An angle-controllable reciprocating torsional fatigue loading system

Abstract

The present invention provides a reciprocating torsional fatigue loading system with controllable angles. The loading system is provided with a connecting mechanism between a torsional loading unit and a motor drive unit. A circular flange base is installed at the bottom of the torsional loading unit. The motor drive unit includes a single-phase stepping motor, a reducer and an eccentric wheel. The connecting mechanism includes a connecting rod A, a connecting rod B, and a connecting rod C. The bottoms of the torsional loading unit and the motor drive unit are both fixed on a loading platform. The reciprocating torsional fatigue loading system has better coaxiality. The upper and lower ends of the sample are placed between two symmetrically designed flanges and fixed by threaded connections. The operation is simple and a fully centered reciprocating torsional fatigue test can be achieved. The loading is controlled by a single-phase motor, and only the deflection angle and the number of reciprocating cycles need to be set. At the same time, the single-phase motor is very smooth during the startup process, reducing the mechanical vibration caused by violent startup.

Description

Technical Field

[0001] The invention relates to the technical field of processing machinery manufacturing, in particular to a reciprocating torsional fatigue loading system with controllable angle. Background Art

[0002] With the rapid development of modern industrial society, mechanical stresses are increasing, and operating conditions are becoming increasingly harsh. Torsional fatigue failure is the primary form of component failure in many industrial equipment. Currently, most commonly used torsional fatigue testing machines use stepper motors to provide the driving force for the experiment. Each pulse signal input to a stepper motor causes the rotor to rotate one degree or advance one step. The output angular or linear displacement is proportional to the number of input pulses, and the rotational speed is proportional to the pulse frequency. Therefore, stepper motors are also called pulse motors. As a switch-controlled system, stepper motors are intrinsically linked to modern digital control technology.

[0003] In the current domestic digital control systems, stepper motors also have some disadvantages. First, low-frequency vibrations are prone to occur when running at low speeds, so when stepper motors are working at low speeds, damping technology is usually required to overcome the low-frequency vibration phenomenon. Secondly, the fatigue life is low, the operating system is complex, and long-term fatigue loading cannot be performed. Finally, almost all torsion testing machines clamp the specimens by fixing them at both ends, and the problem of misalignment of the clamping ends is also common, which causes many uncertainties in the torsional fatigue test of the samples. Therefore, this invention provides a reciprocating torsional fatigue loading system with controllable angles. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a reciprocating torsional fatigue loading system with controllable angle to solve the problems raised in the above background technology. The present invention is simple to operate and can realize fully aligned reciprocating torsional fatigue tests. It has the advantages of good coaxiality, simple operation of single-phase motors, high cost performance and easy maintenance.

[0005] In order to achieve the above-mentioned purpose, the present invention is implemented through the following technical scheme: a reciprocating torsional fatigue loading system with controllable angle, the loading system includes a torsional loading unit and a motor drive unit, and a connecting mechanism is arranged between the torsional loading unit and the motor drive unit, a circular flange base is installed at the bottom of the torsional loading unit, the motor drive unit includes a single-phase stepper motor, a reducer and an eccentric wheel, the connecting mechanism includes a connecting rod A, a connecting rod B, and a connecting rod C, the bottoms of the torsional loading unit and the motor drive unit are fixed on the loading platform, and the single-phase stepper motor and the reducer are adjusted and controlled by an external CNC program controller.

[0006] Furthermore, a pressure sensor is installed in the middle of the circular flange base, and a torsion clamp base is provided on the surface of the pressure sensor. A plurality of axial guide columns are installed on the side of the surface of the circular flange base.

[0007] Furthermore, a sample to be tested is embedded in the middle of the top of the torsion fixture base, a flange pressure plate is provided on the top of the sample to be tested, and a cross cylindrical roller bearing is provided on the top of the axial guide column.

[0008] Furthermore, a torque sensor is installed in the middle of the cross cylindrical roller bearing, an angle connector is installed on the top of the cross cylindrical roller bearing, a mounting plate is provided on the top of the angle connector, and a second torque sensor is provided on the side of the mounting plate.

[0009] Furthermore, the cross cylindrical roller bearing includes an inner ring and an outer ring, and the inner ring and the outer ring cooperate with each other, and the outer ring is connected to the circular flange base through an axial guide column.

