Method for manufacturing a lightweight axle with a weight-reducing gap

Abstract

The present invention relates to a method for manufacturing a lightweight axle with a weight-reducing notch. The method comprises the following steps: first, making a sand mold, providing a front half sand core of the weight-reducing notch in a front recess, and providing a rear half sand core of the weight-reducing notch in a rear recess; when the front and rear mold halves are closed, the front recess and the rear recess form an axle cavity, and when the front and rear mold halves are closed, the front half sand core of the weight-reducing notch and the rear half sand core of the weight-reducing notch are butted together to form a weight-reducing notch sand core; second, casting; third, cooling: cooling the molten iron in the axle cavity, forming a lightweight axle with a weight-reducing notch after cooling, the weight-reducing notch sand core forming a weight-reducing notch, and forming a leaf spring seat in the leaf spring seat cavity; and fourth, demolding: separating the two mold halves, knocking off the axle sand mold, and removing the lightweight axle with the weight-reducing notch. The present invention aims to provide a method for manufacturing a lightweight axle with a weight-reducing notch, for reducing the weight of the axle.

Description

Technical Field

[0001] The invention relates to a vehicle axle, and in particular to a method for manufacturing a lightweight vehicle axle with a weight-reducing notch. Background Art

[0002] The front axle of an automobile, also known as the front axle or sometimes the vehicle bridge, is used to mount the front wheels, support the front weight of the vehicle, and is connected to the vehicle frame via a front suspension. Chinese Patent Application No. 2011201792654, published on December 28, 2011, and entitled "Automobile Front Axle Assembly," discloses a conventional front axle structure. The front axle comprises a crossbar and two cantilever arms (large bends). Each end of the crossbar is provided with a frame support (cover spring seat). Connected to each of the two crossbar arms is a cantilever arm with a kingpin hole. In use, the steering knuckle is connected to the front axle via a kingpin inserted into the kingpin hole. The front wheels are mounted on the steering knuckle. Original automotive front axles had the following shortcomings: the crossbar and cantilever were separate structures connected by welding, which easily led to misalignment between the cantilever and the crossbar, resulting in low yields. Steering components were prone to colliding with the cantilever. To prevent deformation in collisions, the cantilever needed to be thicker to improve impact resistance, which increased vehicle weight and fuel consumption. To address this issue, our company developed a "flat-bottom cast structure automotive front axle." The crossbar of this axle consists of an upper sidewall, a connecting wall, and a lower sidewall, arranged in an I-shaped configuration. These three panels are all flat-plate structures. Lightweighting (i.e., reducing axle weight while meeting impact resistance requirements and avoiding material inconvenience) has been a key research and development focus for our company in recent years. Lightweighting not only reduces axle manufacturing costs but also fuel consumption, benefiting both manufacturers and users. After years of research and numerous experiments, we developed the method described in this paper. Summary of the Invention

[0003] The present invention aims to provide a method for manufacturing a lightweight vehicle axle with a weight-reducing notch, so as to reduce the weight of the vehicle axle.

