Processing technology for rubber-coated sprocket

Abstract

A processing technology for a rubber-coated sprocket, comprising the following steps: S1, mixing; S2, forming; S3, sintering; S4, oil impregnation; S5, sizing; S6, steam treatment; S7, heat treatment; S8, sand blasting; and S9, adhesive application; S10, rubber coating: putting a sprocket skeleton (1) into a rubber coating mold, wherein the rubber coating mold comprises a master mold (9) and a slave mold (10), a positioning groove (11) is formed in the slave mold (10), the slave mold (10) is provided, in the positioning groove (11), with a plurality of positioning columns (12) used for being inserted into through holes (7), an injection molding runner (13) is formed in the slave mold (10), outlets (19) of the injection molding runner (13) are located on side walls of the positioning columns (12), and the positions of the outlets (19) of the injection molding runner (13) correspond to the positions of rubber coating holes (8); and injecting rubber into the injection molding runner (13) for rubber injection molding, followed by heat preservation, and then vulcanization; and S11, finishing: performing finishing on the rubber-coated sprocket. According to the technology, injection molding of rubber rings on both sides of the sprocket skeleton can be completed in one step, significantly improving rubber coating efficiency, improving the production efficiency of rubber-coated sprockets.

Description

Processing technology of encapsulated sprocket TECHNICAL FIELD

[0001] The present application relates to the powder metallurgy technical field, especially to a processing technology of encapsulated sprocket. BACKGROUND

[0002] The sprocket is a kind of wheel with embedded tooth type chain tooth, which is used to mesh with the block with accurate pitch on the chain ring or cable, and is widely used in the transmission equipment field due to its good mechanical transmission performance, but it is easy to wear, so the encapsulated sprocket is also born.

[0003] The common encapsulated sprocket structure at present is shown in Figure 1, which comprises a sprocket framework, the sprocket framework is integrally provided with a tooth on the outer periphery side, the sprocket framework is integrally connected with a rib plate on both sides, an annular encapsulation groove is formed between the rib plate and the sprocket framework, a rubber ring is arranged in the annular encapsulation groove, the rib plate is embedded in the side of the rubber ring away from the sprocket framework, a convex rib is integrally arranged on the inner wall of the sprocket framework, and a through hole is formed in the convex rib.

[0004] When producing the encapsulated sprocket with the structure, it is essential to encapsulate the annular encapsulation groove, and the existing rubber injection machine basically injects from one side, so twice encapsulation is needed during processing because the annular encapsulation grooves on both sides are not connected, which greatly affects the production efficiency of the encapsulated sprocket.

[0005] SUMMARY

[0006] In order to improve the production efficiency of the encapsulated sprocket, the present application provides a processing technology of encapsulated sprocket.

[0007] The processing technology of encapsulated sprocket provided by the present application adopts the following technical scheme:

[0008] The processing technology of encapsulated sprocket comprises the following steps:

[0009] S1, mixing: uniformly mixing powder raw materials according to mass percentage;

[0010] S2, forming: forming the mixed powder raw materials into a sprocket framework green body by die pressing, and the sprocket framework green body is provided with an encapsulation hole communicating with the through hole and the annular encapsulation grooves on both sides;

[0011] S3, sintering: placing the sprocket framework green body in a sintering furnace for sintering;

[0012] S4, oil immersion: immersing the sintered sprocket framework in rust-proof oil;

[0013] S5, shaping;

[0014] S6, steam treatment: the shaping piece is subjected to steam treatment in a continuous steam furnace, and a dense oxide layer is formed on the surface of the shaping piece;

[0015] S7, heat treatment: the sprocket skeleton is subjected to high-frequency induction hardening treatment, and then the sprocket skeleton is washed and then subjected to tempering treatment;

[0016] S8, sand blasting;

[0017] S9, adhesive coating;

[0018] S10, rubber coating: the sprocket skeleton is loaded into a rubber coating mold, the rubber coating mold includes a main mold and a slave mold, the slave mold is provided with a plurality of positioning columns for plugging with the through holes in the positioning groove, and the slave mold is provided with an injection flow channel, the outlet of the injection flow channel is located on the side wall of the positioning column, and the outlet position of the injection flow channel corresponds to the position of the rubber coating hole. Rubber is injected into the injection flow channel, rubber injection is performed, and after injection, heat preservation and vulcanization are performed;

[0019] S11, finishing: the rubber-coated sprocket is finished.

