used for outputting rubber,

[0014] A feeding screw is arranged in the feeding channel, and a feeding motor for driving the feeding screw to rotate is arranged on the feeding barrel.

[0015] A thread groove opposite to the rotation direction is arranged at the lower part of the injection rod.

[0016] A rubber injection method, the method comprising the following steps:

[0017] Step 1: First, position the mold on the sliding lower hot plate; then, the sliding lower hot plate moves upward under the push of the mold clamping cylinder and squeezes with the fixed upper hot plate to clamp the mold to the set pressure; secondly, the feeder works, and the rubber material is in a molten state under the extrusion and mixing action of the feeding screw; thirdly, the feeding motor drives the feeding screw to rotate in the feeding barrel, and the rubber material is plasticized and squeezed into the injection barrel through the feeding channel;

[0018] Step 2: In the injection barrel, the injection cylinder drives the hydraulic motor, and the injection rod overcomes the gravity as the rubber material is pressed in, and is continuously lifted until it reaches the required height;

[0019] Step 3: During injection, under the action of the injection cylinder, the injection rod moves downward to squeeze the rubber material, while the hydraulic motor drives the injection rod to rotate and increase pressure;

[0020] Step 4: The molten rubber is injected into the mold through the injection head. By controlling the temperature of the mold, vulcanization and shaping are completed within the set time. After the vulcanization time is up, the mold is opened and the part is taken out.

[0021] The present invention effectively changes sliding friction into rolling friction and greatly overcomes resistance because the injection rod pushes and rotates at the same time during the injection process, thereby reducing the pressure of the hydraulic system, reducing the hydraulic load during the injection process, protecting the hydraulic station, and increasing the service life of the hydraulic station; during the injection process, the rotation of the injection rod straightens its swing in linear motion and overcomes the gnawing phenomenon between the injection rod and the barrel caused by the reaction force of the material; during the injection process, the reverse thread structure of the injection rod head with a helical lead angle of 8°∽12° and its rotation increase the pushing effect and prevent the molten rubber from flowing back under high pressure. It prevents the workpiece from having defects such as insufficient density and bubbles due to insufficient injection of rubber.

[0022] The invention has reasonable design, low cost, durability, safety and reliability, simple operation, time and labor saving, money saving, compact structure and convenient use. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the prior art.

[0024] Figure 2 It is a structural schematic diagram of the present invention.

[0025] Figure 3 It is a partial structural schematic diagram of the present invention.

[0026] Among them: 1. Mold; 2. Hydraulic motor; 3. Injection cylinder; 4. Injection rod; 5. Injection barrel; 6. Fixed upper hot plate; 7. Injection head; 8. Injection fixed sleeve; 9. Sliding lower hot plate; 10. Clamping cylinder; 11. Feeding barrel; 12. Feeding screw; 13. Feeding motor; 14. Feeding channel; 15. Injection channel; 16. Thread groove. DETAILED DESCRIPTION

[0027] like Figure 2-3As shown, the rubber injection molding machine of this embodiment includes a frame assembly, a mold clamping cylinder 10 is vertically arranged on the frame assembly, a sliding lower hot plate 9 is arranged on the mold clamping cylinder 10 and is lifted and lowered on the frame assembly, a fixed upper hot plate 6 is arranged above the sliding lower hot plate 9, and a mold 1 whose upper surface is pre-set on the upper surface of the sliding lower hot plate 9 for pressure contact with the lower surface of the fixed upper hot plate 6, an injection cylinder 3 is arranged on the frame assembly, a hydraulic motor 2 is lifted and lowered on the injection cylinder 3, an injection rod 4 is transmission-connected at the lower end of the hydraulic motor 2, an injection barrel 5 is arranged on the fixed upper hot plate 6, the injection rod 4 performs lifting and rotating movements in the vertical injection channel 15 of the injection barrel 5, and an injection fixing sleeve 8 is arranged on the fixed upper hot plate 6, the injection fixing sleeve 8 has its upper end connected to the injection channel 15, and its lower end is provided with an injection head 7 for injecting rubber into the inner cavity of the mold 1.

[0028] A feeder is arranged on the frame assembly.

[0029] The feeder includes a feeder barrel 11 which is tilted and arranged; a feeder channel 14 which is tilted in the feeder barrel 11 and has a lower end output port connected to an injection channel 15 and is used to output rubber.

[0030] A feeding screw 12 is arranged in the feeding channel 14 , and a feeding motor 13 for driving the feeding screw 12 to rotate is arranged on the feeding barrel 11 .

[0031] A thread groove 16 is provided at the lower part of the injection rod 4 in the opposite direction to the rotation direction.

[0032] The rubber injection method of this embodiment comprises the following steps:

[0033] Step 1: First, position the mold on the sliding lower hot plate; then, the sliding lower hot plate moves upward under the push of the mold clamping cylinder and squeezes with the fixed upper hot plate to clamp the mold to the set pressure; secondly, the feeder works, and the rubber material is in a molten state under the extrusion and mixing action of the feeding screw; thirdly, the feeding motor drives the feeding screw to rotate in the feeding barrel, and the rubber material is plasticized and squeezed into the injection barrel through the feeding channel;

[0034] Step 2: In the injection barrel, the injection cylinder drives the hydraulic motor, and the injection rod overcomes the gravity as the rubber material is pressed in, and is continuously lifted until it reaches the required height;

[0035] Step 3: During injection, under the action of the injection cylinder, the injection rod moves downward to squeeze the rubber material, while the hydraulic motor drives the injection rod to rotate and increase pressure;

[0036] Step 4: The molten rubber is injected into the mold through the injection head. By controlling the temperature of the mold, vulcanization and shaping are completed within the set time. After the vulcanization time is up, the mold is opened and the part is taken out.

