Automobile welding fixture thermal deformation compensation device

Abstract

This invention relates to the field of welding fixture technology, specifically disclosing a thermal deformation compensation device for an automotive welding fixture. The device includes: a base housing fixed to a welding fixture support, with a receiving cavity inside the base housing; a temperature-sensing drive assembly vertically disposed within the receiving cavity for axial expansion deformation under heat, the top of the receiving cavity being away from the top of the temperature-sensing drive assembly and forming a deformation area; a floating positioning assembly slidably disposed on the base housing, its upper part for supporting the positioning pin of the welding clamping support, and the sliding direction of the floating positioning assembly being parallel to the axial direction of the temperature-sensing drive assembly; and a lever compensation mechanism disposed within the base housing and located at the deformation area, with its two ends connected to the top of the temperature-sensing drive assembly and the bottom of the floating positioning assembly, respectively. This device achieves dynamic compensation for the thermal deformation of the positioning pin, thereby effectively ensuring the positioning accuracy of the automotive welding fixture under continuous heating conditions.

Description

Technical Field

[0001] This invention relates to the field of welding fixture technology, and in particular to a thermal deformation compensation device for automotive welding fixtures. Background Technology

[0002] Automotive welding fixtures are specialized, fundamental equipment used in the body-in-white manufacturing process for precisely positioning and securely clamping sheet metal stampings. During automated welding, the fixture, through support units such as locating pins, strictly constrains the spatial freedom of the workpiece to ensure the geometric accuracy and consistency of the assembled body, making it a crucial step in guaranteeing the overall vehicle manufacturing quality.

[0003] However, during continuous welding operations, the high-frequency heat generated by the welding torch is rapidly conducted through the workpiece to the positioning pin and the supporting structure below. Due to the physical properties of thermal expansion and contraction, the metal supporting structure will inevitably expand and deform after being heated, which will directly cause the positioning reference to shift upward, resulting in the workpiece welding position being out of tolerance.

[0004] To address the aforementioned thermal deformation problem, current technologies often employ passive suppression strategies, such as using expensive low-expansion-coefficient materials (like Invar alloys) to manufacture the support structure or arranging complex water-cooling circulation systems. However, these existing methods have significant drawbacks: firstly, using low-expansion materials only reduces the rate of thermal expansion but cannot generate reverse displacement to offset the physical elongation that has already occurred, leaving positioning errors unresolved and unable to be eliminated; secondly, active water-cooling systems have complex piping structures and occupy a large space, significantly increasing manufacturing costs and maintenance difficulty, and also posing a process risk of coolant leakage contaminating the welding environment. Summary of the Invention

[0005] The main objective of this invention is to provide a thermal deformation compensation device for automotive welding fixtures, which aims to solve the aforementioned problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides a thermal deformation compensation device for automotive welding fixtures, the device comprising:

[0007] The base housing is fixed on the welding fixture bracket, and a receiving cavity is provided inside the base housing;

[0008] A temperature-sensing drive assembly is vertically disposed within the receiving cavity and is used to perform axial expansion deformation when heated. The top of the receiving cavity is away from the top of the temperature-sensing drive assembly and forms a deformation area.

[0009] A floating positioning component is slidably mounted on the base housing. Its upper part is used to support the positioning pin of the welding clamping bracket, and the sliding direction of the floating positioning component is parallel to the axial direction of the temperature sensing drive component.

[0010] The lever compensation mechanism is located inside the base housing and in the deformation area. The two ends of the lever compensation mechanism are connected to the top of the temperature-sensing drive component and the bottom of the floating positioning component, respectively.

[0011] Furthermore, the temperature-sensing drive assembly includes a thermally conductive alloy column, a ball joint connector that is hinged at the top of the thermally conductive alloy column and ball jointed to the end of the lever compensation mechanism, the thermally conductive alloy column includes a thermally conductive core whose bottom end is fixedly connected to the receiving cavity, and a deformation drive sleeve sleeved outside the thermally conductive core. The deformation drive sleeve is made of shape memory alloy and is used to generate axial expansion displacement, and the top of the deformation drive sleeve is connected to the ball joint connector.

[0012] Furthermore, the lever compensation mechanism includes a transmission lever and a fulcrum shaft;

[0013] The pivot shaft is located in the receiving cavity inside the base housing;

[0014] The transmission lever is rotatably mounted on the fulcrum shaft at its center, and one end of it is provided with a ball joint structure that connects to the ball joint connector, while the other end extends to the floating positioning component and is movably connected to it.