[0020] By adopting the above technical scheme, the production efficiency of the rubber-coated sprocket is improved; in the rubber coating, rubber is injected into the injection flow channel, and the outlet of the injection flow channel injects rubber into the rubber coating hole, so that the injection molding of the rubber rings on both sides of the sprocket skeleton is completed at one time, the rubber coating speed is greatly improved, and the production efficiency of the rubber-coated sprocket is improved.

[0021] Preferably, in step S10, during the rubber injection process, the main mold and the slave mold rotate synchronously and coaxially at high speed.

[0022] By adopting the above technical scheme, the main mold and the slave mold rotate synchronously and coaxially at high speed, and the injected rubber is thrown to the edge of the forming cavity by centrifugal force, so that the forming degree of the rubber ring is higher and the yield is higher.

[0023] Preferably, a plurality of driven columns are arranged on the side of the slave mold facing the main mold, and a plurality of plug holes are arranged on the main mold and matched with the driven columns.

[0024] By adopting the above technical scheme, it is ensured that the main mold is stationary relative to the slave mold during rotation, and the slave mold is driven to rotate by the main mold.

[0025] Preferably, the length of the positioning column is greater than the thickness of the convex rib, and the side of the main mold close to the slave mold is provided with a plug hole matched with the end of the positioning column.

[0026] By adopting the above technical scheme, it is ensured that the main mold is stationary relative to the slave mold during rotation, and the slave mold is driven to rotate by the main mold.

[0027] Preferably, in step S10, the inlet of the injection flow channel is arranged at the center of the side of the mold away from the main mold, and the injection rotating ring is arranged to rotate with the mold in the inlet of the injection flow channel.

[0028] By adopting the above technical scheme, the friction between the injection gun and the mold is reduced during the rotation of the mold.

[0029] Preferably, in step S2, two rubber coating holes are arranged in each rib of the sprocket skeleton green body, and the two rubber coating holes are respectively connected to the two side annular rubber coating grooves and the through hole.

[0030] By adopting the above technical scheme, the uniformity of injecting rubber into the annular forming cavity is ensured.

[0031] Preferably, in step S1, the following raw materials are mixed uniformly according to mass percentage: C: 0.6-0.8%, Cu: 1-2%, powder lubricant: 0.5-0.8%, and Fe: the balance.

[0032] Preferably, in step S3, the sintering temperature is 1100-1130°C, and the sintering is carried out in a protective atmosphere, and the holding time is greater than 25 minutes, so that sintering necks are formed between the particles of the sprocket skeleton green body.

[0033] In summary, the present application includes at least one of the following beneficial technical effects:

[0034] 1. Improve the production efficiency of rubber-coated sprocket; the scheme of the present application can complete the injection molding of the rubber rings on both sides of the sprocket skeleton at one time, greatly improving the rubber coating efficiency;

[0035] 2. Improve the injection molding degree of the rubber ring; in the process of injection molding, the main mold and the mold keep high-speed synchronous coaxial rotation, and the injected rubber is thrown to the edge of the forming cavity by centrifugal force, so that the molding degree of the rubber ring is higher, and the yield is higher;

[0036] 3. No need to trim the gate, and the product has high aesthetic degree; after the rubber-coated sprocket is taken out, the positioning column is pulled out from the through hole, and the gate remains in the rubber coating hole, without cutting, and since the gate is located on the inner wall of the through hole, it cannot be observed in normal use, and the aesthetic degree is high;

