Method for manufacturing cast axle with weight-reducing channel

Abstract

This invention relates to a method for manufacturing a cast axle with weight-reducing grooves. The method includes: Step 1: Creating a sand mold; placing a front weight-reducing groove sand core in the front half of the leaf spring seat cavity and a rear weight-reducing groove sand core in the rear half of the leaf spring seat cavity; when the front and rear mold halves are closed, the front and rear recesses form the axle cavity; Step 2: Casting; Step 3: Cooling; cooling the molten iron in the axle cavity, resulting in a lightweight axle with circular weight-reducing holes. The front weight-reducing groove sand core forms the front weight-reducing groove, and the rear weight-reducing groove sand core forms the rear weight-reducing groove. A leaf spring seat is formed within the leaf spring seat cavity; Step 4: Demolding; separating the two mold halves and knocking off the axle sand mold to remove the lightweight axle with circular weight-reducing holes. This invention has the advantage of being able to cast axles with reduced weight and minimal impact on axle strength, thus achieving axle lightweighting.

Description

Technical Field

[0001] This invention relates to axles, and more specifically to a method for manufacturing a cast axle with a weight-reducing through groove. Background Technology

[0002] The front axle, also known as the front axle or sometimes simply the axle, is used to mount the front wheels and support the weight of the front of the vehicle. It is connected to the chassis via the front suspension. A conventional front axle structure is disclosed in Chinese patent application number 2011201792654, published on December 28, 2011, entitled "Automotive Front Axle Assembly." This front axle includes a crossbar and two cantilever arms (large bends). Each end of the crossbar has a chassis support (cover spring seat), and each cantilever arm is connected to one of the two crossbars. Each cantilever arm has a kingpin hole. In use, the steering knuckle is connected to the front axle by passing the kingpin through the kingpin hole, and the front wheels are mounted on the steering knuckle. The initial automotive front axle had the following shortcomings: the crossbar and cantilever were separate structures connected by welding, which easily led to misalignment between the cantilever and crossbar, resulting in low yield; the steering components were prone to collisions with the cantilever, and to prevent deformation upon impact, the cantilever needed to be made thicker to increase impact resistance, thus increasing vehicle weight and fuel consumption. To address these issues, our company has designed an improved version called the "Flat-bottom Cast Structure Automotive Front Axle." The crossbar of this axle includes an upper side panel, a connecting panel, and a lower side panel arranged sequentially from top to bottom. These three panels are connected in an I-shape and are all flat. Axle lightweighting (i.e., reducing axle weight while meeting impact resistance requirements and addressing material limitations) has been a key research focus for our company in recent years. Achieving lightweighting not only reduces axle manufacturing costs but also lowers vehicle fuel consumption, benefiting both manufacturers and users. After years of research and countless experiments, we have developed the method of this invention. Summary of the Invention

[0003] The present invention aims to provide a method for manufacturing a cast axle with a weight-reducing through-slot that can reduce the weight of the cast axle and have little impact on the axle strength, thereby achieving axle lightweighting.

[0004] The above technical problems are solved by the following technical solution: A method for manufacturing a cast axle with a weight-reducing through groove, characterized in that the cast axle with the weight-reducing through groove includes a crossbar and two large bends connected to both ends of the crossbar. A kingpin hole is provided at the end of each large bend away from the crossbar. Steel leaf spring seats are provided on the upper surfaces of both ends of the crossbar. The crossbar includes an upper side wall plate, a connecting wall plate, and a lower side wall plate arranged sequentially from top to bottom. The upper side wall plate, connecting wall plate, and lower side wall plate are connected together in an I-shape. The front and rear sides of the steel leaf spring seats extend beyond the crossbar. The upper side panel, the spring steel plate seat has a front weight-reducing groove in the middle of the front edge and a rear weight-reducing groove in the middle of the rear edge. Both the front and rear weight-reducing grooves penetrate the spring steel plate seat vertically. The manufacturing method includes: First, making a sand mold: The axle mold for the vehicle axle includes a front mold half and a rear mold half distributed along the front-rear direction of the axle. Sand is laid in the front mold half to form the front sand mold half, and sand is laid in the rear mold half to form the rear sand mold half. The axle mold has a pouring hole located in the front mold half. At the interface between the front and rear mold halves; a front recess is provided on the rear surface of the front mold half, and the front half cavity of the leaf spring seat is located within the front recess, with a front weight-reducing groove sand core placed within the front half cavity of the leaf spring seat; a rear recess is provided on the front surface of the rear mold half, and the rear half cavity of the leaf spring seat is located within the rear recess, with a rear weight-reducing groove sand core placed within the rear half cavity of the leaf spring seat; when the front and rear mold halves are closed, the front and rear recesses form an axle cavity, and the front and rear mold halves form an axle mold, with the front half cavity of the leaf spring seat and the leaf spring... The first step involves casting: molten iron is poured into the axle cavity through the pouring gate, filling the cavity completely. The second step involves cooling: the molten iron in the axle cavity is cooled, forming a cast axle with partial side reinforcement. A front weight-reducing groove sand core forms the front weight-reducing groove, and a rear weight-reducing groove sand core forms the rear weight-reducing groove. A leaf spring seat is formed within the leaf spring seat cavity. The third step involves demolding: the two mold halves are separated, and the axle sand mold is knocked off to remove the cast axle with partial side reinforcement. Numerous experiments on reducing material and weight in different parts of the axle have shown that reducing the weight in the middle of the leaf spring seat has virtually no impact on the axle strength. Therefore, this technical solution can achieve weight reduction while maintaining axle strength.

