Forming device and forming method for special-shaped rubber mat

Abstract

The forming device comprises an upper die, a lower die, an insert and a mold core, the mold core is arranged in a forming cavity of the lower die, the top face of the mold core is attached to the bottom face of the upper die after die assembly, the lower die and the mold core are combined to form an annular groove used for containing the insert, the top of the insert is flush with the top face of the lower die, and the insert is arranged in the annular groove. The upper mold forming cavity, the insert and the mold core are combined to form a molded surface of the special-shaped rubber mat, the contact surface of the outer circular surface of the insert and the lower mold is a conical surface, the insert is convenient to assemble, disassemble and position, and a plurality of through holes for ejecting the insert are formed in the bottom of the lower mold; the insert is divided into a plurality of petals, one of the joint surfaces of the two petals of the insert at the petals is provided with a convex surface, the other surface is provided with a convex surface, and the concave surface is tightly matched with the convex surface, so that the petals of the insert are ensured to be consistent up and down without dislocation, a step surface at the joint of parts is eliminated, and the special-shaped rubber mat is ensured to be difficult to demould at lower cost. Steps at the joint of the parts are eliminated, the part quality is improved, and part demolding is facilitated.

Description

Technical Field

[0001] The invention relates to the field of forming and processing of mixed rubber materials, in particular to a forming device and a forming method for a special-shaped rubber pad. Background Art

[0002] When the machine is working, some of its parts, such as gears, turbines, pulleys and sprockets, need to rotate. These parts are usually mounted on the shaft. When these parts and the shaft need to be sealed, rubber pads are usually set between the shaft and the parts. However, the connection between the conventional rubber pads and the parts is tight, and there is a problem of poor sealing. Figure 7 The figure shows the structure schematic diagram of the special-shaped rubber pad. The cross-section of the special-shaped rubber pad is a circular ring. The outer circumferential surface of the ring is provided with a recessed portion. The special-shaped rubber pad is sleeved on the outer surface of the shaft. The inner side of the part is embedded in the recessed portion of the special-shaped rubber pad. The special-shaped rubber pad and the shaft are interference fit, and the inner side of the part and the recessed portion are interference fit, thereby enhancing the sealing between the part and the shaft.

[0003] However, the forming of the special-shaped rubber pad requires considering the precise shape and size of the rubber pad when designing the mold, which increases the complexity of the design. For the same rubber product, a variety of rubber molds with different structural forms can be designed according to different processing equipment and its forming process methods. The structural form is directly related to the product quality, production efficiency, mold manufacturing cost and its service life, etc. Therefore, the mold structure design is very important. Summary of the invention

[0004] The present invention aims to provide a forming device and a forming method for a special-shaped rubber pad. The upper mold forming cavity, the insert, and the core are combined to form the mold surface of the special-shaped rubber pad. The part where the petals meet is designed with convex and concave surfaces to ensure that the two petals of the insert are aligned and not misaligned up and down, and the step surface at the part where the parts meet is eliminated. At a lower cost, it is ensured that the parts are not easy to demold, the steps at the part where the parts meet are eliminated, and the quality of the parts is improved.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows: A forming device for a special-shaped rubber pad comprises an upper die, a lower die, an insert and a core, the lower surface of the upper die and the upper surface of the lower die are fitted together, a forming cavity is respectively arranged inside the upper die and the lower die, the core is arranged in the forming cavity of the lower die, the top surface of the core fits with the bottom surface of the upper die after the die is closed, the core is a circular ring structure, the upper part of the outer circular surface of the core and the inner surface of the forming cavity of the lower die are formed with an annular groove for placing the insert, the insert is a circular ring structure, the top of the inner circular surface of the insert is provided with a convex portion matching with a concave portion of the special-shaped rubber pad, the inner circular surface of the top of the insert and the outer circular surface of the top of the core are combined to form the lower surface of the special-shaped rubber pad and the forming surface inside the concave portion, The molding cavity of the upper mold matches the upper surface of the special-shaped rubber pad, the top surface of the core and the insert fits the lower surface of the upper mold, the outer cylindrical surface of the insert and the contact surface of the lower mold are conical surfaces, which are convenient for loading and unloading and positioning of the insert, and the bottom of the lower mold is provided with a plurality of through holes for ejecting the insert; the insert is divided into multiple petals, and one side of the joint surface of the two petals of the insert at the petal is set as a convex surface, and the other side is set as a convex surface, and the concave surface and the convex surface are tightly matched; it is ensured that the upper and lower petals of the insert are consistent and not misaligned, and the step surface at the joint of the parts is eliminated, so that the special-shaped rubber pad is not easy to demold at a lower cost, the step at the joint of the parts is eliminated, the quality of the parts is improved, and the demolding of the parts is convenient.

