Rockwell hardness tester and hardness measuring method

Abstract

The invention provides a Rockwell hardness tester and a hardness measuring method. The Rockwell hardness tester comprises a rack, a driving part, a pressure sensor, a guide rod and a distance measuring module, a test bed is arranged at the bottom of the rack; the driving part comprises a fixed seat and a moving shaft, the fixed seat is mounted at the top of the rack, and the moving shaft faces the test bed; in a natural state, the pressure sensor is separated from the moving shaft; in the working state, the pressure sensor abuts against the moving shaft. One surface of the pressure sensor facing the motion shaft is a spherical surface; one end of the guide rod is connected with the pressure sensor, and the other end is connected with a pressure head; the distance measuring module is located on one side of the motion shaft and used for measuring the motion distance of the motion shaft. The hardness measuring method adopts the Rockwell hardness tester. One end face of the pressure sensor is designed into the spherical surface, so that the contact between the pressure sensor and the moving shaft of the driving part is changed into point contact, the vertex of the spherical surface is a stress point, the accuracy of the stress position of the pressure sensor is ensured, and the hardness measurement precision is improved.

Description

Technical Field

[0001] This application belongs to the technical field of hardness measuring devices, and more specifically, relates to a Rockwell hardness tester and a hardness measuring method. Background Technology

[0002] Hardness measurement is a crucial technical indicator in modern industrial production and quality control. The Rockwell hardness tester is a commonly used hardness measuring device that calculates the hardness value by measuring the depth to which an indenter penetrates the surface of the test object under a specific test force. However, traditional Rockwell hardness testers suffer from low hardness measurement accuracy due to unreasonable structural design. Summary of the Invention

[0003] The purpose of this application is to provide a Rockwell hardness tester and a hardness measurement method to solve the technical problem of low measurement accuracy of Rockwell hardness testers in the prior art.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows: A Rockwell hardness tester is provided, comprising a frame, a drive unit, a pressure sensor, a guide rod, and a distance measuring module. The bottom of the frame is a test bench for placing the object to be tested. The drive unit includes a fixed base and a motion shaft, the motion shaft being capable of telescopic movement within the fixed base, the fixed base being mounted on the top of the frame, and the motion shaft facing the test bench. The pressure sensor is movably connected to the motion shaft, and has a natural state and a working state. In the natural state, the pressure sensor is separated from the motion shaft; in the working state, the pressure sensor abuts against the motion shaft. The side of the pressure sensor facing the motion shaft is spherical. One end of the guide rod is connected to the pressure sensor, and the other end of the guide rod is connected to an indenter for pressing the object to be tested. The distance measuring module is located on one side of the motion shaft and is used to measure the movement distance of the motion shaft.

[0005] Furthermore, the side of the motion shaft is provided with a movable hole, and the Rockwell hardness tester also includes a connector. One end of the connector is connected to the side of the pressure sensor; the other end of the connector is provided with a hook, which is movably disposed in the movable hole and can move along the axial direction of the motion shaft within the movable hole.

[0006] Furthermore, the connector is equipped with a sensor switch. When the motion shaft contacts the pressure sensor, the sensor switch is triggered to start. The sensor switch is used to control the start and stop of the ranging module.

[0007] Furthermore, the Rockwell hardness tester also includes a fixing member, which is fixedly disposed relative to the frame, and the guide rod passes through the fixing member and is slidably connected to the fixing member.

[0008] Furthermore, the fixing component is a cylindrical structure, which is connected to the fixing base, and the motion shaft is located in the cylindrical structure; the ranging module is installed on one side of the fixing base;

[0009] Alternatively, the fixing component is a plate-shaped structure, which is connected to the frame by a support rod; the plate-shaped structure is provided with a connecting plate, which is located on one side of the motion axis, and the ranging module is mounted on the connecting plate.

[0010] Furthermore, the ranging module includes a slider, a slide rail, a first locking element, a distance sensing probe, and a displacement baffle; the slider is fixedly disposed relative to the frame; the slide rail is slidably connected to the slider; the first locking element is fixedly disposed relative to the frame, and the first locking element is capable of locking and releasing the slide rail; the distance sensing probe is installed at one end of the slide rail; one end of the displacement baffle abuts against the distance sensing probe, and the other end of the displacement baffle is connected to the guide rod.

[0011] Further, the distance sensing probe includes a housing, a detection circuit board, a test object, and an elastic element; one end of the housing is connected to the slide rail, and the other end of the housing is provided with a first spherical body, which abuts against the displacement baffle; the detection circuit board is disposed inside the housing, and a detector is provided on the detection circuit board; the test object is movably disposed inside the housing, and one end of the test object is provided with a second spherical body, which passes through the housing and abuts against the displacement baffle; the distance between the detector and the test object is read by the detection circuit board, and the hardness of the test object is calculated; the elastic element is disposed between the detector and the test object.

[0012] Furthermore, the detector is an eddy current sensor, and the detected component is a conductor.

[0013] Alternatively, the detector may be a magnetic induction sensor, and the detected object may be a magnetic metal object.

[0014] Furthermore, an extension rod is detachably connected between the guide rod and the pressure head.

[0015] This application also provides a hardness measurement method using the aforementioned Rockwell hardness tester, the hardness measurement method comprising:

[0016] The object to be tested is placed at the bottom of the frame. Under the action of gravity, the pressure sensor separates from the motion axis of the drive component. When the drive component is activated, the pressure sensor, guide rod, and pressure head move together with the drive component.

