Hydraulic welding device of automobile auxiliary frame

Abstract

The invention belongs to the technical field of automobile hardware machining, and particularly relates to a hydraulic welding device for an automobile auxiliary frame. Comprising a base assembly which is provided with a guide inner hole extending in the axial direction; the floating supporting assembly is arranged in the guide inner hole in a sliding mode; according to the internal expansion type slotted elastic supporting structure, the radial uniform expansion of the elastic supporting cylinder is used for replacing the traditional lateral extrusion locking, so that the interference of lateral thrust on the coaxiality of the supporting shaft is eliminated, the supporting cylinder is ensured not to incline or deviate from the center at the locking moment, and the welding positioning precision is improved; the stress release hole is formed in the root of the axial deformation groove, stress concentration of a deformation area is dispersed, the problem that a traditional expansion sleeve is prone to fatigue fracture is solved, and it is guaranteed that the device can be rapidly and thoroughly reset after being unlocked through the active hooping effect of the elastic convergence ring.

Description

Technical Field

[0001] This invention belongs to the field of automotive hardware processing technology, specifically a hydraulic welding device for automotive subframes. Background Technology

[0002] As a core load-bearing component of the chassis system, the automotive subframe has a complex structure and requires extremely high dimensional accuracy. On automated welding production lines, due to the inherent springback and manufacturing tolerances of the subframe workpiece, in addition to the main positioning points, floating support devices are usually required at the suspended parts of the workpiece. These devices primarily employ a spring-floating and hydraulic locking structure. The spring force causes the support shaft to move and conform to the workpiece surface, and then the locking mechanism fixes the position of the support shaft, forming a rigid support to resist the thermal deformation and downward pressure generated during the welding process.

[0003] In existing technologies, the accuracy of automotive subframe positioning welding is severely affected by lateral forces. Since the locking force is applied unidirectionally or laterally, the huge lateral thrust will force the support shaft to tilt or laterally displace slightly within the guide hole. This causes the support shaft to deviate from its original floating center at the moment of locking, introducing a non-negligible coaxiality error, which affects the final welding accuracy of the subframe. Furthermore, lateral locking is usually point contact or line contact with a limited friction area. When facing the downward pressure of the welding robot or the impact of welding thermal stress, the support shaft is prone to slight axial slippage, leading to support failure. Some devices using traditional expansion sleeve structures lack targeted anti-fatigue and anti-hysteresis designs. The root of the deformation groove of the expansion sleeve is prone to fatigue cracks due to stress concentration during repeated opening and closing, leading to fracture failure. Metal materials exhibit elastic hysteresis after long-term stress, causing the expansion sleeve to fail to retract and reset quickly after unlocking, which can easily cause the workpiece to jam or scratch the inner hole of the base. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies and solve the problem of coaxiality error caused by the support shaft deviating from the original floating center at the moment of locking, this invention proposes a hydraulic welding device for automotive subframes.

[0005] The technical solution adopted by this invention to solve its technical problem is: the hydraulic welding device for automobile subframes of this invention includes: A base assembly having an axially extending guide bore; A floating support assembly, slidably disposed in the guide bore, includes a hollow elastic support cylinder and a floating spring for providing axial biasing force, wherein at least a portion of the elastic support cylinder is configured as a deformation zone with radial expansion capability. A tensioning assembly is coaxially inserted inside the elastic support cylinder. The tensioning assembly includes a central tie rod and an expansion cone connected to the top of the central tie rod. The tensioning assembly is configured to move axially under the action of a driving force, causing the expansion cone to press against the inner wall of the elastic support cylinder, forcing the elastic support cylinder to expand radially and form an interference fit with the inner wall of the guide bore.

[0006] Preferably, the base assembly has a partition shoulder inside, which divides the internal space of the base into the upper guide inner hole and the lower bottom receiving cavity. The floating spring abuts against the upper surface of the partition shoulder, and the driving part of the tensioning assembly is located below the partition shoulder. The two are isolated from each other in axial space, and the base housing is installed outside the partition shoulder.

