Fatigue strength testing device and fatigue strength detecting system

Abstract

The utility model provides a fatigue strength testing device and a fatigue strength detecting system, and relates to the field of automobile part testing. According to the fatigue strength testing device, through collaborative design of the stress mounting unit and the power unit and staggered distribution of the stress applying parts which are arranged on the two opposite mounting seats at intervals on the same plane, the fatigue strength testing device can correspond to four-point bending characteristics of a planet shaft when the planet shaft is subjected to thrust of a differential shell and resistance of a planet gear in a differential; the stress applying part applies oppositely-staggered bending loads to different shaft body areas of the tested shaft, the problems that traditional simulation analysis is disjointed with actual stress, and the assembly testing efficiency is low are solved, a scheme which is simple in structure, accurate in working condition simulation and high in universality is provided for planet shaft fatigue strength detection, and the fatigue strength of the planet shaft is detected. And the fatigue strength of the planetary shaft of the differential can be efficiently tested. The detection system comprises the fatigue strength testing device and has all the beneficial effects of the fatigue strength testing device.

Description

Technical Field

[0001] This utility model relates to the field of automotive parts testing, and in particular to a fatigue strength testing device and testing system. Background Technology

[0002] The planetary shaft is a crucial component connecting the differential housing and the planetary gears, secured to the differential housing by a coiled pin. During electric drive power transmission, the electric drive force is transmitted to the differential housing via the driving and driven gears. The differential housing then pushes the embedded planetary shaft in a bending motion, which in turn drives the planetary gears to rotate, thus transmitting power to the wheels of the electric vehicle. The differential planetary shaft is a core functional component, and its performance directly affects whether the electric drive product can output power normally to both wheels of the vehicle. The fatigue strength of the differential planetary shaft is an important indicator in the design of electric drive reducers and is the basis for electric drive reliability assessment. Current fatigue strength testing and assessment methods for the planetary shaft component of electric drive differentials in electric vehicles have certain limitations. On the one hand, simulation-based strength verification relies on material library parameters, which deviates from actual operating conditions and lacks effective calibration, leading to inaccurate results. On the other hand, while testing based on the electric drive assembly can simulate actual operating conditions, it requires overall installation and debugging, resulting in low testing efficiency and extremely high costs, making it difficult to meet the needs of batch testing. During operation, the planetary shaft is subjected to the thrust of the differential housing and the resistance of the planetary gears, exhibiting a four-point bending stress characteristic. However, existing devices cannot accurately reproduce this stress state, resulting in test results that do not truly reflect its fatigue performance. Therefore, there is an urgent need for a testing device that can efficiently, cost-effectively, and accurately simulate actual stress conditions to solve the problems of low testing efficiency, high cost, and inaccurate simulation of operating conditions in existing technologies. Utility Model Content

[0003] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a fatigue strength testing device and detection system to solve the related problems in the prior art.

[0004] To achieve the above and other related objectives, this utility model provides a fatigue strength testing device, comprising:

[0005] The force-bearing mounting unit includes two opposing mounting seats, each mounting seat having two force-applying parts spaced apart for supporting the measured shaft;

[0006] The power unit is connected to each of the two mounting bases;

[0007] The force-applying parts corresponding to the two mounting seats are located on the same plane and are staggered to form two sets of support points. When the power unit drives the mounting seats, it applies opposing and staggered bending loads to different shaft areas of the measured shaft through the force-applying parts.

[0008] Furthermore, the mounting base is provided with a U-shaped groove, and the two side walls inside the U-shaped groove are provided with mounting holes to form a force application part. The two mounting holes are centered and coaxially arranged. The mounting holes cooperate with the shaft being measured and provide a force point for the shaft being measured.

[0009] Furthermore, the two U-shaped grooves interlock and are arranged symmetrically at their top and bottom centers, and the mounting holes of the two U-shaped grooves are coaxially aligned to enable the placement and installation of the shaft being measured.

