A double-flanging press die, a press device, and a press method

Abstract

The application relates to a vehicle sheet metal part die design technology, in particular to a secondary flanging stamping die, a stamping device and a stamping method; the stamping device comprises a detection unit, a detection circuit, an upper die and a lower die, the lower die is a male die, the upper die is a female die and is matched with the lower die; the lower die is provided with at least one mounting hole on a bonding surface for bonding with the bottom surface of the vehicle sheet metal part, one telescopic probe is correspondingly mounted in each mounting hole, the telescopic probe is insulated and isolated from the inner periphery of the corresponding mounting hole, the fixed end of the telescopic probe is fixedly connected in the mounting hole, the telescopic end of the telescopic probe extends out of the bonding surface, and the length of the telescopic end of the telescopic probe extending out of the bonding surface is within a preset length range; the lower die is integrally grounded, one end of the detection circuit is connected with the telescopic probe, and the other end of the detection circuit is connected with the detection unit; and the detection unit is used for grounding detection of the detection circuit.

Description

Technical Field

[0001] This invention relates to vehicle sheet metal part mold design technology, specifically to a secondary flanging stamping mold, stamping device and stamping method. Background Technology

[0002] In the automotive manufacturing industry, most vehicle sheet metal parts are formed by stamping dies through multiple processes. Among the forming processes of many vehicle sheet metal parts, the flanging process is an essential step. Furthermore, as the requirements for flanging on vehicle sheet metal parts become increasingly stringent, the flanging process often requires a second flanging step. Therefore, when performing the flanging process on vehicle sheet metal parts, it is usually necessary to prepare two sets of flanging dies (including a primary flanging stamping die and a secondary flanging stamping die) to complete the flanging of the vehicle sheet metal parts.

[0003] However, when using existing secondary flanging stamping dies for secondary flanging of vehicle sheet metal parts, interference with the robot arm's part-feeding is likely to occur, causing deviations in the robot arm's part-feeding position. This results in the bottom surface of the vehicle sheet metal part failing to properly fit with the contact surface on the lower die of the secondary flanging stamping die, which in turn leads to stamping safety accidents and damages to the vehicle sheet metal part and the die.

[0004] To solve the above problems, in the prior art, an inductive proximity switch is usually installed at a specific position on the lower die (usually the punch) of the secondary flanging stamping die, and the detection distance of the proximity switch is adjusted as precisely as possible. After the robot arm feeds the material, if the vehicle sheet metal part does not fit correctly on the mating surface on the lower die, the proximity switch will output a signal to the control unit. The control unit will stop the press slide from descending and sound an alarm to protect the die and parts from being crushed.

[0005] However, the detection distance of inductive proximity switches is usually a vague range. The maximum detection distance of conventional inductive proximity switches varies from 4 to 10 mm. After disassembly, reinstallation, or replacement, readjustment is required, and the actual detection distance is not easy to adjust precisely, only an approximate range. This leads to a technical problem when using existing secondary flanging stamping dies to perform secondary flanging on vehicle sheet metal parts with low flanging heights (2-4 mm) (such as, but not limited to, side panels, fenders, hood outer panels, and door outer panels). Even if there is a deviation in the placement of the vehicle sheet metal part, or a failure to properly fit the bottom surface of the vehicle sheet metal part with the mating surface on the lower die, the gap between the bottom surface of the vehicle sheet metal part and the mating surface on the lower die is often less than the maximum detection distance of the inductive proximity switch. This causes the inductive proximity switch to misjudge that the bottom surface of the vehicle sheet metal part and the mating surface on the lower die are properly fitted, resulting in stamping safety accidents and damage to the vehicle sheet metal parts and the die. Summary of the Invention

[0006] This invention provides a secondary flanging stamping die, stamping device, and stamping method to solve the technical problem that existing secondary flanging stamping dies often fail to properly fit the bottom surface of the vehicle sheet metal parts (such as, but not limited to, side panels, fenders, hood panels, and door panels) with low flanging heights (2-4mm). Even if the part placement deviates and the bottom surface of the vehicle sheet metal part fails to properly fit with the mating surface on the lower die, the gap between the bottom surface of the vehicle sheet metal part and the mating surface on the lower die is often less than the maximum detection distance of the inductive proximity switch. This leads to the inductive proximity switch misjudging that the bottom surface of the vehicle sheet metal part and the mating surface on the lower die are properly fitted, resulting in stamping safety accidents and damage to the vehicle sheet metal parts and the die.

[0007] The technical solution adopted in this invention is: a secondary flanging stamping die, including a detection unit, a detection circuit, an upper die and a lower die, wherein the lower die is a punch and the upper die is a die and is adapted to the lower die;

[0008] The lower mold has at least one mounting hole on its mating surface for contacting the bottom surface of the vehicle sheet metal part. Each mounting hole contains a corresponding telescopic probe, which is insulated from the inner circumferential surface of the corresponding mounting hole. The fixed end of the telescopic probe is fixedly connected to the mounting hole, and the telescopic end extends beyond the mating surface, with the extension length of the telescopic end outside the mating surface within a preset range. The lower mold is grounded as a whole. One end of the detection circuit is connected to the telescopic probe, and the other end is connected to the detection unit. The detection unit is used to perform grounding detection on the detection circuit.