[0007] Preferably, the elastic support cylinder is divided into an upper deformation zone and a lower rigid zone in the axial direction. The cylinder wall of the deformation zone is provided with a plurality of axial deformation grooves. The rigid zone is a closed ring structure. The outer wall of the elastic support cylinder is provided with a load-bearing step. The load-bearing step is located in the rigid zone, and the top end of the floating spring abuts against the load-bearing step.

[0008] Preferably, the inner wall of the elastic support cylinder is provided with an inner conical mating surface, and the outer wall of the expansion cone is provided with an outer conical driving surface. The outer conical driving surface and the inner conical mating surface are fitted together in the locked state. The outer diameter of the central tie rod is smaller than the inner diameter of the elastic support cylinder, forming a floating gap between them.

[0009] Preferably, the bottom end of the axial deformation groove extends to the junction of the deformation zone and the rigid zone, and a stress relief hole penetrating the cylinder wall is provided there, the diameter of which is larger than the width of the axial deformation groove.

[0010] Preferably, an annular convergence groove is formed on the outer peripheral surface of the elastic support cylinder, and an elastic convergence ring is embedded in the annular convergence groove. The elastic convergence ring is configured to apply a continuous inward radial preload to the elastic support cylinder to assist the elastic support cylinder in resetting after unlocking.

[0011] Preferably, the outer surface of the elastic support cylinder is machined with micro-tooth patterns, which are mesh-like textures or vertical stripes, used to increase the static friction coefficient between the cylinder and the inner wall of the guide hole during locking.

[0012] Preferably, the tensioning assembly further includes a hydraulic piston and a reset disc spring. The hydraulic piston is connected to the bottom end of the central pull rod and is slidably sealed within the bottom receiving cavity. The reset disc spring is located below the hydraulic piston and is used to push the central pull rod upward to unlock during hydraulic unloading.

[0013] Preferably, the base assembly has a sealing end cap at its bottom, a sensor mounting groove at its center, and an induction magnetic ring embedded in the bottom end face of the central tie rod. The sensor mounting groove is used to install a displacement sensor capable of detecting the position of the induction magnetic ring to obtain the height data of the workpiece contact surface.

[0014] Preferably, a pressure monitoring interface is provided on the side wall of the base housing, and the pressure monitoring interface is connected to the bottom receiving cavity for installing a pressure sensor to monitor the hydraulic locking force in real time.

[0015] The beneficial effects of this invention are as follows: 1. The hydraulic welding device for automotive subframes described in this invention utilizes an internally expanding slotted elastic support structure. The radial uniform expansion of the elastic support cylinder replaces traditional lateral compression locking, eliminating interference from lateral thrust on the coaxiality of the support shaft. This ensures the support cylinder does not tilt or shift center during locking, improving welding positioning accuracy. Stress relief holes at the root of the axial deformation groove disperse stress concentration in the deformation zone, solving the problem of fatigue fracture common in traditional expansion sleeves. Combined with the active clamping action of the elastic convergence ring, the springback hysteresis of the metal material is eliminated, ensuring the device can quickly and completely reset after unlocking. The micro-toothed design on the support cylinder surface enhances locking rigidity and resistance to lateral slippage without damaging the base guide hole, meeting the high-load support requirements of automotive subframe welding.

[0016] 2. The hydraulic welding device for automotive subframes described in this invention, through a coaxial nested drive layout and physical isolation design, balances structural compactness and intelligent level. The physical spatial isolation between the floating spring and the hydraulic piston is achieved through the partition shoulder inside the base, avoiding the risk of interference between the power component and the floating component during the movement stroke, and preventing hydraulic oil from contaminating the upper precision mating surface, thus improving the operational stability of the device. Through the sensor mounting slot, induction magnetic ring, and pressure monitoring interface, sensing capability is provided. The system can acquire support height data in real time to identify the workpiece model and monitor the hydraulic locking force closed loop, thereby achieving adaptive adjustment of welding process parameters. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the practical structure of the present invention; Figure 3 This is a three-dimensional schematic diagram of the external structure of the base assembly of the present invention; Figure 4 This is a cross-sectional view of the internal structure of the base housing of the present invention; Figure 5 This is a schematic diagram of the axial deformation groove structure distribution of the present invention; Figure 6 This is a three-dimensional schematic diagram of the external structure of the floating support component of the present invention; Figure 7 This is a cross-sectional view showing the structural cooperation relationship between the floating support component and the tensioning component of the present invention; Figure 8 This is a three-dimensional schematic diagram of the external structure of the tensioning component of the present invention; Figure 9 This is a cross-sectional view of the tensioning component structure of the present invention; Figure 10 This is a cross-sectional view of the internal structure of the sealing end cap of the present invention; Figure 11 This is a three-dimensional schematic diagram of the induction magnetic ring structure of the present invention.

