A lightweight vehicle axle with wave sections connecting wall panels and a manufacturing method thereof

Abstract

The present invention relates to a lightweight vehicle axle with a connecting wall panel having a wavy section, comprising a crossbar, wherein the crossbar comprises an upper side wall panel, a connecting wall panel, and a lower side wall panel arranged in sequence from top to bottom, wherein the upper side wall panel, the connecting wall panel, and the lower side wall panel are connected together in an I-shape, wherein the connecting wall panel comprises a middle section and side sections connected to both ends of the middle section, wherein the middle section is wavy, wherein the upper side of the middle section is connected to the upper side wall panel, and the lower side is connected to the lower side wall panel, and the upper side of the side section is connected to the upper side wall panel, and the lower side is connected to the lower side wall panel; a method for manufacturing a lightweight vehicle axle with a connecting wall panel having a wavy section, comprising manufacturing a sand mold, casting, cooling, and demolding. The present invention aims to have the advantage of being able to achieve lightweight vehicle axles, and is used to reduce the weight of existing vehicle axles while maintaining the material of the vehicle axles unchanged.

Description

Technical Field

[0001] The invention relates to a vehicle axle, and in particular to a lightweight vehicle axle with connecting wall panels provided with wave sections and a manufacturing method thereof. 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. This lightweighting not only reduces axle manufacturing costs but also fuel consumption, benefiting both manufacturers and users. This invention was developed after years of research and numerous experiments. Summary of the Invention

[0003] The present invention aims to provide a lightweight axle with a connecting wall panel provided with a wave section and a manufacturing method thereof, which can achieve lightweighting of the axle, and is used to reduce the weight of the existing axle while maintaining the material of the axle unchanged.

[0004] The above technical problems are solved by the following technical solutions: a lightweight axle with a connecting wall panel and a wavy section, comprising a cross bar and two large bends connected at both ends of the cross bar, a main pin hole being provided at the end of the large bend away from the cross bar, and a steel leaf spring seat being provided on the upper surface of both ends of the cross bar, the cross bar comprising an upper side wall panel, a connecting wall panel and a lower side wall panel arranged in sequence from top to bottom, the upper side wall panel, the connecting wall panel and the lower side wall panel being connected together in an I-shape, characterized in that the connecting wall panel comprises a middle section and side sections connected at both ends of the middle section, the middle section is wavy, the upper side of the middle section 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 side section is connected to the upper side wall panel, and the lower side is connected to the lower side wall panel. This technical solution creates a relief for shrinkage (maximum shrinkage along the length of the axle) during cooling interruptions during axle casting or quenching. The wavy midsection creates space for this shrinkage (maximum shrinkage along the axle's length). This prevents the deformation forces from being forced to dissipate, leading to internal cracking or force concentration (which can easily cause the axle to break at these locations). This increases axle strength, allowing the slide bar component's wall thickness to be reduced while maintaining comparable strength to the pre-modified structure, resulting in a weight reduction. Experimental impact tests have shown that while maintaining the required number of impacts, the maximum weight reduction can reach approximately 18%. (The weight reduction is particularly significant when the wall thickness of the connecting wall panels is the majority.)

[0005] Preferably, the crossbar and the large bend are both cast, integrally formed together, and the upper sidewall, connecting wall, lower sidewall, and leaf spring seat are all cast, integrally formed together. This allows the axle to be cast, achieving weight reduction with the axle structure of the present invention, with the weight reduction effect of a cast axle being greater than that of a forged axle.

[0006] Preferably, the distance between the wave crest of the middle section and a vertical plane passing through the widthwise midline of the upper sidewall is equal to the distance between the wave trough of the middle section and a vertical plane passing through the widthwise midline of the upper sidewall. This can better mitigate the effects of cold shrinkage. The "wave crest of the middle section" refers to the forwardmost point of the arched portion of the front surface of the middle section; the "wave trough of the middle section" refers to the rearmost point of the arched portion of the rear surface of the middle section.

[0007] Preferably, a vertical plane passing through the trough of the front surface of the middle section is located in front of a vertical plane passing through the crest of the rear surface of the middle section. "The trough of the front surface of the middle section" refers to the rearmost point of the rearward concave portion of the front surface of the middle section; "the crest of the rear surface of the middle section" refers to the frontmost point of the forward concave portion of the rear surface of the middle section. This ensures strength.

