Plastic engine block and method of manufacturing the same and engine

Abstract

The application discloses a plastic engine cylinder and a manufacturing method and an engine thereof. The manufacturing method of the plastic engine cylinder comprises the following steps: injecting molten plastic into a mold, and setting the temperature of a hot runner of an injection molding device to 400-405 DEG C; and forming a surplus part which is connected with a target engine cylinder and needs to be cut later after gating of the mold, wherein the cross section of the connection between the surplus part and the target engine cylinder is a cutting surface, the area of the cutting surface is 1000-1100 mm 2 2, and the carbon fiber content in the carbon fiber composite PEEK plastic is 38-42%. The engine cylinder is manufactured by the manufacturing method provided in the embodiments of the application. The engine comprises the engine cylinder. The plastic engine cylinder manufactured by the manufacturing method provided in the application has better performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine manufacturing, in particular to a plastic engine cylinder body, a manufacturing method thereof and an engine. BACKGROUND

[0002] In order to realize the light weight of vehicles and reduce the weight of engines, an injection molded engine has been developed. The injection molded engine is composed of a plastic cylinder body and a metal cylinder sleeve. Such a structure makes the engine cylinder body made of a large amount of plastic material, which greatly reduces the production process cost and energy consumption, and greatly reduces the weight. In the production of plastic cylinder bodies, injection molding process or 3D printing production method can be used. However, there are the following problems in manufacturing the plastic engine cylinder body by using the conventional manufacturing process of plastic parts:

[0003] ① Concave pits on the surface of the cylinder body; ② There are many air holes inside, and the distribution is uneven, which seriously affects the quality of the plastic parts and leads to unqualified products.

[0004] The specific structure of the plastic engine cylinder body can be referred to the prior patents of the applicant, such as patent CN202123385383.3 and patent CN202221532031.8.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application aims to provide a plastic engine cylinder body, a manufacturing method thereof and an engine.

[0007] The present application is implemented as follows:

[0008] In a first aspect, the present application provides a manufacturing method of a plastic engine cylinder body, comprising:

[0009] Injecting molten plastic into the mold, and setting the temperature of the hot runner of the injection molding equipment to 400-405℃;

[0010] The gating opening of the mold after casting forms a redundant part connected with the target engine cylinder body and which needs to be cut later, the cross section of the connection between the redundant part and the target engine cylinder body is a cutting surface, and the area of the cutting surface is 1000-1100mm 2 ;

[0011] The plastic is carbon fiber composite PEEK plastic, and the content of carbon fiber in the carbon fiber composite PEEK plastic is 38-42%.

[0012] In an optional embodiment, the cutting surface is rectangular, and the height thereof is 20-28mm.

[0013] In an optional embodiment, the mold has a mold body for forming the target engine cylinder block and a feeding part connected to the mold body, a pouring opening is formed in the feeding part, the feeding part is further provided with a gate communicated with the pouring opening and used for communicating with the hot runner, the bottom wall of the feeding part corresponding to the pouring opening is inclined, so that the longitudinal sectional dimension of the pouring opening gradually increases from the gate to the mold body.

[0014] In an optional embodiment, the injection of the molten plastic into the mold further includes a pressure maintaining for 200-260s.

[0015] In an optional embodiment, the temperature of the barrel of the injection molding equipment close to the end of the hot runner is 390-400℃.

[0016] In an optional embodiment, the barrel is segmented and heated, and the temperature gradually increases from the first end to the end close to the hot runner.

[0017] In an optional embodiment, the temperature of the first end of the barrel is 180-220℃.

[0018] In an optional embodiment, the temperature of the mold is 180-220℃.

[0019] In an optional embodiment, the feeding is performed by using a screw stirring device in the barrel.

[0020] In a second aspect, the present application provides a plastic engine cylinder block manufactured by using the manufacturing method according to any one of the preceding embodiments.

[0021] In a third aspect, the present application provides an engine comprising the plastic engine cylinder block according to the preceding embodiments.

[0022] The present application has the following advantages:

[0023] The manufacturing method provided by the embodiments of the present application uses the composite PEEK plastic with a high carbon fiber content as the raw material to ensure the strength of the plastic cylinder block. However, the plastic engine cylinder block manufactured by using the conventional injection molding process has the disadvantages of surface lack of meat and the like. Therefore, in the present application, the size of the cutting surface (equal to the size of the actual feeding diameter of the pouring opening) and the temperature of the hot runner are specially designed to be within a suitable range, so that the plastic filled in the mold has a relatively consistent crystallization time, the problem of surface lack of meat of the manufactured plastic engine cylinder block can be obviously improved, the surface of the manufactured plastic cylinder block is smooth, and the yield is high. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation to the scope. Other related drawings can also be obtained by those of ordinary skill in the art without any creative effort based on the drawings.

