Workpiece centering positioning tool and mold

Abstract

The utility model relates to the technical field of body parts assembly positioning, specifically relates to a work piece centering positioning tool and mould, work piece centering positioning tool includes installation base and centering positioning mechanism, installation base includes the positioning area of placing work piece, centering positioning mechanism sets up in installation base, centering positioning mechanism includes: synchronous transmission assembly is connected with power source transmission, first locating block and second locating block are respectively connected with both sides transmission of synchronous transmission assembly, synchronous transmission assembly is configured as, can drive first locating block and second locating block, and the first partial direction of moving path is synchronous and moves to the centering of work piece to make, wherein, the synchronous and moving displacement of first locating block and second locating block in the first partial direction is equal, and the first partial direction is perpendicular with preset work piece centering line, the work piece centering positioning tool of the utility model can improve the centering accuracy, and reduce error accumulation.

Description

Technical Field

[0001] This utility model relates to the field of vehicle body component assembly and positioning technology, specifically to a workpiece centering and positioning fixture and mold. Background Technology

[0002] As the automotive consumer market increasingly demands a refined perception of product appearance, the tailgate trim, as a visual focal point at the rear of the vehicle, directly impacts the overall harmony and premium feel of the vehicle through its assembly precision with the side panels. Traditional tailgate trim positioning fixtures often employ a single-sided positioning pin structure, relying on constraints in a single direction to achieve the positioning and fit between the inner and outer panels. However, positioning in the vehicle width direction is achieved solely through the cumulative tolerances of individual parts. This results in fluctuations in the gap between the two sides of the trim due to accumulated manufacturing errors (with a difference approaching 1.5mm). After assembly into the actual vehicle, the matching gap difference between the trim and the side panels exceeds 2mm, creating a visually visible asymmetry defect.

[0003] In existing technologies, although the problem can be partially alleviated by optimizing part tolerances or manual adjustments, it is difficult to systematically eliminate the deviation transmission path. Moreover, the process efficiency and consistency of relying on manual intervention are low, which has become the core bottleneck restricting the appearance quality of high-end models. Therefore, there is an urgent need for a positioning tool that can solve or reduce the defects of excessive gap difference between the tailgate trim panel and the side panel assembly and visual asymmetry caused by the accumulation of errors in traditional single-sided positioning, so as to meet consumers' stringent requirements for the refinement of vehicle appearance. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a workpiece centering and positioning fixture and mold that improves centering accuracy and reduces error accumulation. This fixture can significantly reduce the gap fluctuation of the tailgate trim panel in the vehicle width direction, thereby improving assembly accuracy.

[0005] To achieve the above and other related objectives, this utility model provides a workpiece centering and positioning fixture, comprising:

[0006] Mounting base, including a positioning area for placing the workpiece;

[0007] A centering and positioning mechanism is disposed on the mounting base, and the centering and positioning mechanism includes:

[0008] Synchronous transmission components are connected to the power source for transmission.

[0009] The first positioning block and the second positioning block are respectively connected to the two sides of the synchronous transmission assembly. The synchronous transmission assembly is configured to drive the first positioning block and the second positioning block to move synchronously towards each other in a first part of the movement path so that the workpiece is centered.

[0010] Wherein, the synchronous opposite displacement of the first positioning block and the second positioning block in the first sub-direction is equal, and the first sub-direction is perpendicular to the preset workpiece centerline.

[0011] In one embodiment of this utility model, the mounting base is provided with a plurality of positioning structures for initially positioning the workpiece within the positioning area.

[0012] In one embodiment of this utility model, the synchronous transmission assembly includes:

[0013] First transmission belt;

[0014] The second transmission belt moves in the same direction as the first transmission belt along the first branch direction, or in the opposite direction, and the synchronous displacements in opposite directions are equal.

[0015] A guide constraint assembly is used to constrain the transmission paths of the first and second drive belts.

[0016] In one embodiment of this utility model, the movement directions of the first positioning block and the second positioning block are perpendicular to the end faces of the two ends of the workpiece, respectively.

[0017] The first transmission belt is connected to the first positioning block, and the first transmission belt is constrained by the guide constraint component to be consistent with the normal direction of one end face of the workpiece;

[0018] The second transmission belt is connected to the second positioning block, and the second transmission belt is constrained by the guide constraint assembly to be consistent with the normal direction of the other end face of the workpiece.

[0019] In one embodiment of the present invention, the first positioning block is connected to the first transmission belt through a first connecting member, and the first positioning block is guided by a first guide member;

[0020] The second positioning block is connected to the second transmission belt via the second connector, and the second positioning block is guided by the second guide.

[0021] In one embodiment of this utility model, the first transmission belt and the second transmission belt are connected as a whole to form a ring structure. The first transmission belt is the upper region of the ring structure, and the second transmission belt is the lower region of the ring structure. The guide constraint component includes a meshing transmission part, and the ring structure meshes with the guide constraint component for transmission.