[0015] Furthermore, the lever compensation mechanism also includes a fulcrum adjustment assembly, which is used to adjust the position of the fulcrum shaft on the transmission lever;

[0016] The fulcrum adjustment assembly includes a pivot and a sliding displacement block;

[0017] The pivot component includes a slide plate, which is located between the fulcrum shaft and the transmission lever and is rotatably connected to the top of the fulcrum shaft, and is slidably connected to the bottom of the transmission lever via a guide groove therein;

[0018] The sliding displacement block is located at the bottom end of the fulcrum shaft, and is slidably connected to the base housing via a slide rail at the bottom of the receiving cavity.

[0019] Locking bolts are installed on both the slide plate and the sliding displacement block, and the positions of the slide plate and the sliding displacement block are locked by the locking bolts.

[0020] Furthermore, the floating positioning component includes a sliding support block, the top of which penetrates the base housing and is connected to the positioning pin, and its bottom end is movably connected to the other end of the transmission lever. The sliding support block and the base housing slide together to form a linear sliding pair.

[0021] Preferably, a reset elastic element is provided between the deformation driving sleeve and the receiving cavity. The bottom end of the reset elastic element is connected to the bottom of the receiving cavity, and its top end is connected to the deformation driving sleeve.

[0022] Preferably, a heat shielding assembly is provided inside the base housing. The heat shielding assembly includes a heat insulation liner provided inside the base housing and a heat insulation cylinder coaxially sleeved outside the deformation drive sleeve. At the bottom end of the heat-conducting core, a heat-conducting flexible transmission bundle is also provided, which extends through to the outside of the base housing and is connected to the bottom of the positioning pin. The heat-conducting flexible transmission bundle is woven from a high thermal conductivity metal.

[0023] Compared with the prior art, the beneficial effects that the present invention can achieve include at least the following:

[0024] This solution solves the technical problem in existing technologies where low-expansion materials or water cooling methods can only passively suppress the expansion rate and cannot eliminate the physical elongation that has already occurred, as well as the lack of a self-regulating conversion mechanism that utilizes ambient thermal energy. It achieves the real-time conversion of the positive thermal expansion displacement that causes positioning errors into the reverse mechanical pull-back displacement that eliminates the errors. Without the need for external active intervention, it provides real-time dynamic compensation for the thermal deformation of the positioning pin, thereby effectively ensuring the positioning accuracy of the automotive welding fixture under continuous heating conditions.

[0025] Meanwhile, this solution further solves the technical problems of inaccurate fixed compensation ratio due to differences in the thermal deformation rate of different specifications of clamps, and the offsetting of effective compensation stroke due to the unidirectional expansion of the device body caused by heating by setting an adjustable fulcrum adjustment component and combining the thermal shielding component with the thermally conductive flexible transmission bundle. It realizes flexible adjustment of the lever transmission ratio, ensuring that the reverse pull-back distance and the forward thermal rise distance are accurately matched numerically. At the same time, by using the cooperation of the thermally conductive flexible transmission bundle and the thermal shielding component, it ensures that the temperature-sensing drive component can quickly capture the heat of the positioning pin, while effectively maintaining the dimensional stability of the base shell and avoiding the impact of its thermal deformation on the compensation accuracy. Thus, while ensuring the long-term stable operation of the device, it significantly improves the overall reliability and final use effect of the device. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0027] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the internal structure of the base shell in Embodiment 1 of the present invention;

[0029] Figure 3 This is a schematic diagram of the compensation state of the present invention. Figure 3 a is a schematic diagram of the temperature-sensing drive component and lever compensation mechanism in the initial state. Figure 3 b is a schematic diagram of the temperature-sensing drive component and lever compensation mechanism under heated conditions;

[0030] Figure 4 This is a schematic diagram of the internal structure of the base shell in Embodiment 2 of the present invention.

[0031] In the above figures, the reference numerals are as follows: 1. Base shell; 21. Heat-conducting core; 22. Deformation drive sleeve; 23. Ball joint connector; 24. Reset elastic element; 31. Transmission lever; 32. Pivot shaft; 331. Slide plate; 332. Sliding displacement block; 41. Sliding support block; 51. Heat insulation liner; 52. Heat insulation cylinder; 53. Heat-conducting flexible transmission bundle; 61. Waist-shaped transmission groove; 62. Cylindrical pin; 7. Positioning pin; 8. Welding fixture bracket; 91. Displacement sensor; 92. Temperature sensor.

