Inserts cast in the aluminum alloy cylinder that connect the main bearing seat and the balance bearing seat

Abstract

The present invention discloses an insert cast in an aluminum alloy cylinder, which connects the main bearing seat and the balance bearing seat, and belongs to the field of diesel engine cylinder blocks. The insert is cast in the aluminum alloy cylinder block and connected to the aluminum alloy cylinder block by casting. The insert is composed of an insert in the main bearing seat area, an insert in the balance shaft bearing seat area, and connecting ribs. The insert in the main bearing seat area is used to replace the main bearing seat of the cylinder block as a contact with the main shaft diameter of the crankshaft. The insert in the balance shaft bearing seat area is used to replace the balance shaft bearing seat of the cylinder block as a contact with the main shaft diameter of the balance shaft. The insert in the main bearing seat area and the block balance shaft bearing seat area are connected by connecting ribs. 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.

Description

Technical Field

[0001] The invention relates to a diesel engine cylinder, in particular to an insert cast in an aluminum alloy cylinder and connecting 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, lightweight and clean.

[0003] The diesel engine cylinder block is the skeleton of the engine and is also the heaviest component in the diesel engine. Its design is becoming more and more compact. At present, the structural compactness has reached its extreme. If we want to achieve lightweighting from a structural perspective, there is little space. It is urgent to achieve lightweighting by replacing the materials of diesel engine components.

[0004] Aluminum alloy materials are light in weight and have fast heat dissipation, which meet 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 pre-tightening force after installation.

[0007] In current single-, two-, and three-cylinder diesel engines, a balancer shaft is often used to counteract the reciprocating inertial forces of the crank-connecting rod mechanism. Adding a balancer shaft is widely used to balance this reciprocating inertial force. To maintain a compact cylinder block structure, the balancer shaft and crankshaft bearing seats are typically located very close together. During operation, the inertial forces of the balancer shaft and crankshaft rotation cause the area between the two bearing seats to be subjected to alternating loads, which weaker materials such as aluminum alloys may struggle to withstand. Bench test results and simulation calculations have shown that failure in cylinder blocks with a balancer shaft structure primarily occurs in the area between the main bearing seat and the balancer bearing seat. This is because the crankshaft and balancer shaft rotate independently, subjecting the intermediate area to alternating stresses and vibrations caused by the imbalance. This, combined with potential casting defects, uneven material distribution, and residual stresses from machining, increases the probability of cracking failure during operation. Therefore, inserts containing only the main bearing are not suitable for engines with a balancer shaft structure and often present the risk of cracking between the main bearing seat and the balancer bearing seat.

[0008] Existing technical solutions generally use aluminum alloy materials to form a one-piece cylinder block when manufacturing the cylinder block. Some products will insert cast iron cylinder liners in the cylinder bore. 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 made of cast iron. 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 an engine crankcase lower case insert structure. They adopt a similar main bearing seat insert design, can manufacture the main bearing seat surface and bolt support with higher strength materials to bear the load brought by the crankshaft and bolts, and also include aluminum alloy inclusion holes to prevent the insert from moving up and down. However, in actual operation, the direction of force applied to such inserts tends to pull the insert out of the cylinder body, which may cause the insert to fall out of the cylinder body, or fatigue cracks may occur at the junction of the aluminum alloy and the insert, ultimately leading to cylinder failure. The main problem with this solution is that the force direction design of the insert is unreasonable. It simply shifts the stress area originally bearing the crankshaft and bolt forces of the aluminum alloy to the area where the insert and the aluminum alloy cylinder body meet. This increases the stress area to a certain extent, but does not balance the forces applied to the cylinder body in all directions, so the reliability improvement of the multi-cylinder body is limited.

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

[0011] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide an insert cast in an aluminum alloy cylinder for connecting the main bearing seat and the 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 is cast in an aluminum alloy cylinder, connecting the main bearing seat and the balance 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 balance shaft bearing seat area 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.

[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 to 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 slipping 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 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 outer shape is obtained according to 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 included 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 almost one piece. When the insert is manufactured, there is no main bearing seat threaded hole 17 and thread. Only the bolt bracket 15 for processing the threaded hole is reserved on the surface 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.

[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. The balancing shaft bearing seat bearing surface 22 is contained within 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 in contact with the balancing shaft main shaft diameter, playing the role of bearing load and providing a lubrication platform. The balancing shaft bearing seat body 21 can be obtained by offsetting a certain thickness according to the side contour line of the balancing shaft bearing seat bearing surface 22. The offset thickness is mainly determined by 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 of triangle stability and is optimized for force flow 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.

[0024] Furthermore, between the mesh connecting ribs 31, there is an aluminum inclusion process hole 32 that 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, only the position is different.

[0025] Furthermore, the insert is made of materials such as ductile iron, steel or gray cast iron.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) The elastic modulus of cast iron is higher than that of aluminum alloy, and the linear expansion coefficient is lower than that of aluminum alloy. The temperature at the main bearing seat is generally between 100°C and 200°C. At this temperature, the mechanical properties of ductile iron or steel are more stable. Compared with aluminum alloy, they are more adaptable to the high explosion pressure and high temperature working environment of high-strength diesel engines. When used under normal working conditions, they produce less elastic deformation and are less prone to plastic deformation and cracking, thereby improving the overall stiffness of the cylinder block main bearing seat.