[0022] In one embodiment of this utility model, the ring structure is a ring-shaped toothed belt or a ring-shaped chain.

[0023] In one embodiment of this utility model, the guiding constraint component includes multiple sets of guide wheels, each set of guide wheels includes two guide wheels symmetrical about the preset workpiece centerline, and the connecting line of each set of guide wheels is perpendicular to the preset workpiece centerline.

[0024] In one embodiment of this utility model, the centering and positioning mechanism is embedded in the mounting base, and the height of the first positioning block and the second positioning block of the centering and positioning mechanism protruding from the positioning area is both less than a preset height, and the preset height is less than or equal to the height of the workpiece protruding from the positioning area.

[0025] To achieve the above objectives and other related objectives, this utility model provides a mold, including the workpiece centering and positioning fixture, wherein the mounting base of the workpiece centering and positioning fixture is the upper mold and / or lower mold of the mold.

[0026] In summary, this invention effectively overcomes or reduces the defects of excessive gap difference and visual asymmetry on both sides of the tailgate trim panel caused by the single-direction constraint and tolerance chain superposition of the traditional single-sided positioning fixture by driving the positioning blocks on both sides to move equidistantly towards each other along the vertical direction of the preset workpiece centerline through a synchronous transmission component. Specifically, firstly, the synchronous transmission component (such as a gear belt) forces the positioning blocks on both sides to have consistent displacement through rigid or flexible transmission, eliminating the random error of manual adjustment and the asynchronous risk caused by mechanical clearance, thereby compressing the gap fluctuation range of the tailgate trim panel in the vehicle width direction to a lower level; secondly, the movement direction of the positioning blocks is aligned with the first component direction (i.e., the horizontal direction) after the decomposition of the normal direction of the workpiece end face, combined with the synergistic effect of the cavity pre-positioning and guide constraint components, blocking the centering accuracy of the inner and outer panels during the assembly process, reducing error accumulation, significantly improving the assembly consistency of the tailgate trim panel assembly, and thus significantly reducing the gap fluctuation of the tailgate trim panel in the vehicle width direction, thereby improving the overall assembly accuracy. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the workpiece centering and positioning fixture in one embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the centering and positioning mechanism in one embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the mold structure in one embodiment of the present utility model;

[0031] Component labeling description: workpiece 100, end face 101, mounting base 10, positioning structure 11, synchronous transmission assembly 20, power source 30, first positioning block 31, second positioning block 32, first transmission belt 21, second transmission belt 22, guide constraint assembly 23, guide wheel 231, first guide component 311, second guide component 321, upper mold 200, upper and lower mold positioning blocks 201, lower mold 300, first sub-direction A, preset workpiece centerline B, normal direction C. Detailed Implementation

[0032] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. It should also be understood that the terminology used in the embodiments of this utility model is for describing specific implementation schemes and not for limiting the scope of protection of this utility model. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0033] Please see Figures 1 to 3 It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0034] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention.

[0035] As a rear exterior component of a vehicle, the tailgate trim panel typically consists of an outer panel and an inner panel. One side of the outer panel faces the exterior of the vehicle, while the other side connects to the inner panel. The symmetry of the tailgate trim panel's assembly with the side panel directly affects the overall visual harmony and perceived quality of the vehicle. Currently, the tailgate trim panel positioning fixtures commonly used in the industry suffer from the following technical defects:

[0036] Limitations of Positioning: Traditional solutions use a single-sided locating pin structure to achieve positioning and fit between the inner and outer panels. Positioning in the vehicle width direction relies solely on single-part constraints in a single direction, failing to effectively eliminate the cumulative effect of multi-directional manufacturing errors. Actual measurements show that the cumulative fluctuation difference in tolerances for individual inner and outer panels, the tailgate assembly, and the vehicle body assembly can reach 1.5mm. For example, even with a locating part on the inner side of the tailgate trim's outer panel, due to shrinkage errors (e.g., 0.3%) at both ends of the outer panel relative to the locating part during injection molding, accurate positioning between the outer and inner panels cannot be achieved, even with the locating part on the inner side of the outer panel.

[0037] Visual matching defects: When the above-mentioned cumulative tolerances are reflected in the actual vehicle assembly, the matching gap difference between the tailgate trim panel and the left / right side panel will exceed the perception threshold of 2mm, resulting in obvious visual asymmetry, which has become a key issue restricting the improvement of product quality.

[0038] Lack of tolerance compensation: The existing positioning structure lacks an active centering adjustment mechanism before the welding process, which cannot compensate for existing assembly deviations during the connection stage of inner and outer plates, resulting in defects being solidified in the assembly.