[0010] Furthermore, the force-bearing mounting unit also includes a fixing component for fixing the measured shaft in the mounting base.

[0011] Furthermore, the fixing component includes a pin hole and a fixing pin. The pin hole is located on the top of the mounting base, the pin hole intersects perpendicularly with and communicates with the mounting hole, and the fixing pin passes through the pin hole and is fixedly engaged with the shaft being measured.

[0012] Furthermore, the force-bearing mounting unit also includes two connecting base plates, which are respectively installed on the side of the mounting base away from the force-applying part, and the mounting base is connected to the power unit through the connecting base plates.

[0013] Furthermore, the connecting base plate and the mounting base are connected by bolts, welding, riveting, or integral molding.

[0014] Furthermore, the power unit includes a power application component and a power fixing component. The power fixing component fixes one of the mounting seats in position, and the power application component drives the other mounting seat to apply periodically varying pressure or tension in the direction of the line connecting the two mounting seats.

[0015] The measured shaft extends along its own shaft direction and includes a first region, a second region, a third region and a fourth region in sequence. The first region and the third region correspond to the two force-applying parts of one of the mounting seats, and the second region and the fourth region correspond to the two force-applying parts of the other mounting seat.

[0016] When the power application component applies pressure, the first region and the third region are subjected to pressure in a first preset direction, and the second region and the fourth region are subjected to a reverse force in a second preset direction.

[0017] When the power application component applies a pulling force, the first region and the third region are subjected to a pulling force in the second preset direction, and the second region and the fourth region are subjected to a reverse force in the first preset direction.

[0018] Furthermore, the load-bearing mounting unit is made of aluminum alloy, iron, steel, or magnesium alloy.

[0019] This application further discloses a testing system, which includes the above-mentioned fatigue strength testing device and a data acquisition computer. The data acquisition computer is communicatively connected to the fatigue strength testing device to obtain test data, wherein the test data includes at least the driving parameters of the power unit.

[0020] As described above, the fatigue strength testing device and detection system of this utility model have at least the following beneficial effects, including but not limited to:

[0021] This invention, through the collaborative design of the force-bearing mounting unit and the power unit, can be used to construct a four-point bending test model that accurately simulates the actual stress conditions of a differential planetary shaft. In this application, force-applying parts are staggered on the same plane, spaced apart on two opposing mounting bases. This corresponds to the four-point bending characteristics of the planetary shaft in the differential under the thrust of the differential housing and the resistance of the planetary gears. When the power unit drives the mounting base, the force-applying parts apply opposing and staggered bending loads to different shaft areas under test, solving the problems of disconnect between traditional simulation analysis and actual stress, and low assembly testing efficiency. Simultaneously, the spaced force-applying parts can be adapted to different specifications of planetary shafts by adjusting the spacing. Combined with the compatibility of the power unit and general testing equipment, this significantly reduces testing costs and improves efficiency. It provides a simple, accurate, and versatile solution for planetary shaft fatigue strength testing, enabling efficient testing of differential planetary shaft fatigue strength. Attached Figure Description

[0022] Figure 1 The diagram shown is an overall structural schematic of a fatigue strength testing device provided in this application.

[0023] Figure 2 The diagram shown is one of the structural schematic diagrams of the load-bearing installation unit provided in this application;

[0024] Figure 3 The second schematic diagram shows the structure of the load-bearing installation unit provided in this application.

[0025] Figure 4 The diagram shown is a force diagram of the measured shaft provided in this application.

