Cold extrusion strengthening test system

Abstract

The invention discloses a cold extrusion strengthening test system, and belongs to the technical field of material mechanical property testing. The system comprises a cold extrusion strengthening test device and a special core rod. The testing device adopts a symmetrical layout, the left side and the right side of the testing device are respectively provided with a driving motor and a transmission mechanism composed of a belt wheel nut and a threaded push rod, the output end of the transmission mechanism is connected with a sliding block capable of sliding along a guide rail, and a core rod connecting part is arranged in the middle of the sliding block. The two ends of the special core rod are detachably connected with the connecting parts in a threaded or quick bolt mode. According to the invention, the left and right driving motors are coordinated to operate synchronously through the control system, and bidirectional loading of pulling and pushing is applied to the core rod, so that the net tensile stress borne by the core rod is obviously reduced, the problem that the core rod is easy to break in a test is fundamentally solved, the service life is effectively prolonged, and the controllability and data accuracy of the test process are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material mechanical property testing and process equipment technology, in particular to a test system for simulating cold extrusion strengthening process of a test piece provided with a hole. BACKGROUND

[0002] In the field of high technology such as aviation and aerospace, cold extrusion strengthening is a key process to improve the fatigue life of connecting holes of structural parts. Before the actual part strengthening, process test needs to be carried out on test pieces with the same material and thickness to verify the parameters. The existing technology mostly uses a one-way drawing type equipment, and the cold extrusion mandrel bears all the tensile load during the extrusion process, with internal tensile stress concentration, which easily leads to overload fracture or fatigue fracture of the expensive mandrel. This not only causes direct economic loss and test interruption, but also leads to test cycle extension, large data dispersion, and seriously restricts the process development efficiency. Therefore, a special test system is urgently needed to effectively protect the mandrel and prevent its fracture. SUMMARY

[0003] In view of the above defects, the present application aims to provide a cold extrusion strengthening test system to solve the problem of easy fracture of the cold extrusion mandrel in the prior art, thereby prolonging the service life of the mandrel and improving the accuracy and reliability of the test data.

[0004] To achieve the above technical purpose, the following technical scheme is adopted: A cold extrusion strengthening test system, comprising a cold extrusion strengthening test device and a cold extrusion strengthening mandrel; The cold extrusion strengthening test device comprises a rack, a support platform, a driving motor, a transmission mechanism, a sliding mechanism and a test piece fixing mechanism; The rack is symmetrically distributed on the left and right sides of the support platform and is used to install the driving motor and the transmission mechanism; The driving motor and the transmission mechanism are both symmetrically fixed and installed on the racks on the left and right sides, and the driving motor is connected with the corresponding transmission mechanism, and the output end of the transmission mechanism is connected with the sliding mechanism; The sliding mechanism is symmetrically distributed on the left and right ends of the support platform and comprises a guide rail and a sliding block slidingly arranged on the guide rail, the sliding block is connected with the output end of the corresponding side transmission mechanism, and the middle part of the sliding block is provided with a mandrel connecting part for connecting the cold extrusion mandrel; The test piece fixing mechanism is arranged in the middle part of the support platform and is used to fix the test piece to be strengthened; The cold extrusion mandrel comprises connecting zones arranged at both ends, a cold extrusion working zone arranged in the middle part and a cold extrusion transition zone for connecting the cold extrusion working zone and the connecting zones; the connecting zones are detachably connected with the mandrel connecting part.

[0005] Furthermore, the transmission mechanism includes a pulley nut and a threaded push rod; the pulley nut is driven by a drive motor and has a tapered roller bearing inside; one end of the threaded push rod is threadedly engaged with the pulley nut, and the other end is connected to the slider on the corresponding side.

[0006] Furthermore, the threaded push rod has an integrated mechanical sensor for real-time monitoring of the axial load on the threaded push rod.

[0007] Furthermore, it also includes a control system electrically connected to the mechanical sensors and the drive motor, used for closed-loop control of the drive motor's operating status based on the monitored axial load data.

