Insert cast in aluminum alloy air cylinder and used for connecting main bearing seat and balance bearing seat

Abstract

The invention discloses an insert cast in an aluminum alloy cylinder and used for connecting a main bearing seat and a balance bearing seat, and belongs to the field of diesel engine cylinders. The insert is cast in the aluminum alloy air cylinder body in an embedded mode and connected with the aluminum alloy air cylinder body in a casting mode, the insert is composed of a main bearing seat area insert, a balance shaft bearing seat area insert and a connecting rib, and the main bearing seat area insert is used for replacing a cylinder body main bearing seat to make contact with the main shaft diameter of a crankshaft. The balance shaft bearing seat area insert is used for replacing a cylinder balance shaft bearing seat to be in contact with the main shaft diameter of a balance shaft, and the main bearing seat area insert is connected with the balance shaft bearing seat area through a connecting rib. The insert is made of a high-strength material, the main bearing seat and the balance bearing seat are communicated together, the strength of the area between the main bearing seat and the balance bearing seat can be effectively improved, and the service life of the area between the main bearing seat and the balance bearing seat can be effectively prolonged.

Description

Technical Field

[0001] The invention relates to a diesel engine cylinder, in particular to an insert which is cast in an aluminum alloy cylinder and connects a main bearing seat and a balance bearing seat. Background Art

[0002] Currently, the design optimization of diesel engines mainly tends to be high power, light weight and clean.

[0003] The diesel engine cylinder block is the skeleton of the engine and the heaviest component in the diesel engine. Its design is becoming more and more compact. At present, the compactness of the structure has reached its limit. There is little space to achieve lightweight structure. It is urgent to achieve lightweight by replacing the materials of diesel engine parts.

[0004] Aluminum alloy materials are light in weight and have fast heat dissipation, which meets the requirements of diesel engine cylinder blocks. They can effectively reduce the overall weight of diesel engines, improve the power-to-weight ratio of diesel engines, and reduce fuel consumption.

[0005] Cylinder blocks made of aluminum alloy materials are currently widely used in the field of gasoline engines. A small number of diesel engine manufacturers have also tried to invest in the research and development of aluminum alloy cylinder blocks for diesel engines. However, due to the large size, poor material strength, large temperature changes, easy deformation, high friction coefficient and corrosion resistance of aluminum alloy cylinder blocks, the use of all-aluminum alloy cylinder blocks is difficult to fully meet the requirements of high explosion pressure and high operating temperature in the diesel engine cylinder. Therefore, there are generally problems such as low power output, low degree of strengthening and short life.

[0006] The cylinder block main bearing seat is an important structure of the engine cylinder block that supports the crankshaft. It needs to bear the load transmitted by the explosion pressure in the cylinder through the crank-connecting rod mechanism, and at the same time, it needs to meet the lubrication conditions necessary for the rotation of the crankshaft. In order to ensure the stability of the engine crank-connecting rod mechanism and reduce the leakage of the main bearing seat lubricating oil, there are also high requirements for the tightening process of the main bearing seat bolts and the bolt preload after installation.

[0007] In the current single-cylinder, two-cylinder and three-cylinder diesel engines, a balance shaft is often used to balance the reciprocating inertia force brought by the crank-connecting rod mechanism. The method of adding a balance shaft is widely used to balance the reciprocating inertia force of the crank-connecting rod mechanism. In order to make the overall structure of the cylinder compact, the bearing seat of the balance shaft and the crankshaft is generally very close. In the actual working process, the inertia force of the balance shaft and the crankshaft rotation makes the part between the balance shaft and the crankshaft bearing seat always bear the alternating load, and materials with lower strength such as aluminum alloy may be difficult to bear; from the bench test results and simulation calculations, it is found that the cylinder with a balance shaft structure will first fail in the area between the main bearing seat and the balance bearing seat of the cylinder block. This is because the crankshaft and the balance shaft rotate separately, and the middle area will bear the alternating stress, vibration and other loads brought by the imbalance. In addition, the defects that may exist during casting, uneven material distribution, and residual stress during processing increase the probability of cracking failure during work. Therefore, the insert containing only the main bearing is difficult to meet the needs of the engine with a balance shaft structure, and there is often still a risk of cracking on the wall between the main bearing seat and the balance shaft bearing seat.

