A welding device and method for producing an electric vehicle rear axle

Abstract

The present application relates to the technical field of electric vehicle rear axle production, and particularly relates to a welding device and method for electric vehicle rear axle production, which comprises: a welding unit, including a welding gun, a driving rod, a flow guide plate for limiting the spatter direction of welding slag, a transmission gear and a driven gear for providing a rotating torque to the driving rod, a supporting cylinder for providing a supporting force, a jacket for cooling, and a gas spray gun for cleaning the spattered welding slag; a stability feature detection unit for obtaining the concentration of lubricating oil volatiles, the first radial component of the spatter speed of welding slag at a first height, and the second radial component of the spatter speed of welding slag at a second height; and a welding stability regulation unit for determining the water inlet position of the jacket opening according to the concentration of lubricating oil volatiles, determining the vertical inclination angle of the flow guide plate according to the first radial component, and determining the opening of the gas spray gun according to the second radial component. The present application realizes the improvement of the welding quality of electric vehicle rear axles.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle rear axle manufacturing technology, and in particular to a welding equipment and method for manufacturing electric vehicle rear axles. Background Technology

[0002] The rear axle of an electric vehicle is a key load-bearing component in the power transmission system of an electric vehicle. Its welding quality directly affects the driving safety and durability of the entire vehicle. Currently, the production of electric vehicle rear axles in China mainly adopts a stamping and welding structure. That is, two stamped half-shells are first welded together to form the axle housing, and then accessories such as axle tubes, flanges, spring seats, and reinforcing rings are welded to the axle housing body in sequence to form a complete rear axle assembly. On automated welding production lines, the above welding process is usually completed by welding units to ensure welding accuracy by improving the overall rigidity of the worktable. However, in the welding unit, the active turntable carries the workpiece and achieves rotational displacement through the slewing bearing. The slewing bearing will experience progressive wear during long-term service. Therefore, there is an urgent need for a welding equipment and method for the production of electric vehicle rear axles.

[0003] Chinese Patent Publication No. CN215432315U discloses a welding fixture assembly for assembling two halves of a bridge housing, including a worktable; a support and clamping mechanism, respectively disposed at the left and right ends of the top of the worktable, the support and clamping mechanism including a first fixed frame and a second fixed frame, the first fixed frame being disposed at the bottom of the bridge housing for supporting and fixing the bridge housing, and the second fixed frame including two identical ones, respectively disposed on the front and rear sides of the first fixed frame for clamping and fixing the bridge housing; a moving positioning mechanism, disposed at the top of the worktable, the moving positioning mechanism being disposed to the right of the support and clamping mechanism, the moving positioning mechanism including a positioning frame for pushing the bridge housing for alignment; and a center positioning mechanism, disposed in the middle of the top of the worktable, including a positioning plate, the positioning plate being disposed at the bottom of the bridge housing; Therefore, it can be seen that during the welding of the electric vehicle rear axle by the welding unit, the high-temperature hot air generated by the welding arc rebounds upward, which will continuously convect and heat the sliding components used to support the rotation of the welding torch in the equipment, causing the lubricating oil on the working surface of the slide rail to evaporate, and thus reducing the motion stability of the welding torch during the welding process. Summary of the Invention

[0004] To address this issue, the present invention provides a welding equipment and method for producing electric vehicle rear axles, which overcomes the problem in the prior art where, during the welding process of electric vehicle rear axles via a welding unit, the high-temperature hot air generated by the welding arc rebounds upwards, causing continuous convection heating of the sliding components in the equipment used to support the rotation of the welding torch, resulting in the evaporation of lubricating oil on the working surface of the slide rail, and consequently reducing the motion stability of the welding torch during the welding process.

