Self-resetting stretching mechanism for stretch-bending machine and stretch-bending machine

Abstract

The utility model belongs to the technical field of stretch bending device, provide a kind of for the self-resetting extension mechanism and stretch bending machine of stretch bending machine, self-resetting extension mechanism includes: outer frame;Inner frame, it is rotationally arranged in outer frame;Extension oil cylinder, it is rotationally arranged on inner frame, and the rotation axis of extension oil cylinder and the rotation axis of inner frame are perpendicular to each other, and extension oil cylinder is used to exert tensile force to the workpiece to be stretched bending;First positioning block, it is movably arranged on inner frame;Second positioning block, it is fixed on extension oil cylinder;Rolling element, it is arranged between first positioning block and second positioning block.Compared with prior art, the utility model changes the "surface contact" or "sliding friction" in traditional reset structure to "rolling contact" by setting rolling element between first positioning block and second positioning block, significantly reduces the frictional resistance between the two.

Description

Technical Field

[0001] This utility model belongs to the technical field of bending devices, specifically relating to a self-resetting extension mechanism for a bending machine and a bending machine. Background Technology

[0002] In the stretch bending forming process of metal pipes, profiles, and other workpieces, the stretch bending machine is a key piece of equipment for achieving high-precision bending. The drawing mechanism, as one of the core components of the stretch bending machine, is mainly used to apply axial tensile force to the workpiece during the bending process to reduce wrinkles on the inner side of the bend and thinning on the outer side, thereby improving the forming quality. To meet the needs of complex curvatures or three-dimensional bending, modern stretch bending machines are typically equipped with a rotatable drawing cylinder, which can rotate synchronously with the workpiece during the bending process, thus ensuring that the direction of the tensile force is consistent with the workpiece axis.

[0003] After the bending action is completed, the drawing cylinder needs to automatically return to its initial position in order to clamp and process the next workpiece. This process relies on the "self-resetting" function of the drawing mechanism. Traditional self-resetting structures usually achieve the resetting action through mechanical contact between a positioning block (such as the first positioning block) set on the inner frame and another positioning block (such as the second positioning block) fixed on the drawing cylinder. For example, Chinese patent CN114833231A discloses a self-resetting drawing mechanism for a three-dimensional bending machine, which adopts a direct surface contact method between the two positioning blocks. During the process of the drawing cylinder rotating back to its initial position, the first positioning block pushes the second positioning block, thereby driving the drawing cylinder to reset.

[0004] However, this surface-contact-based reset structure has significant technical drawbacks in practical applications. When the drawing cylinder rotates to its limit angle position with the workpiece, the workpiece generates a large reverse torque on the drawing cylinder under the action of bending reaction force, causing the drawing cylinder and its second positioning block to be "locked" in the current position. At this time, even if the first positioning block applies a pushing force, due to the rigid surface contact between the two, the friction is extremely large, and there is a lack of effective guidance and rolling release mechanism. The first positioning block is unable to overcome the static friction and external load to push the second positioning block to complete the reset action. As a result, the drawing cylinder cannot return to the initial position smoothly, causing the mechanism to jam, seriously affecting the automated operation efficiency and processing cycle of the equipment, and may even cause equipment failure or safety accidents.

[0005] Furthermore, surface contact structures are prone to wear and deformation under repeated impacts and high load conditions, leading to decreased positioning accuracy and further weakening reset reliability. Therefore, existing self-resetting extension mechanisms still have significant shortcomings in terms of dynamic adaptability, operational smoothness, and long-term stability, and there is an urgent need for a new structural design that can achieve reliable and smooth reset under high load conditions. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a self-resetting extension mechanism for a bending machine and a bending machine in light of the current state of the technology.

[0007] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a self-resetting extension mechanism for a bending machine is proposed, comprising: an outer frame;

[0008] The inner frame is rotatably disposed within the outer frame;

[0009] An extension cylinder is rotatably mounted on the inner frame, and the rotation axis of the extension cylinder is perpendicular to the rotation axis of the inner frame. The extension cylinder is used to apply a tensile force to the workpiece to be bent.