[0010] Furthermore, eight axial guide pillars are provided, and during the loading process, the outer ring is fixed and the inner ring is torsionally rotated under the action of the connecting mechanism.

[0011] Furthermore, the reducer is installed on the top of the single-phase stepper motor, and an eccentric wheel is installed on the output shaft of the reducer.

[0012] Furthermore, the single-phase stepper motor transmits torque to the uppermost eccentric wheel through a middle reducer, and the reduction ratio of the reducer is 10.

[0013] Furthermore, a plurality of angle adjustment holes are provided on the surface of the connecting rod C, and the connecting rod C is combined and connected with the connecting rod B through the angle adjustment holes.

[0014] Furthermore, the end of the connecting rod C is connected to the connecting rod A, and both the connecting rod A and the connecting rod B are linked to the torsion loading unit.

[0015] Beneficial effects of the present invention:

[0016] 1. This invention offers improved coaxiality. During loading, the sample maintains good coaxiality. The upper and lower ends of the sample are placed between two symmetrically designed flanges and secured by threaded connections. Adjusting the height of the thread lock modifies the sample's axial compressive strain. The threads are engraved with a precise scale similar to a micrometer.

[0017] 2. This angle-controlled reciprocating torsional fatigue loading system uses a single-phase motor to control loading. Simply set the deflection angle and the number of reciprocating cycles. Single-phase motors offer a very smooth startup process, reducing mechanical vibrations caused by abrupt startups. Furthermore, since single-phase motors do not require a high-voltage power supply, they maintain very low temperatures. Therefore, with proper maintenance, they can operate for extended periods of time.

[0018] 3. The single-phase motor used in this angle-controlled reciprocating torsional fatigue loading system is simpler to design and manufacture than multi-phase stepper motors, resulting in a relatively low price. Compared to three-phase motors, single-phase motors are a more cost-effective and reliable solution for small machines and equipment. They are also significantly easier to install and maintain than three-phase motors. Because single-phase motors operate on a 220V power supply, similar to household electricity, no specialized electrical installation is required. Furthermore, if a part needs to be replaced, the relatively simple structure of a single-phase motor makes replacement easier than with a three-phase motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an assembly diagram of the core components of the torsional fatigue loading system of the present invention;

[0020] Figure 2 This is a schematic structural diagram of the appearance of a reciprocating torsional fatigue loading system with controllable angle according to the present invention;

[0021] Figure 3 This is a schematic structural diagram of a torsional loading unit in the torsional fatigue loading system of the present invention;

[0022] Figure 4 This is a schematic structural diagram of a single-phase motor drive unit in the torsional fatigue loading system of the present invention;

[0023] Figure 5 A structural diagram of the connection mechanism between the torsion loading unit and the motor drive unit of the present invention;

[0024] Figure 6 This is a detailed view of the torsion clamp base of the present invention;

[0025] Figure 7 Detailed diagram of the sample of the present invention;

[0026] Figure 8 This is a cross-sectional view of a sample fixing the torsion portion of the present invention;

[0027] Figure 9 This is a cross-sectional view of the torsion loading portion of the present invention;

[0028] Figure 10 This is a schematic diagram of the dynamic operation of the torsional fatigue loading system of the present invention;

[0029] In the figure: 1. Circular flange base; 2. Pressure sensor; 3. Torsion fixture base; 4. Axial guide column; 5. Sample to be tested; 6. Flange pressure plate; 7. Crossed cylindrical roller bearing; 8. First torque sensor; 9. Angle connector; 10. Mounting plate; 11. Second torque sensor; 12. Single-phase stepper motor; 13. Reducer; 14. Eccentric wheel; 15. Connecting rod A; 16. Connecting rod B; 17. Angle adjustment hole; 18. Connecting rod C; 19. Loading platform. DETAILED DESCRIPTION

[0030] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0031] See also Figures 1 to 10 The present invention provides a technical solution: a reciprocating torsional fatigue loading system with controllable angle, the loading system comprising a torsional loading unit and a motor drive unit, and a connecting mechanism is arranged between the torsional loading unit and the motor drive unit, a circular flange base 1 is installed at the bottom of the torsional loading unit, the motor drive unit comprises a single-phase stepper motor 12, a reducer 13 and an eccentric wheel 14, the connecting mechanism comprises a connecting rod A15, a connecting rod B16, and a connecting rod C18, the bottoms of the torsional loading unit and the motor drive unit are both fixed on a loading platform 19, the single-phase stepper motor 12 and the reducer 13 are both adjusted and controlled by an external CNC program controller, wherein the CNC program controller is an existing mature mechanism, and a CNC program controller of corresponding specifications can be selected for installation according to the specific loading experiment. The CNC program controller in this embodiment adopts the Reisai DM870 micro-step driver component.