[0005] On one hand, the present invention provides a welding device for the production of electric vehicle rear axles, comprising: A welding unit for welding the rear axle connecting rod and the rear axle inner shaft of an electric vehicle includes a welding torch for performing the welding action, a drive rod connected to the welding torch for limiting the extension of the welding torch, and a guide plate connected to the drive rod for limiting the direction of welding slag spatter. The welding auxiliary assembly includes a transmission gear and a driven gear that cooperate to provide rotational torque to the drive rod, a support cylinder connected to the driven gear to provide support force to the driven gear, a jacket sleeved on the outside of the support cylinder for cooling, and an air spray gun connected to the motor of the transmission gear for cleaning welding slag. A sliding assembly, located between the driven gear and the support cylinder, is used to provide rotational support; A stability feature detection unit, which is connected to the sliding assembly, is used to obtain the lubricant volatile concentration of the slide rail of the sliding assembly, the first radial component of the slag spatter velocity at the first height, and the second radial component of the slag spatter velocity at the second height. A welding stability control unit, which is connected to the welding unit and the stability feature detection unit respectively, is used to determine the opening of the water inlet of the jacket based on the concentration of volatiles in the lubricating oil, determine the vertical tilt angle of the guide plate based on the first radial component, and determine the opening of the air spray gun based on the second radial component.

[0006] Furthermore, the sliding component includes: An arc-shaped slider, which is connected to the driven gear, is used to limit the rotational trajectory of the driven gear; A slide rail, which is movably connected to the arc-shaped slider, is used to define the sliding path of the arc-shaped slider, wherein... The slide rail is provided with a layer of lubricating oil.

[0007] Furthermore, the support cylinder also includes a fixed disc for providing support force to the support cylinder.

[0008] Furthermore, the stable feature detection unit includes: A concentration sensor array, which is equally spaced around the circumference of the support cylinder behind the slide rail, is used to obtain the concentration of lubricating oil volatiles in the slide rail. A first photoelectric sensor is disposed at a first height on the inner wall of the fixed disk to obtain a first radial component of the welding slag splash velocity at the first height. A second photoelectric sensor, disposed at a second height on the inner wall of the fixed disk, is used to acquire the second radial component of the weld spatter velocity at the second height. The second height is greater than the first height.

[0009] Furthermore, the welding stability control unit includes a lubrication failure segment determination unit, which is connected to the concentration sensor array to determine the slide rail segment covered by the maximum length formed by connecting the lubrication oil volatile concentration sampling points on the slide rail where the lubrication oil volatile concentration is greater than the critical concentration.

[0010] Furthermore, the welding stability control unit also includes an inlet opening control unit, which is connected to the lubrication failure section determination unit and the jacket respectively, to open the inlet of the jacket with the shortest straight distance to the lubrication failure section.

[0011] Furthermore, the welding stability control unit also includes a guide plate angle control unit, which is connected to the guide plate and the first photoelectric sensor respectively, to determine that the influence of the welding slag on the smoothness of the guide rail surface that has lost its lubrication protection does not meet the requirements based on the fact that the first radial component of the welding slag splash velocity at the first height is greater than the critical velocity component, and to control the reduction of the vertical tilt angle of the guide plate.

[0012] Furthermore, the vertical tilt angle is the acute angle between the upper surface of the guide plate and the vertical direction, wherein, The vertical tilt angle is negatively correlated with the first radial component.

[0013] Furthermore, the welding stability control unit also includes a gas torch activation control unit, which is connected to the second photoelectric sensor and the gas torch respectively, to determine that the gear meshing jam does not meet the requirements for the uniformity of welding heat input based on the fact that the second radial component of the weld slag spatter velocity at the second height is greater than the critical velocity component, and to activate the gas torch.

[0014] On the other hand, the present invention provides a welding method for welding equipment used in the production of electric vehicle rear axles, comprising: Welding is performed on the rear axle connecting rod and the inner shaft of the rear axle of the electric vehicle. To obtain the concentration of volatile lubricating oil in the slide rail of the sliding component during the welding process; The lubrication failure section on the slide rail is determined based on the concentration of volatile components in the lubricating oil. The location of the inlet for opening the jacket is determined based on the lubrication failure segment. Cooling water is introduced into the jacket according to the opened inlet position, and the first radial component of the slag spatter velocity at the first height of the inner wall of the fixed plate and the second radial component of the slag spatter velocity at the second height are obtained. The vertical tilt angle of the guide plate used to limit the direction of slag spatter during the welding process is determined based on the first radial component, and the opening time of the air gun used to clean up the slag spatter is determined based on the second radial component. The welding process is completed according to the position of the water inlet of the jacket, the vertical tilt angle of the guide plate, and the opening time of the air spray gun. The weld seam is then ground and cleaned, the material is unloaded, and the welding unit is cleaned in sequence.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: By opening the water inlet of the jacket at the corresponding position, the present invention solves the problem that during the welding process, the high-temperature hot air generated by the welding arc rebounds upward, forming convective heating on the working surface of the slide rail, causing the base oil components in the lubricating oil to evaporate, resulting in a thinning of the oil film between the slide rail and the arc-shaped slider, increasing the sliding resistance between the slide rail and the arc-shaped slider, and thus reducing the stability during the welding torch rotation process. Therefore, by using a concentration sensor array evenly spaced on the circumference of the support cylinder behind the slide rail to obtain the concentration of lubricating oil volatiles at various angle positions, the lubrication failure section on the slide rail can be determined. Then, by opening the water inlet of the jacket with the shortest straight distance to the lubrication failure section, the heat of the support cylinder wall is discharged along the path from the working surface of the slide rail to the support cylinder wall to the cooling water channel through convective heat transfer, reducing the local temperature of the slide rail, thereby reducing the saturated vapor pressure of the lubricating oil in the lubrication failure section and preventing the continuous evaporation of the lubricating oil.

