A mandrel structure for a tube bender for electric vehicle frame production

Abstract

The application discloses a pipe bending machine core rod structure for electric vehicle frame production, which comprises a core cable, a limiting head fixedly connected to the front end of the core cable, and an air inlet pipe arranged in the core cable along the axial direction of the core cable; a core head, a perforated part being formed in the core head along the radial direction of the core head, and the core cable penetrating through the perforated part; an air bag, which is sleeved on the outer periphery of the core cable and is communicated with the air inlet pipe, and the air bag and the core head are staggered; and a push rod, the core cable penetrating through the push rod, and the air bag and the core head being located between the limiting head and the push rod, and the limiting head and the push rod being used for limiting the moving distance of the core head. After the core rod is inserted into the pipe material, the core head is located at the bending part of the pipe material, and when the pipe material is bent and after the bending is completed, the air bag is inflated and deflated, the air bag is expanded and contracted, the core head is driven to reciprocate along the radial direction of the pipe material, the supporting range of the core head in the pipe material is increased, the flatness of the surface of the bending part after the pipe material is bent is improved, and the quality of the produced electric vehicle frame is improved.

Description

Technical Field

[0001] This invention belongs to the field of tube bending machine technology, and particularly relates to a tube bending machine mandrel structure for electric vehicle frame production. Background Technology

[0002] A pipe bending machine primarily achieves bending by applying a certain force to cause plastic deformation of the pipe within a mold. In the production of electric vehicle frames, pipe bending machines are used to bend and shape the pipes used for the frame. During the bending process, to prevent the bent portion of the pipe from being flattened or wrinkled, a mandrel is placed inside the pipe for support.

[0003] Chinese invention patent CN209206153U discloses a mandrel for a tube bending machine. Multiple balls in the mandrel are connected by a universal ball structure. During the bending process, the gaps between the multiple balls supporting the tube cannot be eliminated. This causes the tube located at the gaps between the balls to not receive reliable support and to sink inward. Ultimately, this results in an uneven surface on the bent part of the tube, affecting the quality of the final electric vehicle frame.

[0004] Therefore, it is necessary to improve the mandrel structure of the existing tube bending machine. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects in the prior art and provide a bending mandrel structure for electric vehicle frame production, which improves the flatness of the bending part of the tube.

[0006] To achieve the above objectives, the specific technical solution of the bending mandrel structure for electric vehicle frame production of the present invention is as follows: A bending mandrel structure for electric vehicle frame production includes: A flexible core cable, wherein a limiting head is fixedly connected to the front end of the core cable, and an air inlet pipe is provided inside the core cable along its axial direction; A spherical core head is used to support the tube from the inside. The core head has a through-hole in its radial direction, and the core cable passes through the through-hole. An annular airbag is fitted around the outer periphery of the core cable and communicates with the air inlet pipe. The airbag and the core head are staggered. When the airbag is inflated or deflated, it pushes the core head to move along the axial direction of the tube. A tubular push rod is provided, through which the core cable passes. The airbag and the core head are located between the limiting head and the push rod. The limiting head and the push rod are used to limit the movement distance of the core head.

[0007] Preferably, in order to accommodate the airbag and allow two adjacent cores to dock and limit each other, each core has a notch at both ends along the axial direction of the perforation portion, which communicates with the perforation portion, wherein the outer diameter of one end is smaller than the inner diameter of the notch at the other end.

[0008] Preferably, in order to enable the spherical surface of the core tip to abut against the inner wall of the tube and improve the support effect on the tube, anti-deflection components are circumferentially distributed along the edges of the openings of the two recesses, and the anti-deflection components protrude from the spherical surface of the core tip.

[0009] Preferably, in order to give the core cable better flexibility and strength, the core cable includes an inner core and an outer sheath covering the outer surface of the inner core, and the air inlet pipe is embedded inside the outer sheath.

[0010] Preferably, in order to prevent the air inlet pipe from being flattened when the core cable bends, a plurality of support rings are also embedded inside the outer sheath. Each support ring is coaxially arranged with the inner core and is evenly distributed along the extension direction of the inner core. The air inlet pipe passes through the inner side of the support ring.

[0011] Preferably, in order to improve the convenience of inflating and deflating the airbag, the end of the air inlet pipe is connected to the first end of a three-way pipe, and the second and third ends of the three-way pipe are both equipped with valves, one of which is connected to an air pump.