[0026] Icons: 1. Load-bearing installation unit, 101. Mounting base, 102. Load-bearing application part, 103. U-shaped groove, 104. Fixing pin, 105. Connecting base plate;

[0027] 2. Power unit, 201. Power application component, 202. Power fixing component;

[0028] 30. Measured axis, 301. First region, 302. Second region, 303. Third region, 304. Fourth region. Detailed Implementation

[0029] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0030] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0031] Please refer to Figures 1-3 This application discloses a fatigue strength testing device, including a force-bearing mounting unit 1 and a power unit 2. The force-bearing mounting unit 1 includes two opposing mounting seats 101. Two force-applying parts 102 for supporting the tested shaft 30 are spaced apart on the mounting seats 101. The power unit 2 is connected to the two mounting seats 101 respectively. The force-applying parts 102 corresponding to the two mounting seats 101 are located on the same plane and are staggered to form two sets of support points. When the power unit 2 drives the mounting seats 101, it applies opposing and staggered bending loads to different shaft areas of the tested shaft 30 through the force-applying parts 102.

[0032] It is worth noting that this device, through the collaborative design of the force-bearing mounting unit 1 and the power unit 2, can be used to construct a four-point bending test model that accurately simulates the actual stress conditions of the differential planetary shaft. In this application, the force-applying parts 102, which are spaced apart on two opposing mounting seats 101 and staggered on the same plane, correspond to the four-point bending characteristics of the planetary shaft under the thrust of the differential housing and the resistance of the planetary gears in the differential. When the power unit 2 drives the mounting seat 101 to move, the force-applying parts 102 apply opposing and staggered bending loads to different shaft areas of the tested shaft 30, solving the problems of disconnect between traditional simulation analysis and actual stress and low assembly testing efficiency. At the same time, the spaced force-applying parts 102 can be adapted to different specifications of planetary shafts by adjusting the spacing. Combined with the compatibility of the power unit 2 and general testing equipment, the testing cost is significantly reduced and the efficiency is improved. This provides a simple, accurate, and versatile solution for planetary shaft fatigue strength testing, enabling efficient testing of differential planetary shaft fatigue strength.

[0033] Please see Figures 1-3 The mounting base 101 is provided with a U-shaped groove 103. The two side walls of the U-shaped groove 103 are provided with mounting holes to form a force application part 102. The two mounting holes are centered and coaxially arranged. The mounting holes cooperate with the measured shaft 30 and provide a force point for the measured shaft 30.

[0034] Specifically, in this technical solution, the physical limiting effect of the mounting holes constrains the radial displacement of the tested shaft 30, forming a force-bearing point, while the coaxial mounting holes on both sides create a precise force transmission path. During testing, the bending load is transmitted to the designated position of the tested shaft 30 through the mounting holes. The synergistic effect of the U-groove 103 and the mounting holes improves the installation stability of the tested shaft 30.

[0035] It is worth noting that the U-shaped groove 103 on the mounting base 101 not only provides mounting space for the measured shaft 30, allowing the mounting base 101 to support the measured shaft 30 more stably and avoid inaccurate test results due to external vibration or displacement, but also, the mounting holes on both sides, in conjunction with the measured shaft 30, effectively provide two force application points for the force application part 102, enabling the force application part 102 to effectively act on a specific area of ​​the measured shaft 30, simulating the force distribution under actual working conditions.

[0036] Please see Figure 3 The two U-shaped grooves 103 interlock with each other and are arranged symmetrically at the top and bottom centers. The mounting holes of the two U-shaped grooves 103 are coaxially aligned to realize the placement and installation of the measured shaft 30.

[0037] Specifically, the interlocking of the two U-shaped grooves 103 means that the opening directions of the two U-shaped grooves 103 are opposite, and the protruding part of one U-shaped groove 103 is embedded in the concave part of the other U-shaped groove 103. The coaxial alignment of the mounting holes means that the central axes of the mounting holes on the two U-shaped grooves 103 coincide, ensuring that the tested shaft 30 can pass through smoothly and be accurately positioned. Its centrally symmetrical layout allows the tested shaft 30 to bear a uniform load, and the coaxial installation ensures accurate positioning of the test area, accurately simulating the four-point bending stress state under actual working conditions. Compared with existing technologies, this scheme achieves stable installation and positioning, providing a reliable foundation for subsequent bending load testing.