[0016] Furthermore, this invention addresses the issue of high-temperature welding slag being thrown tangentially under centrifugal force during welding. The greater the radial velocity component of the slag at the slide rail, the greater its kinetic energy, increasing the risk of slag impacting the slide rail. If the slag impacts the area where lubricating oil evaporates at the slide rail, the roughness of the slide rail further increases, reducing welding stability. Therefore, by reducing the vertical tilt angle of the guide plate, the radial component of the reflected slag decreases while the tangential component increases after impact, guiding the slag vertically downwards. This reduces the probability of contact between the slag and areas with lubrication failure, thereby improving the stability of the welding torch during the welding process.

[0017] Furthermore, this invention addresses the issue of increased meshing resistance in the transmission and driven gears due to weld slag impacting the gears, leading to increased friction between the gear teeth and decreased stability of the drive rod connected to the transmission gear. This is achieved by activating the air jet gun at the corresponding position when the radial velocity component of the weld slag at the height of the transmission and driven gear reaches a critical velocity component. The air jet gun nozzle is aligned with the meshing area of ​​the transmission and driven gears, and the shearing force of the high-speed airflow blows the adhered weld slag away from the meshing area, thereby reducing the meshing resistance of the transmission and driven gears and further improving the stability of the drive rod connected to the transmission gear. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the welding unit, rear axle connecting rod, and rear axle inner shaft of the welding equipment used for producing electric vehicle rear axles according to an embodiment of the present invention. Figure 2 This is a logic block diagram for determining the vertical tilt angle of the guide plate in a welding equipment used for producing the rear axle of an electric vehicle according to an embodiment of the present invention. Figure 3 This is a logic block diagram for determining the activation of the air jet gun in the welding equipment used for producing the rear axle of an electric vehicle according to an embodiment of the present invention. Figure 4 This is an overall flowchart of the welding method for welding equipment used in the production of electric vehicle rear axles according to an embodiment of the present invention; Explanation of reference numerals in the attached drawings: 1-Rear axle connecting rod, 2-Rear axle inner shaft, 3-Welding torch, 4-Drive rod, 5-Transmission gear, 6-Driven gear, 7-Cladle, 8-Guide plate, 9-Air spray torch, 10-Fixed plate, 11-Hinge shaft. Detailed Implementation

[0019] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0020] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0021] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0022] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Please see Figure 1 The diagram shown is a schematic representation of the overall structure of the welding equipment for producing electric vehicle rear axles according to an embodiment of the present invention. The welding equipment for producing electric vehicle rear axles according to an embodiment of the present invention includes: The welding unit is used to weld the rear axle connecting rod 1 and the rear axle inner shaft 2 of the electric vehicle rear axle. It includes a welding torch 3 for performing the welding action, a drive rod 4 connected to the welding torch 3 for limiting the extension of the welding torch 3, and a guide plate 8 connected to the drive rod 4 for limiting the direction of the spatter. The welding auxiliary assembly includes a transmission gear 5 and a driven gear 6 that cooperate to provide rotational torque to the drive rod 4, a support cylinder connected to the driven gear 6 to provide support force to the driven gear 6, a jacket 7 sleeved on the outside of the support cylinder for cooling, and an air spray gun 9 connected to the motor of the transmission gear 5 for cleaning welding slag. A sliding assembly, located between the driven gear 6 and the support cylinder, is used to provide rotational support; A stability feature detection unit, which is connected to the sliding assembly, is used to obtain the lubricant volatile concentration of the slide rail of the sliding assembly, the first radial component of the slag spatter velocity at the first height, and the second radial component of the slag spatter velocity at the second height. A welding stability control unit, which is connected to the welding unit and the stability feature detection unit respectively, is used to determine the opening of the water inlet of the jacket 7 based on the concentration of the lubricating oil volatiles, determine the vertical tilt angle of the guide plate 8 based on the first radial component, and determine the opening of the air spray gun 9 based on the second radial component.