[0025] Figure 1 A schematic view of a manufacturing method for injection molding a target engine block according to the present application;

[0026] Figure 2 A schematic view of a target engine block to be cut according to the present application, wherein the part enclosed by the dashed line is the excess part to be cut;

[0027] Figure 3 A schematic view of a target engine block to be cut according to the present application, wherein the part enclosed by the dashed line is the excess part to be cut;

[0028] Figure 4 A partial schematic view of a target engine block to be cut according to the present injection molding process, wherein the part enclosed by the dashed line is the excess part to be cut;

[0029] Figure 5 A partial schematic view of a target engine block to be cut according to the injection molding process of the present application, wherein the part enclosed by the dashed line is the excess part to be cut;

[0030] Figure 6 A schematic view of the cut surface (1025mm 2 ) of the intake side of a plastic engine block prepared according to Example 1, indicating the height;

[0031] Figure 7 A schematic view of the cut surface (1025mm 2 ) of the intake side of a plastic engine block prepared according to Example 1, indicating the length;

[0032] Figure 8 A schematic view of the cut surface (1000mm 2 ) of the intake side of a plastic engine block prepared according to Example 2, indicating the height;

[0033] Figure 9 A schematic view of the cut surface (1000mm 2 ) of the intake side of a plastic engine block prepared according to Example 2, indicating the length;

[0034] Figure 10 A schematic view of the cut surface (1100mm 2 ) of the intake side of a plastic engine block prepared according to Example 3, indicating the height;

[0035] Figure 11A schematic view of a cutting surface (1100mm 2 ) of the intake side of the plastic engine cylinder block prepared in Example 2 indicating the length. DETAILED DESCRIPTION

[0036] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If specific conditions are not indicated in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are adopted. If the reagents or instruments used are not indicated by the manufacturers, they are all conventional products that can be purchased in the market.

[0037] The plastic engine cylinder block, the manufacturing method thereof and the engine provided by the embodiments of the present application will be described in detail below.

[0038] As shown in Figure 1 , the manufacturing method of the plastic engine cylinder block provided by the embodiments of the present application comprises the following steps.

[0039] The molten plastic is injected into the mold, and the temperature of the hot runner of the injection molding equipment is set to 400-405℃.

[0040] The gating opening of the mold after casting forms the excess part that is connected with the target engine cylinder block and needs to be cut later, the cross section of the connection between the excess part and the target engine cylinder block is a cutting surface, and the area of the cutting surface is 1000-1100mm 2 .

[0041] The plastic is carbon fiber composite PEEK plastic, and the content of carbon fiber in the carbon fiber composite PEEK plastic is 38-42%.

[0042] In order to ensure the strength of the plastic cylinder block, the manufacturing method provided by the embodiments of the present application uses the composite PEEK plastic with a high content of carbon fiber as the raw material for manufacturing, but due to the high content of carbon fiber in the plastic, the plastic engine cylinder block manufactured by the conventional injection molding process has the defects such as surface lack of meat, and the inventor finds that one of the reasons affecting the plastic engine cylinder block to have the defects such as surface lack of meat is that the size of the gating opening in the previous process is too small, as shown in Figure 4 , so that the place with thick meat of the product is not completely cooled, and the glue joint has been frozen. The pressure holding cannot supplement the filling in the place with thick meat. Therefore, in the present application, the size of the actual feeding caliber of the mold gating opening is particularly increased (as shown in Figure 5 , the size of the cutting surface is equal to the actual effective size of the gating opening), and the temperature of the hot runner is in a suitable range, so that the plastic filled in the mold has a relatively consistent crystallization time, the problem of surface lack of meat of the prepared plastic engine cylinder block can be obviously improved, the surface of the prepared plastic cylinder block is smooth, and the yield is high.

[0043] Specifically, the cutting surface is rectangular, and its length is 40-48 mm (eg, 40 mm, 42 mm, 44 mm, 46 mm, or 48 mm), that is, the length of the connection between the excess portion and the target engine cylinder block is 40-48 mm.