[0008] Furthermore, the control system is configured to execute the following loading procedure: first, control the net load to increase from zero to a preset target value, and then control the net load to remain constant until the extrusion stroke is completed.

[0009] Furthermore, the test piece fixing mechanism includes a plurality of symmetrically arranged fixing pins for positioning and clamping the test piece.

[0010] Furthermore, the bottom of the support platform is provided with multiple symmetrically distributed load-bearing columns.

[0011] Furthermore, the cold-extruded strengthening mandrel is integrally formed, and the diameter of its cold-extruded working area is designed according to the diameter of the hole to be strengthened.

[0012] Furthermore, the connection area between the mandrel connecting part and the cold-extruded reinforced mandrel is detachably connected by a threaded structure; the mandrel connecting part is provided with an internal threaded hole for clamping, and the connection area is provided with a connecting external threaded section that mates with the internal threaded hole.

[0013] Furthermore, the connection area between the mandrel connecting part and the cold-extruded reinforced mandrel is detachably connected by a quick-release pin structure; a U-shaped clamping opening is provided on the mandrel connecting part, and a clamping block matching the clamping opening is provided at the end of the connection area; the mandrel connecting part is also provided with a pin that is perpendicular to the mandrel connecting part and inserted. When the clamping block is aligned with the clamping opening, inserting the pin can lock the mandrel axially.

[0014] The beneficial effects achieved by this invention are: This invention provides a cold extrusion strengthening test system. Compared with existing technologies, this system adopts a symmetrical layout and bidirectional loading (pull and push), which can apply a balanced force to the test piece during cold extrusion, minimizing the net tensile load on the mandrel and fundamentally eliminating the risk of mandrel breakage, thus significantly extending its service life. Simultaneously, the cold-extruded strengthening mandrel is integrally molded, ensuring its overall strength and rigidity, making it less prone to deformation during cold extrusion and enabling stable extrusion of the holes to be strengthened. Furthermore, a mechanical sensor is integrated inside the threaded push rod to monitor the axial load in real time, and a closed-loop control system is formed with the drive motor. The control system can increase the net load from zero to the target value according to a preset loading program and maintain it constant until the extrusion stroke is completed, ensuring precise load control during cold extrusion and guaranteeing the consistency and reliability of test data. The connection between the mandrel connecting part and the cold-extruded strengthening mandrel is detachable, providing both threaded and quick-plug structures. When tests are required on holes of different diameters to be strengthened, the corresponding cold-extruded strengthening mandrel can be replaced quickly and conveniently without complicated operating procedures, which significantly improves the flexibility and adaptability of the test and reduces the test preparation time and cost. Attached Figure Description

[0015] The present invention will now be described with reference to the accompanying drawings.

[0016] Figure 1 This is a front view of the cold extrusion strengthening test system described in this invention.

[0017] Figure 2 This is a left view of the cold extrusion strengthening test apparatus described in this invention.

[0018] Figure 3 This is a top view of the cold extrusion strengthening test apparatus described in this invention.

[0019] Figure 4 This is a schematic diagram of the cold extrusion reinforced mandrel structure described in Embodiment 1 of the present invention.

[0020] Figure 5 This is a schematic diagram of the connection between the cold extrusion reinforced mandrel and the mandrel connection part as described in Embodiment 2 of the present invention.

[0021] In the diagram: 1-Pulley nut; 2-Frame; 3-Drive motor; 4-Support platform; 5-Guide rail; 6-Threaded push rod; 7-Fixing pin; 8-Mandrel connection; 81-Pin; 9-Slider; 10-Bearing column; 11-Cold extrusion reinforced mandrel; 111-Connecting area; 112-Cold extrusion transition area; 113-Cold extrusion working area. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0023] like Figures 1-3 As shown, the present invention provides a cold extrusion strengthening test system, which mainly consists of a cold extrusion strengthening test device, a specially made cold extrusion strengthening mandrel 11 and a control system (not shown in the figure).