[0037] 4. The rubber coating mold structure is compact and has high integration degree; in the present application, the function of the positioning column is highly concentrated, which is not only used to limit the position of the sprocket skeleton in the positioning groove, but also used as the outlet of the injection flow channel, and the end of the positioning column is inserted into the insertion hole, so that the main mold and the mold rotate synchronously. BRIEF DESCRIPTION OF DRAWINGS

[0038] Fig. 1 is a structural schematic diagram of a prior art rubber-coated sprocket;

[0039] Fig. 2 is a flow chart of the processing technology of a rubber-coated sprocket according to an embodiment of the present application;

[0040] Fig. 3 is a schematic structural diagram of a rubber-coated sprocket manufactured by a processing technology of a rubber-coated sprocket disclosed in the present application;

[0041] Fig. 4 is a schematic diagram of a rubber-coated mold structure in the embodiment of the present application;

[0042] Fig. 5 is a sectional view of the rubber-coated mold in the embodiment of the present application;

[0043] Fig. 6 is a schematic diagram of another embodiment of the rubber-coated mold in the embodiment of the present application;

[0044] Reference signs: 1, sprocket framework; 2, tooth; 3, rib plate; 4, annular rubber-coated groove; 5, rubber ring; 6, convex rib; 7, through hole; 8, rubber-coated hole; 9, main mold; 10, slave mold; 11, positioning groove; 12, positioning column; 13, injection runner; 14, driven column; 15, plug hole; 16, insertion hole; 17, injection rotating ring; 18, inlet; 19, outlet. DETAILED DESCRIPTION

[0045] The present application is further described in detail below in combination with Figs. 2-6.

[0046] The present application discloses a processing technology of a rubber-coated sprocket.

[0047] Referring to Fig. 2, the processing technology of the rubber-coated sprocket comprises the following steps:

[0048] S1, mixing: the following raw materials are mixed uniformly according to mass percentage: C: 0.6-0.8%, Cu: 1-2%, powder lubricant: 0.5-0.8%, and Fe: the balance;

[0049] S2, forming: the mixed powder raw material is formed by die pressing to obtain a sprocket framework 1 green body, referring to Fig. 3, the sprocket framework 1 green body is provided with rubber-coated holes 8 which communicate with through holes 7 and annular rubber-coated grooves 4 on both sides, two rubber-coated holes 8 are provided at each convex rib 6 of the sprocket framework 1 green body, the two rubber-coated holes 8 respectively communicate with the annular rubber-coated grooves 4 on both sides and the through holes 7, the length direction of the two rubber-coated holes 8 is arranged along the radial direction of the sprocket framework 1, and the arrangement is convenient for the design of the forming mold;

[0050] S3, sintering: the sprocket framework 1 green body is placed in a sintering furnace for sintering, the sintering temperature is 1100-1130°C, and the sintering is performed in a protective atmosphere, and the holding time is greater than 25 minutes, so that sintering necks are formed between the particles of the sprocket framework 1 green body;

[0051] S4, oil immersion: the sintered sprocket framework 1 is immersed in rust-proof oil;

[0052] S5, shaping;

[0053] S6, steam treatment: the shaped part is subjected to steam treatment in a continuous steam furnace, and a dense oxide layer is formed on the surface of the shaped part;

[0054] S7, heat treatment: the sprocket tooth is subjected to high-frequency induction hardening treatment, and the sprocket frame 1 is then washed and subsequently subjected to tempering treatment;

[0055] S8, sand blasting;

[0056] S9, adhesive coating;

[0057] S10, rubber coating: the sprocket frame 1 is loaded into a rubber coating mold, and rubber injection molding is performed, followed by heat preservation and vulcanization after heat preservation;