[0044] Optionally, the mold has a mold body for forming a target engine cylinder block and a feed portion connected to the mold body, a casting port is provided in the feed portion, and the feed portion is further provided with a gate connected to the casting port and used to connect to the hot runner (after the casting is completed, the gate is formed correspondingly). Figure 3 The bottom wall of the corresponding casting port in the feed portion is an inclined surface (i.e., the bottom surface of the redundant portion is an inclined surface, such as Figure 3 As shown, the angle with the vertical plane can be, for example, 60 degrees), so that the longitudinal cross-sectional dimension of the casting gate gradually increases from the gate to the mold body. Due to the complex structure of the mold, for the sake of simplicity and clarity in describing this solution, only the structure after mold forming is provided.

[0045] Furthermore, after injecting the molten plastic into the mold, the pressure is maintained for 200 to 260 seconds (eg, 200 seconds, 240 seconds, or 260 seconds).

[0046] The above holding time is much longer than the ordinary holding time. After the above holding time, the pores on the surface of the plastic cylinder are significantly reduced, the appearance is better, and the strength is higher.

[0047] Furthermore, the temperature of the barrel of the injection molding equipment near the hot runner end is 390-400° C. (eg, 390° C., 395° C., or 400° C.).

[0048] Heating the barrel to the above temperature range can ensure that the temperature can be raised to 400-405°C (for example, 400°C, 402°C or 405°C) after entering the hot runner, thereby ensuring the quality of the product.

[0049] Furthermore, the barrel is heated in sections, with the temperature gradually increasing from the head end to the end close to the hot runner.

[0050] Since PEEK material is hygroscopic, the PEEK material entering the barrel contains a certain amount of moisture. The temperature of the barrel gradually increases from the head end to the tail end, and the moisture in the PEEK material will slowly evaporate during the feeding process, which can play a certain dehumidification role.

[0051] Furthermore, a screw stirring device is used to feed the material into the barrel. Since the heating temperature of the barrel gradually increases from the head end to the tail end, the fluidity of the PEEK material is poor when it is first added. To ensure manufacturing efficiency, the use of a screw stirring device not only ensures that the PEEK and carbon fiber are fully mixed, but also ensures smoother feeding.

[0052] Preferably, the temperature of the first end of the barrel (i.e. the temperature of the feed) is 180-220°C (for example 180°C, 200°C or 220°C). The temperature of the material increases from the first end to the second end of the barrel from 180-220°C to 390-400°C (for example 390°C, 395°C or 400°C).

[0053] Further, the heating element in the barrel of the device used can be a resistance wire or hydraulic oil, and the hydraulic oil can be preferably used, so that the temperature of the barrel heated by the hydraulic oil is more accurate.

[0054] Preferably, the temperature of the mold is 180-220°C. Controlling the temperature of the mold to be 180-220°C during injection molding can further ensure the mechanical properties of the plastic engine cylinder body produced.

[0055] The plastic engine cylinder body provided by the embodiment of the present application is produced by the manufacturing method provided by the embodiment of the present application. The plastic engine cylinder body has good quality and has better mechanical properties.

[0056] The engine provided by the embodiment of the present application comprises the plastic engine cylinder body provided by the embodiment of the present application.

[0057] The features and properties of the present application are further described in detail below in combination with embodiments.

[0058] Embodiment 1

[0059] The cutting surface area of the target engine cylinder body to be cut is designed to be 1025mm 2 which is a rectangle with a length of 41mm and a height of 25mm. As shown in Figure 6 and Figure 7 the cross sections shown in the two figures seem to have different length and height ratios, which is actually caused by the scaling of the view, and the cross sections shown in the two figures are essentially the same.

[0060] The pouring gates are arranged at the upper end of the mold and are uniformly distributed.

[0061] Carbon fiber composite PEEK plastic is used as the raw material, in which the content of carbon fiber is 40%, and the balance is PEEK.

[0062] The temperature of the first end of the barrel is set to 200°C, the temperature near the hot runner end is set to 395°C, the temperature in the hot runner is set to 400°C, and the temperature in the mold is set to 200°C.

[0063] The holding pressure time is set to 230s.

[0064] Embodiment 2

[0065] The cutting surface area of the target engine cylinder body to be cut is designed to be 1000mm 2 which is a rectangle with a length of 40mm and a height of 25mm.Figure 8 and Figure 9 As shown in Figs. 2 and 3, the length and height ratios of the cross sections of the two figures appear to be different, but in fact the cross sections shown in the two figures are essentially the same.