[0032] The realization of the objective, functional features and advantages of the present invention will be further explained below with reference to the embodiments and the accompanying drawings. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0035] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0037] Example 1:

[0038] This embodiment provides a thermal deformation compensation device for automotive welding fixtures. Obviously, this device is applied to automotive welding fixtures. Specifically, it is located between the welding fixture bracket 8 and the positioning pin 7 that directly contacts the workpiece. It can be understood that in a conventional automotive body-in-white welding line, the welding fixture bracket 8 serves as a rigid support base, which will undergo Z-axis thermal expansion displacement due to heat during the welding process. This device, as a functional intermediate connecting module, can be installed on the top of the welding fixture bracket 8 by bolts or pins, replacing the traditional rigid connecting block. It is used to support the positioning pin 7 above and perform real-time reverse correction of its Z-axis height.

[0039] For example, please refer to Figures 1 to 3 The device includes:

[0040] The base housing 1 is fixed on the welding fixture bracket 8, and a receiving cavity is provided inside the base housing 1;

[0041] A temperature-sensing drive assembly is vertically disposed within the receiving cavity and is used to perform axial expansion deformation when heated. The top of the receiving cavity is away from the top of the temperature-sensing drive assembly and forms a deformation area.

[0042] A floating positioning component is slidably mounted on the base housing 1, with its upper part used to support the positioning pin 7 of the welding clamping bracket, and the sliding direction of the floating positioning component is parallel to the axial direction of the temperature sensing drive component.

[0043] The lever compensation mechanism is installed inside the base housing 1 and located in the deformation area. The two ends of the lever compensation mechanism are connected to the top of the temperature-sensing drive component and the bottom of the floating positioning component, respectively.

[0044] It should be noted that existing automotive welding fixtures undergo irreversible unidirectional physical expansion due to heat. Analysis shows that their main drawback is that existing low-expansion materials or water-cooling methods only passively reduce the expansion rate or suppress temperature rise, and cannot generate mechanical displacement opposite to the direction of thermal deformation to offset the physical elongation that has already occurred. Furthermore, they lack a corresponding conversion mechanism that can directly utilize ambient heat energy for self-regulation. Therefore, they have significant limitations in compensating for the thermal deformation of automotive welding fixtures, cannot achieve precise dynamic correction, and cannot meet the stringent requirements of high-precision positioning in modern car body manufacturing processes, resulting in poor actual compensation effects.

[0045] Based on this, this solution specifically adopts a lever compensation mechanism installed inside the base housing 1 to cooperate with the temperature-sensing drive component to solve the above problems.

[0046] Specifically, the compensation device of this solution includes a base housing 1 fixed to the welding fixture bracket 8. A temperature-sensing drive assembly is vertically arranged within the receiving cavity of the base housing 1, and a slidable floating positioning assembly is arranged on the base housing 1. A lever compensation mechanism is located at the deformation area at the top of the receiving cavity, with its two ends physically connected to the top end of the temperature-sensing drive assembly and the bottom end of the floating positioning assembly, respectively. The aim is that when the welding fixture generates heat, the temperature-sensing drive assembly can undergo corresponding axial expansion deformation based on the heat, thereby applying an upward pushing force to the lever compensation mechanism. The drive lever compensation mechanism rotates around its axis and uses the reversing action of the lever compensation mechanism to convert the upward expansion displacement of the temperature-sensing drive component into a reverse displacement that forces the floating positioning component to move towards the bottom of the base housing 1. This generates a mechanical pull-back action opposite to the direction of thermal deformation, thereby accurately offsetting the axial position deviation of the positioning pin 7 caused by environmental heating. This achieves real-time tracking and adaptive dynamic compensation of the thermal expansion error of the fixture system without the need for external active mechanism intervention, and ensures the positioning accuracy of the automotive welding fixture under continuous heating conditions.

[0047] Based on the above, we can see that the core of this solution is to use the thermal expansion and deformation of the temperature-sensing drive component as the active power source to drive the operation of the entire device, thereby providing the corresponding physical stroke and thrust for the subsequent lever compensation mechanism. This requires the temperature-sensing drive component to not only have extremely high sensitivity to changes in ambient temperature, but also to have the physical characteristic of being able to produce significant axial elongation deformation after being heated.