[0032] In this embodiment, the reciprocating torsion fatigue loading system adopts a gear coupling self-tightening fixing method, so there are certain requirements for sample preparation. The torsion fixture base 3 and the upper flange pressure plate 6 are each designed with a raised gear small column, such as Figure 6 Therefore, the sample cross-section design must match the raised gear columns on the torsion fixture base 3 and the flange pressure plate 6, and they must mesh with each other to achieve complete rigid fixation, so that there will be no unstable clamping or slipping during the torsion process. This loading system is currently designed for round tube samples with an outer diameter of 10mm and an internal gear shape. The sample details are as follows: Figure 7 shown.

[0033] The way the sample is fixed in this loading system needs to be protected. The sample is fixed by 8 axial guide columns 4 to ensure that the sample is in a completely centered state. During the entire reciprocating torsion experiment, the axial center point of the sample remains unchanged, presenting a pure torsion state. During the loading process, the inner ring of the cross roller bearing is fixed together with the flange pressure plate 6 below by screws, and the outer ring of the cross roller bearing is connected by 8 axial guide columns 4 to achieve 100% coaxiality. During the torsion process, the motor system drives the middle connecting rod to drive the inner ring of the cross roller bearing on the torsion system to rotate, thereby realizing the reciprocating torsion motion of the sample.

[0034] In this embodiment, a connecting rod is used as a torque transmission method, and multiple angle adjustment holes 17 are opened on the connecting rod to adjust the maximum reciprocating torsion angle. This transmission method greatly reduces the working resistance of the driver. At the same time, the purely mechanical connecting rod transmission method is simple and convenient, and almost no workpiece loss occurs during the torsion process. The subsequent maintenance cost is extremely low, and long-term reciprocating torsion fatigue can be achieved. A pressure sensor 2 is installed in the middle of the circular flange base 1, and a torsion fixture base 3 is provided on the surface of the pressure sensor 2. Multiple axial guide columns 4 are installed on the side of the surface of the circular flange base 1. A sample to be tested 5 is embedded in the middle of the top of the torsion fixture base 3. A flange pressure plate 6 is provided on the top of the sample to be tested 5, and a cross cylindrical roller bearing 7 is provided on the top of the axial guide column 4.

[0035] In this embodiment, a first torque sensor 8 is installed in the middle of the cross cylindrical roller bearing 7, an angle connector 9 is installed on the top of the cross cylindrical roller bearing 7, a mounting plate 10 is provided on the top of the angle connector 9, and a second torque sensor 11 is provided on the side of the mounting plate 10. The cross cylindrical roller bearing 7 includes an inner ring and an outer ring, and the inner ring and the outer ring cooperate with each other. The outer ring is connected to the circular flange base 1 through an axial guide column 4. There are eight axial guide columns 4, and the outer ring is fixed during loading, and the inner ring is torsionally rotated under the action of the connecting mechanism.

[0036] The reducer 13 in this embodiment is installed on the top of the single-phase stepper motor 12, and an eccentric wheel 14 is installed on the output shaft of the reducer 13. The single-phase stepper motor 12 transmits torque to the eccentric wheel 14 at the top through the middle reducer 13. The reduction ratio of the reducer 13 is 10. The loading is controlled by the single-phase motor, and only the deflection angle and the number of reciprocating cycles need to be set. The single-phase motor is very smooth during the startup process, reducing the mechanical vibration caused by violent startup. In addition, since the single-phase motor does not require a high-voltage power supply, the temperature of the single-phase motor is very low. Therefore, with proper maintenance, it can operate for a longer time.

[0037] In this embodiment, a plurality of angle adjustment holes 17 are provided on the surface of the connecting rod C18, and the connecting rod C18 is combined and connected with the connecting rod B16 through the angle adjustment holes 17. The end of the connecting rod C18 is connected to the connecting rod A15, and the connecting rod A15 and the connecting rod B16 are both linked to the torsion loading unit. Specifically, the reciprocating torsion angle during torsional loading is changed by changing the position of the connecting rod B16 fixed to the different angle adjustment holes 17 on the connecting rod C18, thereby finally realizing the fatigue loading test at the above-mentioned different torsion angles.