[0009] The preset length range is determined by the allowable error gap between the bottom surface of the vehicle sheet metal part and the mating surface on the lower mold when the bottom surface of the vehicle sheet metal part is correctly mated to the mating surface on the lower mold. Then, the extension length of the telescopic probe beyond the mating surface is within the preset length range. This ensures that the bottom surface of the vehicle sheet metal part can only contact the telescopic probe when the parting position is correct and the mating surface on the lower mold is properly mated, thus electrically connecting the telescopic probe to the lower mold. The lower die (i.e., the grounded detection line) enables the secondary flanging stamping die provided by this invention to perform grounding detection on the detection line through the detection unit, thereby determining whether the bottom surface of the vehicle sheet metal part is correctly fitted with the mating surface on the lower die. Furthermore, in the secondary flanging stamping die provided by this invention, the maximum detection distance of the telescopic probe (i.e., the length of the telescopic probe's telescopic end extending beyond the mating surface) is a precise value that can be accurately adjusted. Moreover, the maximum detection distance of the telescopic probe can be adjusted to a value greater than that of a conventional inductor. The smaller maximum detection distance of the proximity switch makes it possible to avoid situations where, during the secondary flanging process of vehicle sheet metal parts with a low flanging height (2-4mm) using the secondary flanging stamping die provided by this invention, if the placement position of the vehicle sheet metal part deviates and the bottom surface of the vehicle sheet metal part fails to properly fit with the contact surface on the lower die, the gap between the bottom surface of the vehicle sheet metal part and the contact surface on the lower die will not be less than the maximum detection distance of the telescopic probe. This solves the problem of existing secondary flanging stamping dies being ineffective for vehicle sheet metal parts with a low flanging height (2-4mm). For example, but not limited to: side panels, fenders, hood outer panels, and door outer panels, during the secondary flanging process, even if the position of the vehicle sheet metal parts deviates and the bottom surface of the vehicle sheet metal parts fails to properly fit with the mating surface on the lower mold, the inductive proximity switch may misjudge that the bottom surface of the vehicle sheet metal parts and the mating surface on the lower mold are properly fitted because the gap between the bottom surface of the vehicle sheet metal parts and the mating surface on the lower mold is less than the maximum detection distance of the inductive proximity switch. This can lead to a stamping safety accident and damage to the vehicle sheet metal parts and the mold.

[0010] Furthermore, the preset length range is 0.1 mm to 1 mm.

[0011] By setting the preset length range to 0.1 mm to 1 mm, the detection unit of the secondary flanging stamping die provided by the present invention can accurately determine whether the bottom surface of the vehicle sheet metal part and the contact surface on the lower die are correctly attached, based on whether the detection line is grounded, during the secondary flanging process of vehicle sheet metal parts with a low flanging height (2-4 mm).

[0012] Furthermore, the secondary flanging stamping die includes two detection lines, and the lower die has a left-right symmetrical structure; the lower die has two left-right symmetrically arranged mounting holes on the mating surface for mating with the bottom surface of the vehicle sheet metal part, and each mounting hole is equipped with a telescopic probe.

[0013] Each of the two telescopic probes is electrically connected to the detection unit via a detection line.

[0014] When the vehicle sheet metal part being stamped by the secondary flanging stamping die has a symmetrical structure (e.g., but not limited to: car hood, car rear hood, car front bumper, and car rear bumper), the lower die also has a symmetrical structure. Two symmetrically arranged mounting holes are provided on the mating surface of the lower die for contacting the bottom surface of the vehicle sheet metal part, and a telescopic probe is installed in each mounting hole. Each of the two telescopic probes is then electrically connected to the detection unit via a detection line. This allows the detection unit to determine that the bottom surface of the vehicle sheet metal part is correctly mated to the mating surface on the lower die only when both detection lines are grounded. This further improves the accuracy of the detection unit in determining whether the bottom surface of the vehicle sheet metal part is correctly mated to the mating surface on the lower die during secondary flanging stamping of symmetrical vehicle sheet metal parts, and reduces the false judgment rate of the detection unit.

[0015] The present invention also provides a secondary flanging stamping device, including a drive mechanism, a controller, and a secondary flanging stamping die provided according to the present invention;

[0016] Both the driving mechanism and the detection unit are electrically connected to the controller. The output end of the driving mechanism is fixedly connected to the upper die of the secondary flanging stamping die. The driving mechanism is used to drive the upper die to press down on the lower die of the secondary flanging stamping die.

[0017] The controller is used to control the operation of the drive mechanism;

[0018] The detection unit also sends down-voltage information to the controller based on the grounding detection results of the detection line;

[0019] The controller controls the drive mechanism to drive the upper mold to press down based on the received pressing information.

[0020] By having the detection unit send the downward pressure information to the controller based on the grounding detection result of the detection line, and having the controller control the drive mechanism to drive the upper die downward based on the received downward pressure information, the secondary flanging stamping device provided by the present invention can only have the controller control the drive mechanism to drive the upper die downward when the detection unit determines that the bottom surface of the vehicle sheet metal part and the mating surface on the lower die are correctly mated. Compared with the control method where the controller only stops the drive mechanism when the detection unit determines that the bottom surface of the vehicle sheet metal part and the mating surface on the lower die are not correctly mated, the safety guarantee is higher.

[0021] Furthermore, a displacement sensor is installed in each of the mounting holes. The displacement sensor is electrically connected to the detection unit and is used to send the corresponding contraction amount information of the telescopic probe to the detection unit.