[0005] Preferably, the connecting wall panel includes a plurality of front panels and a plurality of rear panels spaced apart. The front panels are distributed along the extension direction of the crossbar, and the rear panels are distributed along the extension direction of the crossbar. Adjacent front and rear panels are connected together by connecting panels. The upper end of the front panel is connected to the upper side wall panel, and the lower end of the rear panel is connected to the upper side wall panel, and the lower end of the rear panel is connected to the lower side wall panel. The upper end of the connecting panel is connected to the upper side wall panel, and the lower end of the connecting panel is connected to the lower side wall panel. The included angle between the front panel and the connecting panel is greater than 90° and less than 180°, and the included angle between the rear panel and the connecting panel is greater than 90° and less than 180°. 180°; The front recess is provided with a front cavity, and a front protrusion is formed between adjacent front cavities. The top wall of the front protrusion and the bottom wall of the front cavity are connected by a front inclined surface; The rear recess is provided with a rear cavity, and a rear protrusion is formed between adjacent rear cavities. The top wall of the rear protrusion and the bottom wall of the rear cavity are connected by a rear inclined surface. The top surface of the front protrusion is aligned with the bottom surface of the rear cavity to form a rear plate cavity, the bottom surface of the front cavity is aligned with the top surface of the rear protrusion to form a front plate cavity, and the front inclined surface is aligned with the rear inclined surface to form a connecting wall cavity. Molten iron in the front plate cavity forms a front plate, molten iron in the rear plate cavity forms a rear plate, and molten iron in the connecting wall cavity forms a connecting wall. This technical solution addresses the issue of intermittent cooling and shrinkage during axle casting. The inclined design of the connecting plate provides space for releasing the shrinkage deformation (the largest deformation occurs along the axle's length). During shrinkage, tensile or compressive forces are generated at different points along the axle's length; the connecting plate's oscillation accommodates and releases this deformation. This prevents internal cracking or force concentration due to unreleased deformation forces (both of which can lead to axle breakage at these points). This increases the axle's strength. Conversely, this structure can reduce axle weight by lowering the wall thickness of the crossbeam components to maintain strength equal to existing I-beam crossbeams. Impact tests show that, while maintaining the required number of impacts, a maximum weight reduction of approximately 15% can be achieved (with a larger weight reduction when the wall thickness of the connecting plate is reduced most frequently).

[0006] Preferably, the distance between the vertical plane passing through the centerline of the thickness direction of the front panel and the vertical plane passing through the centerline of the width direction of the upper side panel is equal to the distance between the vertical plane passing through the centerline of the thickness direction of the rear panel and the vertical plane passing through the centerline of the width direction of the upper side panel. This can better eliminate the effects of cold contraction.

[0007] Preferably, the thickness of the front panel is more than twice the distance between a vertical plane passing through the centerline of the thickness direction of the front panel and a vertical plane passing through the centerline of the width direction of the upper side panel; the thickness of the rear front panel is more than twice the distance between a vertical plane passing through the centerline of the thickness direction of the rear panel and a vertical plane passing through the centerline of the width direction of the upper side panel. This improves strength.

[0008] Preferably, the angle between the rear plate and the connecting plate is greater than 160° and less than 180°. This provides good impact resistance.