[0024] In this embodiment, the actual welding current for welding the rear axle of the electric vehicle is 320A and the arc voltage is 28V. In this embodiment, the electric vehicle rear axle is formed by welding two stamped half-shells together to form the axle housing body. The axle housing body further includes a rear axle connecting rod 1 and a rear axle inner shaft 2. The rear axle connecting rod 1 and the rear axle inner shaft 2 are fixedly connected by an annular weld. The material of the electric vehicle rear axle is Q235B low alloy high strength steel, and the welding rod for the weld seam is ER50-6 flux-cored welding wire.

[0025] In this embodiment, the sliding component includes: An arc-shaped slider, which is connected to the driven gear 6, is used to limit the rotation trajectory of the driven gear 6; A slide rail, which is movably connected to the arc-shaped slider, is used to define the sliding path of the arc-shaped slider, wherein... The slide rail is provided with a layer of lubricating oil.

[0026] Specifically, the support cylinder also includes a fixed disk 10 for providing support force to the support cylinder.

[0027] In this embodiment, the stable feature detection unit includes: A concentration sensor array, which is equally spaced around the circumference of the support cylinder behind the slide rail, is used to obtain the concentration of lubricating oil volatiles in the slide rail. A first photoelectric sensor is disposed at a first height on the inner wall of the fixed disk 10 to obtain the first radial component of the welding slag splash velocity at the first height. A second photoelectric sensor, disposed at a second height on the inner wall of the fixed disk 10, is used to acquire the second radial component of the weld spatter velocity at the second height. The second height is greater than the first height.

[0028] In this embodiment, the spacing of the concentration sensor array is determined based on the diameter of the support cylinder. In a specific embodiment, the diameter of the support cylinder is 300 mm, and the spacing of the concentration sensors is 150 mm, that is, six concentration sensors are arranged equidistantly along the circumference of the support cylinder, and the central angle between each sensor is 60°. Those skilled in the art can adaptively adjust the spacing of the concentration sensor array according to the actual diameter of the support cylinder, the requirements for detection accuracy, and the data processing capability of the control system. The adjustment of the spacing of the concentration sensor array only needs to ensure that there are no undetectable blind spots between adjacent concentration sensors and that the lubrication failure section can be covered by at least one sensor, which will not be elaborated here.

[0029] Specifically, the welding stability control unit includes a lubrication failure section determination unit, which is connected to the concentration sensor array to determine the slide rail section covered by the maximum length of the sampling points where the concentration of lubricating oil volatiles on the slide rail is greater than the critical concentration. Understandably, during the welding process, the high-temperature hot air generated by the welding arc rebounds upward, forming convection heating on the working surface of the slide rail. This causes the base oil components in the lubricating oil to evaporate, resulting in a thinning of the oil film between the slide rail and the arc-shaped slider. This increases the sliding resistance between the slide rail and the arc-shaped slider, which in turn leads to a decrease in stability during the welding process of the welding torch 3 rotary welding machine. In this embodiment, a higher concentration of volatile components in the lubricating oil indicates that the surface temperature of the slide rail corresponding to the lubrication failure section is higher, the time of baking by hot air is longer or the intensity is greater, the volatilization of light components in the lubricating oil is more intense, the thickness of the residual oil film is thinner, the lubrication performance is worse, the friction coefficient between the slide rail and the arc-shaped slider is greater, the sliding resistance has a stronger ability to interfere with the rotation speed of the welding torch 3, and the stability of the welding process is worse. When the concentration of volatile components in the lubricating oil exceeds the critical concentration, it indicates that the surface temperature of the slide rail in this angle sector has exceeded the flash point temperature of the lubricating oil, the volatilization rate of the lubricating oil has entered an exponential increase stage, the oil film thickness is lower than the minimum critical value required to maintain boundary lubrication, and the lubrication state between the slide rail and the arc-shaped slider changes from boundary lubrication to dry friction or semi-dry friction. In this state, the sliding friction coefficient increases sharply and exhibits non-periodic fluctuations. The sliding resistance generated when the arc-shaped slider passes through this angle sector increases, which directly causes the rotational angular velocity of the welding torch 3 to decelerate instantaneously at this angle position, the welding linear velocity pulsates, and the risk of defects in the arc segment corresponding to this angle of the weld increases. It should be noted that the critical concentration is the threshold for determining whether the slide rail has entered a lubrication failure state. Those skilled in the art can adaptively adjust the critical concentration according to the type of lubricating oil and its flash point temperature, the design gap between the slide rail and the arc-shaped slider, and the maximum sliding resistance allowed by the welding process. It is sufficient to accurately distinguish between the normal lubrication state and the lubrication failure state of the slide rail surface, which will not be elaborated further here.