[0022] When the detection unit detects that the detection line is grounded, it also determines whether the shrinkage of the telescopic probe has reached a preset condition based on the received shrinkage information. If the preset condition is reached, the detection unit sends a pressure-down message to the controller.

[0023] By setting the displacement sensor, the secondary flanging stamping device provided by this invention can detect the maximum contraction distance of the telescopic probe during the secondary flanging stamping process (that is, the contraction distance of the telescopic probe when the upper die is pressed against the lower die); thereby obtaining the length of the telescopic probe's telescopic end extending beyond the mating surface (that is, the maximum detection distance of the telescopic probe); and updating the preset conditions based on the current length of the telescopic probe's telescopic end extending beyond the mating surface to make corrections, so as to avoid the detection unit from changing the length of the telescopic probe's telescopic end extending beyond the mating surface due to the telescopic probe becoming loose or aging during use, or due to the telescopic probe's fixation in the mounting hole becoming loose. When the length of the telescopic probe extending beyond the mating surface increases, and the bottom surface of the vehicle sheet metal part is not properly mated with the mating surface on the lower mold, it may be mistakenly judged that the bottom surface of the vehicle sheet metal part and the mating surface on the lower mold are properly mated. Conversely, when the length of the telescopic probe extending beyond the mating surface decreases, and the bottom surface of the vehicle sheet metal part and the mating surface on the lower mold are properly mated, it may be mistakenly judged that the bottom surface of the vehicle sheet metal part and the mating surface on the lower mold are not properly mated. This eliminates the impact of changes in the length of the telescopic probe extending beyond the mating surface on the accuracy of the detection unit's judgment, further improving the accuracy of the detection unit's judgment. At the same time, it can also reduce the maintenance and replacement work of the telescopic probe, reduce costs, and improve work efficiency.

[0024] According to the secondary flanging stamping apparatus provided by the present invention, the present invention also provides a secondary flanging stamping method, the secondary flanging stamping method comprising the following steps:

[0025] Step 1: Place the vehicle sheet metal parts onto the lower mold;

[0026] Step 2: The detection unit performs grounding detection on all the detection lines; if the detection unit detects that all the detection lines are grounded, the detection unit sends a down-voltage message to the controller and proceeds to step 3;

[0027] Step 3: The controller controls the drive mechanism to drive the upper die to press down according to the received pressing information, thereby completing the secondary flanging stamping of the vehicle sheet metal part.

[0028] Furthermore, in step 2, if the detection unit detects that all the detection lines are grounded, the detection unit determines whether the shrinkage of each telescopic probe has reached the preset condition based on the received shrinkage information corresponding to each telescopic probe. If the preset condition is reached, the detection unit sends a downward pressure information to the controller and proceeds to step 3; otherwise, after adjusting the position of the vehicle sheet metal part on the lower mold, step 2 is executed again.

[0029] Furthermore, the method for determining whether the contraction amount of any of the aforementioned telescopic probes reaches the preset condition includes the following sub-steps:

[0030] The detection unit obtains the first shrinkage distance value of the telescopic probe after the vehicle sheet metal part is placed onto the lower mold based on the shrinkage amount information corresponding to the telescopic probe received.

[0031] The detection unit performs detection based on the obtained first contraction distance value and the preset contraction distance value of the telescopic probe stored in the detection unit. If the first contraction distance value is not less than the preset contraction distance value, the detection unit determines that the contraction amount of the telescopic probe has reached the preset condition; otherwise, the detection unit determines that the contraction amount of the telescopic probe has not reached the preset condition.

[0032] The initial value of the preset retraction distance of the telescopic probe is zero;

[0033] In step 3, the detection unit also obtains a second shrinkage distance value of the telescopic probe based on the received shrinkage amount information corresponding to the telescopic probe; the second shrinkage distance value is the maximum shrinkage distance value of the telescopic probe during the secondary flanging and stamping process of the vehicle sheet metal part; the detection unit also updates the preset shrinkage distance value based on the second shrinkage distance value and the initial extension length value of the telescopic probe extending beyond the mating surface stored in the detection unit.

[0034] The second shrinkage distance value is the maximum shrinkage distance value of the telescopic probe during the secondary flanging and stamping process of the vehicle sheet metal part, that is, the shrinkage distance value of the telescopic probe when the upper die is pressed against the lower die (when the end of the telescopic probe is flush with the mating surface); thus, the second shrinkage distance value is equal to the length of the telescopic probe extending beyond the mating surface (that is, the maximum detection distance of the telescopic probe); the detection unit updates the preset shrinkage distance value according to the second shrinkage distance value and the initial extension length value of the telescopic probe extending beyond the mating surface stored in the detection unit, thereby eliminating the influence of the change in the length of the telescopic probe extending beyond the mating surface on the accuracy of the detection unit's judgment.

[0035] Furthermore, the method by which the detection unit updates the preset contraction distance value based on the second contraction distance value and the initial extension length value includes:

[0036] The detection unit performs detection based on the second contraction distance value and the initial extension length value;

[0037] If the second contraction distance value is detected to be greater than the initial extension length value, the preset contraction distance value is updated to the absolute value of the difference between the second contraction distance value and the initial extension length value; if the second contraction distance value is detected to be less than the initial extension length value, the preset contraction distance value is updated to zero.