[0012] Preferably, in order to adjust the moving distance of the core cable, an adjustment mechanism is provided between the end of the core cable away from the limiting head and the push rod, and the adjustment mechanism is used to adjust the interval between the limiting head and the push rod.

[0013] Preferably, in order to improve the convenience of adjusting the distance between the limiting head and the push rod, the adjustment mechanism includes a base that is detachably connected to the push rod at one end, a sliding seat that is slidably connected to the base along the axial direction of the push rod, the sliding seat being detachably connected to the core cable, and the base being provided with a driving member for driving the sliding seat to move.

[0014] Preferably, in order to improve the stability of the core head positioning, the end of the push rod and the limiting head near the core head are inserted into the notch.

[0015] Preferably, in order to effectively prevent the core tip from deflecting, the anti-deflection component is a ball or a roller.

[0016] The mandrel structure of the tube bending machine for electric vehicle frame production of the present invention has the following advantages: After the mandrel is inserted into the tube, the mandrel head is located at the bending part of the tube. During and after the tube is bent, the air bladder is inflated and deflated, causing the air bladder to expand and contract. The air bladder drives the mandrel head to move back and forth along the radial direction of the tube, thereby increasing the support range of the mandrel head inside the tube, improving the flatness of the bending part surface after the tube is bent, and thus improving the quality of electric vehicle frame production. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the mandrel in the pipe bending machine of the present invention; Figure 2 This is an exploded structural diagram of the mandrel of the pipe bending machine of the present invention; Figure 3 This is a schematic diagram of the chip head structure of the present invention; Figure 4 This is a cross-sectional view of the core tip of the present invention; Figure 5 This is a schematic diagram of the structure of the airbag of the present invention; Figure 6 This is a schematic diagram of the core cable structure of the present invention; Figure 7 for Figure 6 Enlarged view of part A; Figure 8 This is a schematic diagram of the adjustment mechanism of the present invention; The markings in the diagram are as follows: 1. Core head; 2. Airbag; 3. Push rod; 4. Core cable; 5. Adjustment mechanism; 101. Notch; 102. Perforation; 103. Ball bearing; 104. Groove; 401. Limiting head; 402. Outer sheath; 403. Inner core; 404. Air inlet pipe; 405. Connecting plate; 406. Support ring; 407. Valve; 408. T-connector; 501. Base; 502. Sliding seat; 503. Drive component; 504. Air pump; 505. Slot; 506. Collar. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0019] The terms "top surface," "bottom surface," and "full surface" are used with reference to the normal operating state of the mandrel in the tube bending machine. They are used only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0020] like Figure 1-7As shown, a mandrel structure for a bending machine used in the production of electric vehicle frames includes: a flexible core cable 4, with a limiting head 401 fixedly connected to the front end of the core cable 4, and an air inlet pipe 404 arranged axially inside the core cable 4; a spherical mandrel 1 for supporting the tube from the inside, with a perforation 102 opened radially on the mandrel 1, through which the core cable 4 passes; an annular airbag 2, which is sleeved on the outer periphery of the core cable 4 and communicates with the air inlet pipe 404, with the airbag 2 and mandrel 1 arranged alternately, and the airbag 2 pushing the mandrel 1 to move axially along the tube when inflated or deflated; and a tubular push rod 3 through which the core cable 4 passes, with the airbag 2 and mandrel 1 located between the limiting head 401 and the push rod 3, the limiting head 401 and the push rod 3 used to limit the movement distance of the mandrel 1.