[0019] In the picture: 100. Base assembly; 110. Base housing; 111. Guide bore; 112. Bottom receiving cavity; 113. Mounting interface; 114. Separating shoulder; 115. Pressure monitoring interface; 200. Floating support assembly; 210. Elastic support cylinder; 211. Axial deformation groove; 212. Workpiece contact surface; 213. Inner conical mating surface; 214. Load-bearing step; 215. Stress relief hole; 216. Annular convergence groove; 220. Floating spring; 230. Anti-rotation pin; 240. Elastic convergence ring; 250. Micro-tooth pattern; 300. Tensioning assembly; 310. Central tie rod; 320. Expansion cone; 321. Outer conical drive surface; 330. Hydraulic piston; 331. Return disc spring; 340. Sealing end cap; 341. Sensor mounting slot; 350. Induction magnetic ring. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0021] like Figure 1 As shown, this embodiment discloses a hydraulic welding device for an automotive subframe, including a base assembly 100, a floating support assembly 200, and a tensioning assembly 300.

[0022] like Figure 2 and Figure 3 As shown, the main body of the base assembly 100 is a cylindrical base shell 110, and the internal space of the base shell 110 is designed as a non-uniform diameter structure, such as... Figure 4As shown, the inner wall of the base housing 110 is integrally formed with an inwardly protruding annular dividing shoulder 114 in the middle section. The dividing shoulder 114 physically divides the interior of the base into two independent chambers, upper and lower. The upper chamber is a high-precision guide inner hole 111, and the lower chamber is a larger diameter bottom receiving cavity 112. The inner wall of the guide inner hole 111 is precision ground to serve as the reaction force reference surface for the entire internal expansion locking process. The guide inner hole 111 is used to accommodate and constrain the sliding of the floating support assembly 200. The two are fitted with a micro-clearance, which ensures both smooth sliding and... It can limit excessive lateral swaying. The bottom receiving cavity 112 is used to install the power part of the tensioning assembly 300. Its inner wall is machined to meet the hydraulic sealing requirements. The partition shoulder 114 forms a physical barrier in the axial direction, which can ensure that the hydraulic oil and moving parts below will not invade the space above. A combined sealing ring is provided at the central through hole of the partition shoulder 114 to further enhance the isolation effect. It also prevents the lower parts from hitting the upper spring structure when moving upward, thereby avoiding the risk of the upper precision mating surface jamming due to oil contamination.

[0023] like Figure 3 As shown, an installation interface 113 is provided on the bottom exterior of the base housing 110 for locking the entire device onto the base plate of the welding production line. A pressure monitoring interface 115 is provided on the lower side wall of the base housing 110, which leads directly to the bottom receiving cavity 112. The pressure monitoring interface 115 allows the installation of a pressure sensor to monitor the pressure fluctuations in the hydraulic cavity in real time. The pressure monitoring interface 115 is directly connected to the working cavity of the hydraulic cylinder through an oil circuit, which can capture short-term pressure changes. By calculating the relationship between pressure and clamping force, the system can determine whether the preset clamping force has been reached, thereby solving the problem of unknown optimal clamping force. If the monitored pressure is lower than the set threshold during operation, the hydraulic cylinder will automatically compensate for the pressure. If the pressure is too high and may cause workpiece deformation, the hydraulic cylinder will automatically depressurize and fine-tune to ensure that the clamping pressure is within a suitable range.