[0038] In another technical solution, the method by which the detection unit updates the preset contraction distance value based on the second contraction distance value and the initial extension length value includes: the detection unit performing detection based on the second contraction distance value and the initial extension length value;

[0039] If the second contraction distance value is detected to be greater than the initial extension length value, the preset contraction distance value is updated to the absolute value of the difference between the second contraction distance value and the initial extension length value; if the second contraction distance value is detected to be no greater than the initial extension length value and no less than the minimum extension length value, the preset contraction distance value is updated to zero; if the second contraction distance value is detected to be less than the minimum extension length value, the detection unit issues a fault alarm.

[0040] Since the telescopic probe of the secondary flanging stamping die provided by the present invention is required to extend beyond the mating surface by a length within a preset length range, the minimum extension length value only needs to be no greater than the minimum value of the preset length range. The specific value of the minimum extension length value can be determined according to actual needs, so as to avoid the detection unit misjudging that the bottom surface of the vehicle sheet metal part and the mating surface on the lower die are not properly mated when the current extension length of the telescopic probe beyond the mating surface is too short.

[0041] Furthermore, when the preset length range is 0.1 mm to 1 mm, the minimum extension length value ranges from 0.05 mm to 0.1 mm. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the lower die of the secondary flanging stamping die in the embodiment;

[0043] Figure 2 This is a schematic diagram of the structure in which the vehicle sheet metal parts are cast onto the lower mold in the embodiment.

[0044] Figure 3 This is a cross-sectional view of the mounting structure of the telescopic probe within the mounting hole in the embodiment;

[0045] Wherein: 1—lower mold, 2—vehicle sheet metal parts, 3—detection circuit;

[0046] 11—Mounting hole, 12—Mating surface, 13—Telescopic probe. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings:

[0048] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment provides a secondary flanging stamping die, including a detection unit, a detection circuit 3, an upper die and a lower die 1. The lower die 1 is a punch, and the upper die is a die and is adapted to the lower die 1.

[0049] The lower mold 1 has at least one mounting hole 11 on its mating surface 12 for mating with the bottom surface of the vehicle sheet metal part 2. Each mounting hole 11 has a corresponding telescopic probe 13 installed in it. The telescopic probe 13 is insulated from the inner circumferential surface of the corresponding mounting hole 11. The fixed end of the telescopic probe 13 is fixedly connected to the mounting hole 11. The telescopic end of the telescopic probe 13 extends out of the mating surface 12, and the length of the telescopic end of the telescopic probe 13 extending out of the mating surface 12 is within a preset length range. The lower mold 1 is grounded as a whole. One end of the detection line 3 is connected to the telescopic probe 13, and the other end of the detection line 3 is connected to the detection unit. The detection unit is used to perform grounding detection on the detection line 3.

[0050] By determining the allowable error gap between the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower mold 1 when the bottom surface of the vehicle sheet metal part 2 is correctly mated with the mating surface 12 on the lower mold 1, a preset length range is determined. Then, the length of the telescopic probe 13 extending beyond the mating surface 12 is within the preset length range. This ensures that the bottom surface of the vehicle sheet metal part 2 can only contact the telescopic probe 13 when the parting position is correct and the mating surface 12 on the lower mold 1 is correctly mated, thus electrically connecting the telescopic probe 13 and the lower mold through the vehicle sheet metal part 2. 1 (that is, the detection line 3 is grounded), so that the secondary flanging stamping die provided by the present invention can perform grounding detection on the detection line 3 through the detection unit to determine whether the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are correctly mated. In the secondary flanging stamping die provided by the present invention, the maximum detection distance of the telescopic probe 13 (that is, the length of the telescopic end of the telescopic probe 13 extending beyond the mating surface 12) is a definite value that can be precisely adjusted. Moreover, the maximum detection distance of the telescopic probe 13 can be adjusted to a value greater than that of a conventional inductive proximity switch. The smaller detection distance ensures that during the secondary flanging process of vehicle sheet metal parts 2 with a low flanging height (2-4mm) using the secondary flanging stamping die provided by this invention, if the placement position of the vehicle sheet metal part 2 deviates and the bottom surface of the vehicle sheet metal part 2 fails to properly fit with the contact surface 12 on the lower die 1, the gap between the bottom surface of the vehicle sheet metal part 2 and the contact surface 12 on the lower die 1 will not be less than the maximum detection distance of the telescopic probe 13. This solves the problem of existing secondary flanging stamping dies being ineffective when flanging vehicle sheet metal parts with a low flanging height (2-4mm) (e.g., ...). During the secondary flanging process of (but not limited to) side panels, fenders, hood outer panels, and door outer panels, even if there is a deviation in the placement of the vehicle sheet metal parts, or if the bottom surface of the vehicle sheet metal parts and the mating surface on the lower mold are not properly mated, the inductive proximity switch may misjudge that the bottom surface of the vehicle sheet metal parts and the mating surface on the lower mold are properly mated because the gap between the bottom surface of the vehicle sheet metal parts and the mating surface on the lower mold is less than the maximum detection distance of the inductive proximity switch. This can lead to a stamping safety accident and damage to the vehicle sheet metal parts and the mold.

[0051] Preferably, in this embodiment, the preset length range is 0.1 mm to 1 mm.

[0052] By setting the preset length range to 0.1 mm to 1 mm, the detection unit of the secondary flanging stamping die provided by the present invention can accurately determine whether the bottom surface of the vehicle sheet metal part 2 and the contact surface 12 on the lower die 1 are correctly attached when the secondary flanging of the vehicle sheet metal part 2 with a low flanging height (2-4 mm) is performed, based on whether the detection line 3 is grounded.