[0004] The above technical problems are solved by the following technical solutions: a method for manufacturing a lightweight axle with a weight-reducing notch, characterized in that the lightweight axle with a weight-reducing notch comprises a cross bar and two large bends connected at both ends of the cross bar, a kingpin hole is provided at one end of the large bend away from the cross bar, a leaf spring seat is provided on the upper surface of both ends of the cross bar, the cross bar comprises an upper side wall plate, a connecting wall plate and a lower side wall plate arranged in sequence from top to bottom, the upper side wall plate, the connecting wall plate and the lower side wall plate are connected together in an I-shape, and the end of the large bend away from one end of the cross bar is provided with a weight-reducing notch. The weight-reducing notch runs through the large bend in the front-to-back direction, and the weight-reducing notch is connected to the kingpin hole; the manufacturing method includes: the first step, making a sand mold: the axle mold for making the axle includes a front mold half and a rear mold half distributed along the front-to-back direction of the axle, sand is spread in the front mold half to form the front sand mold half, and sand is spread in the rear mold half to form the rear sand mold half, the axle mold is provided with a pouring hole, and the pouring hole is located at the interface between the front mold half and the rear mold half; a front pit 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 pit, A front half sand core of the weight reduction gap is provided inside the mold. When the front and rear mold halves are closed, the front half sand core of the weight reduction gap and the rear half sand core of the weight reduction gap are butted together to form a weight reduction gap sand core; a rear pit is provided on the front surface of the rear sand mold half, and the rear pit is provided with a rear half cavity of the leaf spring seat, and the rear pit is provided with a rear half sand core of the weight reduction gap; when the front and rear mold halves are closed, the front pit and the rear pit form an axle cavity, the front sand mold half and the rear sand mold half form an axle sand mold, the front half cavity of the leaf spring seat and the rear half cavity of the leaf spring seat form a leaf spring seat cavity, and the front and rear mold halves When the two halves are closed, the sand core in the front half of the weight-reducing gap and the sand core in the back half of the weight-reducing gap are connected together to form a sand core with a weight-reducing gap; the second step is casting: molten iron is poured into the axle cavity through the pouring port and fills the axle cavity; the third step is cooling: the molten iron in the axle cavity is cooled, and the molten iron in the axle cavity forms a lightweight axle with a weight-reducing gap after cooling, the weight-reducing gap sand core forms a weight-reducing gap, and a leaf spring seat is formed in the leaf spring seat cavity; the fourth step is demoulding: after separating the two halves of the mold, the sand mold of the axle is knocked off and the lightweight axle with the weight-reducing gap is taken out. After numerous experiments on reducing the material and weight of different parts of the axle, it was found that the removal of the outer side of the cancellation hole has little effect on the strength of the axle, so this technical solution can reduce the weight and achieve lightweighting while ensuring the strength of the axle.

[0005] Preferably, the connecting wall panels include a plurality of front panels and a plurality of rear panels arranged at intervals, the front panels are distributed along the extension direction of the cross bar, the rear panels are distributed along the extension direction of the cross bar, the adjacent front panels 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 side is connected to the lower side wall panel, the upper end of the rear panel is connected to the upper side wall panel, and the lower side is connected to the lower side wall panel, the upper side of the connecting panel is connected to the upper side wall panel, and the lower side is connected to the lower side wall 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°; a front concave cavity is provided in the front pit, a front convex block is formed between adjacent front concave cavities, and the top wall of the front convex block and the bottom wall of the front concave cavity are connected by a front bevel; a rear concave cavity is provided in the rear pit, a rear convex block is formed between adjacent rear concave cavities, and the top wall of the rear convex block and the bottom wall of the rear concave cavity are connected by a rear bevel, the top surface of the front convex block is aligned with the bottom surface of the rear concave cavity to form a rear plate cavity, the bottom surface of the front concave cavity is aligned with the top surface of the rear convex block to form a front plate cavity, the front bevel is aligned with the rear bevel to form a connecting wall plate cavity, the molten iron in the front plate cavity forms the front plate, the molten iron in the rear plate cavity forms the rear plate, and the molten iron in the connecting wall plate cavity forms the connecting wall plate. This technical solution, when shrinkage occurs during cooling interruptions in the axle casting process, creates space for shrinkage deformation (maximum along the length of the axle) by tilting the connecting plate. Shrinkage generates tensile or compressive forces at different locations along the length of the axle, which are then accommodated by the swinging of the connecting plate. This prevents deformation forces from being unable to be released, leading to internal cracking or force concentration (both of which can easily cause the axle to break at these concentrated or cracked locations). This increases the strength of the axle. This structure, in turn, reduces the wall thickness of the crossbar components, maintaining strength equivalent to that of existing I-beams, thereby reducing the weight of the axle. Experimental impact tests revealed that while maintaining the required number of impacts, the maximum weight reduction can reach approximately 15%. (The weight reduction is most pronounced when the wall thickness of the connecting wall panels is the majority.)

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

[0007] Preferably, the thickness of the front panel is at least twice the distance between a vertical plane passing through the center line of the front panel in the thickness direction and a vertical plane passing through the center line of the upper side wall in the width direction; the thickness of the rear front panel is at least twice the distance between a vertical plane passing through the center line of the rear panel in the thickness direction and a vertical plane passing through the center line of the upper side wall in the width direction. This can improve strength.