[0009] Preferably, the upper sidewall panel has an upper heat dissipation channel extending along the extension direction of the crossbar. Both ends of the upper heat dissipation channel penetrate the upper surfaces of the two leaf spring seats to form upper air vents. The centerline of the upper heat dissipation channel is located on a vertical plane passing through the centerline of the width direction of the upper sidewall panel. Similarly, the lower sidewall panel has a lower heat dissipation channel extending along the extension direction of the crossbar. Both ends of the lower heat dissipation channel penetrate the lower surface of the lower sidewall panel to form two lower air vents. The centerline of the lower heat dissipation channel is located on a vertical plane passing through the centerline of the width direction of the lower sidewall panel. The front mold half is the same as the rear mold half. The connecting surface of the half-part connection is provided with two upper suspension protrusions and two lower suspension protrusions. The rear mold half has two upper limit notches corresponding to the two upper suspension protrusions and two lower limit notches corresponding to the two lower suspension protrusions. The upper suspension protrusions have upper air channels connecting the inner and outer surfaces of the front mold half. The lower end of the upper air channel is connected to an upper air pipe, which is buried by the front mold half with only the lower end of the upper air pipe exposed. The lower suspension protrusions have lower air channels connecting the inner and outer surfaces of the rear mold half. The upper end of the lower air channel is connected to a lower air pipe, which is buried by the front mold half with only the lower end of the upper air pipe exposed. The front sand mold half is buried with only the upper end face of the lower air pipe exposed; an upper heat dissipation channel sand core forming an upper heat dissipation channel and a lower heat dissipation channel sand core forming a lower heat dissipation channel are provided in the axle sand mold; the cross-section of the upper heat dissipation sand core is larger than the opening area of ​​the lower end of the upper air pipe, and the upper heat dissipation channel sand core is formed by bonding sand together with resin. The two ends of the upper heat dissipation channel sand core are connected to the lower ends of the two upper air pipes one-to-one and cover the entire lower end face of the upper air pipes; the cross-section of the lower heat dissipation sand core is larger than the opening area of ​​the upper end of the lower air pipe, and the lower heat dissipation channel sand core is formed by bonding sand together with resin. The lower heat dissipation channel core is molded together, with both ends corresponding to the upper ends of the two lower air pipes and covering the entire upper surface of the lower air pipes. The pouring hole is located between two upper suspension protrusions. During pouring, when molten iron is injected into the axle cavity, the resin constituting the upper and lower heat dissipation channel cores is heated and discharged, thereby increasing the air permeability of the upper and lower heat dissipation channel cores. In the cooling step, the heat dissipation airflow is introduced from one upper air pipe and flows out from another upper air pipe, and introduced from one lower air pipe and flows out from another lower air pipe, thereby improving the cooling rate inside the axle. The parts where the upper and lower side walls of the axle crossbeam are aligned with the connecting wall plates are the slowest in terms of heat dissipation during cooling, resulting in a large time difference between internal and external curing. A large time difference leads to a high probability and many microcracks on the axle surface, resulting in a significant decrease in axle strength. This technical solution can dissipate heat through the heat dissipation channels during cooling to improve internal heat dissipation efficiency, thereby reducing the amount of surface microcracks caused by cooling and improving axle strength. The construction of the heat dissipation channel sand core improves its permeability by allowing resin to be lost during the casting process. This increased permeability enables ventilation and heat dissipation even with the sand core present. This allows for heat dissipation even when the axle is cast.

[0010] Preferably, a reinforcing bridge plate is provided at each of the left and right ends of the lower surface of the lower side wall plate. The reinforcing bridge plate at the left end spans the right end of the cover plate spring seat at the left end, and the reinforcing bridge plate at the right end spans the left end of the cover plate spring seat at the right end. In the first step, a front half cavity of the reinforcing bridge plate is provided in the front recess, and a rear half cavity of the reinforcing bridge plate is provided in the rear recess. When the front and rear mold halves are closed, the front half cavity and the rear half cavity of the reinforcing bridge plate form a reinforcing bridge plate cavity. In the third step, molten iron forms a reinforcing bridge plate in the reinforcing bridge plate cavity. By changing the thickness to reduce weight, it was found that the fracture point was basically located at the center of the leaf spring seat corresponding to the connecting side wall (hereinafter referred to as the first fracture point). After reinforcing the first fracture point, the weight of each side wall of the crossbar was further reduced by thinning. It was found that the fracture point was at the inner end of the lower side wall plate corresponding to the leaf spring seat (hereinafter referred to as the second fracture point). This technical solution locally reinforces the second fracture point, so that the axle strength can meet the requirements while reducing the overall weight, thereby further realizing the lightweighting of the axle.