[0006] The upper die or the lower die is provided with a temperature measuring hole, and a thermometer is arranged in the temperature measuring hole.

[0007] The upper mold or the lower mold is provided with a mold opening groove, which is a step provided at the junction of the two sides of the upper mold or the lower mold, so as to facilitate the removal of the upper mold through the mold opening groove when disassembling the mold.

[0008] Handles are respectively installed on both sides of the upper die and the lower die.

[0009] The outer cylindrical surface of the core is provided with a boss, and the outer surface of the boss is clearance-matched with the insert to facilitate the disassembly and assembly of the mold; the lower part of the boss of the core is interference-fitted with the inner surface of the molding cavity of the lower mold to facilitate the installation and positioning of the core to the lower mold.

[0010] An annular overflow groove is arranged on the outer side of the upper mold forming cavity. The overflow groove is provided with a through hole connected to the outside. The excess rubber in the mold is squeezed out of the mold through the overflow groove and the through hole, which is convenient for the forming of the special-shaped rubber pad.

[0011] The upper die and the lower die are respectively provided with guide pin holes at corresponding positions, and guide pins are arranged in the guide pin holes. The upper die and the lower die are positioned by the guide pins.

[0012] The forming device of the special-shaped rubber pad also includes a bottom plate, and the bottom plate is provided with an ejector pin at a position corresponding to the through hole of the lower mold, and the ejector pin is in clearance fit with the through hole of the lower mold.

[0013] The upper die and the lower die are respectively provided with a plurality of forming cavities, and a plurality of special-shaped rubber pads can be formed simultaneously, thereby improving work efficiency.

[0014] A method for forming a special-shaped rubber pad comprises the following steps: 1) Add blank: Heat the mold to 143±2℃. After the temperature stabilizes, punch the rubber sheet directly after the part is removed according to the shape of the part and put it into the molding cavity after the insert and core are combined. The weight of the blank is 6~8% greater than the weight of the product; 2) Vulcanization forming: After the upper mold and the lower mold are closed, they are sent to the vulcanizer. Within 10 minutes, the mold temperature is raised to the standard vulcanization temperature of 143±2℃, and the pressure is increased to 2-5.8MPa. From the time the mold temperature reaches the vulcanization temperature, the vulcanization takes 33-34 minutes to form. The excess blank flows out from the overflow groove; 3) Demolding: After forming is completed, remove the upper mold, and eject the insert and the formed parts upward through the through hole of the lower mold. After ejection, separate the insert into petals and take out the parts. Complete demolding and reassemble to produce the next special-shaped rubber pad.

[0015] Furthermore, the forming method of the special-shaped rubber pad also includes a trial mold, and the trial mold includes the following steps: S1: During the vulcanization process, the mold is pressurized to 2Mpa, and the rubber is vulcanized and then demolded; S2: After demolding, check whether the special-shaped rubber pad has problems such as incomplete product forming, unstable internal structure and surface defects. If no problems exist, stop the mold trial and continue production at the pressure. If yes, increase the pressure and continue the mold trial until the above problems no longer exist. S3: After demoulding, check the thickness of the burr of the special-shaped rubber pad (15). When the burr thickness is less than 0.15 mm, stop the mold trial and continue production at this pressure. When the burr thickness is greater than 0.15 mm, increase the pressure and continue the mold trial until the burr thickness is less than 0.15 mm.

[0016] In the step 3), during demoulding, after the upper mold is removed, the lower mold is placed on the bottom plate, and the ejector pins on the bottom plate pass through the bottom through holes of the lower mold to eject the insert and the formed parts upward.