[0021] The aforementioned mandrel is used to support the bent portion of the pipe from the inside when bending pipes in a pipe bending machine. In use, the push rod 3, multiple mandrel heads 1, and multiple air bladders 2 are all fitted onto the core cable 4, with each mandrel head 1 and each air bladder 2 positioned between the limiting head 401 and the push rod 3. An air bladder 2 is positioned between each adjacent mandrel head 1. Before bending the pipe, the mandrel is inserted entirely into the pipe. At this time, all the air inside the air bladders 2 is expelled, causing the air bladders 2 to contract. Simultaneously, the push rod 3 is pushed forward along the core cable 4. The push rod 3 and the limiting head 401 clamp each mandrel head 1 and each air bladder 2 from both sides, ensuring that each mandrel head 1 is tightly pressed against each other. This allows the mandrel to be in a rigid state, facilitating its insertion into the tube. During insertion, the length of the push rod 3 outside the tube is measured to control its insertion length, aligning the front end of the push rod 3 with the end of the tube to be bent and fixing its relative position. Then, the core cable 4 is pushed forward along the push rod 3. Measuring the length of the core cable 4 outside the push rod 3 controls the position of its front end, which in turn controls the position of the limiting head 401. This aligns the limiting head 401 with the front end of the tube to be bent and fixes its relative position to the push rod 3. The distance between 01 and the front end of push rod 3 corresponds to the length of the bent section of the pipe. At this time, the pipe bending machine is started to bend the pipe. During this process, the airbags 2 are inflated and deflated through the air inlet pipe 404. Each airbag 2 is independently controlled for inflation and deflation through an air inlet pipe 404. This allows the airbags 2 to push each mandrel 1 to move back and forth along the axial direction of the pipe, increasing the support range of the mandrel 1 inside the pipe, thus keeping the pipe flat after bending and improving the quality of the pipe bending machine. After the pipe is bent, the airbags 2 can still push each mandrel 1 to move back and forth inside the pipe, thereby causing the mandrel 1 to create a concave shape at the bent section of the pipe groove. The parts are trimmed to improve the flatness of the pipe after bending, further ensuring the quality of the pipe after bending by the pipe bending machine; after the pipe bending machine finishes bending the pipe, the air inside each airbag 2 is discharged to reduce the friction between the airbag 2 and the inner wall of the pipe. Then the mandrel is pulled out of the pipe as a whole. When taking it out, the push rod 3 and the core cable 4 are fixed together. Then the push rod 3 is pulled out of the pipe. While the push rod 3 moves out of the pipe, the limit head 401 and the core cable 4 pull each mandrel 1 out of the pipe. At this time, the mandrel 1 is in a free rotation state, which can reduce the friction between the mandrel 1 and the pipe, making it easier to take out the mandrel from the inside of the pipe.

[0022] Compared to existing methods that connect the core heads via hinges or ball joints, the aforementioned core rod structure allows for the clamping or loosening of each core head 1 using the limiting head 401 and push rod 3. This enables switching between a rigid state and a free bending state for each core head 1 on the core rod. In the rigid state, it facilitates the insertion of the core rod into the tube; in the free bending state, it allows the core rod to follow the bending shape of the tube, greatly improving the ease of use of the core rod. Furthermore, the inflation and deflation of the airbags 2 allows for the switching between static and dynamic states for each core head 1. In the static state, the inflation of different airbags 2 can be controlled. The position of each mandrel 1 can be freely adjusted, thereby providing better support for the bent parts of the pipe. In dynamic situations, the support range can be increased by moving the mandrel 1, and the concave parts of the pipe can be lifted during the movement of the mandrel 1, thereby correcting the flatness of the pipe. Furthermore, when the bending angle of the pipe is large, the interference between two adjacent mandrel 1 can be reduced by adjusting the interval between each mandrel 1, ensuring the support effect for the pipe. In addition, the inflated airbag 2 can also provide good support from the inside of the pipe.

[0023] Further improvements include, for example Figure 3 and 4 As shown, the core head 1 has a notch 101 that connects to the perforation 102 at both ends along the axial direction of the perforation 102, wherein the outer diameter of one end is smaller than the inner diameter of the notch 101 at the other end.

[0024] Specifically, after the airbag 2 contracts, the ends of the two core heads 1 connect with each other, so that the two notches 101 form a cavity that can accommodate the airbag 2, reducing the chance of the airbag 2 being pinched and damaged by the core heads 1; when the limiting head 401 and the push rod 3 clamp each core head 1 from both sides, the opposite ends of two adjacent core heads 1 can be inserted into each other, thereby achieving mutual limiting, so that when the mandrel is in a rigid state, the connection between each core head 1 is more stable, making it easier to insert the mandrel into the inside of the pipe; and the setting of the notch 101 can shorten the length of the core head 1 along the axial direction of the perforation 102, thereby expanding the range of movement of the contact part between the core head 1 and the inner wall of the pipe, and improving the support and correction effect of the core head 1 on the pipe.

[0025] Further improvements include, for example Figure 3 and 4 As shown, anti-deflection components are circumferentially distributed along the edges of the openings of the two recesses 101. The anti-deflection components protrude from the spherical surface of the core head 1 and are either ball bearings 103 or rollers.