[0017] When the pressure head contacts the object to be tested, the pressure sensor, the guide rod, and the pressure head stop moving, while the motion shaft continues to move. When the motion shaft contacts the spherical surface of the pressure sensor, the speed of the motion shaft slows down, and the ranging module is activated to continuously read the pressure value of the pressure sensor. When the pressure value of the pressure sensor is equal to the initial test force F0, the distance H0 of the ranging module is read.

[0018] The motion axis continues to move. When the total test force F is reached, timing begins. At the same time, the pressure value is continuously detected, and the drive component is adjusted to keep the pressure at F. When the timing time reaches the holding time T, the drive component begins to move in the opposite direction.

[0019] When the test force returns to the initial test force F0, read the current distance H from the ranging module;

[0020] Calculate the indentation depth of the test object: h = H - H0, and calculate the hardness of the test object using h.

[0021] The beneficial effects of the Rockwell hardness tester and hardness measurement method provided in this application are as follows: Compared with the prior art, the Rockwell hardness tester of this application has an extremely simple structure, low cost, and convenient maintenance; one end face of the pressure sensor is designed as a spherical surface, so that the contact between the pressure sensor and the motion shaft of the drive component becomes a point contact, and the vertex of the spherical surface is the force point, which ensures the accuracy of the force position of the pressure sensor, thereby ensuring that the guide rod and the indenter are subjected to uniform force, thus improving the accuracy of hardness measurement. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the structure of a Rockwell hardness tester (excluding the housing) provided in an embodiment of this application;

[0024] Figure 2 A schematic diagram of the structure of the Rockwell hardness tester (excluding the housing and fixing parts) provided in the embodiments of this application. Figure 1 ;

[0025] Figure 3 A schematic diagram of the structure of the Rockwell hardness tester (excluding the housing and fixing parts) provided in the embodiments of this application. Figure 2 ;

[0026] Figure 4 for Figure 3Enlarged view of part A in the middle;

[0027] Figure 5 This is an assembly diagram of the ranging module in the Rockwell hardness tester provided in the embodiments of this application;

[0028] Figure 6 for Figure 5 Enlarged view of part B in the diagram;

[0029] Figure 7 This is a schematic diagram of the overall appearance of the Rockwell hardness tester provided in the embodiments of this application;

[0030] Figure 8 This is a partial schematic diagram of a Rockwell hardness tester (the fastener is a plate-shaped structure) provided in an embodiment of this application.

[0031] The following are the labeling elements in the figure:

[0032] 100-Frame; 101-Test bench; 102-Upper fixing plate; 103-Connecting rod; 104-Support rod;

[0033] 200-Drive component; 201-Fixed base; 202-Motion shaft; 221-Moving hole; 203-Connector; 231-Hook;

[0034] 300 - Pressure sensor; 301 - Spherical surface;

[0035] 400 - Guide rod; 401 - Pressure head; 402 - Extension rod;

[0036] 500-Distance measuring module; 501-Slider; 502-Slide rail; 503-First locking element; 504-Distance sensing probe; 541-Housing; 542-Detection circuit board; 543-Detector; 544-Detected object; 545-Elastic element; 546-First sphere; 547-Second sphere; 505-Displacement baffle;

[0037] 600-Induction switch;

[0038] 701 - Cylindrical structure; 702 - Plate structure; 703 - Linear bearing; 704 - Connecting plate;

[0039] 800 - Housing;

[0040] 900 - Display screen. Detailed Implementation

[0041] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0042] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0043] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0045] Please refer to the following: Figure 1 and Figure 2 The Rockwell hardness tester provided in this application embodiment will now be described. This Rockwell hardness tester includes a frame 100, a drive unit 200, a pressure sensor 300, a guide rod 400, and a ranging module 500. The bottom of the frame 100 is a test bench 101, used to place the object to be tested. The drive unit 200 includes a fixed base 201 and a motion shaft 202. The motion shaft 202 can extend and retract within the fixed base 201, which is mounted on the top of the frame 100. The motion shaft 202 faces the test bench 101. The pressure sensor 300 is movably connected to the motion shaft 202. It has a natural state and a working state. In the natural state, the pressure sensor 300 is separated from the motion shaft 202. In the working state, the pressure sensor 300 is in contact with the motion shaft 202. The side of the pressure sensor 300 facing the motion shaft 202 is a spherical surface 301. One end of the guide rod 400 is connected to the pressure sensor 300, and the other end of the guide rod 400 is connected to the pressure head 401, which is used to squeeze the object to be tested. The distance measuring module 500 is located on one side of the motion shaft 202 and is used to measure the movement distance of the motion shaft 202.

[0046] Compared with the prior art, the Rockwell hardness tester provided in this application has an extremely simple structure, low cost, and convenient maintenance. One end face of the pressure sensor 300 is designed as a spherical surface 301, which changes the contact between the pressure sensor 300 and the motion shaft 202 of the drive component 200 to a point contact. The vertex of the spherical surface 301 is the force point, which ensures the accuracy of the force position of the pressure sensor 300, thereby ensuring that the guide rod 400 and the indenter 401 are subjected to uniform force, thus improving the accuracy of hardness measurement.

[0047] In this embodiment, the axis of the motion shaft 202 coincides with the axis of the guide rod 400. It is understood that the pressure sensor 300 and the motion shaft 202 are typically in surface contact. Due to tolerance issues, it is difficult to make the pressure sensor 300 and the motion shaft 202 perfectly parallel and tightly fitted. When they are not parallel, the surface-to-surface contact will result in force being applied at the edges of the surfaces, causing the force point to be outside the axis of the pressure sensor 300. This leads to uneven force on the guide rod 400, thus affecting the accuracy of the hardness measurement.