[0030] Specifically, the welding stability control unit also includes an inlet opening control unit, which is connected to the lubrication failure section determination unit and the jacket 7 respectively. It is used to open the inlet of the jacket 7, which has the shortest straight-line distance to the lubrication failure section. By opening the inlet of the jacket 7, which has the shortest straight-line distance to the lubrication failure section, the heat of the support cylinder wall is discharged by convective heat transfer along the path from the slide rail working surface to the support cylinder wall to the cooling water channel, thereby reducing the local temperature of the slide rail and reducing the saturated vapor pressure of the lubricating oil in the lubrication failure section, thus preventing the continuous evaporation of the lubricating oil.

[0031] In this embodiment, the welding stability control unit is a plurality of PLC controllers.

[0032] Specifically, the opening position of the water inlet of the jacket 7 is adjusted by a number of cooling water channels arranged at equal intervals inside the jacket 7 and an electronically controlled valve at the inlet of each cooling water channel. In this embodiment, each cooling water channel also includes a water outlet and a return water pipe connected to the water outlet.

[0033] Please see Figure 2 As shown, it is a logic block diagram of the welding equipment for producing the rear axle of an electric vehicle according to an embodiment of the present invention for determining the vertical tilt angle of the guide plate. The welding stability control unit also includes an angle control unit for the guide plate 8, which is connected to the guide plate 8 and the first photoelectric sensor respectively. It is used to determine that the influence of the welding slag on the smoothness of the guide rail surface that has lost its lubrication protection does not meet the requirements based on the fact that the first radial component of the welding slag splash velocity at the first height is greater than the critical velocity component, and to control the reduction of the vertical tilt angle of the guide plate 8. If the first radial component of the slag spatter velocity at the first height is less than or equal to the critical velocity component, the effect of the slag on the smoothness of the guide rail surface that has lost its lubrication protection is deemed to meet the requirements.

[0034] Specifically, the vertical tilt angle is the acute angle between the upper surface of the guide plate 8 and the vertical direction, wherein, The vertical tilt angle is negatively correlated with the first radial component; In this embodiment, the first height is the shortest vertical length between the slide rail and the fixed plate 10; the second height is the shortest vertical length between the driven gear 6 and the transmission gear 5. In a specific embodiment, the first height is 35mm and the second height is 50mm.