[0011] Preferably, the bottom wall of the front weight-reducing groove is a planar structure, and the side wall of the front weight-reducing groove is a sloping structure; the bottom wall of the rear weight-reducing groove is a planar structure, and the side wall of the rear weight-reducing groove is a sloping structure. In the first step, a sand core for the front weight-reducing groove is set in the front half of the cavity of the leaf spring seat, and a sand core for the rear weight-reducing groove is set in the rear half of the cavity of the leaf spring seat. This minimizes the impact on strength during weight reduction.

[0012] The beneficial effects of this invention are as follows: it can reduce the weight of the axle; the preferred solution allows for space to release shrinkage during the cooling and contraction of the cast axle (i.e., by straightening the connecting plates to provide space for shrinkage), thereby minimizing internal tearing damage caused by cooling during the axle manufacturing process. Less tearing damage improves the axle strength, allowing for a reduction in axle wall thickness while maintaining axle strength, thus achieving weight reduction and lightweighting; the design of heat dissipation channels increases the heat dissipation rate inside the axle during casting, achieving a balance between internal and external heat dissipation rates, preventing surface hardening followed by internal hardening, which can lead to microcracks on the surface and internal structures, resulting in decreased axle strength; removing parts that do not contribute significantly to strength increases can reduce weight; and localized reinforcement of parts that play a crucial role in strength ensures that the drive mechanism allows for thinning of other parts of the crossbar, thereby reducing the overall weight of the axle and achieving lightweighting. Attached Figure Description

[0013] Figure 1 A front view schematic diagram of an embodiment of a cast axle with partial side reinforcement; Figure 2 for Figure 1 A-A sectional view; Figure 3for Figure 2 A magnified view of a portion of point A; Figure 4 This is a sectional view of the crossbar when it is cut by a vertical plane extending in the left and right directions through the center line of the crossbar. Figure 5 This is a schematic diagram of the cross-section of the crossbar; Figure 6 This is a top view of the axle mold; Figure 7 This is a schematic diagram of the axle mold in Embodiment 1 when viewed in section through the vertical plane of the interface between the two mold halves; Figure 8 for Figure 7 A magnified view of a portion at point C; Figure 9 This is a top view of Example 1; Figure 10 A three-dimensional structural schematic diagram of Embodiment 2 of a cast axle with partial side reinforcement; Figure 11 This is a schematic diagram of the axle mold in Embodiment 2 when viewed in section through the vertical plane of the interface between the two mold halves.