[0024] The cold extrusion strengthening test apparatus includes a support platform 4, the bottom of which is supported by multiple symmetrically distributed load-bearing columns 10. Frames 2 are symmetrically distributed and fixed on the left and right sides of the support platform 4. Drive motors 3 and transmission mechanisms are fixedly installed on the left and right sides of the frame 2, respectively. The transmission mechanism includes a pulley nut 1 and a threaded push rod 6. The output shaft of the drive motor 3 drives the pulley nut 1 to rotate via a synchronous belt. The pulley nut 1 contains tapered roller bearings to withstand axial force. One end of the threaded push rod 6 is threadedly engaged with the pulley nut 1, and the other end is connected to a sliding mechanism. A mechanical sensor (not shown in the figure) is integrated inside the threaded push rod 6 for monitoring axial load. The control system is electrically connected to the mechanical sensor and the drive motor 3, and is used to control the operation of the drive motor 3 in a closed-loop manner based on the monitored axial load data. The control system is configured to execute the following loading procedure: first, control the net load to increase from zero to a preset target value, and then control the net load to remain constant until the extrusion stroke is completed.

[0025] The sliding mechanism is symmetrically distributed at both ends of the support platform 4, including a guide rail 5 and a slider 9 slidably disposed on the guide rail 5. The slider 9 is connected to a threaded push rod 6 on the corresponding side, and the middle of the slider 9 is provided with a mandrel connecting part 8 for connecting the cold extrusion strengthening mandrel 11. A test piece fixing mechanism is provided in the middle of the support platform 4. This mechanism includes multiple symmetrically distributed fixing pins 7 for clamping the test piece to be strengthened.

[0026] The cold-extruded reinforced mandrel 11 is integrally formed from a connecting area 111, a cold-extruded transition area 112, and a cold-extruded working area 113. The connecting areas 111 are located at both ends of the cold-extruded reinforced mandrel 11, the cold-extruded working area 113 is located in the middle of the cold-extruded reinforced mandrel 11, and the cold-extruded transition area 112 is used to connect the connecting areas 111 and the cold-extruded working area 113. The connecting areas 111 at both ends are used to achieve a detachable connection with the mandrel connecting parts 8 on the left and right sliders 9.

[0027] likeFigure 4 As shown, as a detachable connection method, the mandrel connecting part 8 can be machined with an internal threaded hole, and at the same time, the end of the connecting area 111 of the cold extrusion reinforced mandrel 11 is machined with a matching external threaded section, so that reliable connection and disassembly can be achieved by screwing.

[0028] In operation, the test piece is first fixed to the middle of the support platform 4 using fixing pins 7. A suitable cold-extruded strengthening mandrel 11 is selected based on the diameter of the hole to be strengthened in the test piece. The cold-extruded strengthening mandrel 11 is then passed through the hole to be strengthened in the test piece, and both ends of the connecting area 111 are securely connected to the mandrel connecting parts 8 on the left and right sliders 9. The system is then started, and the control system controls two drive motors 3 to run synchronously. One motor drives the slider 9 through a transmission mechanism to apply tension to the cold-extruded strengthening mandrel 11, while the other motor drives the other slider 9 to apply thrust to the cold-extruded strengthening mandrel 11. Mechanical sensors monitor the load in real time and feed it back to the control system. The control system adjusts the motor output through a closed-loop control algorithm to ensure that the extrusion process proceeds smoothly according to the preset load program (first increasing force, then constant force) until the entire extrusion stroke is completed. Example 2

[0029] The difference from Embodiment 1 is that the connecting area 111 of the cold-extruded reinforced mandrel 11 and the mandrel connecting part 8 are connected in another detachable manner, as shown in Embodiment 1. Figure 5 As shown, the mandrel connecting part 8 is designed with a U-shaped clamp, and a clamping block matching the shape of the clamp is machined at the end of the connecting area 111. During clamping, the clamping block is aligned with the U-shaped clamp and inserted, and then the pin 81 is inserted perpendicularly to the pin hole of the mandrel connecting part 8, thereby locking the cold-extruded reinforced mandrel 11. For disassembly, simply pull out the pin 81.

[0030] Other aspects of this invention that are not detailed herein are all conventional techniques known to those skilled in the art.