[0010] A first positioning block is movably disposed on the inner frame;

[0011] The second positioning block is fixed on the extension cylinder;

[0012] A rolling element is disposed between the first positioning block and the second positioning block; wherein...

[0013] The rolling element is configured as an indirect contact component between the first positioning block and the second positioning block, and rotates when the first positioning block and the second positioning block approach or move away from each other, so as to allow the first positioning block and the second positioning block to roll contact; and when the second positioning block rotates together with the extension cylinder, the rolling element keeps the first positioning block and the second positioning block in indirect contact at all times.

[0014] In the aforementioned self-resetting extension mechanism for a bending machine, the rolling element includes a first rotating shaft disposed on the first positioning block or the second positioning block, and at least one bearing sleeved on the first rotating shaft.

[0015] In the above-mentioned self-resetting extension mechanism for a bending machine, the first positioning block is provided with a first groove on the side facing the second positioning block, and at least two rolling elements are provided at intervals on the inner wall of the first groove. The second positioning block is provided with a first protrusion adapted to the first groove on the side facing the first positioning block, and each rolling element rolls against the outer wall of the first protrusion.

[0016] In the above-mentioned self-resetting drawing mechanism for a bending machine, the first positioning block is provided with a second protrusion on the side facing the second positioning block, the second positioning block is provided with a second groove on the side facing the first positioning block, at least two of the rolling elements are spaced apart on the inner wall of the second groove, and the outer wall of the second protrusion rolls against each of the rolling elements.

[0017] In the aforementioned self-resetting extension mechanism for a bending machine, the second protrusion is formed by two adjacent inclined surfaces and a transition surface located between the two inclined surfaces.

[0018] In the aforementioned self-resetting extension mechanism for a bending machine, a fixed seat is provided on the inner frame, a first driving member and a slide rail are provided on the fixed seat, a slider is provided on the first positioning block, the slider is slidably disposed on the slide rail, the first positioning block is connected to the output end of the first driving member, and the first driving member is used to drive the first positioning block to move along the slide rail.

[0019] In the above-mentioned self-resetting extension mechanism for a bending machine, a first locking plate is fixedly installed on the extension cylinder, and a second locking plate is rotatably installed on the fixed seat. The first driving member includes a body and a driving rod. The driving rod passes through the body, with one end connected to the first positioning block and the other end movably abutting against the second locking plate.

[0020] When the drive rod abuts against the second locking plate, it drives the extension cylinder to lock onto the inner frame.

[0021] In the aforementioned self-resetting extension mechanism for a bending machine, the first locking plate has a first arc surface on the side facing the second locking plate, and the second locking plate has a second arc surface adapted to the first arc surface, with the first arc surface and the second arc surface movably abutting against each other.

[0022] The self-resetting extension mechanism for a bending machine described above also includes a second driving member, which is disposed on the outer frame and a second rotating shaft is fixed on the inner frame. One end of the second rotating shaft is connected to the output end of the second driving member.

[0023] This utility model solves the above-mentioned technical problems and also proposes a bending machine, including the above-mentioned self-resetting extension mechanism for bending machines.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) By setting a rolling element between the first positioning block and the second positioning block, the "surface contact" or "sliding friction" in the traditional reset structure is changed to "rolling contact", which significantly reduces the frictional resistance between the two.

[0026] (2) Using bearings as rolling elements results in a simple structure, flexible rotation, and strong load-bearing capacity, effectively withstanding impact loads and lateral forces during the resetting process. By mounting the bearings on the first rotating shaft, a modular design of the rolling elements is achieved, facilitating assembly and maintenance.

[0027] (3) By setting up a slide rail and slider guide structure, and cooperating with the first driving component (such as a cylinder, oil cylinder or electric push rod) to precisely control the movement of the first positioning block, the automation and controllability of the reset action are realized. Attached Figure Description

[0028] Figure 1 This is a perspective view of a self-resetting extension mechanism for a bending machine in operation.

