Method for machining an engine block and engine

Abstract

The application relates to a machining method of an engine cylinder body and an engine. The machining method of the engine cylinder body comprises the following steps: S1. obtaining a cylinder body blank through casting; S2. sequentially performing semi-finishing on the bush end assembly end face, the cylinder sleeve end assembly end face and the four side assembly end faces of the cylinder body blank respectively to obtain a first cylinder body semi-product; S3. sequentially performing finishing on the bush end assembly end face and the four side assembly end faces of the first cylinder body semi-product respectively to obtain a second cylinder body semi-product; S4. assembling the bushes to the second cylinder body semi-product respectively to obtain a third cylinder body semi-product; S5. performing finishing on the cylinder sleeve end assembly end face and the inner circumferential faces of all the bush holes of the third cylinder body semi-product to obtain a fourth cylinder body semi-product; and S6. sequentially performing honing on the inner circumferential faces of all the cylinder sleeve holes in the cylinder sleeve end assembly end face of the fourth cylinder body semi-product to obtain an engine cylinder body finished product. The machining precision of the cylinder sleeve holes can be effectively improved, and the waste rate after machining is low.

Description

Technical Field

[0001] This invention relates to the field of engine manufacturing technology, and in particular to a method for machining an engine cylinder block and an engine. Background Technology

[0002] The engine block is the main body of the engine, used to connect the various cylinders and crankcase into one unit. It is the supporting skeleton for mounting pistons, crankshaft, and other parts and accessories. Its machining quality is directly related to the overall performance, lifespan, and fuel economy of the engine.

[0003] In existing technologies, the machining process of engine cylinder blocks includes major steps such as die casting, rough machining, precision milling of assembly surfaces, and precision boring of assembly holes. Among these, precision boring of the cylinder liner bore is a crucial step in ensuring a tight fit between the cylinder block and the cylinder liner, achieving efficient combustion and power output. However, traditional boring machine machining methods, when faced with the machining requirements of high-precision cylinder liner bores, directly lead to an increased scrap rate due to insufficient machining accuracy, thereby increasing production costs and time.

[0004] In conclusion, in order to meet the high-precision machining requirements of the modern automotive industry for engine blocks, it is urgent to introduce more advanced and efficient machining processes to replace traditional boring machine machining, reduce scrap rates, and improve machining efficiency and accuracy. Summary of the Invention

[0005] In response to the shortcomings of the existing production technology, the applicant provides a method for machining an engine cylinder block and an engine. Through six machining steps, the machining accuracy of the cylinder liner bore can be effectively improved, and the scrap rate after machining is low, which can meet the needs of mass production and meet the usage requirements of the modern automotive industry.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for machining an engine cylinder block includes the following steps:

[0008] S1. Obtain cylinder blanks through casting;

[0009] S2. The bearing end assembly face, cylinder liner end assembly face, and four side assembly faces of the cylinder block blank are semi-finished in sequence to obtain the first cylinder block semi-finished product.

[0010] S3. The bearing end assembly face and the four side assembly faces of the first cylinder block semi-finished product are respectively precision machined to obtain the second cylinder block semi-finished product;

[0011] S4. Prepare several bearing shells, align the assembly end face of a single bearing shell with the corresponding bearing shell assembly end face of the bearing shell in the second cylinder block semi-finished product, and use a bolt assembly to fix the bearing shell to the second cylinder block semi-finished product, thereby completing the assembly of the corresponding bearing shell. A bushing hole that mates with the crankshaft is formed between the single bearing shell and the second cylinder block semi-finished product.

[0012] The remaining bearings are then assembled onto the second cylinder block semi-finished product to obtain the third cylinder block semi-finished product.

[0013] S5. The cylinder liner end assembly face and the inner circumferential surface of all bushing holes of the third cylinder block semi-finished product are precision machined to obtain the fourth cylinder block semi-finished product.