[0048] Therefore, in some specific embodiments, such as Figure 2As shown, the temperature-sensing drive assembly includes a thermally conductive alloy column, a ball joint connector 23 that is hinged to the top of the thermally conductive alloy column and ball jointed to the end of the lever compensation mechanism, the thermally conductive alloy column includes a thermally conductive core 21 whose bottom end is fixedly connected to the receiving cavity, and a deformation drive sleeve 22 sleeved outside the thermally conductive core 21. The deformation drive sleeve 22 is made of shape memory alloy and is used to generate axial expansion displacement, and the top end of the deformation drive sleeve 22 is connected to the ball joint connector 23.

[0049] Understandably, in this embodiment, the heat-conducting alloy column, which serves as the temperature-sensing drive component, cleverly employs a composite structure design of inner core heat conduction and outer jacket drive. That is, the heat-conducting core 21, as a rapid heat transfer channel, can utilize its high thermal conductivity (such as copper or aluminum alloy material) to quickly conduct the heat received at the bottom end to the entire axial length of the component, and uniformly heat the entire axial direction of the deformation drive sleeve 22 from the inside, so that the deformation drive sleeve 22 can be heated quickly. After reaching the corresponding temperature, it will produce significant axial expansion deformation, thereby providing thrust to one end of the lever compensation mechanism, causing it to rotate rapidly around the fulcrum axis 32. Utilizing the motion characteristics of the lever, it drives the floating positioning component to produce a reverse displacement toward the bottom of the base housing 1, thereby offsetting the axial position deviation of the positioning pin 7 caused by heating in real time, thus greatly improving the thermal sensitivity and action synchronization of the compensation device, and significantly improving the usage effect.

[0050] Meanwhile, considering the durability and response speed of the automotive welding environment involved in this solution, in this embodiment, the deformation drive sleeve 22 is preferably made of nickel-titanium (Ni-Ti) shape memory alloy or copper-based shape memory alloy to utilize the significant shape memory effect and thermal expansion rate of such materials to achieve drive. For example, it utilizes the unique thermosensitive phase change physical properties of shape memory alloy materials to achieve the drive cycle. When the deformation drive sleeve 22 absorbs heat through the heat-conducting core 21 and reaches the phase change temperature threshold, its internal lattice undergoes a structural transformation (austenitic phase change), the material instantly hardens and generates strong recovery stress, thereby forcibly generating significant axial elongation displacement to drive the lever compensation mechanism; when welding ends and the temperature drops, the material reverses to a low-temperature phase state (martensitic phase change), the material softens and loses its supporting rigidity. At this time, in conjunction with the physical reverse tension of the aforementioned reset elastic element 24, the softened deformation drive sleeve 22 can be compressed and retracted to its initial length, thereby ensuring that the device can quickly and accurately complete the elongation-retraction periodic action.

[0051] Furthermore, considering the change in motion mode, when the temperature-sensing drive component is heated and performs a vertical linear elongation motion, the end of the lever compensation mechanism connected to it actually performs an arc swing around the fulcrum. Therefore, in response to this difference in motion trajectory, this embodiment sets a ball joint connector 23 between the top of the heat-conducting alloy column and the lever compensation mechanism. Utilizing its multi-degree-of-freedom rotational characteristics, it can automatically adapt to and resolve the trajectory deviation between linear motion and arc motion, effectively eliminating the lateral interference force or mechanical jamming that may occur when using a rigid connection, ensuring the smoothness of the compensation action and the service life of the transmission mechanism.

[0052] Based on the above embodiments, the specific structure of the lever compensation mechanism will be further described below. Specifically, as follows: Figure 2 and Figure 3 As shown, the lever compensation mechanism includes a transmission lever 31 and a fulcrum shaft 32;

[0053] The pivot shaft 32 is located in the receiving cavity inside the base housing 1;

[0054] The transmission lever 31 is rotatably mounted on the fulcrum shaft 32 at its middle part, and one end of it is provided with a ball joint structure that connects to the ball joint connector 23, while the other end extends to the floating positioning component and is movably connected to it.