[0053] like Figure 1 and Figure 3 As shown, the secondary flanging stamping die includes two detection lines 3, and the lower die 1 has a left-right symmetrical structure; the lower die 1 has two left-right symmetrical mounting holes 11 on the mating surface 12 for mating with the bottom surface of the vehicle sheet metal part 2, and each mounting hole 11 is equipped with a telescopic probe 13.

[0054] Each of the two telescopic probes 13 is electrically connected to the detection unit via a detection line 3.

[0055] When the vehicle sheet metal part 2 used for stamping by the secondary flanging stamping die has a left-right symmetrical structure (e.g., but not limited to: car front hood, car rear hood, car front bumper and car rear bumper), the lower die 1 also has a left-right symmetrical structure. By opening two left-right symmetrical mounting holes 11 on the mating surface 12 of the lower die 1 for mating with the bottom surface of the vehicle sheet metal part 2, and installing a telescopic probe 13 in each mounting hole 11; and then making each of the two telescopic probes 13 electrically connected to the detection unit through a detection line 3; the detection unit can determine that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are correctly mated only when it detects that both detection lines 3 are grounded. This can further improve the accuracy of the detection unit in determining whether the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are correctly mated when performing secondary flanging stamping on the vehicle sheet metal part 2 with a left-right symmetrical structure, and reduce the misjudgment rate of the detection unit.

[0056] This embodiment also provides a secondary flanging stamping device, including a drive mechanism, a controller, and a secondary flanging stamping die according to this embodiment;

[0057] Both the drive mechanism and the detection unit are electrically connected to the controller. The output end of the drive mechanism is fixedly connected to the upper die of the secondary flanging stamping die. The drive mechanism is used to drive the upper die to press down on the lower die 1 of the secondary flanging stamping die.

[0058] The controller is used to control the operation of the drive mechanism;

[0059] The detection unit also sends a voltage-down signal to the controller based on the grounding detection results of detection line 3;

[0060] Based on the received pressure information, the controller controls the drive mechanism to drive the upper mold to press down.

[0061] By having the detection unit send a downward pressure message to the controller based on the grounding detection result of the detection line 3, and the controller controlling the drive mechanism to drive the upper die downward based on the received downward pressure message, the secondary flanging stamping device provided by this invention can only control the drive mechanism to drive the upper die downward when the detection unit determines that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are correctly mated. Compared with the control method that the controller only controls the drive mechanism to stop running when the detection unit determines that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are not correctly mated, the safety guarantee is higher.

[0062] The aforementioned drive mechanism can be selected from various pressing mechanisms, including but not limited to: pressing cylinders, pressing hydraulic cylinders, and servo electric cylinders.

[0063] Preferably, in this embodiment, a displacement sensor is installed in each mounting hole 11. The displacement sensor is electrically connected to the detection unit and is used to send the corresponding contraction amount information of the telescopic probe 13 to the detection unit.

[0064] When the detection unit detects that the grounding of the detection line 3 is grounded, the detection unit also determines whether the shrinkage of the telescopic probe 13 has reached the preset condition based on the received shrinkage information. If the preset condition is reached, the detection unit sends a pressure information to the controller.

[0065] By setting a displacement sensor, the secondary flanging stamping device provided by this invention can detect the maximum contraction distance of the telescopic probe 13 during the secondary flanging stamping process (that is, the contraction distance of the telescopic probe 13 when the upper die is pressed against the lower die 1); thereby obtaining the length of the telescopic probe 13 extending beyond the contact surface 12 (that is, the maximum detection distance of the telescopic probe 13); and updating the preset conditions based on the current length of the telescopic probe 13 extending beyond the contact surface 12 to make corrections, so as to avoid the detection unit from changing the length of the telescopic probe 13 extending beyond the contact surface 12 due to the telescopic probe 13 becoming loose or aging during use, or due to the telescopic probe 13 becoming loose in the mounting hole 11. When the length of the telescopic probe 13 extending beyond the mating surface 12 increases, and the bottom surface of the vehicle sheet metal part 2 is not properly mated with the mating surface 12 on the lower mold 1, it may be mistakenly judged that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower mold 1 are properly mated. Alternatively, when the length of the telescopic probe 13 extending beyond the mating surface 12 decreases, and the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower mold 1 are properly mated, it may be mistakenly judged that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower mold 1 are not properly mated. This eliminates the impact of changes in the length of the telescopic probe 13 extending beyond the mating surface 12 on the accuracy of the detection unit, further improving the accuracy of the detection unit. At the same time, it can also reduce the maintenance and replacement work of the telescopic probe 13, reduce costs, and improve work efficiency.

[0066] According to the secondary flanging stamping device provided in this embodiment, this embodiment also provides a secondary flanging stamping method, which includes the following steps:

[0067] Step 1: Place the vehicle sheet metal part 2 onto the lower mold 1;

[0068] Step 2: The detection unit performs grounding detection on all detection lines 3; if the detection unit detects that all detection lines 3 are grounded, the detection unit sends a down-voltage message to the controller and proceeds to step 3;

[0069] Step 3: Based on the received pressing information, the controller controls the drive mechanism to drive the upper die to press down, completing the secondary flanging stamping of the vehicle sheet metal part 2.