[0048] In this embodiment, the driving component 200 can be an electric actuator. The electric actuator has the characteristics of compact structure, high control precision, and smooth operation, and can provide a stable and precise driving force for the motion axis 202. Through the extension and retraction of the electric actuator, the motion axis 202 can be moved along a preset direction, thereby pushing the pressure sensor 300, guide rod 400 and pressure head 401 to complete the pressure application process on the object being measured.

[0049] In one embodiment of this application, please refer to Figure 5 The side of the motion shaft 202 is provided with a movable hole 221. The Rockwell hardness tester also includes a connector 203. One end of the connector 203 is connected to the side of the pressure sensor 300. The other end of the connector 203 is provided with a hook 231. The hook 231 is movably disposed in the movable hole 221 and can move along the axial direction of the motion shaft 202 within the movable hole 221.

[0050] In this embodiment, by providing the movable hole 221 and the connector 203, the pressure sensor 300 and the motion shaft 202 are in a movable connection state. When the pressure sensor 300 is not under force, it is separated from the motion shaft 202. When under force, the pressure sensor 300 and the motion shaft 202 make point contact. This design ensures that the swaying or rotation generated by the motion shaft 202 during movement will not affect the pressure sensor 300, the guide rod 400 and the pressure head 401, thus improving the stability of hardness measurement.

[0051] When the motion shaft 202 moves upward, the lower wall of the movable hole 221 of the motion shaft 202 will hook the hook 231, and the hook 231 will drive the pressure sensor 300 to move upward. The guide rod 400 and the pressure head 401 move upward together under the drive of the pressure sensor 300. When the motion shaft 202 is retracted to the end, it stops moving. This is the initial state. In the initial state, there is a small initial distance between the top of the spherical surface 301 of the pressure sensor 300 and the lower end of the motion shaft 202.

[0052] It is understandable that the size of the movable hole 221 along the movement direction of the motion shaft 202 is larger than the initial distance between the pressure sensor 300 and the motion shaft 202; in order to avoid the hook 231 touching the upper wall of the movable hole 221 when the top of the spherical surface 301 of the pressure sensor 300 contacts the lower end face of the motion shaft 202, thereby improving the service life of the hook 231.

[0053] In one embodiment of this application, please refer to the following: Figure 3 and Figure 4 The connector 203 is equipped with an induction switch 600. When the motion shaft 202 contacts the pressure sensor 300, the induction switch 600 is triggered to start. The induction switch 600 is used to control the start and stop of the ranging module 500.

[0054] In this embodiment, by setting an inductive switch 600 and combining the initial distance maintained between the top of the spherical surface 301 of the pressure sensor 300 and the lower end face of the motion shaft 202, the drive member 200 can move rapidly when the pressure head 401 is not in contact with the object being measured, and then begin to move slowly after contacting the object. This not only increases the stroke of the drive member 200 to measure objects of various thicknesses, but also does not affect the measurement speed. Once the pressure head 401 contacts the object, it immediately enters the slow measurement phase. During this process, the pressure value is detected while the pressure head 401 is slowly advanced to press into the object, thereby improving measurement accuracy.

[0055] Understandably, the initial distance between the top of the spherical surface 301 of the pressure sensor 300 and the lower end face of the motion shaft 202 is designed to prevent the sensor from failing to stop immediately upon reaching the initial test force position due to inertia during rapid movement, thus avoiding inaccurate initial test force position H0. This initial distance serves as a buffer.

[0056] In this embodiment, the inductive switch 600 enables precise control of the ranging module 500, thereby further improving the accuracy of hardness measurement. When the motion shaft 202 contacts the pressure sensor 300, the inductive switch 600 responds quickly, ensuring that the ranging module 500 starts or stops at the appropriate time. This design not only reduces the possibility of human intervention but also effectively avoids errors caused by delays or misoperations of the ranging module 500.

[0057] In one embodiment of this application, the Rockwell hardness tester further includes a fixing member, which is fixedly disposed relative to the frame 100, and the guide rod 400 passes through the fixing member and is slidably connected to the fixing member.

[0058] In this embodiment, the fixing member uses a sliding connection structure to limit the movement path of the guide rod 400, ensuring that the pressure head 401 maintains vertical stability when pressing into the object being measured, thereby effectively controlling the measurement deviation caused by skewness.

[0059] In one embodiment of this application, please refer to Figure 1 The fixing component is a cylindrical structure 701, which is connected to the fixing seat 201, and the motion shaft 202 is located in the cylindrical structure 701.

[0060] In this embodiment, the cylindrical structure 701 provides stable guidance for the movement of the motion shaft 202 and the guide rod 400, reducing swaying and deviation during movement. The sliding connection design between the cylindrical structure 701 and the guide rod 400 ensures that the guide rod 400 can move smoothly along the axial direction of the cylindrical structure 701 when subjected to force, thereby further improving the accuracy of the pressure applied by the pressure head 401 to the measured object during the measurement process.

[0061] In another embodiment of this application, please refer to Figure 8 The fastener is a plate-shaped structure 702, which is connected to the frame 100 by a support rod 104.

[0062] In one embodiment of this application, please refer to Figure 1 The ranging module 500 is mounted on one side of the mounting base 201. In another embodiment of this application, please refer to... Figure 8 A connecting plate 704 is provided on the plate-like structure 702. The connecting plate 704 is located on one side of the motion axis 202, and the ranging module 500 is mounted on the connecting plate 704. The mounting position of the ranging module 500 is designed to be flexibly adjusted according to different frame 100 structures and spatial layouts to ensure that it can accurately capture the displacement data of the motion axis 202.