[0055] Through the above structural design, the lever compensation mechanism of this solution essentially constructs a mechanical reversing transmission system with the fulcrum shaft 32 as the rotation center. That is, it cleverly utilizes the lever principle to set the fulcrum shaft 32 as a torque fulcrum that is stationary relative to the base housing 1. When the temperature-sensing drive component generates a vertically upward thrust due to thermal expansion, this thrust is accurately transmitted to the ball socket structure at one end of the transmission lever 31 through the ball joint connector 23, forcing the transmission lever 31 to rotate around the fulcrum shaft 32. During this process, since the fulcrum shaft 32 is located in the middle, the other end of the transmission lever 31 will inevitably generate a vertically downward movement opposite to the direction of the input end, thereby driving the floating positioning component connected to it to move towards the bottom of the base housing 1.

[0056] Based on the above structure, this solution successfully achieves mechanical reversal of the displacement direction, cleverly converting the positive thermal elongation physical quantity that causes positioning errors due to thermal deformation in the automotive welding fixture into a reverse pull-back mechanical quantity that eliminates the errors in real time. Thus, with additional control compensation intervention, the height of the positioning pin 7 is kept constant. Meanwhile, for the transmission lever 31, one end is engaged with the ball joint connector 23 through a ball socket structure, while the other end is movably connected to the floating positioning component. This allows the transmission lever 31 to have a certain amount of movement in the horizontal direction when it moves around the fulcrum axis 32 in a seesaw-like motion, ensuring that both ends are always connected to the heat-conducting alloy column and the floating positioning component to maintain a good stress state, avoiding mechanical jamming during the compensation process, ensuring the normal operation of the compensation device, and improving its performance.

[0057] It should be further added that, as a specific form of active connection, in this embodiment, in Figure 2 and Figure 3 As shown in the figure, its specific structure is as follows: a waist-shaped transmission groove 61 extending horizontally is provided at the bottom end of the sliding support block 41. Correspondingly, a cylindrical pin 62 is connected to the other end of the transmission lever 31. The diameter of the cylindrical pin 62 matches (or is clearance-fitted) the groove width of the waist-shaped transmission groove 61, and the cylindrical pin 62 slides through the waist-shaped transmission groove 61.

[0058] Therefore, based on the above results, it can be seen that when the transmission lever 31 rotates around the fulcrum axis 32, the cylindrical pin 62 fixed at its end moves along an arc trajectory. During this process, utilizing the circular cross-sectional characteristics of the cylindrical pin 62, regardless of how the lever is tilted, the pin always maintains tangential contact with the upper and lower horizontal groove walls of the waist-shaped transmission groove 61 through its cylindrical outer surface.

[0059] In this way, the cylindrical pin 62 can slide freely left and right in the waist-shaped transmission groove 61 to eliminate the horizontal displacement component generated by the rotation of the lever; on the other hand, the cylindrical pin 62 can rotate slightly relative to the groove wall to adapt to the angle change of the lever. Thus, through the sliding cooperation of the two, the complex arc swing of the lever is decoupled into a simple vertical push / pull force, thereby driving the sliding support block 41 to rise and fall smoothly along the linear guide rail, completely avoiding the jamming or deadlock phenomenon during the movement of the mechanism.

[0060] However, it should be noted that in practical applications, due to the differences in size, material properties, and heat source distance of different welding fixtures, the rate and total amount of thermal deformation are not completely consistent. Therefore, for this solution, if the fulcrum position of the lever compensation mechanism is fixed, it means that the device can only provide a single, fixed displacement transmission ratio, which will make it difficult for the device to accurately adapt to all types of fixture thermal deformation conditions, and may result in under-compensation or over-compensation.

[0061] Therefore, in order to avoid this situation and to make the device more versatile and have greater adjustment accuracy, this application further improves the structure of the lever compensation mechanism so that it can compensate and correct for different thermal deformation errors. The details are described below.

[0062] As a preferred embodiment of this application, in Figure 2 As shown in the figure, the lever compensation mechanism also includes a fulcrum adjustment assembly, which is used to adjust the position of the fulcrum shaft 32 on the transmission lever 31;

[0063] The fulcrum adjustment assembly includes a pivot and a sliding displacement block 332;

[0064] The pivot component includes a slide plate 331, which is located between the fulcrum shaft 32 and the transmission lever 31 and is rotatably connected to the top of the fulcrum shaft 32, and is slidably connected to the bottom of the transmission lever 31 through a guide groove therein.

[0065] The sliding displacement block 332 is located at the bottom end of the fulcrum shaft 32, and the sliding displacement block 332 is slidably connected to the base housing 1 through the slide rail at the bottom of the receiving cavity;

[0066] Locking bolts are installed on both the slide plate 331 and the sliding displacement block 332, and the positions of the slide plate 331 and the sliding displacement block 332 are locked by the locking bolts respectively.