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

[0009] Preferably, an upper heat dissipation channel extending along the extension direction of the cross bar is provided in the upper side wall panel, and the two ends of the upper heat dissipation channel pass through the upper surfaces of the two leaf spring seats to form an upper air outlet, and the center line of the upper heat dissipation channel is located on a vertical plane passing through the midline of the width direction of the upper side wall panel; a lower heat dissipation channel extending along the extension direction of the cross bar is provided in the lower side wall panel, and the two ends of the lower heat dissipation channel pass through the lower surface of the lower side wall panel to form two lower air outlets, and the center line of the lower channel is located on a vertical plane passing through the midline of the width direction of the lower side wall panel; the front half of the mold is the same as the rear mold The connecting surface of the two halves is provided with two upper hanging protrusions and two lower hanging protrusions, and the rear mold half is provided with two upper limit notches which are correspondingly sleeved on the two upper hanging protrusions and two lower limit notches which are correspondingly sleeved on the two lower hanging protrusions; the upper hanging protrusion is provided with an upper air duct which is connected to the inner and outer surfaces of the front mold half, and the lower end of the upper air duct is connected to the upper air pipe, which is buried by the front sand mold half with only the lower end surface of the upper air pipe exposed; the lower hanging protrusion is provided with a lower air duct which is connected to the inner and outer surfaces of the front mold half, and the upper end of the lower air duct is connected to the lower air pipe, which is buried by the front sand mold half with only the lower end surface of the upper air pipe exposed. The front half of the sand mold is buried in a state where only the upper end surface of the lower air pipe is 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, the upper heat dissipation channel sand core is formed by bonding sand together with resin, and the two ends of the upper heat dissipation channel sand core are connected to the lower ends of the two upper air pipes one by one and cover the entire lower end surface of the upper air pipe; 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 two ends of the lower heat dissipation channel sand core are connected to the upper ends of the two lower air pipes in a one-to-one correspondence and cover the entire upper end surface of the lower air pipes; the pouring hole is located between the two upper suspension protrusions; when pouring, the molten iron is injected into the axle cavity, causing the resin constituting the upper and lower heat dissipation channel sand cores to be heated and discharged, thereby increasing the air permeability of the upper and lower heat dissipation channel sand cores; during the cooling step, the heat dissipation airflow is input from one upper air duct and then flows out from the other upper air duct, and input from one lower air duct and then flows out from the other lower air duct, thereby increasing the cooling rate inside the axle. The area where the upper and lower sidewalls of the axle crossbeam align with the connecting wall panel is the place where the heat dissipation rate is slowest during cooling, resulting in a large difference in internal and external curing time. The large time difference leads to a high probability and high number of microcracks on the axle surface, thereby significantly reducing the strength of the axle. This technical solution can dissipate heat through the heat dissipation channel during cooling to improve internal heat dissipation efficiency, thereby reducing the amount of surface microcracks caused by cooling and achieving improved axle strength. The heat dissipation channel sand core structure allows resin to be lost during the casting process, thereby increasing the air permeability of the heat dissipation channel sand core. The increased air permeability allows ventilation and heat dissipation even when the sand core is present. This allows heat dissipation through the heat dissipation channel even when the axle is a cast axle.

[0010] As an advantage, the weight reduction notch is located in the middle of the large bend in the vertical direction, so that the kingpin hole has little interference with the fixed limiting function of the kingpin shaft when used.

[0011] Preferably, the weight-reducing notch is a circular notch, so that the increased axle surface area is small.

[0012] The beneficial effects of the present invention are: it can reduce the weight of the axle; the preferred solution can provide space for shrinkage release when the cast axle cools and shrinks (that is, the space for shrinkage release is provided by straightening the connecting plates), so that the internal tearing damage caused by cooling in the axle manufacturing process is small, and the small tearing damage improves the strength of the axle. At this time, the wall thickness of the axle can be reduced under the condition of inconvenience in maintaining the strength of the axle, thereby achieving weight reduction and lightweighting; the setting of the heat dissipation channel can increase the heat dissipation speed inside the axle during casting, achieve a balance between the internal and external heat dissipation speeds, avoid the surface hardening first and the internal hardening later, thereby avoiding microcracks on the surface and inside, and the existence of microcracks will lead to a decrease in the strength of the axle; the weight can be reduced by removing parts that do not play a key role in increasing the strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic front view of a lightweight axle with a weight-reducing notch;