[0058] Referring to FIGS. 4 and 5, the rubber coating mold includes a main mold 9 and a slave mold 10. The main mold 9 is provided with a profiling groove on the side close to the slave mold 10. The slave mold 10 is provided with a positioning groove 11, which is adapted to the shape of the sprocket frame 1. Four positioning columns 12 are fixed in the positioning groove 11 of the slave mold 10 and are inserted and matched with the through holes 7. An injection flow channel 13 is provided in the slave mold 10, and the inlet 18 of the injection flow channel 13 is located at the center of the side of the slave mold 10 away from the main mold 9. The slave mold 10 is coaxially connected with an injection rotating ring 17 at the inlet 18 of the injection flow channel 13. The outlet 19 of the injection flow channel 13 is located on the side wall of the positioning column 12. Two outlets 19 of the injection flow channel 13 are provided on a single positioning column 12 and correspond to the positions of two rubber coating holes 8, respectively.

[0059] The specific steps of rubber coating are as follows: the main mold 9 is installed on a rotating device, such as a three-jaw chuck. Then, the sprocket frame 1 is placed into the main mold 9 or the slave mold 10. The main mold 9 and the slave mold 10 are closed. The rubber injection head is placed on the injection rotating ring 17, and rubber is injected into the injection flow channel 13. At the same time, the rotating device is started, and the main mold 9 and the slave mold 10 are kept in high-speed synchronous coaxial rotation. After the injection is completed, the main mold 9 and the slave mold 10 stop rotating, the mold is opened, and the rubber-coated sprocket is taken out.

[0060] In order to ensure that the main mold 9 and the slave mold 10 keep synchronous rotation, referring to FIGS. 4 and 5, two driven columns 14 are fixed on the side of the slave mold 10 facing the main mold 9. The main mold 9 is provided with an insertion hole 15 matched with the driven column 14. After the main mold 9 and the slave mold 10 are closed, the driven column 14 is inserted into the insertion hole 15. The main mold 9 drives the slave mold 10 to rotate, ensuring that the main mold 9 and the slave mold 10 are relatively stationary during rotation.

[0061] In addition, the encapsulation mold has another structure design under the simplified design. Referring to FIG. 6, the length of the positioning column 12 is greater than the thickness of the convex rib 6, the main mold 9 is provided with a plug hole 16 at the side close to the slave mold 10, the plug hole 16 is in plug connection with the end of the positioning column 12, after the main mold 9 and the slave mold 10 are closed, the end of the positioning column 12 is inserted into the plug hole 16, the main mold 9 drives the slave mold 10 to rotate, and it is ensured that the main mold 9 and the slave mold 10 are relatively static during the rotation.

[0062] S11, finishing: finishing the encapsulated sprocket.

[0063] The processing technology of the encapsulated sprocket provided by the embodiment of the application has at least the following beneficial effects:

[0064] Firstly, the production efficiency of the encapsulated sprocket is improved; the injection molding of the rubber rings 5 on both sides of the sprocket framework 1 can be completed at one time, and the encapsulation efficiency is greatly improved;

[0065] Secondly, the injection molding degree of the rubber ring 5 is improved; during the injection molding, the main mold 9 and the slave mold 10 are kept high-speed synchronous coaxial rotation, the injected rubber is thrown to the edge of the molding cavity by the centrifugal force, the molding degree of the rubber ring 5 is higher, and the yield is higher;

[0066] Thirdly, the gate does not need to be trimmed, and the product has high aesthetic degree; in the traditional injection molding process, the rubber is integrally connected with the gate left by the injection molding after the encapsulated product is taken out, and the gate needs to be trimmed subsequently, which not only wastes time, but also has low aesthetic degree on the product surface. In the application, the positioning column 12 is pulled out from the through hole 7 after the encapsulated sprocket is taken out, the gate is left in the encapsulation hole 8, and the gate does not need to be trimmed. In addition, the gate is located on the inner wall of the through hole 7, and cannot be observed in normal use, so the aesthetic degree is high.