[0063] In one embodiment of this application, such as Figure 1 and Figure 2As shown, a linear bearing 703 is provided on the fixing component, and the guide rod 400 is slidably connected to the linear bearing 703. The linear bearing 703 on the fixing component effectively reduces the friction generated during the sliding process of the guide rod 400, thereby ensuring the smoothness and accuracy of the guide rod 400's movement. The use of the linear bearing 703 also extends the service life of the guide rod 400, avoiding wear problems caused by long-term friction. Furthermore, the design of the fixing component also guides the movement of the guide rod 400, ensuring that its axis always remains aligned with the motion axis 202, further improving the reliability of the measurement results.

[0064] In this embodiment, the end face of the pressure sensor 300 is designed as a spherical surface 301, which ensures that the guide rod 400 is subjected to uniform force, and also improves the durability of the linear bearing 703 and reduces maintenance costs.

[0065] In one embodiment of this application, please refer to the following: Figure 3 and Figure 5 The ranging module 500 includes a slider 501, a slide rail 502, a first locking element 503, a distance sensing probe 504, and a displacement baffle 505. The slider 501 and the first locking element 503 are both fixedly arranged relative to the frame 100. The slide rail 502 is slidably connected to the slider 501. The first locking element 503 can lock and release the slide rail 502. The distance sensing probe 504 is installed at one end of the slide rail 502. One end of the displacement baffle 505 abuts against the distance sensing probe 504, and the other end of the displacement baffle 505 is connected to the guide rod 400.

[0066] In one embodiment of this application, please refer to Figure 1 The slider 501 is mounted on the fixed base 201, and the first locking member 503 is mounted on the outer wall of the cylindrical structure 701; in another embodiment of this application, please refer to Figure 8 Both the slider 501 and the first locking element 503 can be mounted on the connecting plate 704.

[0067] In this embodiment, the ranging module 500 achieves precise displacement measurement through the cooperation of the slider 501 and the slide rail 502. Simultaneously, the design of the first locking element 503 ensures the stability of the slide rail 502 when fixation is required, avoiding measurement errors caused by external force interference. The distance sensing probe 504, through its tight contact with the displacement baffle 505, senses the displacement changes of the guide rod 400 in real time and feeds the data back to the control system, thereby ensuring the accuracy of the measurement results. The clearance groove not only provides space for the movement of the displacement baffle 505 but also optimizes the overall structural compactness and reduces unnecessary component interference.

[0068] It is understandable that the measurement stroke of the distance sensing probe 504 is generally relatively small. In order to ensure that objects of different thicknesses can be measured accurately, the pressure head 401 needs to have a sufficiently large stroke range. In this embodiment, by setting up a slider 501 and a slide rail 502, before the sensing switch 600 is triggered, the slider 501 and the slide rail 502 slide relative to each other, so that the distance sensing probe 504 can move as a whole with the movement of the pressure head 401. After the sensing switch 600 is triggered, the first locking member 503 locks the slide rail 502, and the distance sensing probe 504 begins to measure, thereby improving the thickness measurement range of the object being measured.

[0069] Specifically, the first locking element 503 can be an electromagnet. The use of an electromagnet enables rapid locking and unlocking of the slide rail 502, improving the working efficiency of the ranging module 500. When the slide rail 502 needs to be fixed, the electromagnet is energized to generate magnetic force, firmly attracting the slide rail 502 to the designated position, ensuring no displacement during measurement. When the slide rail 502 needs to be adjusted, simply disconnect the power supply to the electromagnet; the magnetic force disappears, and the slide rail 502 can slide freely.

[0070] In one embodiment of this application, please refer to the following: Figure 5 and Figure 6 The distance sensing probe 504 includes a housing 541, a detection circuit board 542, a test piece 544, and an elastic element 545. One end of the housing 541 is connected to a slide rail 502, and the other end of the housing 541 is provided with a first spherical body 546, which abuts against a displacement baffle 505. The detection circuit board 542 is disposed inside the housing 541, and a detector 543 is provided on the detection circuit board 542. The test piece 544 is movably disposed inside the housing 541, and one end of the test piece 544 is provided with a second spherical body 547, which passes through the housing 541 and abuts against the displacement baffle 505. The distance between the detector 543 and the test piece 544 is read by the detection circuit board 542, and the hardness of the test piece is calculated. The elastic element 545 is disposed between the detector 543 and the test piece 544.

[0071] In this embodiment, a detector 543 is provided on the detection circuit board 542. During hardness measurement, the object to be tested 544 can move within the housing 541. By measuring the change in distance between the detector 543 and the object to be tested 544, the depth of the indenter 401 pressed into the object can be calculated, thereby calculating the hardness of the object. By setting the first spherical body 546 and the second spherical body 547, precise contact between the displacement baffle 505 and the distance sensing probe 504 can be achieved, reducing measurement errors caused by uneven contact surfaces or angular deviations. The design of the first spherical body 546 and the second spherical body 547 ensures that they always maintain point contact during the contact process, thereby improving the stability and accuracy of force transmission.