[0014] Figure 2 for Figure 1 A-A cross-sectional schematic diagram;

[0015] Figure 3 for Figure 2 A local enlarged schematic diagram of point A;

[0016] Figure 4 It is a cross-sectional schematic diagram when the crossbar is cut through a vertical plane extending in the left and right directions through the center line of the slide bar;

[0017] Figure 5 is a schematic diagram of the cross section of the crossbar;

[0018] Figure 6 Schematic diagram of the top view of the axle mold;

[0019] Figure 7 A schematic diagram of the axle mold when viewed in section through a vertical plane at the interface of the two mold halves;

[0020] Figure 8 for Figure 7 A local enlarged schematic diagram of point C.

[0021] In the figure: cross bar 1, large bend 2, kingpin hole 3, leaf spring seat 4, upper side wall plate 5, connecting wall plate 6, lower side wall plate 7, front plate 8, rear plate 9, connecting plate 10, angle D between the front plate and the connecting plate, angle E between the rear plate and the connecting plate, upper heat dissipation channel 11, upper air port 12, lower heat dissipation channel 13, lower air port 14, axle mold 15, front mold half 16, rear mold half 17, front sand mold half 18, pouring hole 20, axle cavity 21, front pit 22, upper suspension protrusion 23, lower suspension protrusion 24, 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 33 of leaf spring seat, weight reduction notch 45, front half sand core 49 of weight reduction notch. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] See also Figures 1 to 8, a method for manufacturing a lightweight vehicle axle with a weight-reducing notch, comprising a crossbar 1 and two large bends 2 connected at both ends of the crossbar, and a kingpin hole 3 is provided at one end of the large bend away from the crossbar. The method for manufacturing a lightweight vehicle axle with a weight-reducing notch of the present invention is a casting vehicle axle. The crossbar and the large bend are both castings, and the crossbar and the large bend are integrally formed together. A leaf spring seat 4 is provided on the upper surface of both ends of the crossbar, and the crossbar includes an upper side wall plate 5, a connecting wall plate 6 and a lower side wall plate 7 arranged in sequence from top to bottom, and the upper side wall plate, the connecting wall plate and the lower side wall plate are connected together in an I-shape. A weight-reducing notch 45 is provided at the end of the large bend away from one end of the crossbar, and the weight-reducing notch passes through the large bend in the front-to-back direction, and is connected to the kingpin hole; the weight-reducing notch is located in the middle of the large bend in the up-down direction; the weight-reducing notch is a circular notch. The upper sidewall, connecting wall, lower sidewall, and leaf spring seat are all cast and integrally formed. The connecting wall comprises a plurality of spaced front panels 8 and a plurality of rear panels 9. The front panels are arranged along the direction of extension of the crossbar, and the rear panels are arranged along the direction of extension of the crossbar. Adjacent front and rear panels are connected by connecting panels 10. The upper ends of the front panels are connected to the upper sidewall, and the lower ends are connected to the lower sidewall. The upper ends of the rear panels are connected to the upper sidewall, and the lower ends are connected to the lower sidewall. The upper ends of the connecting panels are connected to the upper sidewall, and the lower ends are connected to the lower sidewall. The angle D between the front panels and the connecting panels is greater than 90° and less than 180°, and the angle E between the rear panels and the connecting panels is greater than 90° and less than 180°. Specifically, the angle between the front panels and the connecting panels is 176°, and the angle between the rear panels and the connecting panels is 176° and less than 180°. The distance between the vertical plane passing through the centerline of the front panel in the thickness direction and the vertical plane passing through the centerline of the upper sidewall in the width direction is equal to the distance between the vertical plane passing through the centerline of the rear panel in the thickness direction and the vertical plane passing through the centerline of the upper sidewall in the width direction. The thickness of the front panel is at least twice the distance between the vertical plane passing through the centerline of the front panel in the thickness direction and the vertical plane passing through the centerline of the upper sidewall in the width direction; the thickness of the rear panel is at least twice the distance between the vertical plane passing through the centerline of the rear panel in the thickness direction and the vertical plane passing through the centerline of the upper sidewall in the width direction. An upper heat dissipation channel 11 extending along the extension direction of the cross bar is provided in the upper side wall panel, and the two ends of the upper heat dissipation channel penetrate the upper surfaces of the two leaf spring seats to form an upper air outlet 12, and 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 wall panel; a lower heat dissipation channel 13 extending along the extension direction of the cross bar is provided in the lower side wall panel, and the two ends of the lower heat dissipation channel penetrate the lower surface of the lower side wall panel to form two lower air outlets 14, and the center line of the lower channel is located on a vertical plane passing through the center line of the width direction of the lower side wall panel.