[0008] In the existing technical solutions, the cylinder block is generally formed in one piece with aluminum alloy materials when manufacturing. Some products will insert cast iron cylinder liners in the cylinder bores. At the same time, a small number of products try to insert U-shaped cast iron inserts in the main bearing seat of the aluminum alloy cylinder block, so that the contact surface between the cylinder block and the crankshaft is cast iron material. For example:

[0009] The engine crankcase lower case insert structure disclosed in CN201301758Y and the main bearing seat insert for new energy vehicles disclosed in CN207349277U both provide a lower case insert structure for an engine crankcase. They adopt a similar main bearing seat insert design, and can manufacture the main bearing seat surface and bolt bracket with a relatively high strength material to bear the load brought by the crankshaft and the bolts, and at the same time contain an aluminum alloy containing hole to prevent the insert from moving up and down; but in actual work, such inserts tend to pull the inserts out of the cylinder body due to their force direction, and the inserts may have the risk of detaching from the cylinder body, or fatigue cracks may occur at the joint of the aluminum alloy and the inserts, which may eventually lead to cylinder failure. The main problem of this scheme is that the force direction design of the insert is unreasonable, and the original force area of ​​the aluminum alloy bearing the crankshaft and bolt force is only transferred to the area where the insert is combined with the aluminum alloy cylinder body, which increases the force area to a certain extent, but fails to balance the forces in all directions of the cylinder body, so the improvement of the reliability of the multi-cylinder body is limited.

[0010] In the face of the above-mentioned problems in the development of aluminum alloy cylinder blocks for diesel engines, adding main bearing seats and balance shaft bearing seat inserts, optimizing the force flow transmission inside the cylinder block, and guiding the force conduction of various parts of the cylinder block as much as possible to make it as balanced as possible are effective methods to improve the strength and life of the cylinder block. Therefore, it is necessary to design an insert that is connected to the main bearing seat and the balance bearing seat and is cast in the aluminum alloy cylinder block. Summary of the invention

[0011] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an insert cast in an aluminum alloy cylinder for connecting a main bearing seat and a balance bearing seat, so as to solve technical problems such as insufficient strength of the main bearing seat and cracking in the area between the main bearing seat and the balance bearing seat.

[0012] To achieve the above object, the technical solution of the present invention is:

[0013] An insert cast in an aluminum alloy cylinder that connects a main bearing seat and a balancing bearing seat, the insert is cast in the aluminum alloy cylinder body and connected to the aluminum alloy cylinder body by casting, the insert is generally composed of a main bearing seat area insert 1, a balancing shaft bearing seat area insert 2 and a connecting rib 3; the main bearing seat area insert 1 is used to replace the cylinder body main bearing seat as a contact with the crankshaft main shaft diameter; the balancing shaft bearing seat area insert 2 is used to replace the cylinder body balancing shaft bearing seat as a contact with the balancing shaft main shaft diameter; the main bearing seat area insert 1 and the block balancing shaft bearing seat area 2 are connected by a connecting rib 3.

[0014] Furthermore, the main bearing seat area insert 1 is composed of a main bearing seat bearing surface 11, a main bearing seat body 12, a main bearing cover positioning baffle 13, a main bearing seat shoulder 14, a main bearing seat bolt bracket 15, an aluminum inclusion process hole 16, and a main bearing seat threaded hole 17.

[0015] Furthermore, the main bearing seat bearing surface 11 is a semicircular surface, which is located below the main bearing seat area insert 1, and is used to replace the cylinder main bearing seat as the contact with the crankshaft main shaft diameter, and plays the role of bearing load and providing a lubrication platform; the main bearing seat body 12 is offset by a certain thickness according to the side contour line of the main bearing seat bearing surface 11.