[0024] like Figure 1 and Figure 2 As shown, the floating support assembly 200 is slidably disposed within the guide inner hole 111 of the base. The main body of the floating support assembly 200 is an elastic support cylinder 210, which is a hollow, thin-walled tubular component. The elastic support cylinder 210 is clearly divided into two functional areas in the axial direction: a lower rigid area and an upper deformation area. The lower rigid area is a complete, ungrooved circular solid structure with high structural rigidity, capable of withstanding the long-term top pressure of the spring without buckling deformation. At the bottom of this area, a protruding load-bearing step 214 is provided as the stress point of the spring force. Figure 4 and Figure 5The upper deformation zone is a guide inner hole 111 with several (e.g., 6) axial deformation grooves 211 evenly cut along the circumferential direction on the inner wall. These grooves divide the upper cylinder into several elastic petals, giving it the ability to expand radially (thicken). The elastic support cylinder 210 expands evenly into the axial deformation grooves 211 through multiple petals, which can achieve better circumferential contact. Compared with the traditional single-sided pressure block, the force is more uniform and the coaxiality is better maintained.

[0025] like Figure 4 and Figure 6 As shown, in order to limit the circumferential rotation of the elastic support cylinder 210 within the guide inner hole 111, the device is also provided with an anti-rotation pin 230. The anti-rotation pin 230 is fixedly installed on the side wall of the base housing 110 (e.g., screwed in by threads). Its end extends through the base housing 110 into the guide inner hole 111 and is inserted into a vertical long groove (not marked in the figure) opened on the outer wall of the elastic support cylinder 210. The vertical long groove is located in the lower rigid area of ​​the elastic support cylinder 210 and extends axially. Its length covers the maximum floating stroke of the support cylinder. The anti-rotation pin 230 and the vertical long groove are clearance-fitted to ensure that the elastic support cylinder 210 can only float up and down axially and cannot rotate circumferentially. This ensures that the top workpiece contact surface 212 always maintains the correct support orientation and also avoids the situation where the internal floating spring 220 is twisted and deformed due to the rotation of the elastic support cylinder 210, thus affecting its service life.

[0026] like Figure 6 and Figure 7 As shown, the floating spring 220 is located at the bottom of the elastic support cylinder 210. Its lower end abuts against the upper surface of the dividing shoulder 114 of the base, and its upper end abuts against the lower surface of the load-bearing step 214 of the support cylinder. The floating spring 220 is preferably a cylindrical helical spring with moderate stiffness. Its preload must be sufficient to overcome the weight of the support cylinder and the internal tie rod. The floating spring 220 always provides an upward bias force to the support cylinder, keeping it in an extended state. When the workpiece presses against the top workpiece contact surface 212, the spring is compressed, and the support cylinder moves downward accordingly. This process is passive adaptation; the workpiece is in a natural state and is not subjected to any forced clamping force. Because the load-bearing step 214 is located in the rigid zone and is blocked by the dividing shoulder 114 below, the spring's extension and contraction movement is completely confined to the outside of the rigid zone and will not interfere with the expansion action of the upper deformation zone. Figure 4 As shown, a stress relief hole 215 is provided at the root of the axial deformation groove 211 (i.e., the junction of the deformation zone and the rigid zone). The hole is a circular or elliptical through hole with a diameter significantly larger than the groove width. During the repeated expansion and contraction of the elastic support cylinder 210, the root of the axial deformation groove 211 is the point where the stress is most concentrated. The stress relief hole 215 can effectively disperse the stress and prevent cracks from forming at the root due to metal fatigue, thereby greatly extending the service life of the tooling in the mass production environment.