[0014] In the diagram: 1. Crossbar; 2. Large bend; 3. Kingpin hole; 4. Leaf spring seat; 5. Upper side panel; 6. Connecting panel; 7. Lower side panel; 8. Front panel; 9. Rear panel; 10. Connecting panel; 11. Angle D between the front panel and the connecting panel; 12. Angle E between the rear panel and the connecting panel; 13. Upper heat dissipation channel; 14. Upper air vent; 15. Lower heat dissipation channel; 16. Lower air vent; 17. Axle mold; 18. Front mold half; 19. Rear mold half; 20. Front sand mold half; 21. Gating hole; 22. Axle cavity; 23. Front recess; 24. Upper suspension protrusion; 25. Lower suspension protrusion. 4. Upper limit notch 25, upper air duct 26, upper air pipe 27, lower air duct 28, lower air pipe 29, upper heat dissipation channel sand core 30, lower heat dissipation channel sand core 31, front half cavity of steel leaf spring seat 33, reinforced bridge plate 36, right end of cover spring seat located on the left end 37, left end of cover spring seat located on the right end 38, front weight reduction groove 39, rear weight reduction groove 40, bottom wall of front weight reduction groove 41, side wall of front weight reduction groove 42, bottom wall of rear weight reduction groove 43, side wall of rear weight reduction groove 44, front half cavity of reinforced bridge plate 47, sand core of front weight reduction groove 48. Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0016] Example 1, see Figures 1 to 9A method for manufacturing a cast axle with a weight-reducing groove is disclosed, comprising a crossbar 1 and two large bends 2 connected to both ends of the crossbar, wherein a kingpin hole 3 is provided at the end of the large bends away from the crossbar. The method for manufacturing the cast axle with the weight-reducing groove of this invention is a cast axle. Both the crossbar and the large bends are cast parts, integrally formed together. Steel leaf spring seats 4 are provided on the upper surfaces of both ends of the crossbar. The crossbar includes an upper side wall plate 5, a connecting wall plate 6, and a lower side wall plate 7 arranged sequentially from top to bottom, the upper side wall plate, the connecting wall plate, and the lower side wall plate being connected together in an I-shape. The upper side wall plate, the connecting wall plate, the lower side wall plate, and the steel leaf spring seats are all cast parts, integrally formed together. The connecting panel includes several front panels 8 and several rear panels 9 spaced apart. The front panels are distributed along the extension direction of the crossbar, and the rear panels are also distributed along the extension direction of the crossbar. Adjacent front and rear panels are connected together by connecting panels 10. The upper end of the front panel is connected to the upper side panel, and the lower end is connected to the lower side panel. The upper end of the rear panel is connected to the upper side panel, and the lower end is connected to the lower side panel. The upper end of the connecting panel is connected to the upper side panel, and the lower end is connected to the lower side panel. The included angle D between the front panel and the connecting panel is greater than 90° and less than 180°, and the included angle E between the rear panel and the connecting panel is greater than 90° and less than 180°. Specifically, the included angle between the front panel and the connecting panel is 176°, and the included angle between the rear panel and the connecting panel is 176° and less than 180°. The distance between a vertical plane passing through the centerline of the thickness direction of the front panel and a vertical plane passing through the centerline of the width direction of the upper side panel is equal to the distance between a vertical plane passing through the centerline of the thickness direction of the rear panel and a vertical plane passing through the centerline of the width direction of the upper side panel. The thickness of the front panel is more than twice the distance between a vertical plane passing through the centerline of the thickness direction of the front panel and a vertical plane passing through the centerline of the width direction of the upper side panel; the thickness of the rear front panel is more than twice the distance between a vertical plane passing through the centerline of the thickness direction of the rear panel and a vertical plane passing through the centerline of the width direction of the upper side panel. The upper side panel has an upper heat dissipation channel 11 extending along the extension direction of the crossbar. The two ends of the upper heat dissipation channel pass through the upper surfaces of the two leaf spring seats to form upper air inlets 12. The center line of the upper heat dissipation channel is located on a vertical plane passing through the center line of the width direction of the upper side panel. The lower side panel has a lower heat dissipation channel 13 extending along the extension direction of the crossbar. The two ends of the lower heat dissipation channel pass through the lower surface of the lower side panel to form two lower air inlets 14. The center line of the lower air inlets is located on a vertical plane passing through the center line of the width direction of the lower side panel.The front and rear sides of the leaf spring seat extend beyond the upper side wall. The front edge of the leaf spring seat has a front weight-reducing groove 39 in the middle and the rear edge has a rear weight-reducing groove 40 in the middle. The front weight-reducing grooves and the rear weight-reducing grooves both extend through the leaf spring seat in the vertical direction. The bottom wall 41 of the front weight-reducing groove is a planar structure and the side wall 42 of the front weight-reducing groove is a sloping structure. The bottom wall 43 of the rear weight-reducing groove is a planar structure and the side wall 44 of the rear weight-reducing groove is a sloping structure.