[0016] Furthermore, two raised main bearing cover positioning baffles 13 are symmetrically distributed between the two waists of the main bearing seat body 12, which are used for positioning when installing the main bearing cover, and at the same time form an interference fit with the side of the main bearing cover to ensure that the main bearing cover is not prone to slip during assembly and operation; the bearing surface 11 of the main bearing seat and the contact surface between the main bearing seat and the main bearing cover need to be further fine-machined after the insert is cast into the aluminum alloy cylinder block, so a processing allowance should be left when designing the insert.

[0017] Furthermore, main bearing seat shoulders 14 are symmetrically provided on the left and right shoulders of the main bearing seat body 12, which are used to accommodate the main bearing seat bolt bracket 15, the aluminum inclusion process hole 16 and the main bearing seat threaded hole 17, and at the same time play a role in enhancing the overall rigidity of the lower insert. Its shape is obtained based on the internal shape of the cylinder body and the various structures that need to be included, and its edges need to be as smooth as possible.

[0018] Furthermore, the main bearing seat bolt bracket 15 is located above the main bearing seat body 12 and is contained in the main bearing seat shoulder 14, and is used to provide a certain wall thickness for the main bearing seat internal threaded hole 17 to ensure the reliability of the thread.

[0019] Furthermore, the aluminum inclusion process hole 16 is located where the left and right main bearing seat shoulders 14 are close to each other.

[0020] Furthermore, a main bearing seat threaded hole 17 is provided inside the main bearing seat body 12; the insert is connected to the aluminum alloy cylinder block by casting and can be regarded as an integral whole. When the insert is manufactured, there is no main bearing seat threaded hole 17 and thread, only the insert has a bolt bracket 15 reserved for processing the threaded hole on the surface. After the insert is cast into the aluminum alloy cylinder block, the threaded hole and thread are processed. Processing the thread on ductile iron can improve the strength and life of the thread compared to directly starting the thread on the aluminum alloy cylinder block.

[0021] Furthermore, the balancing shaft bearing seat area insert 2 is composed of a balancing shaft bearing seat body 21 and a balancing shaft bearing seat bearing surface 22. The balancing shaft bearing seat body 21 is located obliquely above the shoulder 14 of the main bearing seat on one side, and the balancing shaft bearing seat bearing surface 22 is contained inside the balancing shaft bearing seat body 21, and is a closed circular surface. Its main function is to replace the cylinder balancing shaft bearing seat to contact the balancing shaft main shaft diameter, and play the role of bearing load and providing a lubrication platform; according to the side contour line of the balancing shaft bearing seat bearing surface 22, a certain thickness is offset to obtain the balancing shaft bearing seat body 21, and its offset thickness is mainly determined according to the load size that the balancing shaft bearing seat needs to bear.

[0022] Furthermore, the main bearing seat area 1 and the balance shaft bearing seat area 2 are connected by means of a connecting rib area 3 , and the connecting rib area 3 is composed of a mesh connecting rib 31 and process holes 32 .

[0023] Furthermore, the mesh connecting rib 31 is located between the main bearing seat shoulder 14 and the balance shaft bearing seat body 21. The overall separation follows the principle that the triangle has stability, and the force flow optimization design is performed through topological optimization. Its functions include connecting the main bearing seat shoulder 14 and the balance shaft bearing seat body 21, and bearing the alternating stress in the connecting rib area 3 caused by the main bearing seat and the balance shaft bearing seat being subjected to loads of different directions during operation.

[0024] Furthermore, between the mesh connecting ribs 31, there is an aluminum inclusion process hole 32 penetrating the entire insert, and its function is exactly the same as that of the aluminum inclusion process hole 16 in the main bearing seat area, only the position is different.

[0025] Furthermore, the insert is made of ductile iron, steel, grey cast iron or other materials.