[0039] The root cause of the aforementioned technical defects lies in the failure of traditional positioning schemes to establish an effective multi-directional tolerance compensation mechanism, particularly the systematic lack of a dynamic alignment control stage before the connection of inner and outer panels. Therefore, this utility model provides a workpiece alignment and positioning fixture. It should be understood that the workpiece alignment and positioning fixture of this invention can be applied not only to the positioning of the outer and inner panels of the back door trim panel during assembly, but also to the alignment and positioning of other two workpieces during 100° matching assembly.

[0040] Traditional single-sided positioning fixtures rely on constraints in a single direction and the chain-like superposition of tolerances, resulting in gap differences between the two sides of workpiece 100 exceeding the allowable range, creating visually visible asymmetric defects. In this case, the synchronous transmission assembly 20 drives the positioning blocks on both sides to move equidistantly towards each other along the width direction of workpiece 100 (body width direction), applying symmetrical constraints at the mechanical level, blocking the unilateral error transmission path, and thus compressing the gap fluctuation range to a lower level. Its technical implementation is reflected in three aspects: First, active centering control is achieved through mechanical synchronization or closed-loop feedback mechanisms to ensure consistent displacement of the positioning blocks on both sides, eliminating random errors from manual adjustments; second, the symmetrical constraint mechanism suppresses the chain-like superposition effect of tolerances in the inner panel, outer panel, and body, improving the consistency of the assembly process; third, the integrated design of cavity pre-positioning and pressing processes forms a high-precision, low-manual-intervention integrated assembly solution, adapting to the dual requirements of efficiency and precision for automated production lines.

[0041] Please see Figure 1 This utility model provides a workpiece centering and positioning fixture, including a mounting base 10 and a centering and positioning mechanism;

[0042] The mounting base 10 includes a positioning area 11 for placing the workpiece 100; the centering and positioning mechanism is disposed on the mounting base 10, and the centering and positioning mechanism includes a synchronous transmission assembly 20, a first positioning block 31, and a second positioning block 32; the synchronous transmission assembly 20 is drivenly connected to the power source 30; the first positioning block 31 is drivenly connected to one side of the synchronous transmission assembly 20, and the second positioning block 32 is drivenly connected to the other side of the synchronous transmission assembly 20; the synchronous transmission assembly 20 is configured to drive the first positioning block 31 and the second positioning block 32 to move synchronously towards each other in a first direction A of the movement path so that the workpiece 100 is centered.

[0043] Wherein, the first positioning block 31 and the second positioning block 32 have equal synchronous opposite displacements in the first sub-direction A, and the first sub-direction A is perpendicular to the preset workpiece centerline B.

[0044] It should be noted that the mounting base 10 serves as the basic load-bearing structure of the tooling. Its positioning area 11 needs to provide stable placement and initial positioning of the workpiece 100 (such as the back door trim panel). The positioning area 11 can achieve pre-fixation of the workpiece 100 through cavity, surface or limiting structure 11, so that the workpiece 100 is aligned within the first predetermined error range of the preset workpiece alignment line B. For example, if the workpiece 100 needs to be aligned along the length direction, then the workpiece 100 needs to be placed along the length direction. It is necessary to ensure that the workpiece 100 is in a correct placement posture and can be aligned by the alignment and positioning mechanism.

[0045] The synchronous transmission assembly 20 can be implemented in various ways. For example, in a toothed belt and gear meshing transmission assembly, the first positioning block 31 is connected to the upper side of the toothed belt, and the second positioning block 32 is connected to the lower side of the toothed belt; in a chain and sprocket meshing transmission assembly, the first positioning block 31 is connected to the upper side of the chain, and the second positioning block 32 is connected to the lower side of the chain; in a double helical screw and nut pair, the double helical screw and nut pair includes two reverse threads, which drive the two nuts to move in opposite directions, respectively. The first positioning block 31 is driven by one of the nuts, and the second positioning block 32 is driven by the other nut, thereby realizing the driving of the first positioning block 31 and the second positioning block 32; and so on. The synchronous transmission assembly 20 includes a shaft with a first transmission belt 21 and a second transmission belt 22 connected to it. The first and second transmission belts 21 and 22 are symmetrically arranged and distributed on both sides of the shaft. When the shaft rotates, it winds around the first and second transmission belts 21 and 22, enabling them to move synchronously in opposite directions. Alternatively, it can be a double-helix screw and nut assembly, where nuts are respectively installed on two sections of reverse threads, and the first and second transmission belts 21 and 22 can be connected to the nuts. Alternatively, the synchronous transmission assembly 20 can be a hydraulic / pneumatic synchronous circuit, controlling the hydraulic / pneumatic actuators on both sides through a dual-cylinder synchronous valve or a proportional valve to ensure consistent displacement. The power source 30 can be a motor, cylinder, hydraulic cylinder, or manually driven to meet the alignment requirements of the synchronous transmission assembly 20.