[0017] The temperature of the mold is not allowed to drop by more than 10% during the loading and unloading process. If the temperature difference is too large, it will affect the forming quality and forming accuracy of the parts.

[0018] Beneficial effects of the present invention: 1. In the present invention, the complex shape of the special-shaped rubber pad can be accurately formed through the close cooperation of the upper mold, the lower mold, the insert and the core, ensuring the consistency and high precision of the product. During the forming process, by controlling the vulcanization temperature, pressure and time, the vulcanization quality of the product is improved, the defective rate is reduced, and the overall production efficiency is improved.

[0019] 2. The insert of the present invention is designed as a detachable multi-petal structure, which is convenient for installation and disassembly. At the same time, it can more flexibly adapt to the production needs of special-shaped rubber pads of different shapes, and enhance the versatility and flexibility of the mold. The close matching design of the convex surface and the concave surface ensures that the two petals of the insert are aligned and not misaligned, eliminates the step surface at the joint of the parts, ensures that the special-shaped rubber pad is not easy to demold at a lower cost, eliminates the step at the joint of the parts, improves the quality of the parts, and facilitates the demolding of the parts.

[0020] 3. During the demoulding process of the device of the present invention, the insert and the formed parts can be easily ejected through the cooperation of the bottom plate and the ejector pin, which simplifies the demoulding steps and improves the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of the forming device of the special-shaped rubber pad of the present invention.

[0022] Figure 2 It is a cross-sectional view of the forming device of the special-shaped rubber pad of the present invention.

[0023] Figure 3 It is a schematic diagram of the upper mold structure of the forming device of the shaped rubber pad of the present invention.

[0024] Figure 4 It is a schematic diagram of the lower mold structure of the forming device of the special-shaped rubber pad of the present invention.

[0025] Figure 5 It is a cross-sectional view of an insert of a forming device for a special-shaped rubber pad of the present invention.

[0026] Figure 6 It is a cross-sectional view of the core of the forming device of the special-shaped rubber pad of the present invention.

[0027] Figure 7 It is a cross-sectional view of the special-shaped rubber pad of the present invention.

[0028] Figure 8 It is a schematic diagram of the bottom plate structure of the forming device of the special-shaped rubber pad of the present invention.

[0029] Among them, 1. upper mold; 2. lower mold; 3. insert; 4. core; 5. guide pin; 6. handle; 7. bottom plate; 8. ejector pin; 9. raised part; 10. temperature measuring hole; 11. mold opening groove; 12. boss; 13. overflow glue groove; 14. molding cavity; 15. special-shaped rubber pad; 16. recessed part. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0031] Example 1 This embodiment provides a Figure 1-6The forming device of a special-shaped rubber pad shown in the figure comprises an upper mold 1, a lower mold 2, an insert 3 and a core 4. The lower surface of the upper mold 1 fits with the upper surface of the lower mold 2. The upper mold 1 and the lower mold 2 are respectively provided with a molding cavity 14. The core 4 is arranged in the molding cavity 14 of the lower mold 2. The top surface of the core 4 fits with the bottom surface of the upper mold 1 after the mold is closed. The core 4 is a circular ring structure. The upper part of the outer circumferential surface of the core 4 and the inner surface of the molding cavity 14 of the lower mold 2 form an annular groove for placing the insert 3. The insert 3 is a circular ring structure. The top of the inner circumferential surface of the insert 3 is provided with a protrusion 9 that matches the concave part 16 of the special-shaped rubber pad 15. The inner circumferential surface of the top of the insert 3 and the outer circumferential surface of the top of the core 4 are respectively provided with a protrusion 9 that matches the concave part 16 of the special-shaped rubber pad 15. The circular surface is combined into the lower surface of the special-shaped rubber pad 15 and the inner surface of the recessed portion 16. The molding cavity 14 of the upper mold 1 matches the upper surface of the special-shaped rubber pad 15. The top surface of the core 4 and the insert 3 fits with the lower surface of the upper mold (1). The outer circular surface of the insert 3 and the contact surface of the lower mold 2 are conical surfaces, which are convenient for loading and unloading and positioning of the insert 3. The bottom of the lower mold 2 is provided with a plurality of through holes for ejecting the insert 3. The insert 3 is divided into multiple petals. One side of the joint surface of the two petals of the insert 3 at the petal division is provided with a convex surface, and the other side is provided with a convex surface. The concave surface and the convex surface are closely matched. A circular ring-shaped overflow groove 13 is provided on the outer side of the molding cavity 14 of the upper mold 1. The overflow groove 13 is provided with a through hole connected to the outside.