[0026] Compared with the prior art, the beneficial effects of the present invention include:

[0027] 1) The elastic modulus of cast iron material is higher than that of aluminum alloy material, and the linear expansion coefficient is lower than that of aluminum alloy material. The temperature at the main bearing seat is generally between 100℃ and 200℃. At this temperature, the mechanical properties of ductile iron or steel are more stable. Compared with aluminum alloy material, it is more adaptable to the high explosion pressure and high temperature working environment of high-strength diesel engine. When used under normal working conditions, it produces smaller elastic deformation, is not prone to plastic deformation and cracking, and improves the overall stiffness of the main bearing seat of the cylinder block;

[0028] 2) In existing engines, single-cylinder, two-cylinder and three-cylinder engines use a balance shaft to balance the reciprocating inertia force brought by the crank-connecting rod mechanism, but it is difficult to achieve perfect balance, which causes the area between the main bearing seat of the cylinder block and the balance bearing seat to bear the alternating stress, vibration and other loads brought by the imbalance. In addition, the defects that may exist during casting, uneven material distribution, residual stress during processing, etc., increase the probability of cracking and failure during operation. The present invention uses high-strength materials to manufacture the insert, and connects the main bearing seat and the balance bearing seat together, which can effectively improve the strength and life of the area between the main bearing seat and the balance shaft bearing seat;

[0029] 3) The thread of the threaded hole directly processed on the aluminum alloy cylinder body has low strength and short life. The thread is used in the step of closing the cover during the cylinder body processing, which consumes the life of the thread. Therefore, the number of repeated assembly times of the finished aluminum alloy cylinder body is very limited. The insert of the present invention has better material strength and better processing performance, and the thread processed on the insert has a higher yield rate, higher strength and longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the appearance structure of the insert in Example 1 of the present invention.

[0031] Figure 2 It is a front cross-sectional view of the insert according to Example 1 of the present invention.

[0032] Figure 3 This is a schematic diagram of the front view of the installation position of the insert in the aluminum alloy cylinder body according to Example 1 of the present invention.

[0033] Figure 4 This is a schematic diagram from an axonometric perspective of the installation position of the insert in the aluminum alloy cylinder body according to Example 1 of the present invention.

[0034] In the figure:

[0035] 1-main bearing seat area insert, 11-main bearing seat bearing surface, 12-main bearing seat body, 13-main bearing cover positioning baffle, 14-main bearing seat shoulder, 15-main bearing seat bolt bracket, 16-aluminum inclusion process hole, 17-main bearing seat threaded hole;

[0036] 2-balance shaft bearing seat area insert, 21-balance shaft bearing seat body, 22-balance shaft bearing seat bearing surface;

[0037] 3-connecting ribs, 31-mesh connecting ribs, 32-aluminum inclusion process holes;

[0038] 4-Oil channel hole. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0040] like Figure 1 to Figure 3 As shown, an insert connected to a main bearing seat and a balance bearing seat cast in an aluminum alloy cylinder body is cast in the aluminum alloy cylinder body and connected to the aluminum alloy cylinder body by casting, and the insert is generally composed of an insert 1 in the main bearing seat area, an insert 2 in the balance shaft bearing seat area, and a connecting rib 3; the insert 1 in the main bearing seat area is used to replace the main bearing seat of the cylinder body as a contact with the main shaft diameter of the crankshaft; the insert 2 in the balance shaft bearing seat area is used to replace the balance shaft bearing seat of the cylinder body as a contact with the main shaft diameter of the balance shaft; the insert 1 in the main bearing seat area and the insert 2 in the balance shaft bearing seat area are connected by a connecting rib 3.

[0041] The insert is made of ductile iron, steel or grey cast iron.

[0042] The main bearing seat area insert 1 is composed of a main bearing seat bearing surface 11, a main bearing seat body 12, a main bearing cover positioning baffle 13, a main bearing seat shoulder 14, a main bearing seat bolt bracket 15, an aluminum inclusion process hole 16 and a main bearing seat threaded hole 17.