[0014] S6. All the inner circumferential surfaces of the cylinder liner holes in the assembly end face of the fourth cylinder block semi-finished product are honed in sequence. After the honing is completed, the finished engine cylinder block is obtained.

[0015] As a further improvement to the above technical solution:

[0016] The bearing end assembly face includes a first assembly face that mates with the lower crankcase assembly face, and several bearing assembly faces that mate with the corresponding bearings.

[0017] Several first threaded holes are formed on the first assembly surface.

[0018] The bearing end assembly face also includes the internal thread surface of all the first threaded holes.

[0019] The cylinder liner end assembly face includes a second assembly face that mates with the cylinder head, and several inner circumferential surfaces of the cylinder liner bore that mate with the corresponding piston assemblies.

[0020] In S2 and S3, a three-axis vertical CNC machining equipment is used for processing.

[0021] In S5, a five-axis horizontal CNC machining equipment is used for precision machining.

[0022] In S6, before honing, the honing allowance on one side of the inner circumferential surface of a single cylinder liner hole is 0.03mm.

[0023] In S6, a honing machine is used for honing.

[0024] An engine includes an engine block prepared by the above-described engine block machining method.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention features a compact and rational structure, and is easy to operate. By reserving honing for the final step in six processing steps, it prevents reprocessing from affecting the cylindricity and roundness of the engine cylinder block after honing, thus effectively ensuring processing accuracy. By incorporating honing steps, it significantly improves the roundness, cylindricity, and surface roughness of the cylinder liner bore, reducing friction and wear between the piston and cylinder liner, and improving engine thermal efficiency and fuel economy. Simultaneously, honing improves the geometric accuracy of the cylinder liner bore, facilitating smooth piston movement, reducing engine vibration and noise, resulting in a low scrap rate and high processing efficiency, meeting the needs of mass production and the requirements of the modern automotive industry. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the cylinder block semi-finished product in this invention.

[0028] Figure 2 for Figure 1 Rear view.

[0029] Figure 3 for Figure 1 The right view.

[0030] Figure 4 for Figure 1 Top view.

[0031] Figure 5 This is a schematic diagram of the engine block structure of the present invention. Figure 1 .

[0032] Figure 6 This is a schematic diagram of the engine block structure of the present invention. Figure 2 .

[0033] Among them: 1. Cylinder block semi-finished product; 2. Bearing shell; 3. First assembly surface; 4. Second assembly surface; 5. Bearing shell assembly surface; 6. Inner circumferential surface of cylinder liner bore. Detailed Implementation

[0034] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0035] like Figures 1-6 As shown, the machining method for the engine cylinder block in this embodiment includes the following steps:

[0036] S1. Obtain cylinder blanks through casting;

[0037] The cylinder block blank is formed by casting, providing the basic raw material for subsequent processing. Casting can be used to mass-produce cylinder block semi-finished products 1 with complex shapes that meet production requirements, reducing production costs and improving production efficiency. At the same time, casting can ensure the uniformity and density of cylinder block semi-finished products 1, providing a good foundation for subsequent processing.

[0038] The cylinder block blank is made of aluminum-magnesium alloy AZ91D material, which is lightweight, ensuring that the finished cylinder block is lightweight. Furthermore, cutting fluid is required in the subsequent semi-finishing, finishing, and honing processes to improve processing efficiency, extend tool life, improve surface quality, and maintain the geometric accuracy of the workpiece.

[0039] S2. The bearing end assembly face, cylinder liner end assembly face, and four side assembly faces of the cylinder block blank are semi-finished in sequence to obtain the first cylinder block semi-finished product.

[0040] The cylinder block semi-finished product 1 is cubic in shape and has six end faces, including a top face corresponding to the cylinder liner end, a bottom face corresponding to the bearing end, and four side faces.

[0041] The bearing end assembly face includes a first assembly face 3 that mates with the lower crankcase assembly face, and several bearing assembly faces 5 that mate with the corresponding bearings.