[0037] Step 1: First, the mold 1 is positioned and placed on the sliding lower hot plate 9; then, the sliding lower hot plate 9 moves upward under the push of the mold clamping cylinder 10 and is squeezed with the fixed upper hot plate 6 to clamp the mold 1 to a set pressure; secondly, the feeder works, and the rubber material is in a molten state under the extrusion and mixing action of the feeding screw 12; thirdly, the feeding motor 13 drives the feeding screw 12 to rotate in the feeding barrel 11, and the rubber material is plasticized and squeezed into the injection barrel 5 through the feeding channel 14;

[0038] Step 2: In the injection barrel 5, the injection cylinder 3 drives the hydraulic motor 2, and the injection rod 4 overcomes the gravity of the rubber material as it is pressed in, and is continuously lifted until it reaches the required height;

[0039] Step 3: During injection, under the action of the injection cylinder 3, the injection rod 4 moves downward to squeeze the rubber material, while the hydraulic motor 2 drives the injection rod 4 to rotate and increase pressure;

[0040] Step 4: The molten rubber is injected into the mold 1 through the injection head 7. By controlling the temperature of the mold, vulcanization and shaping are completed within a set time. After the vulcanization time is up, the mold is opened and the part is taken out.

[0041] During injection, the injection rod rotates and pushes to complete the injection. The pushing action of the injection rod realizes pressurization. The rotational movement of the injection rod corrects the swing of the injection rod. At the same time, the reverse thread (thread groove 16) of the injection head forces the return material to move in the reverse direction, thereby preventing the return of material and preventing insufficient injection volume due to leakage of rubber, which may cause quality problems of the workpiece.

[0042] The structural innovation of the present invention lies in changing the smooth (or having multiple annular grooves) head structure of the injection rod to a structure with reverse thread grooves; adding rotational motion to the single linear propulsion motion of the traditional injection rod, and the injection rod implements both linear propulsion and rotational motion at the same time.

[0043] The present invention is fully described for a clearer disclosure, and the prior art is not listed one by one.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein with equivalents; it is obvious for those skilled in the art to combine multiple technical solutions of the present invention. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rubber injection method, Features :With the help of rubber injection molding machine; The rubber injection molding machine comprises a frame assembly, a mold clamping cylinder (10) is vertically arranged on the frame assembly, a sliding lower hot plate (9) is arranged on the mold clamping cylinder (10) and is lifted and lowered on the frame assembly, a fixed upper hot plate (6) is arranged above the sliding lower hot plate (9), a mold (1) is pre-set on the upper surface of the sliding lower hot plate (9) and the upper surface is used for pressure contact with the lower surface of the fixed upper hot plate (6), an injection cylinder (3) is arranged on the frame assembly, and a hydraulic motor is arranged on the injection cylinder (3) to lift and lower the injection cylinder (3). (2), the lower end of the hydraulic motor (2) is connected to an injection rod (4), an injection barrel (5) is arranged on the fixed upper hot plate (6), the injection rod (4) performs lifting and rotating movements in the vertical injection channel (15) of the injection barrel (5), an injection fixing sleeve (8) is arranged on the fixed upper hot plate (6), the upper end of the injection fixing sleeve (8) is connected to the injection channel (15), and the lower end thereof is provided with an injection head (7) for injecting rubber into the inner cavity of the mold (1); a feeder is arranged on the frame assembly; The method comprises the following steps: Step 1: First, position the mold on the sliding lower hot plate; then, the sliding lower hot plate moves upward under the push of the mold clamping cylinder and squeezes with the fixed upper hot plate to clamp the mold to the set pressure; secondly, the feeder works, and the rubber material is in a molten state under the extrusion and mixing action of the feeding screw; Next, the feeding motor drives the feeding screw to rotate in the feeding barrel, and the rubber material is plasticized and squeezed into the injection barrel through the feeding channel; Step 2: In the injection barrel, the injection cylinder drives the hydraulic motor, and the injection rod overcomes the gravity as the rubber material is pressed in, and is continuously lifted until it reaches the required height; Step 3: During injection, under the action of the injection cylinder, the injection rod moves downward to squeeze the rubber material, while the hydraulic motor drives the injection rod to rotate and increase pressure; Step 4: The molten rubber is injected into the mold through the injection head. By controlling the temperature of the mold, vulcanization and shaping are completed within the set time. After the vulcanization time is up, the mold is opened and the part is taken out.

2. The rubber injection method according to claim 1, Features The feeder comprises a feeder barrel (11) arranged obliquely; a feeder channel (14) inclined in the feeder barrel (11) and having a lower end output port connected to an injection channel (15) and used for outputting rubber, A feeding screw (12) is arranged in the feeding channel (14), and a feeding motor (13) for driving the feeding screw (12) to rotate is arranged on the feeding barrel (11).

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