[0043] Below the main bearing seat area insert 1 is a semicircular main bearing seat bearing surface 11, the main function of which is to replace the cylinder main bearing seat as a contact with the crankshaft main shaft diameter, bear the load and provide a lubrication platform; according to the side contour line of the main bearing seat bearing surface 11, a certain thickness is offset to obtain a main bearing seat body 12, and the offset thickness is mainly determined by the load size that the main bearing seat needs to bear; two raised main bearing cover positioning baffles 13 are symmetrically distributed between the two waists of the main bearing seat body 12, such as Figure 3As shown, the main bearing cap positioning baffle 13 is located at the main bearing seat baffle position below the original cylinder body, and contacts the main bearing cap on the left and right to form an interference fit. Its main function is to provide positioning when installing the main bearing cap. At the same time, the interference fit formed with the side of the main bearing cap ensures that the main bearing cap is not easy to slip during assembly and operation. The bearing surface 11 of the main bearing seat and the surface where the main bearing seat contacts the main bearing cap need to be further fine-machined after the insert is cast into the aluminum alloy cylinder body, so a machining allowance should be left when designing the insert.

[0044] Main bearing seat shoulders 14 are symmetrically arranged on the left and right shoulders of the main bearing seat body 12, and their main function is to accommodate the main bearing seat bolt bracket 15, the aluminum inclusion process hole 16, and the main bearing seat threaded hole 17, and at the same time play a role in enhancing the overall rigidity of the lower insert. Its shape is mainly obtained by combining the internal shape of the cylinder body and the various structures that the main bearing seat shoulders 14 need to include, and its edges need to be as smooth as possible.

[0045] The main bearing seat bolt bracket 15 is located above the main bearing seat body 12 and is contained in the main bearing seat shoulder 14. Its function is to provide a certain wall thickness for the main bearing seat internal threaded hole 17 to ensure the reliability of the thread.

[0046] The aluminum inclusion process hole 16 is located on the shoulder 14 of the main bearing seat. There is no specific requirement for its position, as long as it avoids areas with special functions. Its main functions are: 1. reducing the weight of the insert to improve the lightweight of the aluminum alloy cylinder block; 2. the hole allows the molten liquid aluminum alloy to pass through and solidify when casting the cylinder block, so that the aluminum alloy cylinder block and the insert are intertwined after casting, thereby improving the bonding strength between the aluminum alloy cylinder block and the insert; because the hole is the aluminum-iron bonding surface during the casting process, in order to solve the problem that the different shrinkage rates of the aluminum alloy material and the ductile iron material are prone to form gaps, which affects the bonding strength, the aluminum inclusion process hole 16 should be as smooth as possible.

[0047] The interior of the main bearing seat body 12 includes a main bearing seat threaded hole 17; the insert is connected to the aluminum alloy cylinder block by casting and can be almost regarded as an integral whole. When the insert is manufactured, there is no main bearing seat threaded hole 17 and thread, only a bolt bracket 15 for processing the threaded hole is reserved on the appearance of the insert. After the insert is cast into the aluminum alloy cylinder block, the threaded hole and thread are processed. Processing threads on ductile iron can improve the strength and life of the threads compared to directly starting threads on the aluminum alloy cylinder block.

[0048] The balancing shaft bearing seat area insert 2 is composed of a balancing shaft bearing seat body 21 and a balancing shaft bearing seat bearing surface 22 .

[0049] The balancing shaft bearing seat body 21 is located obliquely above the shoulder 14 of the main bearing seat on one side. The balancing shaft bearing seat bearing surface 22 is contained inside the balancing shaft bearing seat body 21 and is a closed circular surface. Its main function is to replace the cylinder balancing shaft bearing seat to contact the balancing shaft main shaft diameter, and play the role of bearing load and providing a lubrication platform. According to the side contour line of the balancing shaft bearing seat bearing surface 22, a certain thickness is offset to obtain the balancing shaft bearing seat body 21, and its offset thickness is mainly determined according to the load size that the balancing shaft bearing seat needs to bear.

