Bending test clamp with automatic centering and bending angle measuring functions

Abstract

The utility model relates to a bending test clamp with automatic centering and bending angle measuring functions, which relates to the field of material bending performance testing and comprises a driving unit and a support, the driving unit and the support are composed of side supports, a bottom plate and a servo motor; the transmission unit is composed of a split lead screw, a polished rod, a bearing, a left supporting die and a right supporting die; the split lead screws are connected through couplings; and the left and right supporting dies are matched with the lead screws through lead screw nuts. And 3) the control display unit is composed of a displacement sensor, a data acquisition card, an AD / DA converter, an angle measurement sensor support and a motor control module. (4) a displacement sensor is installed on the left supporting mold, the distance between the left supporting mold and the right supporting mold is measured and compared with the target distance, the rotating angle of a motor is adjusted, and the left supporting mold and the right supporting mold are driven to be automatically centered to the target distance; and 5) measuring displacement data by a displacement sensor on an angle measurement sensor bracket, and combining mathematical calculation to obtain the bending angle of the sample. Compared with other bending test fixtures, the bending test fixture is richer in function and simpler, more convenient and more efficient to operate.

Description

Technical Field

[0001] The invention relates to a bending test fixture, in particular to a bending test fixture with automatic centering and bending angle measurement functions. Background Art

[0002] Bending test is an important means to explore the mechanical properties of materials in teaching and scientific research activities. Whether the design of the bending test fixture is reasonable directly affects the accuracy and efficiency of the bending test. In the bending test, the two lower support points of the specimen are required to be installed symmetrically about the midpoint of the specimen span. When using traditional bending test fixtures, one can only manually measure the distance between the two lower support molds and the midpoint of the specimen span to meet this requirement. This results in time-consuming and labor-intensive furniture installation and low efficiency.

[0003] In the process of learning and studying material properties, more and more applications require measuring the bending angle of the specimen in the bending test, so as to understand and study major scientific issues such as the pre-bending process and springback control of the material. However, the traditional bending test fixture does not have the function of directly measuring the bending angle, which makes the measurement of the bending angle cumbersome and has large errors. Summary of the invention

[0004] The present invention aims to provide a bending test fixture with automatic centering and bending angle measurement functions, which is easy to operate, low in cost, has few influencing factors, and can improve the efficiency and quality of the bending test.

[0005] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme, including:

[0006] 1) A bracket and power unit consisting of a side bracket, a detachable bottom plate, a servo motor and a motor driver; an automatic centering unit consisting of a split lead screw, a light bar, a bearing, a left support mold, a right support mold and a displacement sensor; a bending angle measurement unit consisting of a displacement sensor and a bending angle measurement bracket; a control and display unit consisting of a signal data acquisition card, an AD / DA converter, a displacement sensor bracket and a motor speed feedback controller.

[0007] 2) The base plate can be removed from the fixture to adapt to more application scenarios. A lubricating oil groove is opened on the contact surface between the base plate and the left and right support molds, and a centering mark is set at the center line of the bracket to facilitate fixture installation. The motor driver adjusts the servo motor speed function, and the motor drive shaft is connected to the split screw power end through a coupling.

[0008] 3) The pair of split lead screws are connected in the middle position by a coupling, ball bearings are installed at the support parts of the lead screw and the bracket, and the connection between the lead screw and the left and right support molds is matched with a lead screw nut. The initial installation position of the left and right support molds should be symmetrical about the center line of the bracket. The light rod is installed in parallel with the lead screw to improve the rigidity of the transmission unit and ensure that when the lead screw rotates coaxially, it drives the left and right support molds to move in a centered manner.

[0009] 4) A displacement sensor mounting hole is set at the center of the left support mold parallel to the direction of the lead screw and a threaded displacement sensor is installed. The sensor signal emission point is coplanar with the center line of the roller on the left support mold. The displacement sensor measures the distance between the left and right support molds and inputs the displacement value into the control and display unit. The motor feedback controller compares it with the target distance, adjusts the motor rotation amount, and drives the left and right support molds to move symmetrically to the target distance.

[0010] 5) The bending angle measurement unit consists of a displacement sensor and a bending angle measurement bracket. Two threaded displacement sensor mounting holes are set on the bending angle measurement bracket. The spacing between the mounting holes is fixed. The threaded displacement sensor is installed vertically toward one side of the specimen. The sensor signal emission point is flush with the upper surface of the bending angle measurement bracket. The displacement data measured by the displacement sensor is displayed on the control and display unit. The bending angle is calculated by the following method:

[0011]

[0012] Where: α is the bending angle, D is the center distance of the displacement sensor installation holes, L1 is the displacement value measured by the first sensor, and L2 is the displacement value measured by the second sensor.