[0067] Fourthly, the encapsulation mold has compact structure and high integration degree; in the application, the function of the positioning column 12 is highly concentrated, which is not only used for limiting the position of the sprocket framework 1 in the positioning groove 11, but also used for the outlet 19 of the injection molding flow channel 13. The end of the positioning column 12 is in plug connection with the plug hole 16, and the main mold 9 and the slave mold 10 are kept synchronous rotation.

[0068] The above are the preferred embodiments of the application, and do not limit the protection scope of the application. Therefore, equivalent changes made on the basis of the structure, shape and principle of the application should be covered within the protection scope of the application.

Claims

1. A process for machining an encapsulated sprocket, characterized by: It comprises the following steps: S1, mixing: uniformly mixing the powder raw materials according to the mass percentage, and uniformly mixing the following raw materials according to the mass percentage in step S1: C: 0.6-0.8%, Cu: 1-2%, powder lubricant: 0.5-0.8%, Fe: the balance; S2, forming: forming the mixed powder raw materials into a sprocket skeleton (1) green body by die pressing, and the sprocket skeleton (1) green body is provided with a through hole (7) and a rubber coating hole (8) communicating with the two side annular rubber coating grooves (4); S3, sintering: placing the sprocket skeleton (1) green body in a sintering furnace for sintering; S4, oil immersion: immersing the sintered sprocket skeleton (1) in rust-proof oil; S5, shaping; S6, steam treatment: steam treating the shaped part in a continuous steam furnace to form a dense oxide layer on the surface of the shaped part; S7, heat treatment: high-frequency induction hardening treatment is performed on the sprocket skeleton (1), and then the sprocket skeleton (1) is washed and then tempered; S8, sand blasting; S9, adhesive coating; S10, rubber coating: the sprocket skeleton (1) is loaded into a rubber coating mold, the rubber coating mold comprises a main mold (9) and a slave mold (10), the slave mold (10) is provided with a plurality of positioning columns (12) for plugging with the through hole (7) in the positioning groove (11) of the slave mold (10), the slave mold (10) is provided with an injection flow channel (13), the outlet (19) of the injection flow channel (13) is located on the side wall of the positioning column (12), the position of the outlet (19) of the injection flow channel (13) corresponds to the position of the rubber coating hole (8), rubber is injected into the injection flow channel (13), rubber injection is performed, and then vulcanization is performed after heat preservation; S11, finishing: finishing the rubber coated sprocket.

2. The process for manufacturing encapsulated sprocket as claimed in claim 1 wherein: In step S10, the main mold (9) and the slave mold (10) rotate synchronously and coaxially at high speed during the rubber injection process.

3. The process for manufacturing encapsulated sprocket as claimed in claim 2 wherein: The slave mold (10) is provided with a plurality of driven columns (14) on the side facing the main mold (9), and the main mold (9) is provided with a plurality of plug-in holes (15) for plugging with the driven columns (14).

4. The process for manufacturing encapsulated sprocket as claimed in claim 2 wherein: The length of the positioning column (12) is greater than the thickness of the rib (6), and the main mold (9) is provided with a plug-in hole (16) for plugging with the end of the positioning column (12) on the side close to the slave mold (10).

5. The process for manufacturing encapsulated sprocket as claimed in claim 2 or 3 wherein: In step S10, the inlet (18) of the injection flow channel (13) is arranged at the center of the side of the slave mold (10) away from the main mold (9), and the slave mold (10) is rotatably provided with an injection rotating ring (17) in the inlet (18) of the injection flow channel (13).

6. The process for machining encapsulated sprocket as claimed in claim 1 wherein: In step S2, the sprocket skeleton (1) green body is provided with two rubber coating holes (8) at each rib (6) thereof, and the two rubber coating holes (8) respectively communicate with the two side annular rubber coating grooves (4) and the through hole (7).

7. The process for machining encapsulated sprocket as claimed in claim 1 wherein: In step S3, the sintering temperature is 1100-1130℃, and the sintering is performed in a protective atmosphere, the heat preservation time is greater than 25 minutes, and the sintering neck is formed between the particles of the sprocket skeleton (1) green body.

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