[0024] The manufacturing method of the lightweight axle with a weight-reducing gap is as follows: the first step is to make a sand mold: the axle mold 15 for making the axle includes a front mold half 16 and a rear mold half 17 distributed along the front and rear directions of the axle, sand is spread in the front mold half to form a front sand mold half 18, and sand is spread in the rear mold half to form a rear sand mold half, the axle mold is provided with a pouring hole 20, and the pouring hole is located at the interface between the front mold half and the rear mold half; a front pit is provided on the rear surface of the front sand mold half, a front cavity is provided in the front pit, and a front bulge is formed between adjacent front cavities, and a front The top wall of the convex block and the bottom wall of the front concave cavity are connected by a front inclined surface, the front pit is provided with a front half cavity 33 of the leaf spring seat, and the front half sand core 49 of the weight reduction notch is provided in the front pit; a rear pit is provided on the front surface of the rear sand mold half, and a rear concave cavity is provided in the rear pit, and a rear convex block is formed between adjacent rear concave cavities, and the top wall of the rear convex block and the bottom wall of the rear concave cavity are connected by a rear inclined surface, the rear pit is provided with a rear half cavity of the leaf spring seat, and the rear pit is provided with a rear half sand core of the weight reduction notch; when the front and rear mold halves are closed, the front pit and the rear pit enclose the axle cavity 21, and the front sand The mold half and the rear sand mold half form the axle sand mold, the top surface of the front convex block is aligned with the bottom surface of the rear concave cavity to form the rear plate cavity, the bottom surface of the front concave cavity is aligned with the top surface of the rear convex block to form the front plate cavity, the front inclined surface is aligned with the rear inclined surface to form the connecting wall plate cavity, the front half cavity of the leaf spring seat and the rear half cavity of the leaf spring seat form the leaf spring seat cavity, when the front and rear mold halves are closed, the front half sand core of the weight reduction gap and the rear half sand core of the weight reduction gap are connected together to form the weight reduction gap sand core; the second step, casting: pouring molten iron into the axle cavity through the pouring port and filling the axle Bridge cavity; the third step, cooling: cooling the molten iron in the axle cavity to below 50°, the molten iron in the axle cavity forms a lightweight axle with a weight-reducing notch after cooling, the molten iron in the front plate cavity forms the front plate, the molten iron in the rear plate cavity forms the rear plate, the molten iron in the connecting wall plate cavity forms the connecting wall plate, the leaf spring seat cavity forms the leaf spring seat, and the weight-reducing notch sand core forms the weight-reducing notch; the fourth step, demoulding: separating the two halves of the mold and knocking off the axle sand mold to take out the lightweight axle with a weight-reducing notch.