[0046] The first positioning block 31 is used to position one end of the workpiece 100, and the second positioning block 32 is used to position the other end of the workpiece 100. When the workpiece 100 is placed horizontally and both ends of the workpiece 100 are inclined surfaces, the first positioning block 31 and the second positioning block 32 generally move along the normal direction of the end face 101 of the workpiece 100. The normal direction is decomposed into a first sub-direction A (horizontal direction) and a second sub-direction (vertical direction), wherein the first sub-direction A is perpendicular to the preset workpiece centerline B. By making the workpiece 100 move synchronously towards each other in the first sub-direction A, and the first positioning block 31 and the second positioning block 32 move synchronously towards each other in the first sub-direction A, the workpiece 100 is positioned. The displacements are equal, thus pushing the workpiece 100 toward the preset workpiece centerline B, thereby centering the workpiece 100 at the preset workpiece centerline B. The preset workpiece centerline B is generally located between the first positioning block 31 and the second positioning block 32. More precisely, the preset workpiece centerline B is located in the middle of the synchronous transmission assembly 20. The preset workpiece centerline B can be a solid line or a virtual line. When the end face 101 is a curved surface, the curved surface can be artificially simplified into a virtual plane, as long as the two ends of the simplified workpiece 100 are symmetrical. The first positioning block 31 and the second positioning block 32 also have corresponding curved surfaces that fit and conform to the workpiece 100.

[0047] The principle of this scheme is to utilize the motion synchronization of a symmetrical transmission system to convert the unidirectional input of the power source 30 into equidistant, opposing outputs from the positioning blocks on both sides. Taking a gear and belt system as an example, the power source 30 drives the toothed belt to move along a fixed path. The two sides of the toothed belt are connected to the positioning blocks through symmetrical gear sets. The gears have the same number of teeth and the toothed belt pitch is uniform, ensuring that the displacement on both sides is equal. At the same time, the first guide 311 and the second guide 321 restrict the corresponding positioning blocks to move only along a preset direction (with a first sub-direction A), avoiding deflection or jamming. When the workpiece 100 is placed in the positioning area 11, the drive signal triggers the power source 30, and the positioning blocks on both sides synchronously move towards the centerline of the workpiece 100 until they contact the edge of the workpiece 100 and apply an equal clamping force. At this time, the centerline of the workpiece 100 coincides with the centerline of the tooling, completing the centering and positioning. This principle ensures accuracy through the inherent symmetry of the mechanical structure, or achieves adaptive adjustment by dynamically correcting the displacement through sensor feedback.

[0048] Please see Figure 1 As an optional embodiment of this case, the mounting base 10 is provided with a plurality of positioning structures 12 for initially positioning the workpiece 100 within the positioning area 11.

[0049] It should be noted that the positioning area 11 of the mounting base 10 needs to achieve preliminary positioning of the workpiece 100 before fine positioning and alignment, so as to restrict the degree of freedom of the workpiece 100 and avoid positioning errors caused by the offset of the workpiece 100 during subsequent alignment. The positioning structure 12 can be implemented in various ways. For example, in one embodiment, the shape of the positioning structure 12 matches the edge of the workpiece 100, and restricts the movement of the workpiece 100 in the horizontal plane through surface contact; for example, in one embodiment, the positioning structure 12 integrates a negative pressure adsorption structure, and uses air path control to adsorb the surface of the workpiece 100 through the suction cup, which is suitable for thin-walled or curved workpieces 100. After the workpiece 100 is adsorbed, it needs to be able to be driven to move by the alignment and positioning mechanism; in one embodiment, the positioning structure 12 adopts a spring or pneumatic gripper structure, and fixes the workpiece 100 through flexible clamping force to avoid surface damage caused by rigid contact, and needs to ensure that the workpiece 100 can be driven to move by the alignment and positioning mechanism. The arrangement of the aforementioned positioning structures 12 needs to cover the key reference areas (such as edges or surfaces) of the workpiece 100, and the number and position are optimized according to the center of gravity and force distribution of the workpiece 100. For example, L-shaped positioning structures 12 can be set at the four corners of the workpiece 100 to constrain X / Y translation, or strip positioning structures 12 can be set along the centerline to restrict rotational degrees of freedom. The accuracy requirement for preliminary positioning is lower than that for final centering positioning, but it is necessary to ensure that the relative positional deviation between the workpiece 100 and the positioning area 11 is within the adjustment range of the subsequent centering positioning mechanism. In this case, by setting multiple positioning structures 12 in the positioning area 11, it is ensured that the workpiece 100 is in a stable and predictable initial position before entering the centering stage, thereby improving the pre-positioning accuracy, controlling the initial positional deviation of the workpiece 100 within the compensation range of the subsequent centering positioning mechanism, reducing the difficulty of adjustment, and improving the positioning efficiency.