[0038] In some embodiments, the force-bearing mounting unit 1 further includes a fixing component for fixing the measured shaft 30 in the mounting base 101.

[0039] This technical solution ensures a constant position of the force application point when a bending load is applied by introducing a fixing component between the tested shaft 30 and the mounting base 101. When the power unit 2 drives the mounting base 101 to apply an alternating load, the fixing component effectively prevents the tested shaft 30 from axially sliding or circumferentially rotating within the mounting hole, thereby avoiding data distortion caused by shaft displacement. Especially for four-point bending tests where precise control of the force application position is required, the introduction of the fixing component ensures consistent force conditions for each test, thus improving the reliability and repeatability of the test results.

[0040] Please see Figure 2 and Figure 3 The fixing component includes a pin hole and a fixing pin 104. The pin hole is located on the top of the mounting base 101. The pin hole intersects perpendicularly with and communicates with the mounting hole. The fixing pin 104 passes through the pin hole and is fixedly engaged with the measured shaft 30.

[0041] Specifically, the pin hole penetrates the top of the mounting base 101, and its axis intersects perpendicularly with the axis of the mounting hole. In this embodiment, the fixing pin 104 is a coiled pin, but cylindrical pins, tapered pins, or threaded pins can also be used, depending on the specific requirements. The engagement between the fixing pin 104 and the measured shaft 30 prevents axial displacement of the measured shaft 30, and the perpendicular arrangement of the pin hole and the mounting hole also restricts radial movement. When a bending load is applied, the position of the force point on the measured shaft 30 remains stable, avoiding test errors caused by displacement. Furthermore, the vertical insertion method of the fixing pin 104 facilitates installation and removal and does not interfere with the normal force-bearing function of the mounting hole.

[0042] In some embodiments, the pin hole can also be a threaded hole, and the fixing pin 104 adopts a bolt structure, achieving locking through threaded engagement. Furthermore, the fixing assembly can also employ a quick-clamping mechanism, such as an eccentric wheel clamping device or a pneumatic gripper, to achieve rapid clamping of the measured shaft 30. For measured shafts 30 of different diameters, the fixing assembly can be designed with an adjustable structure, for example, using replaceable bushings or shims to accommodate shafts of different sizes.

[0043] Please see Figure 2 and Figure 3 The force-bearing mounting unit 1 also includes two connecting base plates 105, which are respectively installed on the side of the mounting base 101 away from the force-applying part 102. The mounting base 101 is connected to the power unit 2 through the connecting base plates 105.

[0044] It should be noted that the connecting base plate 105, as a transitional component for connection, transforms the concentrated load transmitted by the power unit 2 into a surface load, effectively reducing stress concentration at the connection point of the mounting base 101. Compared to a direct connection, this structural design avoids direct interference from the power unit 2 to the force application part 102, while increasing the connection contact area to improve structural rigidity, making the load application process more stable and controllable.

[0045] Optionally, the connecting base plate 105 and the mounting base 101 are connected by bolts, welding, riveting, or integral molding. In other embodiments, other connection structures or methods can also be used, as long as they meet the requirements of the connecting base plate 105 and the connection needs.

[0046] Please see Figures 1-4 The power unit 2 includes a power application component 201 and a power fixing component 202. The power fixing component 202 fixes one of the mounting seats 101 in position. The power application component 201 drives the other mounting seat 101 to apply periodically varying pressure or tension in the direction connecting the two mounting seats 101. The measured shaft 30, along its own axial extension direction, sequentially includes a first region 301, a second region 302, a third region 303, and a fourth region 304, wherein the first region 301 and the third region 303 respectively correspond to the two force-bearing components of one of the mounting seats 101. The first region 102, the second region 302, and the fourth region 304 correspond to the two force-applying parts 102 of the other mounting base 101, respectively. When the power applying member 201 applies pressure, the first region 301 and the third region 303 are subjected to pressure in a first preset direction, and the second region 302 and the fourth region 304 are subjected to a reverse force in a second preset direction. When the power applying member 201 applies tension, the first region 301 and the third region 303 are subjected to tension in a second preset direction, and the second region 302 and the fourth region 304 are subjected to a reverse force in a first preset direction.