[0066] The pouring gates are arranged at the upper end of the mold and are evenly distributed.

[0067] Carbon fiber composite PEEK plastic is used as the raw material, with a carbon fiber content of 38% and the balance being PEEK.

[0068] The temperature at the front end of the barrel is set to 200°C, the temperature near the hot runner end is set to 390°C, the temperature in the hot runner is set to 400°C, and the temperature in the mold is set to 200°C.

[0069] The holding pressure time is set to 260s.

[0070] After the holding pressure ends, cooling and demolding are performed.

[0071] Example 3

[0072] The cutting surface area of the target engine block to be cut is designed to be 1100mm 2 , which is a rectangle with a length of 44mm and a height of 25mm. As shown in Figs. 4 and 5, Figure 10 and Figure 11 As shown in Figs. 4 and 5, the length and height ratios of the cross sections of the two figures appear to be different, but in fact the cross sections shown in the two figures are essentially the same.

[0073] The pouring gates are arranged at the upper end of the mold and are evenly distributed.

[0074] Carbon fiber composite PEEK plastic is used as the raw material, with a carbon fiber content of 42% and the balance being PEEK.

[0075] The temperature at the front end of the barrel is set to 200°C, the temperature near the hot runner end is set to 400°C, the temperature in the hot runner is set to 405°C, and the temperature in the mold is set to 200°C.

[0076] The holding pressure time is set to 200s.

[0077] Comparative Example 1

[0078] This comparative example is basically the same as Example 2, except that the carbon fiber content in the raw material used is 33%.

[0079] Comparative Example 2

[0080] This comparative example is basically the same as Example 3, except that the carbon fiber content in the raw material used is 45%.

[0081] Comparative Example 3

[0082] The comparative example is basically the same as example 3, except that the dwell time is 100 s.

[0083] Comparative example 4

[0084] The comparative example is basically the same as example 3, except that the dwell time is 150 s.

[0085] Comparative example 5

[0086] The comparative example is basically the same as example 2, except that the barrel temperature near the hot runner end is 380 °C, and the temperature in the hot runner is 385 °C.

[0087] Comparative example 6

[0088] The comparative example is basically the same as example 3, except that the area of the designed cutting surface is 1150 mm 2 , and the height is the same as example 1, and the length is 46 mm.

[0089] Comparative example 7

[0090] The comparative example is basically the same as example 2, except that the area of the designed cutting surface is 975 mm 2 , and the length is the same as example 1, and the height is 39 mm 2 .

[0091] Experimental example

[0092] The quality of the plastic engine cylinder prepared in each example and comparative example was tested, and the test mainly had three aspects: 1. The number and distribution of pores; 2. Whether there is a lack of meat on the surface; 3. Mechanical properties.

[0093] 1. The test method for the number and distribution of pores is industrial CT detection.

[0094] 2. The test method for whether there is a lack of meat on the surface is observation by a quality inspector.

[0095] 3. The test method for mechanical properties is tensile test.

[0096] The test results are recorded in Tables 1-3:

[0097] Table 1 Number and distribution of pores

[0098]

[0099]

[0100] As can be seen from Table 1, the plastic engine cylinder bodies prepared by various embodiments of the application contain fewer pores and are regularly distributed in the middle of the product, which is caused by the reason of too thick wall thickness, and injection molding cannot completely avoid it, which can be solved by adding inserts in the middle. Comparative Example 2 has more carbon fiber content, and the flow resistance increases due to the increase of carbon fiber content, so that the filling is not sufficient, thereby leading to the problems of lack of glue and more pores; Comparative Example 3 and Comparative Example 4 have more pores due to the short pressure holding time; Comparative Example 5 has low barrel and hot runner temperature, the viscosity of the melt increases, the fluidity decreases, and the product has various defects such as lack of glue and cracks. Comparative Example 6 has an excessively large design size of the cutting surface (actual effective feeding size of the pouring gate), the pouring gate condenses slowly, excess residual stress is generated around the pouring gate, and the product at the pouring gate position is deformed obviously; Comparative Example 7 has an excessively small size of the cutting surface (actual effective feeding size of the pouring gate), the feeding resistance increases, and the lack of glue phenomenon occurs at the end of the product.