[0050] The main bearing seat area 1 and the balance shaft bearing seat area 2 are connected by means of a connecting rib area 3 , and the connecting rib area 3 is composed of a mesh connecting rib 31 and process holes 32 .

[0051] The mesh connecting rib 31 is located between the main bearing seat shoulder 14 and the balance shaft bearing seat body 21. The overall separation follows the principle that the triangle has stability, and the force flow optimization design is performed through topological optimization. Its functions include connecting the main bearing seat shoulder 14 and the balance shaft bearing seat body 21, and bearing the alternating stress in the connecting rib area 3 caused by the main bearing seat and the balance shaft bearing seat being subjected to loads of different directions and magnitudes during operation.

[0052] Between the mesh connecting ribs 31, an aluminum inclusion process hole 32 is provided which penetrates the entire insert. Its function is exactly the same as that of the aluminum inclusion process hole 16 in the main bearing seat area, and only the position is different.

[0053] The insert includes an oil passage 4, such as Figure 2 As shown, they lead to the main bearing seat and the balance shaft bearing seat respectively. When designing the connecting ribs, the direction of the ribs is arranged along the path of the lubricating oil channel. Since the processing of the oil channel needs to be carried out after the insert is cast into the aluminum alloy cylinder block, in order to reduce the simultaneous action of the tool on the bimetallic surface during the processing, the tool jump and other behaviors that affect the processing accuracy, the oil channel 4 should be included in the insert as much as possible. If it is really difficult to include it in the insert, the oil channel opening should be made perpendicular to the center line of the oil channel as much as possible to facilitate tool processing; at the same time, the connecting rib containing the oil channel is appropriately thickened to ensure that after the oil channel is opened, there is still enough wall thickness to ensure the strength of the connecting rib.

[0054] The surface of the insert is cast with spike-like casting protrusions during the initial manufacturing of the insert, or a rough surface is processed by sandblasting, tool roughening and other processes before being cast into the cylinder block, in order to improve the bonding strength of the insert cast into the aluminum alloy cylinder block.

[0055] It should be noted that, except for the main bearing seat bearing surface 11, the main bearing seat threaded hole 17, the balance shaft bearing seat bearing surface 21 and the internal oil channel 4, all other parts of the insert have been manufactured before the cylinder block is cast.

[0056] like Figure 3 and Figure 4 As shown, during casting, attention should be paid to setting up the structure for placing and accurately positioning the insert position, so that the insert 1 in the main bearing seat area is located at the position of the original cylinder main bearing seat. After machining, the surface of the main bearing seat body 12 that contacts the crankshaft is completely the main bearing seat bearing surface 11 of the insert; the insert 2 in the balance shaft bearing seat area is located at the position of the original cylinder balance shaft bearing seat. After machining, the surface of the balance shaft bearing seat body 21 that contacts the balance shaft is completely the balance shaft bearing seat surface 22 of the insert; it is necessary to ensure that the insert has a certain position accuracy when cast into the cylinder body, so as to ensure that the wall thickness of the cylinder body when machining the bearing surfaces and bolt holes can meet the standards.

Claims

1. An insert cast in an aluminum alloy cylinder connecting a main bearing seat and a balance bearing seat, characterized in that: The insert is cast in the aluminum alloy cylinder body and connected to the aluminum alloy cylinder body by casting; The insert is composed of a main bearing seat region insert (1), a balance shaft bearing seat region insert (2) and a connecting rib (3); The main bearing seat area insert (1) is used to replace the cylinder main bearing seat as a contact with the crankshaft main shaft diameter; the balance shaft bearing seat area insert (2) is used to replace the cylinder balance shaft bearing seat as a contact with the balance shaft main shaft diameter; the main bearing seat area insert (1) and the balance shaft bearing seat area (2) are connected by a connecting rib (3).