[0027] like Figure 6 and Figure 7 As shown, an annular convergence groove 216 is also machined on the upper outer surface of the elastic support cylinder 210. An elastic convergence ring 240 (such as a high-strength spring steel wire ring) is embedded in the groove. The elastic convergence ring 240 is in a pre-tightened state and tightly clamps the outside of the support petal. After long-term stress, the metal material may undergo plastic deformation, resulting in rebound lag. The elastic convergence ring 240 provides an additional active inward clamping force to ensure that once the locking force is removed, the support cylinder can instantly and forcibly retract and reset, avoiding the risk of the workpiece getting stuck and unable to be removed. On the outer cylindrical surface of the elastic support cylinder 210 that contacts the guide inner hole 111, micro-tooth patterns 250 (such as a mesh pattern with a depth of 0.05mm) are machined. These micro-textures can increase the static friction coefficient of the contact surface without compromising the fitting accuracy, so that under the same expansion force, the support cylinder can withstand a greater welding lateral impact force without slippage.

[0028] like Figure 7 As shown, the tensioning assembly 300 is coaxially inserted into the internal cavity of the elastic support cylinder 210 and serves as the power source for the locking action. The core component of the tensioning assembly 300 is a slender central tie rod 310. The outer diameter of the central tie rod 310 is smaller than the inner diameter of the elastic support cylinder 210, thereby creating a clearance between the central tie rod 310 and the inner wall of the elastic support cylinder 210. This clearance ensures that, in the non-locked state, the central tie rod 310 will not rub against or hinder the free floating of the elastic support cylinder 210. A tensioning cone 320 is fixed to the top of the central tie rod 310, and its side is an outer cone driving surface that is larger at the top and smaller at the bottom. 321. The upper part of the inner wall of the elastic support cylinder 210 is provided with an inner conical mating surface 213 with a tapered matching. The axial hydraulic tension is transmitted through the inclined surface. When it is necessary to fix the workpiece, the hydraulic piston 330 at the bottom is driven downward by oil pressure, which drives the central tie rod 310 to pull downward. The expansion cone 320 moves downward accordingly. Its outer conical driving surface 321 strongly squeezes the inner conical mating surface 213 of the support cylinder. Due to the wedge-shaped force amplification effect, the axial tension is converted into a huge radial thrust, which forces the elastic flap at the top of the support cylinder to expand outward, eliminate the gap and firmly support the guide inner hole 111 of the base, thereby achieving rigid locking.

[0029] like Figure 8 and Figure 9As shown, a hydraulic piston 330 is installed in the bottom receiving cavity 112, located below the separating shoulder 114. A return disc spring 331 is located below the hydraulic piston 330. The bottom of the bottom receiving cavity 112 is sealed by a sealing end cap 340. An oil inlet and an oil outlet are provided on the side of the base housing 110. The base housing 110 is connected to an external hydraulic cylinder through the oil inlet and outlet. The return disc spring 331 serves to automatically unlock when the oil supply is cut off. Furthermore, its high rigidity preload prevents the piston from slipping in the non-working state, ensuring that the expansion cone 320 always remains in the released position. Figure 10 As shown, a sensor mounting groove 341 is provided in the center of the sealed end cap 340, such as... Figure 11 As shown, the bottom end of the central tie rod 310 is embedded with an induction magnetic ring 350. When different models of subframes are placed on the tooling, due to the different heights of their support surfaces, the subframes will press the elastic support cylinder 210 to different depths, thereby driving the central tie rod 310 down different distances. The displacement sensor (not shown in the figure) installed in the sensor mounting slot 341 can accurately read the Z-axis height data through the position of the induction magnetic ring 350. Based on this, the control system can automatically identify the workpiece model and call the corresponding hydraulic parameters, thereby realizing adaptive parameter management. For example, for aluminum alloy subframes with poor rigidity, the system automatically reduces the hydraulic input to prevent workpiece deformation, while for steel subframes with strong rigidity, the pressure is increased to ensure stability, thereby realizing intelligent flexible production.

[0030] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic welding device for an automobile subframe, characterized in that, Including: The base assembly (100) has an axially extending guide bore (111). A floating support assembly (200) is slidably disposed in the guide bore (111) and includes a hollow elastic support cylinder (210) and a floating spring (220) for providing axial biasing force. At least a portion of the elastic support cylinder (210) is configured as a deformation zone with radial expansion capability. A tensioning assembly (300) is coaxially disposed inside the elastic support cylinder (210). The tensioning assembly (300) includes a central tie rod (310) and an expansion cone (320) connected to the top of the central tie rod (310). The tensioning assembly (300) is configured to move axially under the action of a driving force, so that the expansion cone (320) squeezes the inner wall of the elastic support cylinder (210), forcing the elastic support cylinder (210) to expand radially and form an interference lock fit with the inner wall of the guide inner hole (111).