[0070] Preferably, in step 2, if the detection unit detects that all detection lines 3 are grounded, the detection unit determines whether the shrinkage of each telescopic probe 13 has reached the preset condition based on the shrinkage information corresponding to each telescopic probe 13 received. If the preset condition is reached, the detection unit sends a downward pressure information to the controller and proceeds to step 3; otherwise, after adjusting the position of the vehicle sheet metal part 2 on the lower mold 1, step 2 is executed again.

[0071] In this embodiment, the method for determining whether the contraction amount of any telescopic probe 13 reaches a preset condition includes the following sub-steps:

[0072] The detection unit obtains the first shrinkage distance value of the telescopic probe 13 after the vehicle sheet metal part 2 is placed onto the lower mold 1 based on the shrinkage amount information corresponding to the telescopic probe 13 received.

[0073] The detection unit performs detection based on the obtained first contraction distance value and the preset contraction distance value of the telescopic probe 13 stored in the detection unit. If the first contraction distance value is not less than the preset contraction distance value, the detection unit determines that the contraction amount of the telescopic probe 13 has reached the preset condition; otherwise, the detection unit determines that the contraction amount of the telescopic probe 13 has not reached the preset condition.

[0074] The initial value of the preset retraction distance of the telescopic probe 13 is zero;

[0075] In step 3, the detection unit also obtains the second shrinkage distance value of the telescopic probe 13 based on the shrinkage amount information corresponding to the telescopic probe 13 received; the second shrinkage distance value is the maximum shrinkage distance value of the telescopic probe 13 during the process of completing the secondary flanging and stamping of the vehicle sheet metal part 2; the detection unit also updates the preset shrinkage distance value based on the second shrinkage distance value and the initial extension length value of the telescopic end of the telescopic probe 13 extending out of the mating surface 12 stored in the detection unit.

[0076] The second shrinkage distance value is the maximum shrinkage distance value of the telescopic probe 13 during the secondary flanging and stamping process of the vehicle sheet metal part 2, that is, the shrinkage distance value of the telescopic probe 13 when the upper mold is pressed on the lower mold 1 (when the end of the telescopic probe 13 is flush with the mating surface 12); thus, the second shrinkage distance value is equal to the length of the telescopic probe 13 extending beyond the mating surface 12 (that is, the maximum detection distance of the telescopic probe 13); the detection unit updates the preset shrinkage distance value according to the second shrinkage distance value and the initial extension length value of the telescopic probe 13 extending beyond the mating surface 12 stored in the detection unit, so as to eliminate the influence of the change in the length of the telescopic probe 13 extending beyond the mating surface 12 on the judgment accuracy of the detection unit.

[0077] In this embodiment, the method by which the detection unit updates the preset contraction distance value based on the second contraction distance value and the initial extension length value includes two methods;

[0078] In one method, the method by which the detection unit updates the preset contraction distance value based on the second contraction distance value and the initial extension length value includes:

[0079] The detection unit performs detection based on the second contraction distance value and the initial extension length value;

[0080] If the second contraction distance value is detected to be greater than the initial extension length value, the preset contraction distance value is updated to the absolute value of the difference between the second contraction distance value and the initial extension length value; if the second contraction distance value is detected to be less than the initial extension length value, the preset contraction distance value is updated to zero.

[0081] In another method, the method by which the detection unit updates the preset contraction distance value based on the second contraction distance value and the initial extension length value includes: the detection unit performing detection based on the second contraction distance value and the initial extension length value;

[0082] If the second contraction distance value is detected to be greater than the initial extension length value, the preset contraction distance value is updated to the absolute value of the difference between the second contraction distance value and the initial extension length value; if the second contraction distance value is detected to be no greater than the initial extension length value and no less than the minimum extension length value, the preset contraction distance value is updated to zero; if the second contraction distance value is detected to be less than the minimum extension length value, the detection unit issues a fault alarm.

[0083] Since the telescopic probe 13 of the secondary flanging stamping die provided by the present invention is required to extend beyond the mating surface 12 by a length within a preset length range, the minimum extension length value only needs to be no greater than the minimum value of the preset length range. The specific value of the minimum extension length value can be determined according to actual needs, so as to avoid the detection unit misjudging that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are not properly mated when the current extension length of the telescopic probe 13 beyond the mating surface 12 is too short.

[0084] Preferably, when the preset length range is 0.1 mm to 1 mm, the minimum extension length value ranges from 0.05 mm to 0.1 mm.

[0085] The secondary flanging stamping die, stamping device, and stamping method provided by this invention have at least the following technical effects or advantages:

[0086] 1. When the bottom surface of the vehicle sheet metal part 2 is correctly fitted with the mating surface 12 on the lower mold 1, the allowable error gap between the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower mold 1 is used to determine the preset length range. Then, the length of the telescopic probe 13 extending beyond the mating surface 12 is within the preset length range. This ensures that the bottom surface of the vehicle sheet metal part 2 can only contact the telescopic probe 13 when the parting position is correct and the bottom surface of the vehicle sheet metal part 2 is correctly fitted with the mating surface 12 on the lower mold 1, thereby electrically connecting the telescopic probe 13 and the lower mold 12. The lower die 1 (i.e., the detection line 3 is grounded) enables the secondary flanging stamping die provided by this invention to perform grounding detection on the detection line 3 through the detection unit, thereby determining whether the bottom surface of the vehicle sheet metal part 2 is correctly fitted with the mating surface 12 on the lower die 1. Furthermore, in the secondary flanging stamping die provided by this invention, the maximum detection distance of the telescopic probe 13 (i.e., the length of the telescopic end of the telescopic probe 13 extending beyond the mating surface 12) is a precise value that can be accurately adjusted. Moreover, the maximum detection distance of the telescopic probe 13 can be adjusted to a level higher than that of a conventional inductive proximity switch. The smaller maximum detection distance ensures that during the secondary flanging process of vehicle sheet metal parts 2 with a low flanging height (2-4mm) using the secondary flanging stamping die provided by this invention, if the placement position of the vehicle sheet metal part 2 deviates and the bottom surface of the vehicle sheet metal part 2 fails to properly fit with the contact surface 12 on the lower die 1, the gap between the bottom surface of the vehicle sheet metal part 2 and the contact surface 12 on the lower die 1 will not be less than the maximum detection distance of the telescopic probe 13. This solves the problem of existing secondary flanging stamping dies being ineffective for vehicle sheet metal parts with a low flanging height (2-4mm). For example, but not limited to: side panels, fenders, hood outer panels and door outer panels) during the secondary flanging process, even if the position of the vehicle sheet metal parts deviates and the bottom surface of the vehicle sheet metal parts fails to properly fit with the mating surface on the lower mold, the inductive proximity switch will often misjudge that the bottom surface of the vehicle sheet metal parts and the mating surface on the lower mold are properly fitted because the gap between the bottom surface of the vehicle sheet metal parts and the mating surface on the lower mold is less than the maximum detection distance of the inductive proximity switch. This can lead to a stamping safety accident and damage to the vehicle sheet metal parts and the mold.

[0087] 2. By setting the preset length range to 0.1 mm to 1 mm, the detection unit of the secondary flanging stamping die provided by the present invention can accurately determine whether the bottom surface of the vehicle sheet metal part 2 and the contact surface 12 on the lower die 1 are correctly attached based on whether the detection line 3 is grounded during the secondary flanging process of the vehicle sheet metal part 2 with a low flanging height (2-4 mm).

[0088] 3. When the vehicle sheet metal part 2 used for stamping by the secondary flanging stamping die has a left-right symmetrical structure (e.g., but not limited to: car front hood, car rear hood, car front bumper and car rear bumper), the lower die 1 also has a left-right symmetrical structure. By opening two left-right symmetrical mounting holes 11 on the mating surface 12 of the lower die 1 for mating with the bottom surface of the vehicle sheet metal part 2, and installing a telescopic probe 13 in each mounting hole 11; and then making each of the two telescopic probes 13 electrically connected to the detection unit through a detection line 3; the detection unit can determine that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are correctly mated only when it detects that both detection lines 3 are grounded. This can further improve the accuracy of the detection unit in determining whether the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are correctly mated when performing secondary flanging stamping on the vehicle sheet metal part 2 with a left-right symmetrical structure, and reduce the misjudgment rate of the detection unit.

[0089] 4. By having the detection unit send a downward pressure information to the controller based on the grounding detection result of the detection line 3, and having the controller control the drive mechanism to drive the upper die downward based on the received downward pressure information, the secondary flanging stamping device provided by this invention can only control the drive mechanism to drive the upper die downward when the detection unit determines that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are correctly mated. Compared with the control method that the controller only controls the drive mechanism to stop running when the detection unit determines that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower die 1 are not correctly mated, its safety guarantee is higher.

[0090] 5. By setting a displacement sensor, the secondary flanging stamping device provided by this invention can detect the maximum contraction distance of the telescopic probe 13 during the secondary flanging stamping process (that is, the contraction distance of the telescopic probe 13 when the upper die is pressed against the lower die 1); thereby obtaining the length of the telescopic probe 13 extending beyond the contact surface 12 (that is, the maximum detection distance of the telescopic probe 13); and updating the preset conditions according to the length of the telescopic probe 13 extending beyond the contact surface 12 to make corrections, so as to avoid the telescopic probe 13 becoming loose or aging during use, or the telescopic probe 13 becoming loose in the mounting hole 11, causing the length of the telescopic probe 13 extending beyond the contact surface 12 to change, and the detection unit will detect the telescopic probe 13. When the length of the telescopic probe 13 extending beyond the mating surface 12 increases, and the bottom surface of the vehicle sheet metal part 2 is not properly mated with the mating surface 12 on the lower mold 1, it may be mistakenly judged that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower mold 1 are properly mated. Alternatively, when the length of the telescopic probe 13 extending beyond the mating surface 12 decreases, and the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower mold 1 are properly mated, it may be mistakenly judged that the bottom surface of the vehicle sheet metal part 2 and the mating surface 12 on the lower mold 1 are not properly mated. This eliminates the impact of changes in the length of the telescopic probe 13 extending beyond the mating surface 12 on the accuracy of the detection unit, further improving the accuracy of the detection unit. At the same time, it can also reduce the maintenance and replacement work of the telescopic probe 13, reduce costs, and improve work efficiency.

[0091] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should be considered within the protection scope of the present invention.