[0067] As can be seen from the above, this application achieves the movement and adjustment of the position of the fulcrum axis 32 by setting the fulcrum adjustment component, thereby realizing the precise adjustment of the compensation effect of the lever compensation mechanism.

[0068] For example, when the compensation ratio needs to be adjusted, the operator can loosen the locking bolt and push the fulcrum shaft 32 together with the slide plate 331 and the sliding displacement block 332 along the guide groove and slide rail, thereby directly changing the length ratio between the input end of the transmission lever 31 (i.e. the connection between the heat-conducting alloy column and the ball socket structure) to the fulcrum shaft 32 and the output end (i.e. the connection between the floating positioning component) to the fulcrum shaft 32.

[0069] For example, during adjustment, moving the fulcrum shaft 32 closer to the heat-conducting alloy pillar shortens the power arm and lengthens the resistance arm, increasing the transmission ratio of the lever. This allows for a larger reverse compensation displacement output while maintaining the same expansion of the temperature-sensing drive component, and vice versa. Therefore, this solution, through the movement adjustment of the fulcrum shaft 32 and the sliding plate 331 on the transmission lever 31, enables the device to directly adjust the displacement conversion ratio between the input expansion stroke of the temperature-sensing drive component and the output compensation stroke of the floating positioning component. This ensures that the final reverse pull-back distance is numerically precisely matched with the actual forward thermal upward distance of the positioning pin 7, effectively avoiding undercompensation or overcompensation caused by a fixed lever ratio. This allows the device to accurately match the actual thermal deformation rate of welding fixtures of different specifications, greatly improving the device's adaptability to different working conditions and the final compensation accuracy.

[0070] Based on the above embodiments, in further embodiments of this application, such as Figure 2 and Figure 3 As shown, the floating positioning component includes a sliding support block 41. The top end of the sliding support block 41 passes through the base housing 1 and is connected to the positioning pin 7. Its bottom end is movably connected to the other end of the transmission lever 31. The sliding support block 41 and the base housing 1 slide together to form a linear sliding pair.

[0071] Understandably, in this embodiment, the floating positioning component uses the sliding support block 41 as a rigid guide medium connecting the positioning pin 7 and the transmission lever 31. Its purpose is to form a high-precision linear sliding pair with the base housing 1, strictly constrain the movement trajectory of the positioning pin 7, and through the movement of the transmission lever 31, pull the sliding support block 41 to move in the vertical direction, thereby compensating for the thermal deformation of the positioning pin 7 on its upper part.

[0072] For example, when the locating pin 7 at the top undergoes thermal deformation due to heat, causing axial expansion and elongation, the temperature-sensing drive component inside the device is also simultaneously heated and generates a significant expansion thrust. This thrust is converted into a pulling force acting on the bottom end of the sliding support block 41 through the reverse transmission of the lever compensation mechanism, driving the sliding support block 41 and the locating pin 7 at the top to retract downwards along the linear sliding joint. During this process, the downward retraction displacement generated by the sliding support block 41 can be compensated and offset by the upward expansion and elongation of the locating pin 7 (this can be achieved by obtaining relevant data based on pre-calibrated experiments or on-site tests, and then making targeted adjustments through the aforementioned fulcrum adjustment), thereby ensuring that the absolute height of the locating reference surface at the top of the locating pin 7 relative to the welding fixture base remains constant, achieving zero compensation for thermal deformation errors, and thus effectively ensuring the positioning accuracy under welding conditions.

[0073] As one of the preferred embodiments, in Figure 2As shown in the figure, this solution also provides a reset elastic element 24 between the deformation drive sleeve 22 and the receiving cavity. The bottom end of the reset elastic element 24 is connected to the bottom of the receiving cavity, and its top end is connected to the deformation drive sleeve 22.

[0074] Understandably, the core purpose of setting the reset elastic element 24 in this solution is to achieve the deformation reset of the deformation driving sleeve 22.

[0075] Specifically, by adding a reset elastic element 24 (connected to the bottom of the cavity and the top of the drive sleeve) between the deformation drive sleeve 22 and the receiving cavity, the physical tension of the reset elastic element 24 is used to pull the deformation drive sleeve 22 to reset and contract when it cools down. This ensures that the deformation drive sleeve 22 can accurately return to its initial position after expansion deformation, forming a closed-loop deformation-reset working cycle. This reduces the performance dependence on the shape memory alloy material itself, thereby simplifying the manufacturing process of the deformation drive sleeve 22 and optimizing the cost. At the same time, the elastic reset capability of the reset elastic element 24 also reduces the fatigue wear of the deformation drive sleeve 22 in repeated thermal cycles to a certain extent, extending its service life and meeting the requirements of actual welding conditions.