[0008] Preferably, the wavelength of the waveform where the middle section is located is between 6 cm and 12 cm. This has a good impact resistance. The "wavelength of the waveform where the middle section is located" is the distance between the peaks of two adjacent middle sections.

[0009] Preferably, the upper side wall panel is provided with an upper heat dissipation channel extending along the extension direction of the crossbar, 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, 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; the lower side wall panel is provided with a lower heat dissipation channel extending along the extension direction of the crossbar, 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, and the center line of the lower heat dissipation channel is located on a vertical plane passing through the center line of the width direction of the lower side wall panel. The portion where the upper and lower side wall panels of the axle crossbeam are aligned with the connecting wall panel is the place where the heat dissipation speed is slowest during cooling, resulting in a large difference in the curing time between the inside and outside. The large time difference leads to a high probability and high number of microcracks on the surface of the axle, thereby causing a large reduction in the strength of the axle. This technical solution can dissipate heat through the heat dissipation channel during cooling to improve the internal heat dissipation efficiency, thereby reducing the amount of surface microcracks caused by cooling and improving the strength of the axle.

[0010] Preferably, a vertical plane passing through the center line of the width direction of the upper side wall plate bisects the side section, and the center line of the wave in the middle section is located on the vertical plane passing through the center line of the width direction of the upper side wall plate. Good driving depends on good horizontal impact resistance.

[0011] Preferably, the upper side wall panel is provided with an upper heat dissipation channel extending along the extension direction of the cross bar, 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, 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; the lower side wall panel is provided with a lower heat dissipation channel extending along the extension direction of the cross bar, 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, 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.

[0012] A method for manufacturing a lightweight axle with a wavy section connecting a wall panel, the first step is to manufacture a sand mold: the axle mold for manufacturing the axle includes a front mold half and a rear mold half distributed along the front and rear directions 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 a front wavy bottom surface section with a wavy bottom surface is provided in the front pit; a rear pit is provided on the front surface of the rear sand mold half, and a rear wavy bottom surface section with a wavy bottom surface is provided in the rear pit; the front and rear When the mold halves are closed, the front concave pit and the rear concave pit form an axle cavity, the front sand mold half and the rear sand mold half form an axle sand mold, and the front wavy bottom surface section and the rear wavy bottom surface section form a middle section cavity. The second step is casting: pouring molten iron into the axle cavity through the pouring port and filling the axle cavity; the third step is cooling: cooling the molten iron in the axle cavity to below 50°. After cooling, the molten iron in the axle cavity forms a lightweight axle with a wavy section connecting the wall panels, and the molten iron in the middle section cavity forms the middle section; the fourth step is demoulding: after separating the two mold halves, knocking off the axle sand mold and taking out the lightweight axle with a wavy section connecting the wall panels.

[0013] Preferably, the connecting surface of the front mold half connected to the rear mold half 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 connecting the inner and outer surfaces of the front mold half, and the lower end of the upper air duct is connected with an 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 rear mold half, and the upper end of the lower air duct is connected with a 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, and the upper heat dissipation sand core The 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 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. 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.

[0014] The beneficial effects of the present invention are: it can provide space for shrinkage release when the cast axle cools and shrinks (that is, the space for shrinkage release is provided by the deformation of the wavy middle section), so that the internal tearing damage caused by cooling in the axle manufacturing process is small, and the small tearing damage has the effect of improving 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 internal and external heat dissipation speed balance, avoid the surface cold hardening first and the internal cold hardening later, thereby causing micro cracks on the surface and inside, and the presence of micro cracks will lead to a decrease in the strength of the axle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic front view of a lightweight axle with a wave section for connecting wall panels;

[0016] Figure 2 for Figure 1 A-A cross-sectional schematic diagram;

[0017] Figure 3 for Figure 2 A local enlarged schematic diagram of point C;

[0018] 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 structural sliding bar;

[0019] Figure 5 Schematic diagram of the cross section of the position crossbar;

[0020] Figure 6 Schematic diagram of the top view of the axle mold;

[0021] 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;

[0022] Figure 8 for Figure 7 A local enlarged schematic diagram of point C;

[0023] Figure 9 Schematic diagram of the three-dimensional structure of a lightweight axle with wavy sections connecting the wall panels.