[0017] The manufacturing method for a cast axle with a weight-reducing groove is as follows: Step 1: Making a sand mold: The axle mold 15 includes a front mold half 16 and a rear mold half 17 distributed along the front-rear direction of the axle. Sand is laid in the front mold half to form a front sand mold half 18, and sand is laid in the rear mold half to form a rear sand mold half. The axle mold is provided with a pouring hole 20, which is located at the interface between the front mold half and the rear mold half. A front recess is provided on the rear surface of the front sand mold half, and a front cavity is provided in the front recess. A front protrusion is formed between adjacent front cavities. The top wall of the front protrusion and the bottom wall of the front cavity are connected by a front inclined surface. A front half cavity 33 of the leaf spring seat is provided in the front recess, and a front weight-reducing groove sand core 48 is provided in the front half cavity of the leaf spring seat. A recessed pit is provided on the front surface of the rear sand mold half, and a rear cavity is provided within the recessed pit. A rear protrusion is formed between adjacent rear cavities. The top wall of the rear protrusion and the bottom wall of the rear cavity are connected by a rear inclined surface. The rear recessed pit contains the rear half cavity of the leaf spring seat, and a rear weight-reducing groove sand core is provided within the rear half cavity of the leaf spring seat. When the front and rear mold halves are closed, the front and rear recessed pits form an axle cavity 21, and the front and rear sand mold halves form an axle sand mold. The top surface of the front protrusion aligns with the bottom surface of the rear cavity to form a rear plate cavity, and the bottom surface of the front cavity aligns with the top surface of the rear protrusion to form a front plate cavity. The front inclined surface aligns with the rear inclined surface to form a connecting wall cavity. The front half cavity of the leaf spring seat and the rear half cavity of the leaf spring seat form a steel... Step 1: Casting. Step 2: Pouring molten iron through the pouring gate into the axle mold cavity and filling it completely. Step 3: Cooling. Cooling the molten iron in the axle mold cavity to below 50°C. The molten iron in the axle mold cavity, after cooling, forms a cast axle with a weight-reducing groove. The molten iron in the front plate mold cavity forms the front plate, the molten iron in the rear plate mold cavity forms the rear plate, the molten iron in the connecting plate mold cavity forms the connecting plate, the leaf spring seat is formed in the leaf spring mold cavity, the front weight-reducing groove sand core forms the front weight-reducing groove, and the rear weight-reducing groove sand core forms the rear weight-reducing groove. Step 4: Demolding. After separating the two mold halves, knock off the axle sand mold to remove the cast axle with the weight-reducing groove.

[0018] Specifically: The connecting surface of the front mold half and the rear mold half is provided with two upper suspension protrusions 23 and two lower suspension protrusions 24. The rear mold half is provided with two upper limit notches 25 corresponding to the two upper suspension protrusions and two lower limit notches corresponding to the two lower suspension protrusions. The upper suspension protrusions are provided with an upper air duct 26 connecting the inner and outer surfaces of the front mold half. The lower end of the upper air duct is connected to an upper air pipe 27, which is buried by the front sand mold half with only the lower end face of the upper air pipe exposed. The lower suspension protrusions are provided with a lower air duct 28 connecting the inner and outer surfaces of the rear mold half. The upper end of the lower air duct is connected to a lower air pipe 29, which is buried by the front sand mold half with only the upper end face of the lower air pipe exposed. An upper heat dissipation channel sand core 30 forming an upper heat dissipation channel and a lower heat dissipation channel sand core 31 forming a lower heat dissipation channel are provided inside the axle sand mold. The cross-section of the upper heat dissipation sand core is larger than the opening at the lower end of the upper air pipe. The upper heat dissipation channel sand core is formed by bonding sand together with resin. Both ends of the upper heat dissipation channel sand core are connected to the lower ends of the two upper air pipes, covering the entire lower end surface of the upper air pipes. The cross-section of the lower heat dissipation sand core is larger than the opening area of ​​the upper end of the lower air pipe. The lower heat dissipation channel sand core is also formed by bonding sand together with resin. Both ends of the lower heat dissipation channel sand core are connected to the upper ends of the two lower air pipes, covering the entire upper end surface of the lower air pipes. The casting hole is located between two upper suspension protrusions. During casting, when molten iron is injected into the axle cavity, the resin constituting the upper and lower heat dissipation channel sand cores is heated and discharged, thereby increasing the permeability of the upper and lower heat dissipation channel sand cores. In the cooling step, the cooling airflow (specifically, air blown by a blower) is input from one upper air duct and flows out from another upper air duct, and input from one lower air duct and flows out from another lower air duct, thereby increasing the cooling rate inside the axle.

[0019] Example 2 differs from Example 1 in that: See Figure 10 and Figure 11 A reinforcing bridge plate 36 is provided at each of the left and right ends of the lower surface of the lower side panel. The reinforcing bridge plate at the left end spans the right end 37 of the cover plate spring seat at the left end, and the reinforcing bridge plate at the right end spans the left end 38 of the cover plate spring seat at the right end.

[0020] In the first step, a cavity 47 for the front half of the reinforcing bridge plate is set in the front recess, and a cavity for the rear half of the reinforcing bridge plate is set in the rear recess. When the front and rear mold halves are closed, the cavity for the front half of the reinforcing bridge plate and the cavity for the rear half of the reinforcing bridge plate form a cavity for the reinforcing bridge plate. In the third step, molten iron forms a reinforcing bridge plate in the cavity for the reinforcing bridge plate.