[0050] Please see Figure 1-2 As an optional embodiment of this case, the synchronous transmission assembly 20 includes a first transmission belt 21, a second transmission belt 22, and a guide constraint assembly 23;

[0051] The synchronous movement directions of the second transmission belt 22 and the first transmission belt 21 are opposite or in the same direction along the first sub-direction A, and the synchronous displacements are equal; the guide constraint component 23 is used to constrain the transmission paths of the first transmission belt 21 and the second transmission belt 22.

[0052] It should be noted that the function of the synchronous transmission component 20 is to realize the synchronous opposite movement of the positioning blocks on both sides. Its design must meet the requirements of equal displacement, controllable direction and stable transmission path. The synchronous movement directions of the first transmission belt 21 and the second transmission belt 22 are opposite or in the same direction along the first branch direction A. They can drive the positioning blocks to move in opposite directions (centering and clamping) or to separate in opposite directions (releasing the workpiece 100). The first transmission belt 21 and the second transmission belt 22 include rigid transmission belts (such as toothed belts and chains) and flexible transmission belts (such as synchronous belts and wire ropes). For example, in a double toothed belt symmetrical transmission, the two toothed belts are connected to the left and right positioning blocks respectively, and rotate synchronously through the meshing of the intermediate drive gear. The pitch of the toothed belt is consistent with the module of the gear to ensure equal displacement. For example, in a cross belt linkage mechanism, the first transmission belt 21 and the second transmission belt 22 are arranged in a cross pattern. When the drive wheel rotates, power is transmitted through the intersection point to realize the opposite movement of the positioning blocks on both sides. For example, in a closed-loop synchronous belt system, the two synchronous belts form a closed loop through the tension wheel and the guide wheel 231. When the drive wheel rotates, the synchronous belts move in opposite directions, driving the positioning blocks to move synchronously. The function of the guide constraint component 23 is to restrict the movement of the transmission belt within a preset path to prevent deflection or slippage. For example, a gear guide rail is provided with guide gears on both sides of the transmission belt, and the transmission belt is constrained to deviate laterally through the tooth grooves. For example, a linear slide rail limiter is used, in which the transmission belt is embedded in a slide rail with limit grooves, and the degree of freedom of the transmission belt is restricted by the cooperation between the slider and the slide rail. It may also include a tension adjustment mechanism, which adjusts the tension of the transmission belt through a spring or screw to ensure that the belt body and the drive wheel are in close contact during transmission.

[0053] In this case, the rigid or flexible connection of the dual drive belts ensures that the positioning blocks on both sides follow the preset displacement, eliminating random deviations caused by manual adjustment or mechanical clearance. The guide constraint component 23 suppresses the vibration and offset of the drive belt under high speed or load changes, improving long-term reliability. This design can adapt to workpieces 100 of different sizes, weights, or materials by changing the type of drive belt or adjusting the guide constraint parameters, enhancing the tooling's versatility. In this design, the constraints of the transmission path are achieved through the inherent symmetry of the mechanical structure, without relying on complex sensors or control systems, thus reducing costs and improving system robustness.

[0054] Please see Figure 1-2 As an optional embodiment of this case, the movement directions of the first positioning block 31 and the second positioning block 32 are respectively perpendicular to the end faces 101 of both ends of the workpiece 100.

[0055] The first transmission belt 21 is connected to the first positioning block 31, and the first transmission belt 21 is constrained by the guide constraint component 23 to be consistent with the normal direction of one end face 101 of the workpiece 100.

[0056] The second transmission belt 22 is connected to the second positioning block 32, and the second transmission belt 22 is constrained by the guide constraint component 23 to be consistent with the normal direction of the other end face 101 of the workpiece 100.

[0057] It should be noted that the movement direction of the first positioning block 31 is perpendicular to one end face 101 of the workpiece 100, and the movement direction of the second positioning block 32 is perpendicular to the other end face 101 of the workpiece 100. For example, guided by a linear slide rail, the positioning block is installed on the linear slide rail, and the direction of the slide rail is parallel to the normal of the end face 101 of the workpiece 100. The cooperation between the slider and the guide rail restricts the positioning block to move only in a single direction. The first transmission belt 21 and the second transmission belt 22 are oriented by the guide constraint component 23 to align the power transmission direction of the transmission belt with the normal of the end face 101 of the workpiece 100. For example, it can be guided by gear meshing, with guide gears on both sides of the transmission belt, and the line connecting the two gears is consistent with the normal direction of the end face 101. The transmission belt path is constrained by the tooth groove meshing. For example, it can be constrained by a limiting groove, with the transmission belt embedded in a guide groove with a limiting protrusion, and the direction of the groove coincides with the normal direction, thus restricting the lateral displacement of the transmission belt.