[0076] Furthermore, the reset elastic element 24 is preferably made of a high fatigue life helical tension spring to ensure that it can still provide stable reset traction under long-term cyclic operation.

[0077] It is understandable that in practical applications, the deformation driving sleeve 22 inside the base housing 1 can only generate expansion driving force when it is in a state of heat absorption and heating. Since the cavity inside the base housing 1 is a closed space and contains structures other than the temperature-sensing driving mechanism (such as a lever compensation mechanism), it is necessary to prevent its heat from causing thermal deformation to other mechanisms and affecting the compensation accuracy of the device. Therefore, this solution proposes a further preferred embodiment, as follows:

[0078] In this embodiment, as Figure 2 As shown, a heat shielding assembly is provided inside the base housing 1. The heat shielding assembly includes a heat insulation liner 51 located inside the base housing 1 and a heat insulation cylinder 52 coaxially sleeved outside the deformation drive sleeve 22. At the bottom end of the heat-conducting core 21, a heat-conducting flexible transmission bundle 53 is provided that extends through to the outside of the base housing 1 and is connected to the bottom of the positioning pin 7. The heat-conducting flexible transmission bundle 53 is woven from a high thermal conductivity metal.

[0079] As can be seen from the above embodiments, this solution first constructs a heat-insulating shielding layer inside the receiving cavity by setting up a heat shielding component, using the heat insulation cylinder 52 and the heat insulation liner 51. This limits the heat radiation range of the deformation drive sleeve 22 after it is heated to the inside of the heat insulation cylinder 52 and blocks the heat from being conducted to the receiving cavity inside the base housing 1. This prevents the base housing 1 and the lever compensation mechanism inside it from undergoing thermal expansion deformation due to heat, avoids their thermal expansion deformation from offsetting the effective compensation stroke of the deformation drive sleeve 22, and ensures the compensation accuracy of the device.

[0080] Building upon this, to ensure that the deformation drive sleeve 22 can receive external heat in a timely manner, this solution further utilizes a thermally conductive flexible transmission bundle 53 to connect the positioning pin 7 and the thermally conductive core 21. Specifically, this structure uses the thermally conductive flexible transmission bundle 53 to directly conduct the heat from the positioning pin 7 to the deformation drive sleeve 22, bypassing the insulation layer, thereby enabling the deformation drive sleeve 22 to expand due to heat. Simultaneously, the flexible structure of the thermally conductive flexible transmission bundle 53, made of woven metal, allows it to bend and deform along with the movement of the floating positioning component. This ensures that while conducting heat, it does not obstruct the linear sliding of the floating positioning component, thus guaranteeing the driving efficiency and smooth movement of the device in a thermally isolated environment, thereby enabling the device's thermal compensation operation to function normally.

[0081] Example 2:

[0082] The difference from Embodiment 1 is that, in this embodiment, in order to accurately know the actual deformation of the positioning pin 7 after being heated, so as to accurately quantify and adjust the compensation effect of the lever compensation mechanism, this solution further provides a detection component on the base housing 1.

[0083] Specifically, such as Figure 4 As shown, the detection component includes a displacement sensor 91 and a temperature sensor 92 fixedly installed on the top end face of the base housing 1. The detection ends of the displacement sensor 91 and the temperature sensor 92 are respectively set with positioning pins 7, which are used to detect the vertical displacement change of the floating positioning component relative to the base housing 1 and the temperature change of the component itself in real time.

[0084] Understandably, in this embodiment, the combination of displacement sensor 91 and temperature sensor 92 enables the device to perform real-time monitoring and quantitative calibration of thermal deformation compensation accuracy.

[0085] Specifically, during practical application or debugging, the temperature sensor 92 is used to obtain the real-time temperature change of the positioning pin 7 to confirm its thermal expansion condition; at the same time, the displacement sensor 91 is used to detect the residual vertical displacement of the positioning pin 7 relative to the base housing 1 after compensation by the lever compensation mechanism. If the displacement sensor 91 shows that there is still a positive or negative displacement deviation, it indicates that the current compensation ratio does not match the actual thermal deformation rate.