Claims

1. A secondary flanging stamping die, characterized in that: It includes a detection unit, a detection circuit, an upper mold and a lower mold, wherein the lower mold is a punch and the upper mold is a concave mold adapted to the lower mold; The lower mold has at least one mounting hole on its mating surface for contacting the bottom surface of the vehicle sheet metal part. Each mounting hole contains a corresponding telescopic probe, which is insulated from the inner circumferential surface of the corresponding mounting hole. The fixed end of the telescopic probe is fixedly connected to the mounting hole, and the telescopic end extends beyond the mating surface, with the extension length of the telescopic end outside the mating surface within a preset range. The lower mold is grounded as a whole. One end of the detection circuit is connected to the telescopic probe, and the other end is connected to the detection unit. The detection unit is used to perform grounding detection on the detection circuit.

2. The secondary flanging stamping die according to claim 1, characterized in that: The preset length range is 0.1 mm to 1 mm.

3. The secondary flanging stamping die according to claim 1, characterized in that: The device includes two detection lines, and the lower mold has a symmetrical structure. The lower mold has two symmetrically arranged mounting holes on its mating surface for mating with the bottom surface of the vehicle sheet metal part, and each mounting hole is equipped with a telescopic probe. Each of the two telescopic probes is electrically connected to the detection unit via a detection line.

4. A secondary flanging stamping device, characterized in that: Includes a drive mechanism, a controller, and a secondary flanging stamping die as described in any one of claims 1-3; Both the driving mechanism and the detection unit are electrically connected to the controller. The output end of the driving mechanism is fixedly connected to the upper die of the secondary flanging stamping die. The driving mechanism is used to drive the upper die to press down on the lower die of the secondary flanging stamping die. The controller is used to control the operation of the drive mechanism; The detection unit also sends down-voltage information to the controller based on the grounding detection results of the detection line; The controller controls the drive mechanism to drive the upper mold to press down based on the received pressing information.

5. The secondary flanging stamping device according to claim 4, characterized in that: Each of the mounting holes is equipped with a displacement sensor, which is electrically connected to the detection unit. The displacement sensor is used to send the corresponding contraction amount information of the telescopic probe to the detection unit. When the detection unit detects that the detection line is grounded, it also determines whether the shrinkage of the telescopic probe has reached a preset condition based on the received shrinkage information. If the preset condition is reached, the detection unit sends a pressure-down message to the controller.

6. A method for secondary flanging stamping, characterized in that: The secondary flanging stamping device as described in claim 4 is used to achieve the secondary flanging stamping method, which includes the following steps: Step 1: Place the vehicle sheet metal parts onto the lower mold; Step 2: The detection unit performs grounding detection on all the detection lines; if the detection unit detects that all the detection lines are grounded, the detection unit sends a down-voltage message to the controller and proceeds to step 3; Step 3: The controller controls the drive mechanism to drive the upper die to press down according to the received pressing information, thereby completing the secondary flanging stamping of the vehicle sheet metal part.

7. The secondary flanging stamping method according to claim 6, characterized in that: In step 2, if the detection unit detects that all the detection lines are grounded, the detection unit determines whether the shrinkage of each telescopic probe has reached the preset condition based on the received shrinkage information corresponding to each telescopic probe. If the preset condition is reached, the detection unit sends a pressure information to the controller. Proceed to step 3; otherwise, adjust the position of the vehicle sheet metal part on the lower mold and repeat step 2.

8. The secondary flanging stamping method according to claim 7, characterized in that: The method for determining whether the contraction amount of any of the aforementioned telescopic probes meets the preset conditions includes the following sub-steps: The detection unit obtains the first shrinkage distance value of the telescopic probe after the vehicle sheet metal part is placed onto the lower mold based on the shrinkage amount information corresponding to the telescopic probe received. The detection unit performs detection based on the obtained first contraction distance value and the preset contraction distance value of the telescopic probe stored in the detection unit. If the first contraction distance value is not less than the preset contraction distance value, the detection unit determines that the contraction amount of the telescopic probe has reached the preset condition; otherwise, the detection unit determines that the contraction amount of the telescopic probe has not reached the preset condition. The initial value of the preset retraction distance of the telescopic probe is zero; In step 3, the detection unit also obtains a second shrinkage distance value of the telescopic probe based on the received shrinkage amount information corresponding to the telescopic probe; the second shrinkage distance value is the maximum shrinkage distance value of the telescopic probe during the secondary flanging and stamping process of the vehicle sheet metal part; the detection unit also updates the preset shrinkage distance value based on the second shrinkage distance value and the initial extension length value of the telescopic probe extending beyond the mating surface stored in the detection unit.

9. The secondary flanging stamping method according to claim 8, characterized in that: The method by which the detection unit updates the preset contraction distance value based on the second contraction distance value and the initial extension length value includes: The detection unit performs detection based on the second contraction distance value and the initial extension length value; If the second contraction distance value is detected to be greater than the initial extension length value, the preset contraction distance value is updated to the absolute value of the difference between the second contraction distance value and the initial extension length value; if the second contraction distance value is detected to be less than the initial extension length value, the preset contraction distance value is updated to zero.

10. The secondary flanging stamping method according to claim 8, characterized in that: The method by which the detection unit updates the preset contraction distance value based on the second contraction distance value and the initial extension length value includes: the detection unit performing detection based on the second contraction distance value and the initial extension length value; If the second contraction distance value is detected to be greater than the initial extension length value, the preset contraction distance value is updated to the absolute value of the difference between the second contraction distance value and the initial extension length value; if the second contraction distance value is detected to be no greater than the initial extension length value and no less than the minimum extension length value, the preset contraction distance value is updated to zero; if the second contraction distance value is detected to be less than the minimum extension length value, the detection unit issues a fault alarm.

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