[0072] In this embodiment, both the first spherical body 546 and the second spherical body 547 can be implemented by embedding a ball into the housing 541 with a portion of the spherical surface exposed. The ball is made of a metal material, such as stainless steel or hard alloy. These materials have high hardness and wear resistance, and can maintain shape stability during long-term use, and are not easily worn due to friction, thereby ensuring that the measurement accuracy of the distance sensing probe 504 is not affected. Compared with machining the corresponding positions of the housing 541 and the detected object 544 into spherical surfaces, the solution of embedding the ball into the housing 541 is more cost-effective.

[0073] It is understandable that the elastic force of the elastic element 545 is less than the sum of the weights of the distance sensing probe 504 and the slide rail 502. In the initial state, due to gravity, the initial distance between the detected element 544 and the detector 543 is the smallest. After the first locking element 503 locks the distance sensing probe 504, the detected element 544 will slowly rise out as the displacement baffle 505 moves down, creating a different distance from the detector 543, thereby achieving distance measurement.

[0074] In one embodiment of this application, the detector 543 is an eddy current sensor and the detected element 544 is a conductor.

[0075] In this embodiment, the eddy current sensor can accurately measure the distance between the detected component 544 and the detector 543 by detecting the displacement change of the detected component 544. Since the detected component 544 is a conductor, the eddy current sensor induces an eddy current effect in the conductor during operation, thereby achieving non-contact distance detection. This method not only improves the measurement sensitivity but also reduces mechanical wear and extends the service life of the equipment.

[0076] Specifically, the conductor can be made of aluminum or copper. The detection circuit board 542 includes a high-frequency oscillation circuit for generating a high-frequency alternating current. The eddy current sensor includes an eddy current coil, which generates a high-frequency alternating electromagnetic field after a high-frequency alternating current is applied. The oscillation frequency of the eddy current coil changes under the feedback effect of the conductor; the closer the conductor is to the eddy current coil, the stronger the feedback signal. This allows the distance between the conductor and the eddy current sensor to be calculated. The indentation depth can then be calculated, thereby determining the material's hardness. The eddy current coil and conductor are measured non-contactly, eliminating fatigue issues and ensuring stable values ​​for the Rockwell hardness tester over long-term use. Utilizing the eddy current induction principle for distance measurement provides high accuracy, and the low cost of eddy current coils makes it suitable for mass production.

[0077] In another embodiment of this application, the detector 543 is a magnetic induction sensor, and the detected element 544 is a magnetic metal element.

[0078] In this embodiment, the magnetic metal component can be made of materials such as iron or 340 stainless steel. These materials possess good magnetic permeability and can generate a stable magnetic coupling effect with the magnetic induction sensor. The detection circuit board 542 includes a low-frequency oscillation circuit for generating a low-frequency alternating current. The magnetic induction sensor contains a magnetic induction coil that emits an alternating magnetic field. This alternating magnetic field, together with the magnetic metal component, forms a closed magnetic circuit. The closed magnetic circuit alters the alternating magnetic field. Due to the distance between the magnetic metal component and the magnetic induction coil, the magnetic reluctance of the magnetic circuit changes, leading to a change in magnetic flux. By measuring the magnetic flux and finding the corresponding curve between distance and magnetic flux, the detection circuit board 542 can calculate the distance between the magnetic metal component and the magnetic induction coil.

[0079] In one embodiment of this application, please refer to the following: Figure 1 and Figure 2 An extension rod 402 is detachably connected between the guide rod 400 and the pressure head 401.

[0080] In this embodiment, by setting the extension rod 402, the thickness of the object being measured can be further increased, the stroke of the drive component 200 can be reduced, and the cost of the drive component 200 can be reduced (the longer the stroke of the drive component 200, the more expensive it is); the detachable design of the extension rod 402 makes it easy to replace extension rods 402 of different lengths to cover objects of various thicknesses.

[0081] Specifically, the first end of the extension rod 402 has an external thread, and the end face of the guide rod 400 has a threaded hole, with the external thread and the threaded hole being threadedly connected; the second end of the extension rod 402 has a mounting hole, and the pressure head 401 is partially inserted into the mounting hole, with a fixing screw screw screwed into the side of the extension rod 402 and abutting against the pressure head 401; this connection method of the extension rod 402 ensures the stability of the structure and facilitates disassembly and replacement.

[0082] In this embodiment, when the drive unit 200 is in its original position and the extension rod 402 is not installed, it is assumed that the distance from the pressure head 401 to the test bench 101 is 180mm and the stroke of the motion shaft 202 is 50mm. Three extension rods 402 of different lengths are designed, namely 135mm, 90mm and 45mm.

[0083] When the thickness of the object being measured is 0-45mm, connect the 135mm extension rod 402; when the thickness of the object being measured is 40-85mm, connect the 90mm extension rod 402; when the thickness of the object being measured is 80-135mm, connect the 45mm extension rod 402; when the thickness of the object being measured is 130-180mm, do not connect the extension rod 402.

[0084] In this way, it is possible to measure various test objects with a thickness range of 0-180mm without the need for a height-adjustable test platform 101.

[0085] In one embodiment of this application, please refer to Figure 1 The frame 100 includes an upper fixed plate 102, a lower fixed plate, and multiple connecting rods 103. The multiple connecting rods 103 are arranged in parallel, and one end of each connecting rod 103 is connected to the upper fixed plate 102, and the other end of each connecting rod 103 is connected to the lower fixed plate. The driving component 200 is installed on the upper fixed plate 102, and the lower fixed plate forms the test bench 101.