[0029] Figure 2 yes Figure 1 A 3D view with the outer frame hidden.

[0030] Figure 3 yes Figure 2 A 3D view after the inner frame is hidden.

[0031] In the figure, 100 is the outer frame; 200 is the inner frame; 210 is the fixed base; 220 is the first driving component; 221 is the body; 222 is the driving rod; 230 is the slide rail; 240 is the second locking plate; 300 is the extension cylinder; 310 is the first locking plate; 400 is the first positioning block; 410 is the second protrusion; 420 is the slider; 500 is the second positioning block; 510 is the second groove; 600 is the rolling element; 610 is the first rotating shaft; 620 is the bearing; 700 is the second driving component; and 710 is the second rotating shaft. Detailed Implementation

[0032] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0033] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0034] like Figures 1 to 3 As shown, the present invention provides a self-resetting extension mechanism for a bending machine, comprising: an outer frame 100, an inner frame 200, an extension cylinder 300, a first positioning block 400, a second positioning block 500, and a rolling element 600.

[0035] Specifically, the outer frame 100 is mounted on the bending machine, the inner frame 200 is rotatably disposed within the outer frame 100, and the inner frame 200 and the outer frame 100 are rotatably connected; the drawing cylinder 300 is rotatably disposed on the inner frame 200, and the rotation axis of the drawing cylinder 300 is perpendicular to the rotation axis of the inner frame 200; the drawing cylinder 300 is used to apply tensile force to the workpiece to be bent; the first positioning block 400 is movably disposed on the inner frame 200; the second positioning block 500 is fixed on the drawing cylinder 300; and the rolling element... 600 is disposed between the first positioning block 400 and the second positioning block 500; wherein, the rolling element 600 is configured as an indirect contact component between the first positioning block 400 and the second positioning block 500, and rotates when the first positioning block 400 and the second positioning block 500 approach or move away from each other, so as to allow the first positioning block 400 and the second positioning block 500 to roll contact; and when the second positioning block 500 rotates together with the extension cylinder 300, the rolling element 600 keeps the first positioning block 400 and the second positioning block 500 in indirect contact at all times.

[0036] This solution reduces the frictional resistance between the two by setting a rolling element 600 between the first positioning block 400 and the second positioning block 500, thus changing the "surface contact" or "sliding friction" in the traditional reset structure to "rolling contact".

[0037] When the extension cylinder 300 rotates to its limit position with the workpiece and bears a large reaction force, the first positioning block 400 can smoothly push the second positioning block 500 through the rolling element 600, avoiding jamming due to excessive friction and ensuring that the extension cylinder 300 can be reliably reset.

[0038] Meanwhile, as an indirect contact component, the rolling element 600 can maintain continuous cooperation with the first positioning block 400 during the rotation of the extension cylinder 300, achieving dynamic adaptive reset, improving the responsiveness and stability of the mechanism, and extending its service life.

[0039] Furthermore, the rolling element 600 includes a first rotating shaft 610 disposed on the first positioning block 400 or the second positioning block 500, and at least one bearing 620 sleeved on the first rotating shaft 610.

[0040] Using bearing 620 as the rolling element 600 results in a simple structure, flexible rotation, and strong load-bearing capacity, effectively withstanding impact loads and lateral forces during the reset process. By mounting bearing 620 on the first rotating shaft 610, a modular design of the rolling element 600 is achieved, facilitating assembly and maintenance. The arrangement of multiple bearings 620 further enhances contact stability and stress uniformity, prevents localized stress concentration, strengthens the overall structural durability, and ensures reliable reset under long-term, high-frequency operation.

[0041] In one embodiment (not shown in the figure), the first positioning block 400 is provided with a first groove on the side facing the second positioning block 500, and at least two rolling elements 600 are provided at intervals on the inner wall of the first groove. The second positioning block 500 is provided with a first protrusion that matches the first groove on the side facing the first positioning block 400, and each rolling element 600 rolls against the outer wall of the first protrusion.