[0024] In the figure: crossbar 1, large bend 2, kingpin hole 3, leaf spring seat 4, upper side wall 5, connecting wall 6, lower side wall 7, middle section 8, side section 9, wave crest 10 of the middle section, vertical plane D passing through the midline of the width direction of the upper side wall, wave trough 32 of the middle section, vertical plane E passing through the wave trough of the front surface of the middle section, vertical plane F passing through the wave crest of the rear surface of the middle section, wavelength G of the wave of the middle section, 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 wavy bottom section 22, upper hanging protrusion 23, lower hanging 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. Implementation Method

[0025] 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.

[0026] See also Figures 1 to 9 A lightweight axle with a connecting wall panel provided with a wavy section comprises a cross bar 1 and two large bends 2 connected at both ends of the cross bar, and a kingpin hole 3 is provided at one end of the large bend away from the cross bar. The lightweight axle with a connecting wall panel provided with a wavy section of the present invention is a cast axle. The cross bar and the large bend are both cast parts, and the cross bar and the large bend are integrally formed together. A leaf spring seat 4 is provided on the upper surface of both ends of the cross bar, and the cross bar comprises an upper side wall panel 5, a connecting wall panel 6 and a lower side wall panel 7 arranged in sequence from top to bottom, and the upper side wall panel, the connecting wall panel and the lower side wall panel are connected together in an I-shape. The upper side wall panel, the connecting wall panel, the lower side wall panel and the leaf spring seat are all cast parts, and the upper side wall panel, the connecting wall panel, the lower side wall panel and the leaf spring seat are integrally formed together. The connecting wall panel comprises a middle section 8 and side sections 9 connected at both ends of the middle section. The middle section is wavy in shape, with its upper side connected to the upper sidewall and its lower side connected to the lower sidewall. The side sections are connected to the upper sidewall and its lower side connected to the lower sidewall. The crossbar and large bend are both cast components, integrally formed. The upper sidewall, connecting wall, lower sidewall, and leaf spring seat are all cast components, integrally formed. The distance between the wave crest 10 of the middle section and a vertical plane D passing through the widthwise centerline of the upper sidewall is equal to the distance between the wave trough 32 of the middle section and a vertical plane passing through the widthwise centerline of the upper sidewall. A vertical plane E passing through the wave trough on the front surface of the middle section is located forward of a vertical plane F passing through the wave crest on the rear surface of the middle section. The wavelength G of the wave pattern in the middle section is between 6 cm and 12 cm. A vertical plane passing through the widthwise midline of the upper sidewall bisects the side segments, with the centerline of the wave in the midsection located on a vertical plane passing through the widthwise midline of the upper sidewall. An upper heat dissipation channel 11 extending along the direction of the crossbar is provided within the upper sidewall. The ends of the upper heat dissipation channel penetrate the upper surfaces of the two leaf spring seats to form an upper air vent 12, with the centerline of the upper heat dissipation channel located on a vertical plane passing through the widthwise midline of the upper sidewall. A lower heat dissipation channel 13 extending along the direction of the crossbar is provided within the lower sidewall. The ends of the lower heat dissipation channel penetrate the lower surface of the lower sidewall to form two lower air vents 14, with the centerline of the lower channel located on a vertical plane passing through the widthwise midline of the lower sidewall.

[0027] The method for making a lightweight axle with a wavy section connecting the wall panels 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, and a front wavy bottom surface section 22 with a wavy bottom surface is provided in the front pit; a rear pit is provided on the front surface of the rear sand mold half, and a rear wavy bottom surface section 22 with a wavy bottom surface is provided in the rear pit Bottom section; when the front and rear mold halves are closed, the front pit and the rear pit form an axle cavity 21, the front sand mold half and the rear sand mold half form an axle sand mold, and the front wavy bottom section and the rear wavy bottom section form a middle section cavity; 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 to below 50°, and the molten iron in the axle cavity forms a lightweight axle with a wavy section connecting the wall panels after cooling, and the molten iron in the middle section cavity forms the said middle section; the fourth step, demoulding: after separating the two mold halves, knocking off the axle sand mold and taking out the lightweight axle with a wavy section connecting the wall panels.