[0013] 6) The control and display unit of the bending fixture consists of a signal data acquisition card, an AD / DA converter, a displacement sensor bracket, and a motor feedback controller. The motor feedback controller receives data including the current spacing and target spacing of the left and right support molds. By comparing the difference between the two, the motor feedback controller sends a control signal to the motor driver to feedback and adjust the forward and reverse rotation and rotation angle of the motor so that the left and right support molds are automatically centered and reach the target position. The display unit receives data including the displacement values ​​of the two displacement sensors in the bending angle measurement unit, and displays the two, combining mathematical calculations to obtain the bending angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural diagram of the present invention.

[0015] Figure 2 It is the work flow chart of the present invention.

[0016] Figure 3 This is a schematic diagram of the bending angle calculation principle of the present invention.

[0017] The reference numerals are described as follows:

[0018] 1. Bracket; 2. Optical bar; 3. Left-hand screw; 4. Right-hand screw; 5. Roller; 6. Right support mold; 7. Left support mold; 8. Coupling; 9. Base plate; 10. Displacement sensor; 11. Motor; 12. Bending angle measurement bracket; 13. Bolt; 14. Nut; 15. Control and display unit. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments, not for limiting the present application.

[0020] See also Figure 1 , is the overall structural diagram of the present invention, and the present invention includes the following structural features:

[0021] 1) The bracket and power unit consists of a side bracket, a detachable bottom plate, a servo motor and a motor driver.

[0022] 2) Automatic centering unit, which is composed of split screws, smooth bars, bearings, left and right support molds, and displacement sensors. The displacement sensor is used to measure the distance between the left support mold and the right support mold, and input the displacement value into the control and display unit. The motor feedback controller compares it with the target distance, and adjusts the motor rotation amount by feedback to drive the left and right support molds to move symmetrically to the target distance;

[0023] 3) Bending angle measurement unit, which consists of a displacement sensor and a bending angle measurement bracket. The displacement data measured by the displacement sensor is displayed in real time through the control and display unit, and combined with mathematical calculations, the bending angle of the sample is obtained;

[0024] 4) Control and display unit, which consists of a signal data acquisition card, an AD / DA converter, a displacement sensor bracket, and a motor speed feedback controller. The control and display unit is used to control the motor rotation speed and direction, and complete the display of the displacement sensor data to calculate the bending angle.

[0025] In structural feature 1), the base plate can be removed from the fixture, a lubricating oil groove is opened on the contact surface with the support mold, a centering mark is set at the center line of the bracket, and the motor drive shaft is connected to the power end of the split screw through a coupling.

[0026] In structural feature 2), the split lead screws are connected in the middle position through a coupling, ball bearings are installed at the support part of the lead screw and the bracket, the connection between the lead screw and the left and right support molds is matched with a lead screw nut, and the initial installation position of the left support mold and the right support mold should be symmetrical about the center line of the bracket. The optical rod is installed parallel to the lead screw, and a displacement sensor installation hole is set at the center of the left support mold parallel to the direction of the lead screw.

[0027] In structural feature 2), a threaded displacement sensor is installed on the left support mold, and the sensor signal emission point is coplanar with the center line of the roller on the left support mold. The displacement sensor measures the distance between the left support mold and the right support mold, and inputs the displacement value into the control and display unit. The motor feedback controller compares it with the target distance, adjusts the motor rotation amount, and drives the left support mold and the right support mold to move to the target distance.

[0028] In structural feature 3), two threaded displacement sensor mounting holes are arranged on the bending angle measuring bracket, the spacing between the mounting holes is fixed, the threaded displacement sensor is installed vertically upward, the sensor signal emission point is flush with the upper surface of the bending angle measuring bracket, the displacement data measured by the displacement sensor is displayed on the control and display unit, and the bending angle is obtained by calculation.

[0029] See also Figure 2 , is a work flow chart of the present invention, comprising the following steps:

[0030] 1) Input the target distance between the left support mold and the right support mold in the control and display unit, and the control and display unit tests the current distance between the left and right support molds through the displacement sensor installed on the left support mold, and compares them;

[0031] 2) The control and display unit controls the power unit, inputs the motor rotation direction and rotation angle information into the motor driver, controls the motor rotation, and adjusts the left support mold and the right support mold to the target spacing through the automatic centering unit.