[0086] In this embodiment, a stable frame structure is constructed between the upper fixed plate 102 and the lower fixed plate through the parallel arrangement of multiple connecting rods 103. This structure can effectively resist external vibration and impact, ensuring the overall stability of the frame 100 during hardness measurement. The number and distribution of the connecting rods 103 are designed according to actual needs to balance the rigidity of the frame 100 and material costs. In addition, the connection between the connecting rods 103 and the upper and lower fixed plates adopts high-strength bolts or welding processes, further enhancing the robustness of the frame 100. The drive component 200 is mounted on the upper fixed plate 102, and its position is precisely calculated to ensure that the axis of the motion shaft 202 always coincides with the axis of the guide rod 400, thereby avoiding measurement deviations caused by installation errors. The lower fixed plate, as the test bench 101, has a specially treated surface with high flatness and wear resistance, and can adapt to the placement requirements of test objects of different shapes and materials. This modular design not only facilitates the assembly and maintenance of the frame 100, but also provides convenience for subsequent functional expansion. For example, a clamp or positioning device can be added to the lower fixing plate to fix irregularly shaped objects to be measured, thereby improving the applicability of the measurement.

[0087] In this embodiment, the motion shaft 202, cylindrical structure 701, linear bearing 703, pressure sensor 300, guide rod 400, extension rod 402, and pressure head 401 are all coaxially designed. The extension and retraction of the motion shaft 202 applies pressure to the pressure sensor 300, which in turn applies pressure to the guide rod 400, extension rod 402, and pressure head 401, pressing the pressure head 401 into the object being measured.

[0088] In one embodiment of this application, please refer to Figure 7 The Rockwell hardness tester also includes a housing 800, which is mounted on the frame 100. The test bench 101, indenter 401, and extension rod 402 are exposed outside the housing 800. The housing 800 not only protects the core components inside the frame 100, such as the drive unit 200, ranging module 500, and pressure sensor 300, from dust, moisture, and impact, but also optimizes the overall appearance of the equipment, making it more suitable for laboratory or industrial environments.

[0089] In one embodiment of this application, the Rockwell hardness tester further includes a control circuit board, which is electrically connected to a detection circuit board 542, an inductive switch 600, a drive unit 200, a pressure sensor 300, and a first locking member 503.

[0090] In this embodiment, the control circuit board, as the core control unit of the entire hardness tester, can receive detection signals transmitted by the detection circuit board 542, status signals from the inductive switch 600, and pressure data collected by the pressure sensor 300. It can also precisely control the movement of the drive component 200 according to preset program logic, such as adjusting the extension and retraction speed and stroke of the motion shaft 202, and the locking timing of the first locking component 503. Simultaneously, the control circuit board can process and analyze the received data, combining the pressure value detected by the pressure sensor 300 with the hardness conversion formula to calculate the Rockwell hardness value of the tested object in real time. The results can be displayed and recorded through an external display device or a built-in storage module, thus achieving automation and intelligence in the hardness measurement process and effectively improving measurement efficiency and data accuracy.

[0091] In one embodiment of this application, please refer to the following: Figure 1 and Figure 7 The Rockwell hardness tester also includes a display screen 900 and at least one button, the button being electrically connected to a control circuit board, and the display screen 900 being electrically connected to the control circuit board.

[0092] In this embodiment, the display screen 900 is used to display the hardness value of the object being measured, while the buttons are used to realize human-machine interaction functions. Operators can input commands to the control circuit board via the buttons, such as starting the measurement program, switching measurement modes, retrieving historical measurement data, or setting equipment parameters. The combined design of the display screen 900 and the buttons allows users to intuitively obtain measurement results and conveniently operate the equipment, further optimizing the user experience. For example, when the user presses the "Start Measurement" button, the control circuit board receives the command and triggers the measurement process. After the measurement is completed, the hardness value will be clearly displayed on the display screen 900 immediately. If it is necessary to adjust the measurement parameters, the user can enter the setting interface through the "Parameter Setting" button and modify various parameters under the guidance of the display screen 900, ensuring that the equipment can adapt to measurement scenarios with different materials and different precision requirements.

[0093] The working principle of the Rockwell hardness tester provided in this application is as follows:

[0094] When the pressure head 401 is not in contact with the object being measured, the pressure sensor 300, guide rod 400, extension rod 402 and pressure head 401 will slide downwards due to gravity. At this time, the top spherical surface 301 of the pressure sensor 300 will separate from the lower end surface of the motion shaft 202 and no contact will occur.

[0095] The object to be tested is placed on the test bench 101. At the start of the measurement, the motion shaft 202 moves rapidly downwards, and the pressure head 401 also moves downwards under gravity. When the pressure head 401 contacts the object, it stops moving, and the extension rod 402, guide rod 400, pressure sensor 300, and inductive switch 600 also stop moving downwards. At this time, the motion shaft 202 continues to move downwards, and its end face contacts the swing arm of the inductive switch 600, triggering a response from the inductive switch 600. After detecting the response from the inductive switch 600, the control circuit controls the drive component 200 to enter a slow-moving state. After moving a short distance, the lower end face of the motion shaft 202 contacts the top spherical surface 301 of the pressure sensor 300, and the hook 231 on the connector 203 gradually separates from the lower wall of the movable hole 221 of the motion shaft 202.

[0096] Simultaneously with the response of the inductive switch 600, the electromagnet activates, attracting the guide rail and stopping the downward movement of the distance sensing probe 504. After locking the distance sensing probe 504, the motion shaft 202 pushes the pressure head 401 to continue moving downward, and the displacement baffle 505 also continues to move downward. Under the elastic force of the elastic element 545, the detected element 544 in the distance sensing probe 504 moves downward with the displacement baffle 505, changing the distance between the detected element 544 and the detector 543. The frequency of the detector 543's acquisition also changes accordingly and is converted into a distance value.