[0042] By setting up mutually matching pushing grooves and pushing protrusions, the guiding and positioning function between the first positioning block 400 and the second positioning block 500 is achieved. Rolling elements 600 are distributed on the inner wall of the groove and roll in contact with the outer wall of the protrusion, ensuring not only the accuracy of the thrust transmission but also limiting the relative offset between the two during the reset process, thus improving the centering and stability of the action. This structure can maintain stable contact even when the extension cylinder 300 is deflected, effectively preventing dislocation or misalignment and improving reset accuracy and safety.

[0043] In another embodiment, the first positioning block 400 is provided with a second protrusion 410 on the side facing the second positioning block 500, and the second positioning block 500 is provided with a second groove 510 on the side facing the first positioning block 400. At least two rolling elements 600 are spaced apart on the inner wall of the second groove 510, and the outer wall of the second protrusion 410 rolls against each of the rolling elements 600.

[0044] This embodiment places the protrusion within the groove of the first positioning block 400 and the rolling element 600 within the groove of the second positioning block 500, forming a reverse-fitting structure that also achieves good guiding and limiting functions. This layout is more conducive to maintaining continuous contact between the rolling element 600 and the protrusion during the rotation of the extension cylinder 300, and is particularly suitable for applications with limited space or where rolling components need to be integrated from the cylinder side. The rolling element 600 being located within the groove also provides protection, reducing the risk of external damage and improving system reliability.

[0045] In this design, the second protrusion 410 is formed by two adjacent inclined surfaces and a transition surface located between the two inclined surfaces.

[0046] The wedge-shaped pushing protrusion structure, composed of double inclined surfaces and a transition surface, allows the first positioning block 400 to achieve "automatic centering" as it approaches or disengages from the second positioning block 500, guided by the inclined surfaces. Even with slight assembly deviations or movement offsets, the inclined surfaces guide the block smoothly into the correct contact position, avoiding rigid collisions or jamming. The transition surface design smoothly connects the two inclined surfaces, reducing stress concentration, improving contact stability, and further enhancing the smoothness and fault tolerance of the reset process.

[0047] A fixed seat 210 is provided on the inner frame 200. A first driving member 220 and a slide rail 230 are provided on the fixed seat 210. A slider 420 is provided on the first positioning block 400. The slider 420 is slidably mounted on the slide rail 230. The first positioning block 400 is connected to the output end of the first driving member 220. The first driving member 220 is used to drive the first positioning block 400 to move along the slide rail 230.

[0048] The fixed base 210 and the inner frame 200 can be integrally formed, or the fixed base 210 can be fixed to the inner frame 200 by threaded connection or welding. In this solution, by setting a guide structure with slide rail 230 and slider 420, and cooperating with the first driving component 220 (such as a cylinder, hydraulic cylinder, or electric push rod) to precisely control the movement of the first positioning block 400, the automation and controllability of the reset action are realized. The sliding guide structure ensures the linearity and stability of the movement of the first positioning block 400, avoids uneven loading or swaying, and ensures that the thrust is accurately transmitted to the rolling component 600 and the second positioning block 500. The entire reset process is responsive and precise in positioning, meeting the needs of high-cycle production and improving the intelligence level and operating efficiency of the equipment.

[0049] It is worth mentioning that a first locking plate 310 is fixedly installed on the extension cylinder 300, and a second locking plate 240 is rotatably installed on the fixed base 210. The first driving member 220 includes a body 221 and a driving rod 222. The driving rod 222 is installed through the body 221, with one end connected to the first positioning block 400 and the other end movably abutting against the second locking plate 240. When the driving rod 222 abuts against the second locking plate 240, it drives the extension cylinder 300 to lock on the inner frame 200.