[0058] Traditional centering fixtures are prone to lateral forces when the movement direction of the positioning block is not perpendicular to the end face 101 of the workpiece 100. This can cause the workpiece 100 to shift or experience localized stress concentration during clamping, exacerbating gap differences and appearance defects. This invention eliminates interference from oblique forces by forcing the positioning block to move along the normal direction of the end face 101. Simultaneously, the guide constraint component 23 ensures that the transmission path is consistent with the normal direction, guaranteeing centering accuracy from a mechanical structure perspective. For example, by ensuring the positioning block's movement trajectory is perpendicular to the end face 101 of the workpiece 100, the accumulation of positioning errors due to directional deviation is avoided. Applying force in the normal direction ensures that the clamping force is perpendicular to the contact surface of the workpiece 100, reducing the risk of localized deformation. This invention can also adapt to end faces 101 of the workpiece 100 with different shapes or angles using the adjustable guide constraint component 23, expanding the fixture's applicability. Specifically, when the drive source is activated, the transmission belt pulls the positioning block along the normal direction until it contacts the end face 101 of the workpiece 100 and applies a uniformly distributed clamping force. At this point, the end face 101 of workpiece 100 is in complete contact with the contact surface of the positioning block, and the centerline coincides with the theoretical centerline of the tooling, achieving zero-deviation centering.

[0059] Please see Figure 1-2 As an optional embodiment of this case, the first positioning block 31 is connected to the first transmission belt 21 through the first connector, and the first positioning block 31 is guided by the first guide 311;

[0060] The second positioning block 32 is connected to the second transmission belt 22 via the second connector, and the second positioning block 32 is guided by the second guide 321.

[0061] It should be noted that the first and second connecting members can be rigid or flexible connections. For example, one end of a connecting rod or connecting belt can be connected to the positioning block, and the other end can be connected to the transmission belt; or the positioning block has a cantilever arm that is directly bonded to the transmission belt. The first guide member 311 and the second guide member 321 are used to restrict the positioning block to move only along a preset direction. For example, a combination of a linear slide rail and a slider, with the slide rail direction consistent with the movement path of the transmission belt, and the positioning block's degree of freedom constrained by the cooperation of the slider and the slide groove; or the positioning block can be guided by a guide rod. In this case, the first guide member 311 and the second guide member 321 are used to forcibly restrict the positioning block to move only along a preset path, eliminating the influence of transmission belt vibration or deflection on positioning accuracy.

[0062] Please see Figure 1-2 As an optional embodiment of this case, the first transmission belt 21 and the second transmission belt 22 are connected as one unit to form a ring structure. The first transmission belt 21 is the upper region of the ring structure, and the second transmission belt 22 is the lower region of the ring structure. The guide constraint component 23 includes a meshing transmission part. The ring structure meshes with the guide constraint component 23 for transmission. For example, the ring structure is a ring toothed belt or a ring chain.

[0063] It should be noted that the first transmission belt 21 is the upper region of the annular structure, and the second transmission belt 22 is the lower region of the annular structure. That is, during the continuous rotation of the annular structure, the transmission belt portion located in the upper region is called the first transmission belt 21, and the transmission belt portion located in the lower region is called the second transmission belt 22. The annular structure can be, for example, formed by connecting the ends of a toothed belt to form a closed loop, transmitting power through the meshing of the drive gear and the driven gear, with the toothed belt pitch matching the gear module to ensure transmission accuracy; or a synchronous belt can be closed and wound between the drive wheel and the tension wheel, achieving slip-free transmission through toothed meshing, suitable for high-speed, light-load scenarios; or the two ends of a chain can be connected by chain links to form a loop, driving the sprocket and the driven sprocket to rotate synchronously, suitable for high-torque, high-load conditions. This invention, through the integration of the annular structure and the meshing transmission part, forces the two transmission belts to form motion coupling, eliminating the risk of asynchrony from the root. The annular layout reduces redundant drive components, reduces tooling complexity and space occupation, and is suitable for the integration requirements of automated production lines.

[0064] Please see Figure 2 As an optional embodiment of this case, the guide constraint component 23 includes multiple sets of guide wheels 231. Each set of guide wheels 231 includes two guide wheels 231 that are symmetrical about the preset workpiece centerline B. The line connecting each set of guide wheels 231 is perpendicular to the preset workpiece centerline B.