[0035] It is understandable that during the welding process, the high-temperature welding slag is thrown out along the tangential direction under the action of centrifugal force. The greater the radial velocity component of the welding slag at the slide rail, the greater the kinetic energy of the welding slag, which makes the risk of the welding slag hitting the slide rail greater. If the welding slag hits the area where the lubricating oil evaporates at the slide rail, the roughness of the slide rail will be further increased, which will reduce the stability of the welding. In this embodiment, the larger the first radial component of the slag splash velocity at the first height, the greater the initial radial velocity of the slag when it leaves the molten pool, the higher the radial climb height of its flight trajectory, the more kinetic energy it has when it reaches the working surface of the slide rail, and the greater the risk of impacting the slide rail surface. When the first radial component of the slag splash velocity at the first height is greater than the critical velocity component, it indicates that the slag has enough radial kinetic energy to pass through the space gap between the fixed plate 10 and the slide rail, and its theoretical climb height has reached or exceeded the installation height of the slide rail. If no intervention is made, the slag will directly impact the working surface of the slide rail. Especially when the slide rail is in a state of lubrication failure and loses the protection of the oil film, the impact will directly act on the bare metal surface, causing irreversible microscopic damage, which in turn causes periodic impact vibration when the arc slider slides, further deteriorating the rotational stability of the welding torch 3. In this embodiment, the critical velocity component is the threshold for determining whether the welding slag has sufficient kinetic energy to reach the slide rail and affect the smoothness of the slide rail surface. Those skilled in the art can adaptively adjust the critical velocity component according to the installation height of the slide rail, the average diameter and mass of the welding slag particles, the flight resistance coefficient of the welding slag in the air, and the maximum allowable variation range of the surface roughness of the slide rail. It is only necessary to distinguish the state in which the welding slag has sufficient kinetic energy to reach and affect the slide rail surface, which will not be elaborated here.

[0036] In this embodiment, the vertical tilt angle of the guide plate 8 is adjusted by controlling the rotation of the output shaft of the stepper motor corresponding to the hinge shaft 11 on the guide plate 8. To ensure that the adjustment of the vertical tilt angle of the guide plate 8 does not interfere with the normal welding trajectory of the welding torch 3 and the extension and retraction stroke of the drive rod 4, the lower limit of the vertical tilt angle of the guide plate 8 after adjustment is 10°. Those skilled in the art can make adaptive adjustments based on the decreasing trend of the first radial component. In addition, the adjustment step of the vertical tilt angle should not exceed 2° to avoid a sudden change in the direction of welding slag reflection caused by excessive adjustment in a single step, which would cause the welding slag to impact the inner wall of the fixed plate 10. By reducing the vertical tilt angle of the guide plate 8, the radial component of the reflection decreases and the tangential component increases after the welding slag hits the inclined surface of the guide plate 8, thereby guiding the welding slag to the vertical downward, thereby reducing the probability of contact between the welding slag and the lubrication failure area, and thus improving the stability of the welding torch 3 during the welding process.

[0037] Please see Figure 3 As shown, it is a logic block diagram of the welding equipment for producing electric vehicle rear axles according to an embodiment of the present invention for determining the opening of the air spray gun. The welding stability control unit also includes an air gun 9 activation control unit, which is connected to the second photoelectric sensor and the air gun 9 respectively. It is used to determine that the gear meshing jam does not meet the requirements for the uniformity of welding heat input based on the fact that the second radial component of the welding slag splash velocity at the second height is greater than the critical velocity component, and then activates the air gun 9. If the second radial component of the slag spatter velocity at the second height is less than or equal to the critical velocity component, the effect of gear meshing jamming on the uniformity of welding heat input is deemed to meet the requirements.

[0038] It is understandable that the impact of welding slag on the drive gear 5 and driven gear 6 increases the meshing resistance of the drive gear 5 and driven gear 6, which in turn increases the friction coefficient between the tooth surfaces, reduces the stability of the drive rod 4 connected to the drive gear 5, and consequently reduces the stability of the welding. In this embodiment, the larger the second radial component of the slag spatter velocity at the second height, the greater the residual radial kinetic energy carried by the dust particles crossing the slide rail height boundary when they reach the gear meshing area. This results in a greater number of particles being deposited between the teeth of the transmission gear 5 and the driven gear 6, stronger adhesion, a greater increase in the equivalent friction coefficient between the tooth surfaces, a greater fluctuation in the rotational resistance of the transmission gear 5, a greater fluctuation in the heat input per unit arc length, and a worse uniformity of the fish scale pattern spacing and the consistency of the weld penetration on the arc segment corresponding to this angle. When the second radial component of the slag spatter velocity at the second height exceeds the critical velocity component, it indicates that the dust particles have sufficient residual kinetic energy to reach the gear meshing area and deposit in the tooth gap. If not removed in time, the deposits will tend to fill the tooth gap and change the contact state of the tooth surface. This causes the transmission gear 5 to have to overcome the sudden increase in meshing resistance every time it rotates past the angle where the deposits exist. This results in periodic vibration of the extension and retraction motion of the drive rod 4, a slight deviation in the welding trajectory of the welding torch 3, and a non-uniform distribution of the welding heat input in the circumferential direction, leading to an increased risk of weld defects. In this embodiment, the initial air pressure of the air spray gun 9 is 0.6 MPa. The opening response speed of the air spray gun 9 should meet the requirement that the time from detecting that the second radial component is greater than the critical velocity component to the effective airflow output from the nozzle of the air spray gun 9 is no more than 50 ms. This is so that when the radial velocity component at the height of the transmission gear 5 and the driven gear 6 is greater than the critical velocity component, the air spray gun 9 can open before the dust particles are completely embedded in the tooth gap, blowing away the dust particles that are suspended or just in contact with the tooth surface from the meshing area, avoiding their accumulation in the tooth gap. The nozzle of the air spray gun 9 is aligned with the meshing area of ​​the transmission gear 5 and the driven gear 6. The shearing force of the high-speed airflow blows the attached welding slag away from the meshing area, thereby reducing the meshing resistance of the transmission gear 5 and the driven gear 6, and further improving the stability of the drive rod 4 connected to the transmission gear 5.