[0038] The loading process of this torsion loading system is as follows: after power is turned on, the motor can provide driving force. When the motor is running, it drives the eccentric wheel 14 above to rotate, and drives the torsion system to perform reciprocating torsion motion through the connecting rod transmission, thereby realizing the reciprocating torsion fatigue loading test of the sample under compression mode. Figure 8 As shown in the figure, by changing the position of the angle adjustment hole 17 where connecting rod B16 connects to connecting rod C18, different maximum torsion angles can be achieved. As angle adjustment holes 17 are positioned from left to right, the maximum torsion angle gradually increases. Angle and torque sensors record angle and force data during the loading process. This loading system can perform reciprocating torsional fatigue loading experiments under constant pressure.

[0039] At a specific torsion angle, the eccentric wheel 14 rotates to the position closest to and farthest from the torsion portion, respectively. During rotation, the rotation of the eccentric wheel 14 drives the movement of the connecting rod C18, which in turn drives the movement of the connecting rods A15 and B16. A section of the connecting rods A15 and B16 is fixed to the inner ring of the cross cylindrical roller bearing 7, driving the inner ring bearing of the cross cylindrical roller bearing 7 to rotate, thereby achieving reciprocating torsional motion of the sample.

[0040] The above shows and describes the basic principles, main features and advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and range of equivalents of the claims are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0041] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A reciprocating torsional fatigue loading system with controllable angle, characterized by: The loading system comprises a torsion loading unit and a motor drive unit, and a connecting mechanism is provided between the torsion loading unit and the motor drive unit. A circular flange base (1) is installed at the bottom of the torsion loading unit. The motor drive unit comprises a single-phase stepper motor (12), a reducer (13) and an eccentric wheel (14). The connecting mechanism comprises a connecting rod A (15), a connecting rod B (16) and a connecting rod C (18). The bottoms of the torsion loading unit and the motor drive unit are both fixed on a loading platform (19). The single-phase stepper motor (12) and the reducer (13) are both controlled by an external numerical control program. The controller is used for adjustment and control, a pressure sensor (2) is installed in the middle of the circular flange base (1), and a torsion clamp base (3) is provided on the surface of the pressure sensor (2), a plurality of axial guide columns (4) are installed on the side of the surface of the circular flange base (1), a sample to be tested (5) is embedded in the middle of the top of the torsion clamp base (3), a flange pressure plate (6) is provided on the top of the sample to be tested (5), a cross cylindrical roller bearing (7) is provided on the top of the axial guide column (4), a first torque sensor (8) is installed in the middle of the cross cylindrical roller bearing (7), and the cross cylindrical roller bearing (7) is provided with a first torque sensor (8). An angle connector (9) is installed on the top of the cylindrical roller bearing (7), a mounting plate (10) is provided on the top of the angle connector (9), and a second torque sensor (11) is provided on the side of the mounting plate (10). The cross cylindrical roller bearing (7) includes an inner ring and an outer ring, and the inner ring and the outer ring cooperate with each other. The outer ring is connected to the circular flange base (1) through an axial guide column (4). There are eight axial guide columns (4). During loading, the outer ring is fixed and the inner ring is torsionally rotated under the action of the connecting mechanism. A plurality of angle adjustment holes (17) are provided on the surface of the connecting rod C (18). The connecting rod C (18) is combined and connected with the connecting rod B (16) through the angle adjustment hole (17), the end of the connecting rod C (18) is connected with the connecting rod A (15), and the connecting rod A (15) and the connecting rod B (16) are both linked with the torsion loading unit; the reducer (13) is installed on the top of the single-phase stepper motor (12), and an eccentric wheel (14) is installed on the output shaft of the reducer (13); the single-phase stepper motor (12) transmits torque to the eccentric wheel (14) at the top through the middle reducer (13), and the reduction ratio of the reducer (13) is 10; One end of the connecting mechanism is hinged to the eccentric wheel (14), and the other end is hinged to the inner ring of the cross cylindrical roller bearing (7); The torsion clamp base (3) and the flange pressure plate (6) are respectively designed with a raised small gear column, and the cross-section of the sample to be tested (5) is designed to match the raised small gear columns on the torsion clamp base (3) and the flange pressure plate (6).

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