[0025] Specifically: two upper hanging protrusions 23 and two lower hanging protrusions 24 are provided on the connecting surface of the front mold half connected to the rear mold half, and two upper limit notches 25 are provided on the rear mold half, which are correspondingly sleeved on the two upper hanging protrusions and two lower limit notches are correspondingly sleeved on the two lower hanging protrusions; an upper air duct 26 connecting the inner and outer surfaces of the front mold half is provided on the upper hanging protrusion, and the lower end of the upper air duct is connected to the upper air pipe 27, and the upper air pipe is buried by the front sand mold half with only the lower end surface of the upper air pipe exposed; a lower air duct 28 connecting the inner and outer surfaces of the front mold half is provided on the lower hanging protrusion, and the upper end of the lower air duct is connected to the lower air pipe 29, and the lower air pipe is buried by the front sand mold half with only the upper end surface 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 in the axle sand mold; the cross-section of the upper heat dissipation sand core is larger than the opening of the lower end of the upper air pipe area, the upper heat dissipation channel sand core is formed by bonding sand together with resin, and the two ends of the upper heat dissipation channel sand core are connected to the lower ends of the two upper air pipes one by one and cover the entire lower end surface of the upper air pipe; 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, and the two ends of the lower heat dissipation channel sand core are connected to the upper ends of the two lower air pipes one by one and cover the entire upper end surface of the lower air pipe; the pouring hole is located between the two upper hanging protrusions; when pouring, the molten iron is injected into the axle cavity so that the resin constituting the upper and lower heat dissipation channel sand cores is heated and discharged, thereby increasing the air permeability of the upper and lower heat dissipation channel sand cores; in the cooling step, the heat dissipation airflow (specifically, blower air) is input from one upper air duct and then flows out from the other upper air duct, and is input from one lower air duct and then flows out from the other lower air duct, thereby increasing the cooling speed inside the axle.

Claims

1. A method for manufacturing a lightweight axle with a weight-reducing notch, characterized in that: A lightweight axle with a weight-reducing notch comprises a cross bar and two large bends connected at both ends of the cross bar, a kingpin hole is provided at one end of the large bend away from the cross bar, and leaf spring seats are provided on the upper surfaces of both ends of the cross bar, the cross bar comprises an upper side wall plate, a connecting wall plate and a lower side wall plate arranged in sequence from top to bottom, the upper side wall plate, the connecting wall plate and the lower side wall plate are connected together in an I-shape, a weight-reducing notch is provided at the end of the large bend away from one end of the cross bar, the weight-reducing notch passes through the large bend in the front-to-back direction, and the weight-reducing notch is connected with the kingpin hole; a manufacturing method comprises: a first step, manufacturing a sand mold: the axle mold for manufacturing the axle comprises a front mold half and a rear mold half distributed along the front-to-back direction of the axle, sand is spread in the front mold half to form a front sand mold half and a rear mold half Sand is laid in the half to form the rear sand mold half, and the axle mold is provided with a pouring hole, which is located at the interface between the front mold half and the rear mold half; a front pit is provided on the rear surface of the front sand mold half, and the front pit is provided with the front half cavity of the leaf spring seat, and the front half sand core of the weight reduction gap is provided in the front pit. When the front and rear mold halves are closed, the front half sand core of the weight reduction gap and the rear half sand core of the weight reduction gap are butted together to form the weight reduction gap sand core; a rear pit 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 pit, and the rear half sand core of the weight reduction gap is provided in the rear pit; when the front and rear mold halves are closed, the front pit and the rear pit form the axle cavity, the front sand mold half and the rear sand mold half form the axle sand mold, and the front half cavity of the leaf spring seat The front and rear half of the mold cavity of the leaf spring seat form a leaf spring seat cavity. When the front and rear mold halves are closed, the front half of the sand core of the weight reduction gap and the rear half of the sand core of the weight reduction gap are butted together to form a weight reduction gap sand core; the second step, casting: pouring molten iron into the axle cavity through the pouring port and filling the axle cavity; the third step, cooling: cooling the molten iron in the axle cavity. After cooling, the molten iron in the axle cavity forms a lightweight axle with a weight reduction gap, the weight reduction gap sand core forms a weight reduction gap, and a leaf spring seat is formed in the leaf spring seat cavity; the fourth step, demoulding: separating the two mold halves and knocking off the axle sand mold to take out the lightweight axle with a weight reduction gap. The upper side heat dissipation channel extending along the extension direction of the cross bar is provided in the upper side wall panel. The two ends of the heat dissipation channel pass through the upper surfaces of the two leaf spring seats to form an upper air outlet, and 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 wall plate; a lower heat dissipation channel extending along the extension direction of the cross bar is provided in the lower side wall plate, and the two ends of the lower heat dissipation channel pass through the lower surface of the lower side wall plate to form two lower air outlets, and the center line of the lower channel is located on a vertical plane passing through the center line of the width direction of the lower side wall plate; two upper hanging protrusions and two lower hanging protrusions are provided on the connecting surface of the front mold half connected to the rear mold half, and the rear mold half is provided with two upper limit notches correspondingly mounted on the two upper hanging protrusions and two lower limit notches correspondingly mounted on the two lower hanging protrusions;The upper hanging protrusion is provided with an upper air duct connecting the inner and outer surfaces of the front mold half, the lower end of the upper air duct is connected to the upper air pipe, and the upper air pipe is buried by the front sand mold half with only the lower end surface of the upper air pipe exposed; the lower hanging protrusion is provided with a lower air duct connecting the inner and outer surfaces of the front mold half, the upper end of the lower air duct is connected to the lower air pipe, and the lower air pipe is buried by the front sand mold half with only the upper end surface 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, the upper heat dissipation channel sand core is formed by bonding sand together with resin, and the two ends of the upper heat dissipation channel sand core are connected to the lower ends of the two upper air pipes one by one and The entire lower end surface of the upper air pipe is covered; 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 formed by bonding sand together with resin. The two ends of the lower heat dissipation channel sand core are connected to the upper ends of the two lower air pipes in a one-to-one correspondence and cover the entire upper end surface of the lower air pipe. The pouring hole is located between the two upper suspension protrusions. During pouring, the molten iron is injected into the axle cavity, causing the resin forming the upper and lower heat dissipation channel sand cores to be heated and discharged, thereby increasing the air permeability of the upper and lower heat dissipation channel sand cores. During the cooling step, the heat dissipation airflow is input from one upper air duct and then flows out from the other upper air duct, and input from one lower air duct and then flows out from the other lower air duct, thereby increasing the cooling rate inside the axle.