2. The hydraulic welding device for an automobile subframe according to claim 1, characterized in that, The base assembly (100) has a partition shoulder (114) inside, which divides the internal space of the base into the upper guide inner hole (111) and the lower bottom receiving cavity (112). The floating spring (220) abuts against the upper surface of the partition shoulder (114). The driving part of the tensioning assembly (300) is located below the partition shoulder (114). The two are isolated from each other in axial space. The base housing (110) is installed outside the partition shoulder (114).

3. The hydraulic welding device for an automobile subframe according to claim 2, characterized in that, The elastic support cylinder (210) is divided into an upper deformation zone and a lower rigid zone in the axial direction; the cylinder wall of the deformation zone is provided with a plurality of axial deformation grooves (211); the rigid zone is a closed ring structure; the outer wall of the elastic support cylinder (210) is provided with a load-bearing step (214); the load-bearing step (214) is located in the rigid zone; and the top of the floating spring (220) abuts against the load-bearing step (214).

4. The hydraulic welding device for an automobile subframe according to claim 3, characterized in that, The inner wall of the elastic support cylinder (210) is provided with an inner conical mating surface (213), and the outer wall of the expansion cone (320) is provided with an outer conical driving surface (321). The outer conical driving surface (321) and the inner conical mating surface (213) are in contact in the locked state. The outer diameter of the central tie rod (310) is smaller than the inner diameter of the elastic support cylinder (210), forming a floating gap between them.

5. The hydraulic welding device for an automobile subframe according to claim 3, characterized in that, The bottom end of the axial deformation groove (211) extends to the junction of the deformation zone and the rigid zone, and a stress relief hole (215) penetrating the cylinder wall is provided there. The diameter of the stress relief hole (215) is larger than the width of the axial deformation groove (211).

6. The hydraulic welding device for an automobile subframe according to claim 1, characterized in that, An annular convergence groove (216) is provided on the outer peripheral surface of the elastic support cylinder (210), and an elastic convergence ring (240) is embedded in the annular convergence groove (216). The elastic convergence ring (240) is configured to apply a continuous inward radial preload to the elastic support cylinder (210) to assist the elastic support cylinder (210) in resetting after unlocking.

7. The hydraulic welding device for an automobile subframe according to claim 1, characterized in that, The outer surface of the elastic support cylinder (210) is processed with micro-tooth texture (250), which is a mesh texture or vertical stripes, used to increase the static friction coefficient between the cylinder and the inner wall of the guide inner hole (111) when locked.

8. The hydraulic welding device for an automobile subframe according to claim 2, characterized in that, The tensioning assembly (300) also includes a hydraulic piston (330) and a reset disc spring (331). The hydraulic piston (330) is connected to the bottom end of the central pull rod (310) and is slidably sealed in the bottom receiving cavity (112). The reset disc spring (331) is located below the hydraulic piston (330) and is used to push the central pull rod (310) upward to unlock during hydraulic unloading.

9. The hydraulic welding device for an automobile subframe according to claim 8, characterized in that, The base assembly (100) is provided with a sealing end cap (340) at the bottom. The sealing end cap (340) is provided with a sensor mounting groove (341) at the center. The bottom end face of the central tie rod (310) is embedded with an induction magnetic ring (350). The sensor mounting groove (341) is used to install a displacement sensor that can detect the position of the induction magnetic ring (350) to obtain the height data of the workpiece contact surface (212).

10. The hydraulic welding device for an automobile subframe according to claim 2, characterized in that, A pressure monitoring interface (115) is provided on the side wall of the base housing (110). The pressure monitoring interface (115) is connected to the bottom receiving cavity (112) and is used to install a pressure sensor to monitor the hydraulic locking force in real time.

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