[0101] Table 2: Lack of meat statistics

[0102]

[0103]

[0104] As can be seen from Table 2, each embodiment does not have a lack of meat. Comparative Example 2 has an increase in flow resistance due to the increase of carbon fiber content, so that the filling is not sufficient, thereby leading to the problem of lack of glue; Comparative Example 5 has a lower hot runner temperature than the embodiments, and the crystallization time of the molten plastic entering the mold is poor in consistency, so there is also a certain degree of lack of meat; Comparative Example 7 has an excessively small size of the cutting surface (actual effective feeding size of the pouring gate), the feeding resistance increases, and the lack of glue phenomenon occurs at the end of the product.

[0105] Table 3: Mechanical properties

[0106] Group Tensile strength / mpa Example 1 324 Example 2 322 Example 3 321 Comparative Example 1 280 Comparative Example 2 103 Comparative Example 3 120 Comparative Example 4 150 Comparative Example 5 140 Comparative Example 6 320 Comparative Example 7 130

[0107] As can be seen from the above table, the plastic engine cylinder bodies prepared in each embodiment all have better mechanical properties. Comparing Example 2 with Comparative Example 1, the carbon fiber content in the plastic of Comparative Example 1 is less, and the tensile strength of the prepared cylinder body is reduced. Comparing Example 3 with Comparative Example 2, the carbon fiber content in the plastic of Comparative Example 2 is higher. Since the flow resistance increases with the increase of the carbon fiber content, the filling is not sufficient, resulting in the problems of lack of glue and more pores, thereby resulting in poor tensile resistance of the prepared cylinder body. Comparing Comparative Examples 3, 4 and 5 with the corresponding embodiments, the tensile resistance is obviously poorer, which shows that the mechanical properties of the plastic cylinder body prepared under the conditions of suitable injection molding temperature and holding time can be better. Since the design size of the cutting surface (the actual effective feeding size of the pouring gate) of Comparative Example 6 is too large, the product pouring gate has defects, but the sampling tensile test position is at the bottom of the product, so there is basically no effect. Since the size of the cutting surface (the actual effective feeding size of the pouring gate) of Comparative Example 7 is too small, the glue feeding resistance becomes large, and the lack of glue phenomenon occurs at the end of the product glue feeding position. This position is the sampling tensile test position.

[0108] In summary, the manufacturing method provided in the embodiments of the present application uses a composite PEEK plastic with a higher carbon fiber content as a raw material to ensure the strength of the plastic cylinder body. However, since the carbon fiber content in the plastic is high, the plastic engine cylinder body prepared by the conventional injection molding process has the defects of surface lack of meat and the like. Therefore, in the present application, the actual effective feeding size (cutting surface size) of the mold pouring gate and the temperature of the hot runner are specially set within a suitable range, so that the plastic filled in the mold has a relatively uniform crystallization time, which can obviously improve the problem of surface lack of meat of the prepared plastic engine cylinder body, and the prepared plastic cylinder body has a smooth surface and a high yield.

[0109] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method of manufacturing a plastic engine block, characterized by, Comprising: injecting molten plastic into the mold, the hot runner temperature of the injection molding equipment is set to 400~405℃; The casting gate of the mold after casting forms a surplus part to be cut later in connection with the target engine block, the cross section of the connection of the surplus part to the target engine block is a cutting surface, and the area of the cutting surface is 1000-1100 mm 2 ; the plastic is carbon fiber composite PEEK plastic, the carbon fiber content in the carbon fiber composite PEEK plastic is 38~42%; the cutting surface is rectangular, the height is 20~28mm; after injecting molten plastic into the mold, it further comprises holding pressure for 200~260s; the mold has a mold body for forming the target engine block and a feeding part connected with the mold body, the feeding part is provided with the gate opening, the feeding part is further provided with a gate communicated with the gate opening and used for communicating with the hot runner, the bottom wall corresponding to the gate opening in the feeding part is inclined, so that the longitudinal sectional dimension of the gate opening gradually increases from the gate to the mold body; the temperature of the barrel of the injection molding equipment close to the hot runner end is 390~400℃.

2. The production method according to claim 1, characterized by the barrel is segmented and heated, the temperature gradually increases from the first end to the end close to the hot runner.

3. The production method according to claim 2, characterized by the temperature of the first end of the barrel is 180~220℃.

4. The production method according to claim 1, characterized by screw stirring device is used for feeding in the barrel.

5. The production method according to claim 1, characterized by the temperature of the mold is 180~220℃.

6. A plastic engine block characterized by, is prepared by the manufacturing method of any one of claims 1~5.

7. An engine characterized by, the plastic engine block of claim 6.

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