[0086] At this point, the operator can directly adjust the fulcrum adjustment component in real time based on the data fed back by the sensor. This will change the lever arm ratio on the transmission lever 31 by pushing the fulcrum shaft 32 and the slide plate 331 to move, thereby correcting the displacement conversion ratio of the lever compensation mechanism until the detection value of the displacement sensor 91 returns to zero or within the allowable error range. This ensures that the reverse pull-back displacement output by the device is strictly equal to the actual thermal expansion displacement of the positioning pin 7, thus guaranteeing the final positioning accuracy.

[0087] Finally, it should be noted that in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0088] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0089] Furthermore, it should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are all schematic diagrams, intended only to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

Claims

1. An automobile welding jig thermal deformation compensation device, characterized by, The device includes: The base housing (1) is fixed on the welding fixture bracket (8), and a receiving cavity is provided inside the base housing (1); A temperature-sensing drive assembly is vertically disposed within the receiving cavity and is used to perform axial expansion deformation when heated. The top of the receiving cavity is away from the top of the temperature-sensing drive assembly and forms a deformation area. The floating positioning component is slidably mounted on the base housing (1), and its upper part is used to support the positioning pin (7) of the welding clamping bracket. The sliding direction of the floating positioning component is parallel to the axial direction of the temperature sensing drive component. The lever compensation mechanism is set inside the base housing (1) and located in the deformation area. The two ends of the lever compensation mechanism are respectively connected to the top of the temperature-sensing drive component and the bottom of the floating positioning component. The temperature-sensing drive assembly includes a thermally conductive alloy column, the top of which is hinged to a ball joint connector (23) that is ball-jointed to the end of the lever compensation mechanism. The thermally conductive alloy column includes a thermally conductive core (21) whose bottom end is fixedly connected to the receiving cavity, and a deformation drive sleeve (22) sleeved outside the thermally conductive core (21). The deformation drive sleeve (22) is made of shape memory alloy and is used to generate axial expansion displacement. The top of the deformation drive sleeve (22) is connected to the ball joint connector (23). The lever compensation mechanism includes a transmission lever (31) and a fulcrum shaft (32). The pivot shaft (32) is located in the receiving cavity inside the base housing (1); The middle part of the transmission lever (31) is rotatably mounted on the fulcrum shaft (32), and one end of it is provided with a ball socket structure connected to the ball joint connector (23), while the other end extends to the floating positioning component and is movably connected to it. The lever compensation mechanism also includes a fulcrum adjustment component, which is used to adjust the position of the fulcrum shaft (32) on the transmission lever (31); The fulcrum adjustment assembly includes a pivot and a sliding displacement block (332); The pivot component includes a slide plate (331), which is located between the fulcrum shaft (32) and the transmission lever (31) and is rotatably connected to the top of the fulcrum shaft (32). The transmission lever (31) is slidably connected to the slide plate (331) through a guide groove opened at its bottom. The sliding displacement block (332) is located at the bottom end of the fulcrum shaft (32), and the sliding displacement block (332) is slidably connected to the base housing (1) through the slide rail at the bottom of the receiving cavity; Locking bolts are installed on both the slide plate (331) and the sliding displacement block (332) to lock the position of the slide plate (331) and the sliding displacement block (332) respectively.

2. The apparatus according to claim 1, wherein The floating positioning component includes a sliding support block (41), the top end of which penetrates the base housing (1) and is connected to the positioning pin (7), and its bottom end is movably connected to the other end of the transmission lever (31). The sliding support block (41) and the base housing (1) slide together to form a linear sliding pair.

3. The automotive welding fixture thermal deformation compensation device according to claim 1, characterized in that, A reset elastic element (24) is provided between the deformation drive sleeve (22) and the receiving cavity. The bottom end of the reset elastic element (24) is connected to the bottom of the receiving cavity, and its top end is connected to the deformation drive sleeve (22).

4. The automotive welding fixture thermal deformation compensation device according to claim 1, characterized in that, A heat shielding assembly is provided inside the base housing (1). The heat shielding assembly includes a heat insulation liner (51) provided inside the base housing (1) and a heat insulation cylinder (52) coaxially sleeved outside the deformation drive sleeve (22). A heat-conducting flexible transmission bundle (53) is also provided at the bottom end of the heat-conducting core (21) that extends through to the outside of the base housing (1) and is connected to the bottom of the positioning pin (7).

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