[0047] Optionally, the power application component 201 can be a hydraulic cylinder, an electric actuator, or a ball screw mechanism driven by a servo motor to generate precise and controllable reciprocating linear motion; no further limitations are imposed here. The power fixing component 202 can be a rigid bracket or a locking device, using bolts or clamps to fix the position of the mounting base 101; no further limitations are imposed here. The first preset direction and the second preset direction are 180° opposite each other. The conversion between pressure and tension is achieved by switching the direction of motion of the power application component 201. The reciprocating power application component 201 can be a sinusoidal power source.

[0048] It is worth noting that in this embodiment, the separation of power fixing and power driving ensures that the direction of force application is strictly along the line connecting the mounting base 101. The power application component 201 ensures linear force transmission through a rigid connection. The division of the four force-bearing zones allows the measured shaft 30 to simultaneously bear two pairs of opposing torques, accurately simulating the alternating bending stress in actual working conditions. Automatic adjustment of the force direction is achieved through mechanical constraints, avoiding errors from manual adjustment. The automatic conversion of the load direction can completely reproduce the bidirectional force state of the planetary shaft in actual operation.

[0049] In some embodiments, the load-bearing mounting unit 1 is made of aluminum alloy, iron, steel or magnesium alloy.

[0050] Specifically, the load-bearing mounting unit 1 includes a mounting base 101 or a connecting base plate 105, which are made of metal materials. Aluminum alloy allows for lightweight design while maintaining sufficient structural strength; iron offers high rigidity and cost advantages; steel exhibits excellent strength and fatigue life; and magnesium alloy is characterized by its lightweight and vibration damping performance. In addition to the above materials, other metal or non-metal materials can be used for related components of the load-bearing mounting unit 1, as long as they meet the corresponding requirements; these will not be elaborated upon here.

[0051] In summary, this fatigue strength testing device, through the collaborative design of the force-bearing mounting unit 1 and the power unit 2, can be used to construct a four-point bending test model that accurately simulates the actual stress conditions of a differential planetary shaft. In this application, the force-applying parts 102, spaced apart on two opposing mounting bases 101 and staggered on the same plane, correspond to the four-point bending characteristics of the planetary shaft under the thrust of the differential housing and the resistance of the planetary gears in the differential. When the power unit 2 drives the mounting base 101, the force-applying parts 102 apply opposing and staggered bending loads to different shaft areas of the tested shaft 30, solving the problems of disconnect between traditional simulation analysis and actual stress, and low assembly testing efficiency. Simultaneously, the spaced force-applying parts 102 can be adapted to different specifications of planetary shafts by adjusting their spacing. Combined with the compatibility of the power unit 2 with general testing equipment, this significantly reduces testing costs and improves efficiency, providing a simple, accurate, and versatile solution for planetary shaft fatigue strength testing, enabling efficient testing of differential planetary shaft fatigue strength.

[0052] This application further discloses a testing system comprising the aforementioned fatigue strength testing device, possessing all its beneficial effects. It also includes a data acquisition computer, which is communicatively connected to the fatigue strength testing device to acquire test data, wherein the test data includes at least the driving parameters of the power unit 2. The data acquisition computer can establish a communication connection with the fatigue strength testing device via wired or wireless means. The data acquisition computer can be configured as an industrial control computer or a general commercial computer, equipped with dedicated data acquisition software, capable of real-time display, storage, and analysis of the received data. Its driving parameters may specifically include its driving displacement and number of cycles; the test data also includes the state parameters of the tested shaft 30, including the magnitude of the deformation displacement, the stress-deformation curve, and the fracture location size of the tested shaft 30. This solution can completely record all key parameters during the testing process, providing accurate data support for subsequent analysis. Through digital monitoring and recording, it improves the reliability and efficiency of the test, enabling a more accurate assessment of the fatigue performance of the tested component. It should be noted that this testing system can also be used for applications of other testing functional modules.