[0050] In this design, after the workpiece completes the bending operation through the tensioning mechanism and bending die, the drive rod 222 of the first drive component 220 pushes the second locking plate 240. By bringing the second locking plate 240 and the first locking plate 310 into close contact, the locking action of the tensioning cylinder is triggered, thus maintaining pressure on the workpiece. This design integrates the dual functions of "reset" and "locking" into one unit, eliminating the need for an additional independent locking device, simplifying the overall structure and saving installation space. When the drive rod 222 pushes the second locking plate 240 to rotate, it works in conjunction with the first locking plate 310 to clamp the tensioning cylinder, achieving rigid fixation on the inner frame 200. This effectively prevents loosening or displacement during processing, ensuring stable transmission of tensile force, thereby improving processing accuracy and operational safety.

[0051] The first locking plate 310 has a first arc surface on the side facing the second locking plate 240, and the second locking plate 240 has a second arc surface that matches the first arc surface. The first arc surface and the second arc surface are in contact with each other.

[0052] The curved surface mating structure allows the first locking plate 310 and the second locking plate 240 to achieve surface contact rather than point contact during the locking process, increasing the contact area and improving the uniformity and stability of the clamping force. The curved design also allows for adaptive fitting within a certain angle range, compensating for assembly errors or minor deformations and avoiding localized wear or breakage caused by stress concentration. This structure ensures high locking rigidity while improving the flexibility and durability of the connection, extending the service life of the locking mechanism.

[0053] This solution also includes a second drive component 700, which is mounted on the outer frame 100 and a second rotating shaft 710 is fixed on the inner frame 200. One end of the second rotating shaft 710 is connected to the output end of the second drive component 700.

[0054] By setting a second driving component 700 (such as a cylinder, hydraulic cylinder, or electric push rod) to drive the inner frame 200 to rotate around the second rotating shaft 710, active swing control of the entire drawing mechanism in space is achieved, which is suitable for stretch bending forming of complex three-dimensional curved surfaces. This structure makes the drawing direction adjustable, and can dynamically adjust the angle to follow the workpiece bending trajectory, ensuring that the tensile force always acts along the workpiece axis, reducing additional bending moment and improving forming quality. Combined with the rotational degree of freedom of the drawing hydraulic cylinder 300 itself, a multi-degree-of-freedom coordinated motion system is formed, greatly expanding the process adaptability of the equipment.

[0055] This solution also proposes a bending machine, including the aforementioned self-resetting stretching mechanism.

[0056] This solution provides a self-resetting drawing mechanism for a bending machine and a bending machine including the mechanism, aiming to solve the technical problem in the prior art where the drawing cylinder 300 is difficult to reset or even jammed under high load conditions due to the large frictional resistance between the contact surfaces of the positioning blocks.

[0057] By setting a rolling element 600 between the movable first positioning block 400 and the second positioning block 500 fixed on the extension cylinder 300, the traditional sliding friction contact is transformed into rolling contact, which significantly reduces the frictional resistance during the reset process. This allows the first positioning block 400 to smoothly push the second positioning block 500, and even at the limit position where the extension cylinder 300 is subjected to the reaction force of the workpiece, reliable reset can be achieved, effectively avoiding mechanism jamming.

[0058] Furthermore, by employing the mating structure of the pushing groove and the pushing protrusion, the guide design of the inclined transition, and the guide system of the slide rail 230 and slider 420, the centering, stability, and motion accuracy of the reset process are improved. More importantly, this solution integrates the reset and locking functions into the same driving component (first driving component 220). The first driving rod 222 triggers the locking plate action after the workpiece bending operation is completed, achieving automatic clamping and positioning of the extension cylinder 300. This results in a compact structure, smooth operation, and high reliability. The arc-contact locking plate design further optimizes the force distribution and enhances connection rigidity and durability.