2. The insert for connecting the main bearing seat and the balance bearing seat cast in the aluminum alloy cylinder according to claim 1 is characterized in that: The main bearing seat area insert (1) comprises a main bearing seat bearing surface (11), a main bearing seat body (12), a main bearing cover positioning baffle (13), a main bearing seat shoulder (14), a main bearing seat bolt bracket (15) and a main bearing seat threaded hole (17); The main bearing seat bearing surface (11) is a semicircular surface, which is located below the main bearing seat area insert (1) and is used to replace the cylinder main bearing seat to contact the crankshaft main shaft diameter, and play the role of bearing load and providing a lubrication platform; the main bearing seat body (12) is obtained by offsetting a certain thickness according to the side contour line of the main bearing seat bearing surface (11); Two raised main bearing cap positioning baffles (13) are symmetrically distributed between the two waists of the main bearing seat body (12), which are used for positioning when installing the main bearing cap and at the same time form an interference fit with the side of the main bearing cap to ensure that the main bearing cap is not prone to slipping during assembly and operation; Main bearing seat shoulders (14) are symmetrically arranged on the left and right shoulders of the main bearing seat body (12) for accommodating the main bearing seat bolt bracket (15) and the main bearing seat threaded hole (17), and at the same time play a role in enhancing the overall rigidity of the lower insert; The main bearing seat bolt bracket (15) is located above the main bearing seat body (12) and is contained in the main bearing seat shoulder (14), and is used to provide a certain wall thickness for the main bearing seat internal threaded hole (17) to ensure the reliability of the thread; A main bearing seat threaded hole (17) is provided inside the main bearing seat body (12).

3. The insert according to claim 2, characterized in that: The balancing shaft bearing seat area insert (2) is composed of a balancing shaft bearing seat body (21) and a balancing shaft bearing seat bearing surface (22), wherein the balancing shaft bearing seat body (21) is located obliquely above a main bearing seat shoulder (14) on one side; the balancing shaft bearing seat bearing surface (22) is contained inside the balancing shaft bearing seat body (21), and is a closed circular surface, which is used to replace the cylinder balancing shaft bearing seat to contact the balancing shaft main shaft diameter, and plays the role of bearing loads and providing a lubrication platform.

4. The insert according to claim 3, characterized in that: The connecting rib area (3) is provided with a mesh connecting rib (31) between the main bearing seat shoulder (14) and the balancing shaft bearing seat body (21). The mesh connecting rib (31) is used to connect the main bearing seat shoulder (14) and the balancing shaft bearing seat body (21), and to withstand the alternating stress of the connecting rib area (3) caused by the main bearing seat and the balancing shaft bearing seat being subjected to loads of different directions and magnitudes during operation.

5. The insert according to claim 2, characterized in that: It also includes an aluminum inclusion process hole (16) located near the left and right lower insert shoulders (14), and the aluminum inclusion process hole (16) is used to reduce the weight of the insert and improve the bonding strength between the aluminum alloy cylinder block and the insert when casting the cylinder block.

6. The insert according to claim 4, characterized in that: Aluminum inclusion process holes (32) penetrating the entire insert are arranged between the mesh holes of the mesh connecting ribs (31). The aluminum inclusion process holes (32) are used to reduce the weight of the insert and to improve the bonding strength between the aluminum alloy cylinder block and the insert when casting the cylinder block.

7. The insert according to claim 3, characterized in that: The balancing shaft bearing seat body (21) is offset to a certain thickness according to the side contour line of the balancing shaft bearing seat bearing surface (22), and the thickness is determined according to the load size that the balancing shaft bearing seat needs to bear.

8. The insert according to claim 2, characterized in that: The main bearing seat threaded hole (17) is formed by post-processing at a reserved position of the main bearing seat bolt bracket (15) formed during the casting of the insert.

9. The insert according to claim 2, characterized in that: The bearing surface (11) of the main bearing seat and the contact surface between the main bearing seat and the main bearing cover are further fine-machined after the insert is cast into the aluminum alloy cylinder body, and a machining allowance is reserved when designing the insert.

10. The insert according to any one of claims 1 to 9, characterized in that: The insert is made of ductile iron, steel or grey cast iron.

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