Claims

1. A method of making a cast axle having a reduced weight tunnel, comprising: The cast axle with a weight-reducing groove includes a crossbar and two large bends connected to both ends of the crossbar. A kingpin hole is provided at the end of each large bend furthest from the crossbar. Leaf spring seats are provided on the upper surfaces of both ends of the crossbar. The crossbar includes an upper side panel, a connecting panel, and a lower side panel arranged sequentially from top to bottom. The upper side panel, connecting panel, and lower side panel are connected together in an I-shape. The front and rear sides of the leaf spring seats extend beyond the upper side panel. A front weight-reducing groove is provided at the center of the front edge of the leaf spring seat, and a rear weight-reducing groove is provided at the center of the rear edge. Both the front and rear weight-reducing grooves penetrate the leaf spring seats vertically. The manufacturing method includes: Step 1, making sand molds: The axle mold for the vehicle axle includes a front mold half and a rear mold half distributed along the front-rear direction of the axle. Sand is laid in the front mold half to form the front sand mold half, and sand is laid in the rear mold half to form the rear sand mold half. The axle mold has a pouring hole located at the interface between the front mold half and the rear mold half. A front recess is provided on the rear surface of the front sand mold half, and the front half cavity of the leaf spring seat is provided in the front recess. A front weight-reducing groove sand core is set in the front half cavity of the leaf spring seat. A rear recess is provided on the front surface of the rear sand mold half, and the rear half cavity of the leaf spring seat is provided in the rear recess. The mold cavity is equipped with a rear weight-reducing groove sand core; when the front and rear mold halves are closed, the front and rear recesses form the axle mold cavity, the front and rear sand mold halves form the axle sand mold, and the front and rear half of the leaf spring seat cavity form the leaf spring seat cavity; the second step, casting: molten iron is poured into the axle mold cavity through the pouring gate and fills the axle mold cavity; the third step, cooling: the molten iron in the axle mold cavity is cooled, and the molten iron in the axle mold cavity forms a cast axle with local side reinforcement after cooling, the front weight-reducing groove sand core forms the front weight-reducing groove, the rear weight-reducing groove sand core forms the rear weight-reducing groove, and the leaf spring seat is formed in the leaf spring seat cavity; Step 4, Demolding: After separating the two mold halves, knock off the axle sand mold to remove the cast axle with partial side reinforcement. The lower surface of the lower side panel has a reinforcing bridge plate at each of the left and right ends. The reinforcing bridge plate at the left end spans across the right end of the left leaf spring seat, and the reinforcing bridge plate at the right end spans across the left end of the right leaf spring seat. In the first step, the front half cavity of the reinforcing bridge plate is set in the front recess, and the rear half cavity of the reinforcing bridge plate is set in the rear recess. When the front and rear mold halves are closed, the front half cavity and the rear half cavity of the reinforcing bridge plate form the reinforcing bridge plate cavity. In the third step, molten iron forms the reinforcing bridge plate in the reinforcing bridge plate cavity.

2. The method for manufacturing a cast axle with a weight-reducing through-slot according to claim 1, characterized in that, The connecting panel includes several front panels and several rear panels spaced apart. The front panels are distributed along the extension direction of the crossbar, and the rear panels are also distributed along the extension direction of the crossbar. Adjacent front and rear panels are connected together by connecting panels. The upper end of the front panel is connected to the upper side panel, and the lower end is connected to the lower side panel. The upper end of the rear panel is connected to the upper side panel, and the lower end is connected to the lower side panel. The upper end of the connecting panel is connected to the upper side panel, and the lower end is connected to the lower side panel. The angle between the front panel and the connecting panel is greater than 90° and less than 180°, and the angle between the rear panel and the connecting panel is greater than 90° and less than 180°. °; The front recess is provided with a front cavity, and a front protrusion is formed between adjacent front cavities. The top wall of the front protrusion and the bottom wall of the front cavity are connected by a front inclined surface; The rear recess is provided with a rear cavity, and a rear protrusion is formed between adjacent rear cavities. The top wall of the rear protrusion and the bottom wall of the rear cavity are connected by a rear inclined surface. The top surface of the front protrusion is aligned with the bottom surface of the rear cavity to form a rear plate cavity, the bottom surface of the front cavity is aligned with the top surface of the rear protrusion to form a front plate cavity, and the front inclined surface is aligned with the rear inclined surface to form a connecting wall cavity. Molten iron in the front plate cavity forms the front plate, molten iron in the rear plate cavity forms the rear plate, and molten iron in the connecting wall cavity forms the connecting wall.