[0059] Furthermore, by setting a second driving component 700 to control the rotation of the inner frame 200, the drawing mechanism is given multi-degree-of-freedom motion capabilities to adapt to the requirements of complex three-dimensional bending processes. In summary, this solution achieves "smooth reset, precise guidance, automatic locking, and stable operation" of the drawing cylinder 300, significantly improving the automation level, processing efficiency, and forming accuracy of the bending machine, demonstrating outstanding technological advancement and good industrial application value.

[0060] It should be noted that in this utility model, the use of terms such as "first," "second," and "a" is 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 as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly defined. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0061] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0062] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A self-resetting drawing mechanism for a tension bending machine, characterized in that, include: outer frame; The inner frame is rotatably disposed within the outer frame; An extension cylinder is rotatably mounted on the inner frame, and the rotation axis of the extension cylinder is perpendicular to the rotation axis of the inner frame. The extension cylinder is used to apply a tensile force to the workpiece to be bent. A first positioning block is movably disposed on the inner frame; The second positioning block is fixed on the extension cylinder; A rolling element is disposed between the first positioning block and the second positioning block; wherein... The rolling element is configured as an indirect contact component between the first positioning block and the second positioning block, and rotates when the first positioning block and the second positioning block approach or move away from each other, so as to allow the first positioning block and the second positioning block to roll contact; and when the second positioning block rotates together with the extension cylinder, the rolling element keeps the first positioning block and the second positioning block in indirect contact at all times.

2. The self-resetting drawing mechanism for a tension bending machine as described in claim 1, characterized in that, The rolling element includes a first rotating shaft disposed on the first positioning block or the second positioning block, and at least one bearing sleeved on the first rotating shaft.

3. The self-resetting drawing mechanism for a tension bending machine as described in claim 1, characterized in that, The first positioning block has a first groove on the side facing the second positioning block. At least two rolling elements are spaced apart on the inner wall of the first groove. The second positioning block has a first protrusion on the side facing the first positioning block that matches the first groove. Each rolling element rolls against the outer wall of the first protrusion.

4. The self-resetting drawing mechanism for a tension bending machine as described in claim 1, characterized in that, The first positioning block has a second protrusion on the side facing the second positioning block, and the second positioning block has a second groove on the side facing the first positioning block. At least two of the rolling elements are spaced apart on the inner wall of the second groove, and the outer wall of the second protrusion rolls against each of the rolling elements.

5. A self-resetting drawing mechanism for a tension bending machine as described in claim 4, characterized in that, The second protrusion is formed by two adjacent inclined surfaces and a transition surface located between the two inclined surfaces.

6. The self-resetting drawing mechanism for a tension bending machine as described in claim 1, characterized in that, A fixed seat is provided on the inner frame, a first driving member and a slide rail are provided on the fixed seat, a slider is provided on the first positioning block, the slider is slidably disposed on the slide rail, the first positioning block is connected to the output end of the first driving member, and the first driving member is used to drive the first positioning block to move along the slide rail.

7. A self-resetting drawing mechanism for a tension bending machine as described in claim 6, characterized in that, A first locking plate is fixedly installed on the extension cylinder, and a second locking plate is rotatably installed on the fixed seat. The first driving member includes a body and a driving rod. The driving rod passes through the body, with one end connected to the first positioning block and the other end movably abutting against the second locking plate. When the drive rod abuts against the second locking plate, it drives the extension cylinder to lock onto the inner frame.

8. A self-resetting drawing mechanism for a tension bending machine as described in claim 7, characterized in that, The first locking plate has a first arc surface on the side facing the second locking plate, and the second locking plate has a second arc surface that matches the first arc surface. The first arc surface and the second arc surface are in movable contact.

9. A self-resetting drawing mechanism for a tension bending machine as described in claim 1, characterized in that, It also includes a second driving component, which is disposed on the outer frame, and a second rotating shaft is fixed on the inner frame, with one end of the second rotating shaft connected to the output end of the second driving component.

10. A bending machine, characterized in that, Includes a self-resetting drawing mechanism for a bending machine as described in any one of claims 1 to 9.

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