[0097] The control circuit simultaneously detects whether the pressure of the pressure sensor 300 has reached the initial test force F0. When the initial test force F0 is reached, the control circuit reads the current distance H0 of the ranging module 500. Subsequently, the motion shaft 202 continues to move downwards slowly. When the total test force F is reached, the motion shaft 202 stops moving and enters the pressure holding phase. During the pressure holding phase, the control circuit continuously monitors the pressure sensor 300. If it detects that the total test force F has decreased, the motion shaft 202 will move downwards a short distance further to maintain a constant test force F.

[0098] Once the holding time reaches the set value, the motion shaft 202 begins to move slowly upwards. When the test force returns to the initial test force F0, the control circuit reads the current distance H from the distance measuring module 500. H-H0 is the indentation depth h, and the hardness can be calculated from h. Afterwards, the electromagnet is turned off, and the motion shaft 202 begins to move rapidly upwards until it returns to the initial state.

[0099] The pressure value detected by the pressure sensor 300 can also be used to determine whether the inductive switch 600 is triggered. When the pressure head 401 is not in contact with the object to be measured, the guide rod 400, extension rod 402, and pressure head 401 will slide downwards due to gravity. The force exerted on the pressure sensor 300 is a pulling force. If the pressure sensor 300 is not under any force, the pressure value is 0. When the pressure head 401 comes into contact with the object to be measured, the negative value becomes 0, which is equivalent to the inductive switch 600 being triggered.

[0100] This application also provides a hardness measurement method using the aforementioned Rockwell hardness tester. The hardness measurement method includes:

[0101] The object to be tested is placed at the bottom of the frame 100. Under the action of gravity, the pressure sensor 300 separates from the motion axis 202 of the drive component 200. When the drive component 200 is started, the pressure sensor 300, the guide rod 400, and the pressure head 401 move together with the drive component 200.

[0102] When the pressure head 401 contacts the object to be tested, the pressure sensor 300, guide rod 400, and pressure head 401 stop moving, while the motion shaft 202 continues to move. When the motion shaft 202 contacts the spherical surface 301 of the pressure sensor 300, the speed of the motion shaft 202 slows down, and at the same time, the distance measuring module 500 is activated to continuously read the pressure value of the pressure sensor 300. When the pressure value of the pressure sensor 300 is equal to the initial test force F0, the distance H0 of the distance measuring module 500 is read.

[0103] The motion shaft 202 continues to move. When the total test force F is reached, timing begins. At the same time, the pressure value is continuously detected, and the drive component 200 is adjusted to keep the pressure at F. When the timing time reaches the holding time T, the drive component 200 begins to move in the opposite direction.

[0104] When the test force returns to the initial test force F0, read the current distance H from the ranging module 500.

[0105] Calculate the indentation depth of the test object: h = H - H0, and calculate the hardness of the test object using h.

[0106] In this embodiment, by setting a spherical contact structure between the pressure sensor 300 and the motion shaft 202, the impact of the motion shaft 202 on the pressure sensor 300 can be effectively buffered, avoiding measurement errors caused by rigid contact. At the same time, the spherical contact structure can make the pressure transmission more uniform and stable, ensuring the detection accuracy of the initial test force F0. The ranging module 500 starts synchronously when the motion shaft 202 contacts the pressure sensor 300, realizing the accurate capture of the starting point of the indentation depth measurement. The real-time detection of the pressure value and the adjustment mechanism of the drive component 200 during the holding pressure stage ensure that the total test force F remains constant within the holding pressure time T, reducing the impact of pressure fluctuations on the indentation depth.

[0107] When the Rockwell hardness tester is placed horizontally, the distance sensing probe 504 loses the gravitational force of the displacement baffle 505 and will not move downwards with the displacement baffle 505. In one embodiment of this application, the Rockwell hardness tester also includes a second locking member, which is fixedly mounted on the displacement baffle 505. The second locking member can lock and release the distance sensing probe 504. The second locking member can also be an electromagnet. When the Rockwell hardness tester is placed horizontally, the second locking member is energized to lock the distance sensing probe 504 and the displacement baffle 505, ensuring that the two move synchronously and avoiding measurement deviations caused by the lack of gravity. This dual-locking design further enhances the stability of the distance measuring module 500 in different placement states, maintaining consistency of measurement data regardless of whether the device is in a vertical or horizontal measurement environment.

[0108] The specific steps for measuring Rockwell hardness and hardness with a second locking element are as follows:

[0109] Step 1: Place the object to be tested, close the first locking mechanism 503, activate the second locking mechanism, and the control circuit board controls the drive unit 200 to push the guide rod 400 and the pressure head 401 downwards rapidly. The displacement baffle 505 also moves downwards, and under the action of the second locking mechanism, the distance sensing probe 504 also moves downwards.

[0110] Step 2: When the pressure head 401 comes into contact with the object being measured, the guide rod 400 and the pressure head 401 stop moving, and the driving component 200 continues to move downward, which will trigger the induction switch 600.

[0111] Step 3: After the control circuit board detects that the inductive switch 600 has been triggered, it activates the first locking element 503 and closes the second locking element, locking the slider 501 guide rail with the first locking element 503 (thus fixing the distance sensing probe 504). At the same time, the eddy current acquisition circuit is activated to begin distance measurement.