[0065] It should be noted that this design utilizes multiple sets of guide wheels 231 in the guide constraint component 23. Through symmetrical layout and path constraints, the transmission belt or chain is forced to move along a preset direction, ensuring the synchronization and consistency of displacement of the positioning blocks on both sides. The guide wheel sets 231 can be implemented in the following ways: for example, a symmetrical gear set, where each set of guide wheels 231 is a meshing gear, with two gears symmetrically arranged about the centerline, and the line connecting the gear axes perpendicular to the centerline, constraining the transmission path through belt meshing; or a pulley guide set, where the pulley surface has grooves or flanges, symmetrically distributed on both sides of the centerline, with the groove shape matching the cross-section of the transmission belt, limiting lateral offset of the transmission belt. This design balances the forces on both sides of the transmission belt through symmetrical wheel sets, suppressing vibration or offset caused by sudden changes in tension on one side; the perpendicular connection layout ensures that the transmission belt moves along a preset trajectory, reducing the difference in displacement of the positioning blocks; and the multiple sets of guide wheels 231 allow for reasonable adjustment of the layout of the annular toothed belt or annular chain, thereby reducing structural interference and space occupancy.

[0066] As an optional embodiment of this case, the centering and positioning mechanism is embedded in the mounting base 10, and the height of the first positioning block 31 and the second positioning block 32 of the centering and positioning mechanism protruding from the positioning area 11 is both less than a preset height, and the preset height is less than or equal to the height of the workpiece 100 protruding from the positioning area 11.

[0067] It should be noted that the purpose of embedding the centering and positioning mechanism into the mounting base 10 is to reduce spatial conflicts between the tooling and the workpiece 100 through structural integration and height control. Embedding can be achieved through mechanical fixing or modular embedding, such as a recessed embedding where a recess is formed on the surface of the mounting base 10, and the centering and positioning mechanism is embedded entirely within the recess and fixed by bolts or clips, with the top of the positioning block flush with or slightly lower than the surface of the workpiece 100; another example is a sliding rail telescopic embedding where the centering and positioning mechanism is connected to the mounting base 10 via a sliding rail, allowing it to extend and retract vertically, retracting into the mounting base 10 when not in use and extending to a preset height when in use; or a split modular embedding where the centering and positioning mechanism is designed as an independent module, plugged into the mounting base 10 via a standard interface, with the module height interchangeable to adapt to different workpiece 100 requirements. The control of the protrusion height of the positioning block must meet the constraint that the preset height is less than or equal to the protrusion height of the workpiece 100. This can be achieved in the following ways: for example, by using a mechanical limit block, with an adjustable limit screw or stop at the bottom of the positioning block to limit its maximum protrusion height; or by using hydraulic / pneumatic stroke control, adjusting the stroke of a hydraulic cylinder or pneumatic cylinder to control the protrusion height of the positioning block; or by using sensor feedback adjustment, integrating a height sensor to monitor the position of the positioning block in real time, and dynamically adjusting the stroke of the drive mechanism through a controller. In this case, if the positioning block protrudes too much, it is easy to collide with adjacent workpieces 100 or equipment during the stacking of multiple workpieces 100 or automated conveying, resulting in assembly failure or equipment damage. This case eliminates the risk of structural interference from a physical perspective through embedded design and height constraints. Taking a recessed embedding as an example, the centering positioning mechanism is completely sunk into the base, with only the top of the positioning block slightly protruding from the base surface, and its height is always lower than the protruding part of the workpiece 100 itself (such as the edge of the back door trim panel or the mounting boss). When workpiece 100 is placed in positioning area 11, the positioning block only contacts the reference surface of workpiece 100 and will not interfere with adjacent workpieces 100 or the conveying mechanism. During the pressing or transfer stage, the protruding part of workpiece 100 can freely pass through the tooling area, avoiding jamming or scratching. If a sliding rail telescopic embedding is used, the positioning block only extends to a preset height when needed and retracts into the mounting base 100 when not in use, further reducing space occupation and thus achieving conflict-free coordination between the tooling and the workpiece 100's movement path.

[0068] Furthermore, the positioning surfaces of the first positioning block 31 and the second positioning block 32 are adapted to the shape of the end of the workpiece 100 to improve structural adaptability and thus improve positioning accuracy.

[0069] It should be understood that the workpiece centering and positioning fixture in this case is mainly used for centering and positioning of workpieces 100 with symmetrical ends. However, if the end face structures of the first and second sub-parts of workpiece 100 are the same or similar at one end and the end face structures of the other end are the same or similar, centering can also be achieved using the workpiece centering and positioning fixture in this case. In this case, the first sub-part generally requires one set of workpiece centering and positioning fixtures for centering, and the second sub-part requires one set of workpiece centering and positioning fixtures for centering. The middle of the two sets of workpiece centering and positioning fixtures overlaps, thereby also achieving the assembly and centering of sub-parts of workpiece 100 with asymmetrical structures at both ends.