[0032] In this embodiment, the forming of the special-shaped rubber pad 15 is completed through the following steps: 1) Adding blanks: Heat the mold to 143±2℃. After the temperature stabilizes, punch the rubber sheet directly after the part is removed according to the shape of the part and put it into the molding cavity 14 after the insert 3 and the core 4 are combined. The weight of the blank is 6~8% greater than the weight of the product; 2) Vulcanization forming: After closing the upper mold 1 and the lower mold 2, send them into the vulcanizer, raise the mold temperature to the standard vulcanization temperature of 143±2℃ within 10 minutes, pressurize to 2~5.8MPa, and vulcanize for 33~34 minutes from the time when the mold temperature reaches the vulcanization temperature, and the excess blank flows out from the overflow groove 13; 3) Demolding: After the forming is completed, the upper mold 1 is removed, and the insert 3 and the formed part are ejected upward through the through hole of the lower mold 2. After ejection, the insert 3 is separated into petals and the part is taken out. The demolding is completed and reassembled to produce the next special-shaped rubber pad 15; The temperature drop of the mold during loading and unloading is not allowed to exceed 10%.

[0033] Example 2 Compared with Example 1, the present embodiment is different in that, in the present embodiment, a boss 12 is provided on the outer cylindrical surface of the core 4, the outer surface of the boss 12 is clearance-fitted with the insert 3, the lower part of the boss 12 of the core 4 is interference-fitted with the inner surface of the molding cavity 14 of the lower mold 2, and the rest of the structure is the same as that of Example 1.

[0034] In this embodiment, the outer surface of the boss 12 is clearance-matched with the insert 3, which is convenient for loading and unloading the insert 3 during mold disassembly and assembly, saving mold loading and unloading time, and avoiding excessive drop in mold temperature due to long loading and unloading time, thereby affecting the part forming quality and forming accuracy; the lower part of the boss 12 of the core 4 is interference-fitted with the inner surface of the molding cavity 14 of the lower mold 2, which is convenient for installing and positioning the core 4 to the lower mold 2.

[0035] Example 3 Compared with Example 1, the present embodiment is different in that, in the present embodiment, the upper mold 1 or the lower mold 2 is provided with a temperature measuring hole 10, and a thermometer is provided in the temperature measuring hole 10; the upper mold 1 or the lower mold 2 is provided with a mold opening groove 11, and the mold opening groove 11 is a step provided at the junction of the two sides of the upper mold 1 or the lower mold 2, and handles 6 are respectively installed on both sides of the upper mold 1 and the lower mold 2, and guide pin holes are respectively provided at the corresponding positions of the upper mold 1 and the lower mold 2, and guide pins 5 are provided in the guide pin holes, and the upper mold 1 and the lower mold 2 are positioned by the guide pins 5; the remaining structure is the same as that of Example 1.

[0036] In this embodiment, by setting temperature measuring holes 10 on the upper mold 1 and the lower mold 2, it is convenient to monitor the mold temperature in real time to avoid the temperature of the special-shaped rubber pad 15 being too high or too low during vulcanization forming, which affects the forming quality; by setting a mold opening groove 11 on the upper mold 1 or the lower mold 2, after the forming is completed, when the upper mold 1 is removed, the upper mold 1 is lifted up through the mold opening groove 11 to remove the upper mold 1; by installing handles 6 on both sides of the upper mold 1 and the lower mold 2 respectively, it is convenient to carry during the loading and unloading of the mold, and the staff can avoid being scalded by the high temperature of the mold during the process of closing and demolding; the upper mold 1 and the lower mold 2 are positioned by the guide pin 5, which is convenient for the upper and lower molds 2 to dock when closing the mold.