[0039] Please see Figure 4 As shown, it is an overall flowchart of the welding method of the welding equipment for producing electric vehicle rear axles according to an embodiment of the present invention; The welding method for producing the rear axle of an electric vehicle according to an embodiment of the present invention includes: Step S1: Weld the rear axle connecting rod and the rear axle inner shaft of the electric vehicle rear axle; Step S2: Obtain the concentration of volatile lubricating oil in the slide rail of the sliding component during the welding process; Step S3: Determine the lubrication failure section on the slide rail based on the concentration of volatile components in the lubricating oil; Step S4: Determine the inlet position of the jacket opening based on the lubrication failure section; Step S5: Cooling water is introduced into the jacket according to the opened water inlet position, and the first radial component of the slag spatter velocity at the first height of the inner wall of the fixed plate and the second radial component of the slag spatter velocity at the second height are obtained. Step S6: Determine the vertical tilt angle of the guide plate used to limit the direction of slag spatter during the welding process based on the first radial component, and determine the opening time of the air gun used to clean up the spatter based on the second radial component. Step S7: The welding process is completed according to the position of the water inlet of the jacket opening, the vertical tilt angle of the guide plate, and the opening time of the air spray gun. The weld seam is then ground and cleaned, the material is unloaded, and the welding unit is cleaned in sequence.

[0040] Specifically, an automatic grinding machine is used to grind and clean the weld between the rear axle connecting rod and the rear axle inner shaft.

[0041] Specifically, the unloading robot moves the electric vehicle rear axle, after the weld seam has been ground and cleaned, to the finished product buffer area to complete the unloading process.

[0042] Specifically, a high-pressure air gun is used to clean the welding torch nozzle, jacket outer wall, and air gun nozzle of the welding unit after the welding process is completed.

[0043] Those skilled in the art will understand that the processes of weld grinding and cleaning, unloading, and cleaning of the welding unit are conventional techniques well-known to them. Therefore, the processes of weld grinding and cleaning, unloading, and cleaning of the welding unit will not be described in detail here.

[0044] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A welding equipment for producing rear axles for electric vehicles, characterized in that, include: A welding unit for welding the rear axle connecting rod and the rear axle inner shaft of an electric vehicle includes a welding torch for performing the welding action, a drive rod connected to the welding torch for limiting the extension of the welding torch, and a guide plate connected to the drive rod for limiting the direction of welding slag spatter. The welding auxiliary assembly includes a transmission gear and a driven gear that cooperate to provide rotational torque to the drive rod, a support cylinder connected to the driven gear to provide support force to the driven gear, a jacket sleeved on the outside of the support cylinder for cooling, and an air spray gun connected to the motor of the transmission gear for cleaning welding slag. A sliding assembly, located between the driven gear and the support cylinder, is used to provide rotational support; A stability feature detection unit, which is connected to the sliding assembly, is used to obtain the lubricant volatile concentration of the slide rail of the sliding assembly, the first radial component of the slag spatter velocity at the first height, and the second radial component of the slag spatter velocity at the second height. A welding stability control unit, which is connected to the welding unit and the stability feature detection unit respectively, is used to determine the opening of the water inlet of the jacket based on the concentration of volatiles in the lubricating oil, determine the vertical tilt angle of the guide plate based on the first radial component, and determine the opening of the air spray gun based on the second radial component.