[0028] 2) Existing single-cylinder, two-cylinder, and three-cylinder engines use a balance shaft to balance the reciprocating inertial force generated by the crank-connecting rod mechanism, but achieving perfect balance is difficult. This causes the area between the cylinder block main bearing seat and the balance bearing seat to be subjected to alternating stress, vibration, and other loads caused by the imbalance. Combined with possible defects in casting, uneven material distribution, and residual stress from machining, the probability of cracking and failure during operation increases. The present invention uses high-strength material 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 block has low strength and short life. The thread is used in the step of closing the cover during the cylinder block processing, which causes the life of the thread to be consumed. Therefore, the number of repeated assembly times of the finished aluminum alloy cylinder block is very limited. The use of the insert of the present invention has better material strength and better processing performance. The thread produced 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 This 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 Example 1 of the present invention within the aluminum alloy cylinder body.

[0034] In the picture:

[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 Figures 1 to 3 As shown, an insert is cast in an aluminum alloy cylinder body and connected to a main bearing seat and a balance 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 balance shaft bearing seat area 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.

[0041] The insert is made of ductile iron, steel, gray cast iron or other materials.

[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 the main bearing seat bearing surface 11 is to replace the cylinder main bearing seat as a contact with the crankshaft main shaft diameter, to 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 the main bearing seat body 12. 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. Figure 3As shown, the main bearing cap positioning baffle 13 is located at the main bearing seat baffle position below the original cylinder block. It contacts the main bearing cap on both sides and forms an interference fit. Its primary function is to provide positioning during installation. The interference fit with the side of the main bearing cap also prevents slippage during assembly and operation. The main bearing seat's bearing surface 11 and the contact surface between the main bearing seat and the main bearing cap require further finishing after the insert is cast into the aluminum alloy cylinder block. Therefore, machining allowance should be allowed when designing the insert.

[0044] Main bearing seat shoulders 14 are symmetrically provided on the left and right shoulders of the main bearing seat body 12. 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. Their 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 their 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 can allow 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; since the hole is at the aluminum-iron bonding surface during the casting process, in order to solve the problem that the different shrinkage rates of aluminum alloy materials and ductile iron materials 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 regarded as almost one piece. When the insert is manufactured, there is no main bearing seat threaded hole 17 and thread. Only the bolt bracket 15 for processing the threaded hole is reserved on the surface 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 within 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 in contact with the balancing shaft main shaft diameter, play the role of bearing load and providing a lubrication platform. The balancing shaft bearing seat body 21 can be obtained by offsetting a certain thickness according to the side contour line of the balancing shaft bearing seat bearing surface 22. The offset thickness is mainly determined by 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 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 of triangle stability and is optimized for force flow 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, there is an aluminum inclusion process hole 32 that 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, 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 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 there is still sufficient wall thickness after the oil channel is opened 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 process, or is roughened by sandblasting, tool roughening and other processes before being cast into the cylinder block, in order to improve the bonding strength of the insert when 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 are 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 is completed, 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 is completed, 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 to ensure that the wall thickness of the cylinder machined various 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 by: The insert is cast in the aluminum alloy cylinder body and connected to the aluminum alloy cylinder body through 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 region insert (1) is used to replace the cylinder main bearing seat as a member in contact with the crankshaft main shaft diameter; the balance shaft bearing seat region insert (2) is used to replace the cylinder balance shaft bearing seat as a member in contact with the balance shaft main shaft diameter; the main bearing seat region insert (1) and the balance shaft bearing seat region insert (2) are connected via a connecting rib (3); The main bearing seat area insert (1) includes 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 as a 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 obtained by offsetting a certain thickness according to the side contour line of the main bearing seat bearing surface (11); 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 slipping during assembly and operation; Main bearing seat shoulders (14) are symmetrically provided 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 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).

2. The insert according to claim 1, 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 the 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 used to replace the cylinder balancing shaft bearing seat in contact with the balancing shaft main shaft diameter, playing the role of bearing load and providing a lubrication platform.

3. The insert according to claim 2, characterized in that: A mesh connecting rib (31) is provided in the area of ​​the connecting rib (3) 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 in the area of ​​the connecting rib (3) caused by the main bearing seat and the balancing shaft bearing seat being subjected to loads of different directions and magnitudes during operation.

4. The insert according to claim 1, characterized in that: It also includes an aluminum inclusion process hole (16) located near the left and right main bearing seat 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.

5. The insert according to claim 3, characterized in that: Aluminum inclusion process holes (32) penetrating the entire insert are provided 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.

6. The insert according to claim 2, 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 that the balancing shaft bearing seat needs to bear.

7. The insert according to claim 1, 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.

8. The insert according to claim 1, 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 block, and a machining allowance is left when designing the insert.

9. The insert according to any one of claims 1 to 8, characterized in that: The insert is made of ductile iron, steel or grey cast iron.

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