[0031] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0032] The scope of protection of this invention is not limited to the technical solutions disclosed in the specific embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of this invention shall fall within the scope of protection of this invention.

Claims

1. A cold extrusion strengthening test system, characterized in that: Includes a cold extrusion strengthening test device and a cold extrusion strengthening mandrel (11). The cold extrusion strengthening test device includes a frame (2), a support platform (4), a drive motor (3), a transmission mechanism, a sliding mechanism, and a test piece fixing mechanism; The frame (2) is symmetrically distributed on the left and right sides of the support platform (4) and is used to install the drive motor (3) and transmission mechanism; The drive motor (3) and the transmission mechanism are symmetrically fixed on the frame (2) on the left and right sides, and the drive motor (3) is connected to the corresponding transmission mechanism. The output end of the transmission mechanism is connected to the sliding mechanism. The sliding mechanism is symmetrically distributed on the left and right ends of the support platform (4), including a guide rail (5) and a slider (9) slidably disposed on the guide rail (5). The slider (9) is connected to the output end of the corresponding side transmission mechanism, and the middle part of the slider (9) is provided with a mandrel connecting part (8) for connecting the cold extrusion strengthening mandrel (11). The test piece fixing mechanism is located in the middle of the support platform (4) and is used to fix the test piece to be strengthened; The cold-extruded reinforced mandrel (11) includes a connecting area (111) at both ends, a cold-extruded working area (113) in the middle, and a cold-extruded transition area (112) for connecting the cold-extruded working area (113) and the connecting area (111); the connecting area (111) is detachably connected to the mandrel connecting part (8).

2. The cold extrusion strengthening test system according to claim 1, characterized in that: The transmission mechanism includes a pulley nut (1) and a threaded push rod (6); the pulley nut (1) is driven by a drive motor (3) and has a tapered roller bearing inside; one end of the threaded push rod (6) is threadedly engaged with the pulley nut (1), and the other end is connected to the slider (9) on the corresponding side.

3. The cold extrusion strengthening test system according to claim 2, characterized in that: The threaded push rod (6) has an integrated mechanical sensor inside, which is used to monitor the axial load of the threaded push rod (6) in real time.

4. The cold extrusion strengthening test system according to claim 3, characterized in that: It also includes a control system that is electrically connected to the mechanical sensor and the drive motor (3) for closed-loop control of the operation status of the drive motor (3) based on the monitored axial load data.

5. The cold extrusion strengthening test system according to claim 4, characterized in that: The control system is configured to execute the following loading procedure: first, control the net load to increase from zero to a preset target value, and then control the net load to remain constant until the extrusion stroke is completed.

6. The cold extrusion strengthening test system according to claim 1, characterized in that: The test piece fixing mechanism includes multiple fixing pins (7) arranged symmetrically for positioning and clamping the test piece.

7. The cold extrusion strengthening test system according to claim 1, characterized in that: The support platform (4) has multiple symmetrically distributed load-bearing columns (10) at its bottom.

8. The cold extrusion strengthening test system according to claim 1, characterized in that: The cold-extruded strengthening mandrel (11) is integrally formed, and the diameter of its cold-extruded working area (113) is designed according to the diameter of the hole to be strengthened.

9. The cold extrusion strengthening test system according to claim 1, characterized in that: The connection area (111) between the mandrel connecting part (8) and the cold extrusion reinforced mandrel (11) is detachably connected by a threaded structure; the mandrel connecting part (8) is provided with an internal threaded hole for clamping, and the connection area (111) is provided with an external threaded section that mates with the internal threaded hole.

10. A cold extrusion strengthening test system according to claim 1, characterized in that: The connection area (111) between the mandrel connecting part (8) and the cold extrusion reinforced mandrel (11) is detachably connected by a quick-release pin structure; a U-shaped clamp is provided on the mandrel connecting part (8), and a clamping block matching the clamp is provided at the end of the connection area (111); a pin (81) perpendicular to the mandrel connecting part (8) is also provided on the mandrel connecting part (8), and when the clamping block is aligned with the clamp, the pin (81) can be inserted to lock the mandrel axially.

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