[0042] Several first threaded holes are opened on the first assembly surface 3, and the bearing end assembly face also includes the internal thread surface of all the first threaded holes.

[0043] The cylinder liner end assembly face includes a second assembly face 4 that mates with the cylinder head, and several inner circumferential surfaces 6 of the cylinder liner bore that mate with the corresponding piston assemblies.

[0044] Several second threaded holes are opened on the second assembly surface 4, and the cylinder liner end assembly surface also includes the internal thread surface of all the second threaded holes.

[0045] In addition, the bearing end assembly face also includes a third assembly face for mating with the crankshaft, which corresponds to the concave arc face of the bearing and is used to limit the crankshaft.

[0046] In this embodiment, the four side assembly end faces include a plurality of fourth assembly faces disposed on the remaining four side walls of the cylinder semi-finished product 1. The fourth assembly faces are used to cooperate and install with the corresponding control equipment components, measuring equipment components and other accessories in the subsequent assembly process.

[0047] Semi-finishing is performed using a three-axis vertical CNC machining equipment; specifically, the three-axis vertical CNC machining equipment is used to semi-finish mill the plane, including the first assembly surface 3, the second assembly surface 4, the fourth assembly surface, and the bearing assembly surface 5; the three-axis vertical CNC machining equipment is used to semi-finish bore the inner wall of the hole, including the internal thread surface of the first threaded hole, the internal thread surface of the second threaded hole, the inner circumferential surface of the cylinder liner hole 6, and the third assembly surface;

[0048] The semi-finishing step prepares the material for subsequent finishing, ensuring uniform machining allowance and improving machining accuracy.

[0049] S3. The bearing end assembly face and the four side assembly faces of the first cylinder block semi-finished product are respectively precision machined to obtain the second cylinder block semi-finished product;

[0050] Semi-finishing is performed using a three-axis vertical CNC machining equipment. Specifically, the first assembly surface 3, the fourth assembly surface, and the bearing assembly surface 5 are precision milled using the three-axis vertical CNC machining equipment; the internal thread surface of the first threaded hole and the third assembly surface are precision bored using the three-axis vertical CNC machining equipment.

[0051] S4. Prepare several bearing shells 2, fit the assembly end face of a single bearing shell 2 with the corresponding bearing shell assembly surface 5 in the assembly end face of the bearing shell of the second cylinder block semi-finished product, and use a bolt assembly to fix the bearing shell 2 to the second cylinder block semi-finished product, thereby completing the assembly of the corresponding bearing shell 2. A bushing hole that mates with the crankshaft is formed between a single bearing shell 2 and the second cylinder block semi-finished product.

[0052] The remaining bearing shells 2 are assembled onto the second cylinder block semi-finished product to obtain the third cylinder block semi-finished product;

[0053] By performing the bearing assembly step after precision milling the bearing assembly surface 5, the fitting accuracy between the bearing 2 and the cylinder block semi-finished product 1 can be guaranteed, which can reduce friction and wear during subsequent engine operation, ensure smooth engine operation, and improve engine service life and performance. At the same time, the precise fit between the bearing 2 and the cylinder block semi-finished product 1 can reduce engine noise and vibration and improve driving comfort.

[0054] S5. The cylinder liner end assembly face and the inner circumferential surface of all bushing holes of the third cylinder block semi-finished product are precision machined to obtain the fourth cylinder block semi-finished product.

[0055] The finishing process is carried out using a five-axis horizontal CNC machining equipment. Specifically, the second assembly surface 4 is precision milled using the five-axis horizontal CNC machining equipment; the internal thread surface of the second threaded hole, the inner circumferential surface of the cylinder liner hole 6, and the inner circumferential surface of the bushing hole are precision bored using the five-axis horizontal CNC machining equipment.

[0056] By performing finishing after semi-finishing, a uniform machining allowance can be provided for finishing, reducing cutting force and heat during finishing, which helps protect the cutting tools and machine tools, and improves machining accuracy and surface quality; finishing ensures the fitting accuracy and sealing performance of various parts of the cylinder block.