[0070] Please see Figure 3 This utility model provides a mold, including the aforementioned workpiece centering and positioning fixture, wherein the mounting base 10 of the workpiece centering and positioning fixture is the upper mold 200 and / or the lower mold 300 of the mold. Further, the mold includes an upper mold 200 and a lower mold 300; the upper mold 200 includes a first cavity for placing a first sub-component of the workpiece 100 assembly; the lower mold 300 includes a second cavity for placing a second sub-component of the workpiece 100 assembly; when the workpiece centering and positioning fixture is disposed on the upper mold 200, the first cavity is a positioning area 11 for placing the workpiece 100; when the workpiece centering and positioning fixture is disposed on the lower mold 300, the second cavity is a positioning area 11 for placing the workpiece 100.

[0071] Taking the tailgate trim panel as an example, the working process of the mold is briefly described as follows: ① The outer panel of the tailgate trim panel is placed into the outer panel positioning cavity of the upper mold 200, and the inner panel is placed into the inner panel cavity of the lower mold 300; ② Press the execution button to start the power source 30, such as the drive cylinder, the toothed belt drives the guide gear to rotate, and drives the first positioning block 31 and the second positioning block 32 on both sides to move until the outer panel of the tailgate trim panel is clamped, thus completing the centering and positioning of the outer panel of the tailgate trim panel; ③ The mold suction cup automatically clamps the outer panel of the tailgate trim panel and fits it with the positioning reference surface; ④ Press the execution button to drive the outer panel positioning cavity and the inner panel positioning cavity to position and fit together to ensure that the inner and outer panels are coated and cured with glue; ⑤ After the glue is applied and cooled by blowing air, the pressing tooling is developed, and the tailgate trim panel assembly is removed to complete the operation.

[0072] In summary, this utility model effectively overcomes some practical problems in the prior art, thus having high utilization value and significance.

[0073] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A workpiece centering and positioning fixture, characterized in that, include: Mounting base, including a positioning area for placing the workpiece; A centering and positioning mechanism is disposed on the mounting base, and the centering and positioning mechanism includes: Synchronous transmission components are connected to the power source for transmission. The first positioning block and the second positioning block are respectively connected to the two sides of the synchronous transmission assembly. The synchronous transmission assembly is configured to drive the first positioning block and the second positioning block to move synchronously towards each other in a first part of the movement path so that the workpiece is centered. Wherein, the synchronous opposite displacement of the first positioning block and the second positioning block in the first sub-direction is equal, and the first sub-direction is perpendicular to the preset workpiece centerline.

2. The workpiece centering and positioning fixture according to claim 1, characterized in that, The mounting base is provided with multiple positioning structures for initially positioning the workpiece within the positioning area.

3. The workpiece centering and positioning fixture according to claim 1, characterized in that, The synchronous transmission assembly includes: First transmission belt; The second transmission belt moves in the same direction as the first transmission belt along the first branch direction, or in the opposite direction, and the synchronous displacements in opposite directions are equal. A guide constraint assembly is used to constrain the transmission paths of the first and second drive belts.

4. The workpiece centering and positioning fixture according to claim 3, characterized in that, The movement directions of the first positioning block and the second positioning block are perpendicular to the end faces of the workpiece at both ends, respectively. The first transmission belt is connected to the first positioning block, and the first transmission belt is constrained by the guide constraint component to be consistent with the normal direction of one end face of the workpiece; The second transmission belt is connected to the second positioning block, and the second transmission belt is constrained by the guide constraint assembly to be consistent with the normal direction of the other end face of the workpiece.

5. The workpiece centering and positioning fixture according to claim 3, characterized in that, The first positioning block is connected to the first transmission belt via a first connector, and the first positioning block is guided by a first guide. The second positioning block is connected to the second transmission belt via the second connector, and the second positioning block is guided by the second guide.

6. The workpiece centering and positioning fixture according to claim 3, characterized in that, The first transmission belt and the second transmission belt are connected as a whole to form a ring structure. The first transmission belt is the upper region of the ring structure, and the second transmission belt is the lower region of the ring structure. The guide constraint assembly includes a meshing transmission part, and the ring structure meshes with the guide constraint assembly for transmission.

7. The workpiece centering and positioning fixture according to claim 6, characterized in that, The ring structure is a ring-shaped toothed belt or a ring-shaped chain.

8. The workpiece centering and positioning fixture according to claim 3, characterized in that, The guiding constraint assembly includes multiple sets of guide wheels. Each set of guide wheels includes two guide wheels that are symmetrical about the preset workpiece centerline. The line connecting each set of guide wheels is perpendicular to the preset workpiece centerline.

9. The workpiece centering and positioning fixture according to claim 1, characterized in that, The centering and positioning mechanism is embedded in the mounting base, and the height of the first positioning block and the second positioning block of the centering and positioning mechanism protruding from the positioning area is both less than the preset height, which is less than or equal to the height of the workpiece protruding from the positioning area.

10. A mold, characterized in that, The workpiece centering and positioning fixture includes any one of claims 1-9, wherein the mounting base of the workpiece centering and positioning fixture is the upper mold and / or lower mold of the mold.

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