[0037] Example 4 The difference between this embodiment and embodiment 1 is that, in this embodiment, Figure 8 As shown, a bottom plate 7 is provided at the bottom of the lower mold 2, and an ejector pin 8 is provided at a position of the bottom plate 7 corresponding to the through hole of the lower mold 2, and the ejector pin 8 is clearance-matched with the through hole of the lower mold 2; the rest of the structure is the same as that of Example 1.

[0038] In this embodiment, when demolding, after removing the upper mold 1, the lower mold 2 is placed on the bottom plate 7, and the ejector pins 8 on the bottom plate 7 pass through the bottom through holes of the lower mold 2 to eject the insert 3 and the formed parts upward, making demolding easier.

[0039] Example 5 The difference between this embodiment and the first embodiment is that, in this embodiment, the upper mold 1 and the lower mold 2 are respectively provided with two molding cavities 14, and the rest of the structure is the same as that of the first embodiment.

[0040] In this embodiment, by respectively providing two forming cavities 14 in the upper mold 1 and the lower mold 2, two special-shaped rubber pads 15 can be formed at the same time, thereby improving work efficiency.

[0041] Example 6 Compared with Example 1, the forming device of the special-shaped rubber pad in this embodiment has the same structure as that in Example 1, except that the forming method of the special-shaped rubber pad in this embodiment further includes a trial mold, and the trial mold includes the following steps: S1: During the vulcanization process, the mold is pressurized to 2Mpa, and the rubber is vulcanized and then demolded; S2: After demolding, check whether the special-shaped rubber pad 15 has problems such as incomplete product forming, unstable internal structure and surface defects. If no problems exist, stop the mold trial and continue production at the pressure. If yes, increase the pressure and continue the mold trial until the above problems do not exist; S3: After demoulding, check the thickness of the burr of the special-shaped rubber pad (15). When the burr thickness is less than 0.15 mm, stop the mold trial and continue production at this pressure. When the burr thickness is greater than 0.15 mm, increase the pressure and continue the mold trial until the burr thickness is less than 0.15 mm.

[0042] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A forming device for a special-shaped rubber pad, characterized in that: The invention comprises an upper die (1), a lower die (2), an insert (3) and a core (4), wherein the lower surface of the upper die (1) is fitted with the upper surface of the lower die (2), and a molding cavity (14) is respectively arranged inside the upper die (1) and the lower die (2), and the core (4) is arranged in the molding cavity (14) of the lower die (2). The core (4) is a circular ring structure, and an annular groove for placing the insert (3) is formed between the upper part of the outer circumference of the core (4) and the inner surface of the molding cavity (14) of the lower die (2). The insert (3) is a circular ring structure, and a protrusion (9) matching with a concave portion (16) of a special-shaped rubber pad (15) is arranged on the top of the inner circumference of the insert (3). The inner cylindrical surface of the top of the insert (3) and the outer cylindrical surface of the top of the core (4) are combined to form the lower surface of the special-shaped rubber pad (15) and the inner surface of the recessed portion (16); the molding cavity (14) of the upper mold (1) matches the upper surface of the special-shaped rubber pad (15); the top surfaces of the core (4) and the insert (3) are in contact with the lower surface of the upper mold (1); the contact surface between the outer cylindrical surface of the insert (3) and the lower mold (2) is a conical surface; the bottom of the lower mold (2) is provided with a plurality of through holes for ejecting the insert (3); the insert (3) is divided into multiple petals; one side of the joint surface of the two petals of the insert (3) at the petal division is provided with a convex surface, and the other side is provided with a convex surface; the concave surface and the convex surface are closely matched.

2. The forming device of the special-shaped rubber pad according to claim 1, characterized in that: The upper die (1) or the lower die (2) is provided with a temperature measuring hole (10), and a temperature measuring meter is provided in the temperature measuring hole (10).

3. The forming device of the special-shaped rubber pad according to claim 1, characterized in that: The upper die (1) or the lower die (2) is provided with a die opening groove (11), and the die opening groove (11) is a step provided at the junction of two sides of the upper die (1) or the lower die (2).