[0026] Because the core cable 4 is flexible, its support and guiding effect on the core head 1 is weak, causing the core head 1 to easily deflect during its movement inside the tube. During this deflection, the notch 101 cannot effectively support the inside of the tube, and bending the tube at this time will cause the tube surface to dent. Therefore, an anti-deflection component is provided to limit the deflection angle of the core head 1. When the deflection angle of the core head 1 is too large, the anti-deflection component abuts against the inner wall of the tube, which can prevent the core head 1 from continuing to deflect, thus ensuring that the spherical surface of the core head 1 is always in contact with the inner wall of the tube, guaranteeing the support effect for the tube. The anti-deflection component is set as a ball bearing 103 or a roller, which can reduce the friction between the anti-deflection component and the inner wall of the tube. This design allows the core head 1 to move more smoothly inside the pipe, and also reduces scratches on the inner wall of the pipe caused by the deflection component when it comes into contact with the pipe's inner wall. Compared with rollers, the ball bearing 103 is a better implementation method. When installing the ball bearing 103, multiple grooves 104 are opened on the spherical surface of the core head 1 to accommodate the ball bearing 103, allowing the ball bearing 103 to roll freely inside the grooves 104. The opening diameter of the grooves 104 is smaller than the diameter of the ball bearing 103, thereby preventing the ball bearing 103 from falling off. Since the rotation direction of the ball bearing 103 is not restricted, the ball bearing 103 can provide better support and reduce friction when the core head 1 deflects in any direction.

[0027] Further improvements include, for example Figure 6 As shown, the core cable 4 includes an inner core 403 and an outer sheath 402 covering the outer surface of the inner core 403, and the air inlet pipe 404 is embedded inside the outer sheath 402.

[0028] Specifically, the inner core 403 is a steel wire rope, one end of which is fixedly connected to the limiting head 401. The outer sheath 402 can be made of polytetrafluoroethylene (PTFE). The steel wire rope, as the inner core 403, can be freely bent, allowing the core cable 4 to better adapt to the bending of the pipe. Furthermore, the steel wire rope has sufficient strength to allow the core cable 4 to resist the resistance of the core head 1, thus removing the core head 1 from inside the pipe. The PTFE outer sheath 402 can effectively protect the inner core 403 of the steel wire rope, preventing corrosion and extending the service life of the core cable 4. In addition, the PTFE outer sheath 402 can also provide good lubrication to reduce the friction between the core cable 4, the core head 1, and the push rod 3.

[0029] A further improvement is shown in Figure 7, where multiple support rings 406 are embedded inside the outer skin 402. Each support ring 406 is coaxially arranged with the inner core 403 and is evenly distributed along the extension direction of the inner core 403. The air intake pipe 404 passes through the inner side of the support ring 406.

[0030] Specifically, the support ring 406 is coaxially arranged with the inner core 403, and there is a gap between two adjacent support rings 406 so that the support ring 406 will not obstruct the bending of the core cable 4. Through the supporting effect of the support ring 406, the pressure generated by the core head 1 and the air bag 2 on the core cable 4 can be offset, preventing the core cable 4 from deforming, thereby ensuring that the air intake pipe 404 is unobstructed, so as to ensure effective control of the inflation and deflation of the air bag 2.

[0031] Further improvements include, for example Figure 7 As shown, the first end of the air intake pipe 404 is connected to the end of the three-way pipe 408. The second and third ends of the three-way pipe 408 are both equipped with valves 407. The valve 407 located on the third end is connected to the air pump 504.

[0032] Specifically, valve 407 can be a solenoid valve, thereby enabling automatic control of valve 407 and improving the ease of use of the equipment. When the airbag 2 needs to be inflated, valve 407 at the second end of the three-way pipe 408 closes and valve 407 at the third end opens, allowing air to be pumped into the airbag 2 via air pump 504. When the airbag 2 needs to be deflated, valve 407 at the second end of the three-way pipe 408 opens and valve 407 at the third end closes, allowing air to be expelled from the second end of the airbag 2 under the elasticity of the airbag 2. In the aforementioned mandrel, each airbag 2 is connected to an air inlet pipe 404, and each air inlet pipe 404 is connected to a three-way pipe 408. Multiple three-way pipes 408 are connected to the same air pump 504 inflation port, thus reducing the need for air pumps and lowering equipment costs.

[0033] Further improvements include, for example Figure 8 As shown, an adjustment mechanism 5 is provided between the end of the core cable 4 away from the limiting head 401 and the push rod 3. The adjustment mechanism 5 is used to adjust the interval between the limiting head 401 and the push rod 3. The adjustment mechanism 5 includes a base 501 that is detachably connected to the push rod 3 at one end. A sliding seat 502 is slidably connected to the base 501 along the axial direction of the push rod 3. The sliding seat 502 is detachably connected to the core cable 4. The base 501 is provided with a driving member 503 for driving the sliding seat 502 to move.