[0032] 3) Install the bending specimens on the left supporting mold and the right supporting mold, and start the bending test.

[0033] 4) The control and display unit receives and displays the displacement data from the bending angle measurement unit and calculates the bending angle.

[0034] In the step 1), when installing the measuring device, the left and right lower molds must be installed symmetrically with respect to the upper mold with reference to the center mark on the center line of the bracket.

[0035] In step 4), the bending angle is calculated according to the following formula:

[0036]

[0037] Where: α is the bending angle, D is the center distance of the displacement sensor installation holes, L1 is the displacement value measured by the first sensor, and L2 is the displacement value measured by the second sensor.

[0038] Compared with other bending test fixtures, the present invention has automatic centering and bending angle functions, which can greatly improve the efficiency of bending tests and reduce the difficulty of operation. It is of great significance for understanding the scientific research or engineering application value of the mechanical properties of metal or non-metallic materials through bending tests, as well as promoting social development.

Claims

1. A bending test fixture with automatic centering and bending angle measurement functions, characterized in that: include: The bracket and power unit consists of a side bracket, a detachable base plate, a servo motor and a motor driver; the automatic centering unit consists of a split screw, a light bar, a bearing, a left support mold, a right support mold and a displacement sensor; the bending angle measurement unit consists of a displacement sensor and a bending angle measurement bracket; the control and display unit consists of a signal data acquisition card, an AD / DA converter, a displacement sensor bracket and a motor speed feedback controller.

2. A bending test fixture with automatic centering and bending angle measurement functions as claimed in claim 1, characterized in that: The base plate can be removed from the fixture to adapt to more application scenarios. A lubricating oil groove is opened on the contact surface between the base plate and the support mold. A centering mark is set at the center line of the side bracket to facilitate fixture installation. The motor driver has a function of adjusting the speed of the servo motor, and the motor drive shaft is connected to the power end of the split screw through a coupling.

3. A bending test fixture with automatic centering and bending angle measurement functions as claimed in claim 2, characterized in that: The split lead screws are connected by a coupling at the middle position, ball bearings are installed at the supporting parts of the lead screw and the bracket, the connections between the lead screw and the left support mold and the right support mold are matched with lead screw nuts, the initial installation positions of the left support mold and the right support mold are symmetrical about the center line of the bracket, the optical rod is installed parallel to the lead screw, and is used to improve the rigidity of the transmission unit to ensure that when the lead screw rotates coaxially, it drives the left support mold and the right support mold to move in a centered manner, and a displacement sensor mounting hole is set at the center of the left support mold parallel to the direction of the lead screw.

4. A bending test fixture with automatic centering and bending angle measurement functions as claimed in claim 3, characterized in that: A threaded displacement sensor is installed on the left supporting mold, and the sensor signal emission point is coplanar with the center line of the roller on the left supporting mold. The displacement sensor is used to measure the distance between the left supporting mold and the right supporting mold, and input the displacement value into the control and display unit. The motor feedback controller compares it with the target distance, adjusts the forward and reverse rotation and rotation angle of the motor, and drives the left supporting mold and the right supporting mold to automatically align and move to the target distance.

5. A bending test fixture with automatic centering and bending angle measurement functions as claimed in claim 4, characterized in that: The bending angle measuring bracket is provided with two thread displacement sensor mounting holes, the mounting hole spacing is fixed, the thread displacement sensor is mounted vertically upward, the sensor signal emission point is flush with the upper surface of the bending angle measuring bracket, the displacement data measured by the displacement sensor is displayed on the control and display unit, and the bending angle is calculated by the following method: Where: α is the bending angle, D is the center distance of the displacement sensor installation holes, L1 is the displacement value measured by the first sensor, and L2 is the displacement value measured by the second sensor.

6. A bending test fixture with automatic centering and bending angle measurement functions as claimed in claim 5, characterized in that: The motor feedback controller receives data including the current spacing and target spacing of the left support mold and the right support mold, compares the gap between the current spacing and the target spacing, and adjusts the forward and reverse rotation and rotation amount of the motor through motor driver feedback. The display unit receives data including the displacement values ​​of the two displacement sensors in the bending angle measurement unit, and displays the displacement values ​​of the two displacement sensors.

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