2. The method for manufacturing a lightweight vehicle axle with a weight-reducing notch according to claim 1, characterized in that: The connecting wall panels include a plurality of front panels and a plurality of rear panels arranged at intervals, the front panels are distributed along the extension direction of the cross bar, the rear panels are distributed along the extension direction of the cross bar, the adjacent front panels and rear panels are connected together by connecting panels, the upper ends of the front panels are connected to the upper side panels, and the lower sides are connected to the lower side panels, the upper ends of the rear panels are connected to the upper side panels, and the lower sides are connected to the lower side panels, the upper sides of the connecting panels are connected to the upper side panels, and the lower sides are connected to the lower side panels, the angle between the front panels and the connecting panels is greater than 90° and less than 180°, and the angle between the rear panels and the connecting panels is greater than 90° and less than 180° °; A front concave cavity is provided in the front pit, and front convex blocks are formed between adjacent front concave cavities, and the top wall of the front convex blocks and the bottom wall of the front concave cavity are connected by a front bevel; a rear concave cavity is provided in the rear pit, and rear convex blocks are formed between adjacent rear concave cavities, and the top wall of the rear convex blocks and the bottom wall of the rear concave cavity are connected by a rear bevel, the top surface of the front convex blocks is aligned with the bottom surface of the rear concave cavity to form a rear plate cavity, the bottom surface of the front concave cavity is aligned with the top surface of the rear convex blocks to form a front plate cavity, the front bevel is aligned with the rear bevel to form a connecting wall plate cavity, the molten iron located in the front plate cavity forms the front plate, the molten iron located in the rear plate cavity forms the rear plate, and the molten iron located in the connecting wall plate cavity forms the connecting wall plate.

3. The method for manufacturing a lightweight vehicle axle with a weight-reducing notch according to claim 2, characterized in that: The distance between the vertical plane passing through the center line of the front panel in the thickness direction and the vertical plane passing through the center line of the upper side wall panel in the width direction is equal to the distance between the vertical plane passing through the center line of the rear panel in the thickness direction and the vertical plane passing through the center line of the upper side wall panel in the width direction.

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

5. The method for manufacturing a lightweight vehicle axle with a weight-reducing notch 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. The method for manufacturing a lightweight vehicle axle with a weight-reducing notch according to claim 1, 2, 3 or 4, characterized in that: The weight reduction gap is located in the middle of the big bend in the up and down directions.

7. The method for manufacturing a lightweight vehicle axle with a weight-reducing notch according to claim 6, characterized in that: The weight-reducing notch is a circular notch.

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