[0034] Specifically, the driving component 503 includes a screw rotatably mounted on the base 501 and a motor fixedly connected to the base 501. The motor is driven by the screw, and the screw is threadedly engaged with the sliding seat 502. A guide groove is provided on the base 501, and a slider that slides in a sliding engagement with the guide groove is fixedly connected to the sliding seat 502. The two work together to improve the stability of the movement of the sliding seat 502. The movement of the sliding seat 502 is powered by the motor and the screw. A slot 505 is fixedly connected to the sliding seat 502. A connector 405 is fixedly connected to the end of the core cable 4 away from the limiting head 401. The connector 405 is inserted into the slot 505 to realize the core cable... 4. Disassembly and connection between the push rod 3 and the sliding seat 502; A collar 506 is fixedly connected to one end of the base 501. The push rod 3 is inserted into the collar 506 to achieve disassembly and connection between the push rod 3 and the base 501, improving the convenience of equipment maintenance; The air pump 504 is installed on the sliding seat 502 and can move together with the sliding seat 502, thereby maintaining relative stillness between it and the air inlet pipe 404, which facilitates the installation and cooperation between the two; When in use, the push rod 3 and the base 501 are relatively still, and the sliding seat 502 pushes the core cable 4 to move, thereby realizing the relative movement between the core cable 4 and the push rod 3 to adjust the movement range of the core head 1.

[0035] The base 501 can be installed on the pipe bending machine's propulsion device, so that the mandrel can move synchronously with the pipe, thereby effectively controlling the position of the mandrel 1 inside the pipe and improving the support effect on the pipe.

[0036] Further improvements include, for example Figure 2 and 6 As shown, the push rod 3 and the limiting head 401 are engaged with the notch 101 at one end near the core head 1.

[0037] Specifically, the push rod 3 and the limiting head 401 are inserted into the notch 101, which can improve the stability of the connection between the push rod 3 and the limiting head 401 and the core head 1, and increase the strength of the core rod when it is in a rigid state.

[0038] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A bending mandrel structure for electric vehicle frame production, characterized in that, include: A flexible core cable (4) is provided with a limiting head (401) fixedly connected to the front end of the core cable (4), and an air inlet pipe (404) is provided inside the core cable (4) along its axial direction. A spherical core head (1) is used to support the tube from the inside. The core head (1) has a perforation (102) in its radial direction. The core cable (4) passes through the perforation (102). An annular airbag (2) is sleeved on the outer periphery of the core cable (4) and connected to the air inlet pipe (404). The airbag (2) and the core head (1) are staggered. When the airbag (2) is inflated or deflated, it pushes the core head (1) to move along the axial direction of the tube. A tubular push rod (3) is provided, through which the core cable (4) passes. The airbag (2) and the core head (1) are located between the limiting head (401) and the push rod (3). The limiting head (401) and the push rod (3) are used to limit the movement distance of the core head (1).

2. The bending mandrel structure for electric vehicle frame production according to claim 1, characterized in that, The core cable (4) includes an inner core (403) and an outer sheath (402) covering the outer surface of the inner core (403), and the air inlet pipe (404) is embedded inside the outer sheath (402).

3. The bending mandrel structure for electric vehicle frame production according to claim 2, characterized in that, The outer skin (402) also has multiple support rings (406) embedded inside. Each support ring (406) is coaxially arranged with the inner core (403) and is evenly distributed along the extension direction of the inner core (403). The air intake pipe (404) passes through the inner side of the support ring (406).

4. The bending mandrel structure for electric vehicle frame production according to claim 1, characterized in that, The end of the air intake pipe (404) is connected to the first end of the three-way pipe (408), and the second and third ends of the three-way pipe (408) are both equipped with valves (407), one of which is connected to an air pump (504).

5. The bending mandrel structure for electric vehicle frame production according to claim 1, characterized in that, An adjustment mechanism (5) is provided between the end of the core cable (4) away from the limiting head (401) and the push rod (3). The adjustment mechanism (5) is used to adjust the interval between the limiting head (401) and the push rod (3).

6. The bending mandrel structure for electric vehicle frame production according to claim 5, characterized in that, The adjustment mechanism (5) includes a base (501) that is detachably connected to the push rod (3) at one end. A sliding seat (502) is slidably connected to the base (501) along the axial direction of the push rod (3). The sliding seat (502) is detachably connected to the core cable (4). The base (501) is provided with a driving member (503) for driving the sliding seat (502) to move.

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