3. The method for manufacturing a cast axle with a weight-reducing through-slot according to claim 2, characterized in that, The distance between the vertical plane passing through the centerline of the thickness direction of the front panel and the vertical plane passing through the centerline of the width direction of the upper side panel is equal to the distance between the vertical plane passing through the centerline of the thickness direction of the rear panel and the vertical plane passing through the centerline of the width direction of the upper side panel.

4. The method for manufacturing a cast axle with a weight-reducing through groove according to claim 3, characterized in that, The thickness of the front panel is more than twice the distance between the vertical plane passing through the centerline of the thickness direction of the front panel and the vertical plane passing through the centerline of the width direction of the upper side panel; the thickness of the rear front panel is more than twice the distance between the vertical plane passing through the centerline of the thickness direction of the rear panel and the vertical plane passing through the centerline of the width direction of the upper side panel.

5. A method for manufacturing a cast axle with a weight-reducing through-slot according to claim 2, 3, or 4, characterized in that, The angle between the front plate and the connecting plate is greater than 160° and less than 180°, and the angle between the rear plate and the connecting plate is greater than 160° and less than 180°.

6. A method for manufacturing a cast axle with a weight-reducing through groove according to claim 1, 2, 3, or 4, characterized in that, The upper side wall panel has an upper heat dissipation channel extending along the extension direction of the crossbar. Both ends of the upper heat dissipation channel penetrate the upper surfaces of the two leaf spring seats to form upper air vents. The centerline of the upper heat dissipation channel lies on a vertical plane passing through the centerline of the width direction of the upper side wall panel. The lower side wall panel has a lower heat dissipation channel extending along the extension direction of the crossbar. Both ends of the lower heat dissipation channel penetrate the lower surface of the lower side wall panel to form two lower air vents. The centerline of the lower heat dissipation channel lies on a vertical plane passing through the centerline of the width direction of the lower side wall panel. The front mold half is connected to the rear mold half. The connecting surface of the joint is provided with two upper suspension protrusions and two lower suspension protrusions. The rear mold half has two upper limit notches corresponding to the two upper suspension protrusions and two lower limit notches corresponding to the two lower suspension protrusions. The upper suspension protrusions have upper air channels connecting the inner and outer surfaces of the front mold half. The lower end of the upper air channel is connected to an upper air pipe, which is buried by the front mold half with only the lower end of the upper air pipe exposed. The lower suspension protrusions have lower air channels connecting the inner and outer surfaces of the rear mold half. The upper end of the lower air channel is connected to a lower air pipe, which is buried by the front mold half with only the lower end of the upper air pipe exposed. The mold half is buried with only the upper end face of the lower air pipe exposed; an upper heat dissipation channel sand core forming an upper heat dissipation channel and a lower heat dissipation channel sand core forming a lower heat dissipation channel are provided in the axle sand mold; the cross-section of the upper heat dissipation sand core is larger than the opening area of ​​the lower end of the upper air pipe, and the upper heat dissipation channel sand core is formed by bonding sand together with resin. The two ends of the upper heat dissipation channel sand core are connected to the lower ends of the two upper air pipes one-to-one and cover the entire lower end face of the upper air pipes; the cross-section of the lower heat dissipation sand core is larger than the opening area of ​​the upper end of the lower air pipe, and the lower heat dissipation channel sand core is formed by bonding sand together with resin. The lower heat dissipation channel core is formed by connecting its two ends to the upper ends of the two lower air pipes, thus covering the entire upper surface of the lower air pipes. The casting hole is located between the two upper suspension protrusions. When molten iron is poured into the axle cavity during casting, the resin constituting the upper and lower heat dissipation channel cores is heated and discharged, thereby increasing the air permeability of the upper and lower heat dissipation channel cores. During the cooling step, the heat dissipation airflow is introduced from one upper air pipe and flows out from another upper air pipe, and introduced from one lower air pipe and flows out from another lower air pipe, thereby increasing the cooling rate inside the axle.

7. A method for manufacturing a cast axle with a weight-reducing through-slot according to claim 1, 2, 3, or 4, characterized in that, The bottom wall of the front weight-reducing trough is a planar structure, and the side wall of the front weight-reducing trough is a sloping structure. The bottom wall of the rear weight-reducing trough is a planar structure, and the side wall of the rear weight-reducing trough is a sloping structure.

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