[0028] 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 rear 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 lightweight vehicle axle with a connecting wall panel having a wavy section, comprising a crossbar and two large bends connected at both ends of the crossbar, wherein a kingpin hole is provided at one end of the large bend away from the crossbar, and leaf spring seats are provided on the upper surfaces of both ends of the crossbar. The crossbar comprises an upper side wall panel, a connecting wall panel, and a lower side wall panel arranged in sequence from top to bottom, wherein the upper side wall panel, the connecting wall panel, and the lower side wall panel are connected together in an I-shape, characterized in that: The connecting wall panel comprises a middle section and side sections connected at both ends of the middle section, the middle section is wavy, the upper side of the middle section 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 side section is connected to the upper side wall panel, and the lower side is connected to the lower side wall panel, and the vertical plane passing through the center line of the width direction of the upper side wall panel bisects the side section, and the center line of the wave where the middle section is located is located on the vertical plane passing through the center line of the width direction of the upper side wall panel. The upper side wall panel is provided with an upper heat dissipation channel extending along the extension direction of the cross bar, 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, and the center line of the upper heat dissipation channel is located on the vertical plane passing through the center line of the width direction of the upper side wall panel; the lower side wall panel is provided with a lower heat dissipation channel extending along the extension direction of the cross bar, 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, and the center line of the lower channel is located on the vertical plane passing through the center line of the width direction of the lower side wall panel.

2. A lightweight vehicle axle with a connecting wall panel having a wave section according to claim 1, characterized in that: The cross bar and the large bend are both castings, and the cross bar and the large bend are integrally formed together. The upper side wall plate, the connecting wall plate, the lower side wall plate and the leaf spring seat are all castings, and the upper side wall plate, the connecting wall plate, the lower side wall plate and the leaf spring seat are integrally formed together.

3. A lightweight vehicle axle with a connecting wall panel having a wave section according to claim 1 or 2, characterized in that: The distance between the wave crest of the middle section and the vertical plane passing through the center line of the width direction of the upper side wall plate is equal to the distance between the wave trough of the middle section and the vertical plane passing through the center line of the width direction of the upper side wall plate.

4. A lightweight vehicle axle with a connecting wall panel having a wave section according to claim 1 or 2, characterized in that: A vertical plane passing through the troughs of the front surface of the middle section is located in front of a vertical plane passing through the peaks of the rear surface of the middle section.

5. A lightweight vehicle axle with a connecting wall panel having a wave section according to claim 1 or 2, characterized in that: The wavelength of the waveform in the middle section is between 6 cm and 12 cm.

6. A method for manufacturing a lightweight vehicle bridge with a connecting wall panel having a wave section according to any one of claims 1 to 5, characterized in that: The first step is to make a sand mold: the axle mold for making the axle includes a front mold half and a rear mold half distributed along the front and rear directions 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 a front wavy bottom surface section with a wavy bottom surface is provided in the front pit; a rear pit is provided on the front surface of the rear sand mold half, and a rear wavy bottom surface section with a wavy bottom surface is provided in the rear pit; when the front and rear mold halves are closed, the front pit and The rear pit forms an axle cavity, the front sand mold half and the rear sand mold half form an axle sand mold, and the front wavy bottom surface section and the rear wavy bottom surface section form a middle section cavity. The second step is casting: pouring molten iron into the axle cavity through the pouring port and filling the axle cavity; the third step is cooling: cooling the molten iron in the axle cavity to below 50°. After cooling, the molten iron in the axle cavity forms a lightweight axle with a wavy section connecting the wall panels, and the molten iron in the middle section cavity forms the middle section; the fourth step is demoulding: separating the two mold halves, knocking off the axle sand mold, and taking out the lightweight axle with a wavy section connecting the wall panels.

7. The method for manufacturing a folded line structure of connecting wall panels according to claim 6, characterized in that: The connecting surface of the front mold half connected to the rear mold half 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 connecting the inner and outer surfaces of the front mold half, and the lower end of the upper air duct is connected with an 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 rear mold half, and the upper end of the lower air duct is connected with a 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, and the upper heat dissipation channel The 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 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.

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