[0057] S6. All the inner circumferential surfaces 6 of the cylinder liner holes in the cylinder liner end assembly face of the fourth cylinder block semi-finished product are honed in sequence. After the honing is completed, the engine cylinder block finished product is obtained.

[0058] Before honing, the honing allowance on one side of the inner circumferential surface 6 of a single cylinder liner hole is 0.03mm.

[0059] Honing is performed using a honing machine;

[0060] Honing can significantly improve the roundness, cylindricity, and surface roughness of cylinder liner bores, reduce friction and wear between piston assemblies and cylinder liners, and improve engine thermal efficiency and fuel economy. At the same time, honing can also improve the geometric accuracy of cylinder liner bores, which is beneficial to the smooth movement of piston assemblies and reduces engine vibration and noise.

[0061] The engine of this embodiment includes an engine block prepared by the above-described engine block machining method. The engine block structure includes a semi-finished cylinder block 1 obtained through casting, semi-finishing, and finishing. Five bearing shells 2 are fitted onto the semi-finished cylinder block 1, and a cylinder head is fitted onto its cylinder liner end. The cylinder head and the inner wall of the cylinder block together form part of the combustion chamber. A lower crankcase is fitted onto the bearing shell end, and the lower crankcase is used to seal the crankcase as an oil reservoir, preventing impurities from entering. Four cylinder liner holes are provided on the engine block, and a piston assembly is fitted into each cylinder liner hole. The engine block of this invention has high machining precision, which can improve the overall performance and service life of the engine.

[0062] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A method for machining an engine cylinder block, characterized in that: Includes the following steps: S1. Obtain cylinder blanks through casting; S2. The bearing end assembly face, cylinder liner end assembly face, and four side assembly faces of the cylinder block blank are semi-finished in sequence to obtain the first cylinder block semi-finished product. S3. The bearing end assembly face and the four side assembly faces of the first cylinder block semi-finished product are respectively precision machined to obtain the second cylinder block semi-finished product; S4. Prepare several bearing shells, fit the assembly end face of a single bearing shell with the corresponding bearing shell assembly end face in the bearing shell assembly end face of the second cylinder block semi-finished product, and use bolt assembly to fix the bearing shell to the second cylinder block semi-finished product, thereby completing the assembly of the corresponding bearing shell. A bushing hole that mates with the crankshaft is formed between the single bearing shell and the second cylinder block semi-finished product. The remaining bearings are then assembled onto the second cylinder block semi-finished product to obtain the third cylinder block semi-finished product. S5. The cylinder liner end assembly face and the inner circumferential surface of all bushing holes of the third cylinder block semi-finished product are precision machined to obtain the fourth cylinder block semi-finished product. S6. All the inner circumferential surfaces of the cylinder liner holes in the cylinder liner end assembly face of the fourth cylinder block semi-finished product are honing sequentially. After honing, the engine cylinder block finished product is obtained. The bearing end assembly face includes a first assembly surface that mates with the lower crankcase assembly face, and several bearing assembly surfaces that mate with the corresponding bearings. Several first threaded holes are opened on the first assembly surface. The bearing end assembly face also includes the internal threaded surfaces of all the first threaded holes. The cylinder liner end assembly face includes a second assembly surface that mates with the cylinder head, and several inner circumferential surfaces of the cylinder liner holes that mate with the corresponding piston assemblies. In S2 and S3, a three-axis vertical CNC machining equipment is used for machining. In S5, a five-axis horizontal CNC machining equipment is used for finishing. In S6, before honing, the honing allowance on one side of the inner circumferential surface of a single cylinder liner hole is 0.03mm. In S6, a honing machine is used for honing.

2. An engine, characterized in that: This includes engine cylinder blocks prepared by the machining method of the engine cylinder block as described in claim 1.

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