2. The welding equipment for producing electric vehicle rear axles according to claim 1, characterized in that, The sliding component includes: An arc-shaped slider, which is connected to the driven gear, is used to limit the rotational trajectory of the driven gear; A slide rail, which is movably connected to the arc-shaped slider, is used to define the sliding path of the arc-shaped slider, wherein... The slide rail is provided with a layer of lubricating oil.

3. The welding equipment for producing electric vehicle rear axles according to claim 2, characterized in that, The support cylinder also includes a fixed plate for providing support force to the support cylinder.

4. The welding equipment for producing electric vehicle rear axles according to claim 3, characterized in that, The stable feature detection unit includes: A concentration sensor array, which is equally spaced around the circumference of the support cylinder behind the slide rail, is used to obtain the concentration of lubricating oil volatiles in the slide rail. A first photoelectric sensor is disposed at a first height on the inner wall of the fixed disk to obtain a first radial component of the welding slag splash velocity at the first height. A second photoelectric sensor, disposed at a second height on the inner wall of the fixed disk, is used to acquire the second radial component of the weld spatter velocity at the second height. The second height is greater than the first height.

5. The welding equipment for producing electric vehicle rear axles according to claim 4, characterized in that, The welding stability control unit includes a lubrication failure section determination unit, which is connected to the concentration sensor array to determine the slide rail section covered by the maximum length formed by connecting the lubrication oil volatile concentration sampling points on the slide rail where the concentration is greater than the critical concentration.

6. The welding equipment for producing electric vehicle rear axles according to claim 5, characterized in that, The welding stability control unit also includes an inlet opening control unit, which is connected to the lubrication failure section determination unit and the jacket respectively, and is used to open the inlet of the jacket with the shortest straight distance to the lubrication failure section.

7. The welding equipment for producing electric vehicle rear axles according to claim 6, characterized in that, The welding stability control unit also includes a guide plate angle control unit, which is connected to the guide plate and the first photoelectric sensor respectively. It is used to determine that the influence of the welding slag on the smoothness of the guide rail surface that has lost its lubrication protection does not meet the requirements based on the fact that the first radial component of the welding slag splash velocity at the first height is greater than the critical velocity component, and to control the reduction of the vertical tilt angle of the guide plate.

8. The welding equipment for producing electric vehicle rear axles according to claim 7, characterized in that, The vertical tilt angle is the acute angle between the upper surface of the guide plate and the vertical direction, wherein, The vertical tilt angle is negatively correlated with the first radial component.

9. The welding equipment for producing electric vehicle rear axles according to claim 8, characterized in that, The welding stability control unit also includes a gas torch activation control unit, which is connected to the second photoelectric sensor and the gas torch respectively. It is used to determine that the gear meshing jam does not meet the requirements for the uniformity of welding heat input, based on the fact that the second radial component of the slag spatter velocity at the second height is greater than the critical velocity component, and then activates the gas torch.

10. A welding method applied to the welding equipment for producing electric vehicle rear axles according to any one of claims 1 to 9, characterized in that, include: Welding is performed on the rear axle connecting rod and the inner shaft of the electric vehicle's rear axle. To obtain the concentration of volatile lubricating oil in the slide rail of the sliding component during the welding process; The lubrication failure section on the slide rail is determined based on the concentration of volatile components in the lubricating oil. The location of the inlet for opening the jacket is determined based on the lubrication failure segment. Cooling water is introduced into the jacket according to the opened inlet position, and the first radial component of the slag spatter velocity at the first height of the inner wall of the fixed plate and the second radial component of the slag spatter velocity at the second height are obtained. The vertical tilt angle of the guide plate used to limit the direction of slag spatter during the welding process is determined based on the first radial component, and the opening time of the air gun used to clean up the slag spatter is determined based on the second radial component. The welding process is completed according to the position of the water inlet of the jacket, the vertical tilt angle of the guide plate, and the opening time of the air spray gun. The weld seam is then ground and cleaned, the material is unloaded, and the welding unit is cleaned in sequence.

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