[0112] Step 4: After the first locking component 503 is activated, the control circuit board switches the drive component 200 to move slowly downwards. When the control circuit board detects that the pressure value reaches the initial test force F0, the control circuit board reads the current distance H0 of the distance sensing probe 504.

[0113] Step 5: The control circuit board controls the drive unit 200 to continue moving downwards slowly. When the total test force F is reached, timing begins, and the pressure value is continuously monitored. The drive unit 200 is adjusted to maintain the pressure at F. When the timing reaches the holding time T, the drive unit 200 begins to move upwards slowly.

[0114] Step 6: When the test force returns to the initial test force F0, the control circuit board reads the current distance H of the distance sensing probe 504.

[0115] Step 7: Calculate the indentation depth: h = H - H0, and the hardness can be calculated from h.

[0116] Step 8: The control circuit board closes the first locking component 503, activates the second locking component, and controls the drive component 200 to move upward quickly, returning to the initial state.

[0117] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A Rockwell hardness tester, characterized in that, include: The frame has a test bench at its bottom, which is used to place the object to be tested. A driving component, comprising a fixed base and a moving shaft, the moving shaft being capable of telescopic movement within the fixed base, the fixed base being mounted on the top of the frame, and the moving shaft facing the test bench; A pressure sensor is movably connected to the motion shaft. The pressure sensor has a natural state and an operating state. In the natural state, the pressure sensor is separated from the motion shaft. In the operating state, the pressure sensor abuts against the motion shaft; the side of the pressure sensor facing the motion shaft is a spherical surface. A guide rod, one end of which is connected to the pressure sensor, and the other end of which is connected to a pressure head, which is used to squeeze the object to be tested; A ranging module is located on one side of the motion axis and is used to measure the motion distance of the motion axis.

2. The Rockwell hardness tester as described in claim 1, characterized in that, The side of the motion shaft is provided with a movable hole. The Rockwell hardness tester also includes a connector. One end of the connector is connected to the side of the pressure sensor. The other end of the connector is provided with a hook. The hook is movably disposed in the movable hole and can move along the axial direction of the motion shaft within the movable hole.

3. The Rockwell hardness tester as described in claim 2, characterized in that, The connector is equipped with a sensor switch. When the motion shaft comes into contact with the pressure sensor, the sensor switch is triggered to start. The sensor switch is used to control the start and stop of the ranging module.

4. The Rockwell hardness tester as described in claim 1, characterized in that, The Rockwell hardness tester also includes a fixing member, which is fixedly disposed relative to the frame, and the guide rod passes through the fixing member and is slidably connected to the fixing member.

5. The Rockwell hardness tester as described in claim 4, characterized in that, The fixing component is a cylindrical structure, which is connected to the fixing base, and the motion axis is located in the cylindrical structure; the ranging module is installed on one side of the fixing base; Alternatively, the fixing component is a plate-shaped structure, which is connected to the frame by a support rod; the plate-shaped structure is provided with a connecting plate, which is located on one side of the motion axis, and the ranging module is mounted on the connecting plate.

6. The Rockwell hardness tester as described in claim 1, characterized in that, The ranging module includes: A slider, which is fixedly disposed relative to the frame; A slide rail, which is slidably connected to the slider; A first locking element is fixedly disposed relative to the frame, and the first locking element is capable of locking and releasing the slide rail; A distance sensing probe, wherein the distance sensing probe is mounted at one end of the slide rail; A displacement baffle, one end of which abuts against the distance sensing probe, and the other end of which is connected to the guide rod.

7. The Rockwell hardness tester as described in claim 6, characterized in that, The distance sensing probe includes: The housing has one end connected to the slide rail and the other end provided with a first spherical body, which abuts against the displacement baffle. A detection circuit board is disposed inside the housing, and a detector is provided on the detection circuit board; The test piece is movably disposed within the housing. One end of the test piece has a second spherical body that passes through the housing and abuts against the displacement baffle. The distance between the detector and the test piece is read through the detection circuit board, and the hardness of the test object is calculated. An elastic element is disposed between the detector and the detected object.

8. The Rockwell hardness tester as described in claim 7, characterized in that, The detector is an eddy current sensor, and the detected component is a conductor. Alternatively, the detector may be a magnetic induction sensor, and the detected object may be a magnetic metal object.

9. The Rockwell hardness tester as described in claim 1, characterized in that, An extension rod is detachably connected between the guide rod and the pressure head.

10. A method for measuring hardness, employing a Rockwell hardness tester as described in any one of claims 1-9, characterized in that, The hardness measurement method includes: The object to be tested is placed at the bottom of the frame. Under the action of gravity, the pressure sensor separates from the motion axis of the drive component. When the drive component is activated, the pressure sensor, guide rod, and pressure head move together with the drive component. When the pressure head contacts the object to be tested, the pressure sensor, the guide rod, and the pressure head stop moving, while the motion shaft continues to move. When the motion shaft contacts the spherical surface of the pressure sensor, the speed of the motion shaft slows down, and at the same time, the distance measuring module is activated to continuously read the pressure value of the pressure sensor. When the pressure value of the pressure sensor is equal to the initial test force F0, the distance H0 of the distance measuring module is read. The motion axis continues to move. When the total test force F is reached, timing begins. At the same time, the pressure value is continuously detected, and the drive component is adjusted to keep the pressure at F. When the timing time reaches the holding time T, the drive component begins to move in the opposite direction. When the test force returns to the initial test force F0, read the current distance H from the ranging module; Calculate the indentation depth of the test object: h = H - H0, and calculate the hardness of the test object using h.

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