4. The forming device of the special-shaped rubber pad according to claim 1, characterized in that: The outer cylindrical surface of the core (4) is provided with a boss (12), and the outer surface of the boss (12) is clearance-fitted with the insert (3); the lower part of the boss (12) of the core (4) is interference-fitted with the inner surface of the molding cavity (14) of the lower mold (2).

5. The forming device of the special-shaped rubber pad according to claim 1, characterized in that: An annular glue overflow groove (13) is provided on the outer side of the molding cavity (14) of the upper mold (1), and the glue overflow groove (13) is provided with a through hole connected to the outside.

6. The forming device of the special-shaped rubber pad according to claim 1, characterized in that: Guide pin holes are respectively arranged at corresponding positions of the upper die (1) and the lower die (2), guide pins (5) are arranged in the guide pin holes, and the upper die (1) and the lower die (2) are positioned by means of the guide pins (5).

7. The forming device of the special-shaped rubber pad according to claim 1, characterized in that: The forming device of the special-shaped rubber pad (15) further comprises a bottom plate (7), wherein the bottom plate (7) is provided with an ejector pin (8) at a position corresponding to the through hole of the lower die (2), and the ejector pin (8) is clearance-matched with the through hole of the lower die (2).

8. The forming device of the special-shaped rubber pad according to claim 1, characterized in that: The upper die (1) and the lower die (2) are respectively provided with a plurality of molding cavities (14).

9. The forming device of the special-shaped rubber pad according to claim 1, characterized in that: Handles (6) are respectively installed on both sides of the upper die (1) and the lower die (2).

10. A method for forming a special-shaped rubber pad, characterized in that: A forming device for the special-shaped rubber pad (15) according to any one of claims 1 to 9 comprises the following steps: 1) Adding blanks: Heat the mold to 143±2°C. After the temperature stabilizes, punch out the blanks directly on the rubber sheet after the part is removed according to the shape of the part and place them into the molding cavity (14) formed by the combination of the insert (3) and the core (4). The weight of the blanks is 6-8% greater than the weight of the product. 2) Vulcanization forming: The upper mold (1) and the lower mold (2) are closed and placed in a vulcanizer. The mold temperature is raised to the standard vulcanization temperature of 143±2°C within 10 minutes, and the pressure is increased to 2-5.8 MPa. The vulcanization is performed for 33-34 minutes from the time when the mold temperature reaches the vulcanization temperature. The excess blank flows out from the overflow groove (13); 3) Demolding: After the forming is completed, the upper mold (1) is removed, and the insert (3) and the formed part are ejected upward through the through hole of the lower mold (2). After ejection, the insert (3) is separated into two parts and the part is taken out. The demolding is completed and the parts are reassembled to produce the next special-shaped rubber pad (15).

11. The forming method according to claim 10, characterized in that: The forming method of the special-shaped rubber pad (15) further comprises a trial mold, and the trial mold comprises the following steps: S1: During the vulcanization process, the mold is pressurized to 2Mpa, and the rubber is vulcanized and then demolded; S2: After demolding, check whether the special-shaped rubber pad (15) has problems such as incomplete product forming, unstable internal structure and surface defects. If no problems exist, stop the mold trial and continue production at the pressure. If no problems exist, increase the pressure and continue the mold trial until the above problems no longer exist. S3: After demoulding, check the thickness of the burr of the special-shaped rubber pad (15). When the burr thickness is less than 0.15 mm, stop the mold trial and continue production at this pressure. When the burr thickness is greater than 0.15 mm, increase the pressure and continue the mold trial until the burr thickness is less than 0.15 mm.

12. The forming method according to claim 10, characterized in that: In the step 3), when demoulding, after the upper mold (1) is removed, the lower mold (2) is placed on the bottom plate (7), and the ejector pin (8) on the bottom plate (7) passes through the bottom through hole of the lower mold (2) to eject the insert (3) and the formed part upward.

13. The forming method according to claim 10, characterized in that: During the loading and unloading process, the mold temperature drops by less than 10%.

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