[0053] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

[0054] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of this application. However, those skilled in the art will recognize that embodiments of this invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of this application.

[0055] Throughout this specification, references to "an embodiment," "an embodiment," or "a specific embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the present invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments described herein may be based on the teachings herein and will be considered part of the spirit and scope of the present invention.

[0056] It should also be understood that one or more of the elements shown in the figures may be implemented in a more separate or more integrated manner, or may even be removed because they are inoperable in certain circumstances or provided because they may be useful for a particular application.

[0057] Furthermore, unless otherwise expressly stated, any arrows in the accompanying drawings should be considered illustrative only and not limiting. Additionally, unless otherwise stated, the term "or" as used herein is generally intended to mean "and / or". Where a term is anticipated to provide a separation or combination capability that is unclear, a combination of components or steps will also be considered as indicated.

[0058] As used herein and throughout the claims below, unless otherwise specified, “a” and “the” include the plural references. Similarly, as used herein and throughout the claims below, unless otherwise specified, “in” means “in” and “on”.

[0059] The above description of the embodiments shown in this utility model (including the content in the abstract of the specification) is not intended to be an exhaustive enumeration or to limit the utility model to the precise forms disclosed herein. Although specific embodiments and examples of the utility model have been described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the utility model, as will be recognized and understood by those skilled in the art. As indicated, these modifications can be made to the utility model in accordance with the above description of the embodiments of this application, and such modifications will be within the spirit and scope of the utility model.

[0060] This document has generally described the systems and methods in detail to aid in understanding the present invention. Furthermore, various specific details have been set forth to provide a general understanding of the embodiments of this application. However, those skilled in the art will recognize that embodiments of the present invention can be practiced without one or more specific details, or using other devices, systems, accessories, methods, components, materials, parts, etc. In other instances, well-known structures, materials, and / or operations have not been specifically shown or described in detail to avoid obscuring various aspects of the embodiments of this application.

Claims

1. A fatigue strength testing device, characterized by, include: The force-bearing mounting unit includes two opposing mounting seats, each mounting seat having two force-applying parts spaced apart for supporting the measured shaft; The power unit is connected to each of the two mounting bases; The force-applying parts corresponding to the two mounting seats are located on the same plane and are staggered to form two sets of support points. When the power unit drives the mounting seats, it applies opposing and staggered bending loads to different shaft areas of the measured shaft through the force-applying parts.

2. The fatigue strength testing device according to claim 1, characterized in that: The mounting base is provided with a U-shaped groove, and the two side walls of the U-shaped groove are provided with mounting holes to form a force application part. The two mounting holes are centered and coaxially arranged. The mounting holes cooperate with the shaft being measured and provide a force application point for the shaft being measured.

3. The fatigue strength testing device according to claim 2, characterized in that: The two U-shaped grooves interlock and are arranged symmetrically at the top and bottom centers. The mounting holes of the two U-shaped grooves are coaxially aligned to enable the placement and installation of the shaft being measured.

4. The fatigue strength testing device according to claim 2, characterized in that: The force-bearing mounting unit also includes a fixing component, which is used to fix the measured shaft in the mounting base.

5. The fatigue strength testing device according to claim 4, characterized in that: The fixing component includes a pin hole and a fixing pin. The pin hole is located on the top of the mounting base. The pin hole intersects perpendicularly with and communicates with the mounting hole. The fixing pin passes through the pin hole and is fixedly engaged with the shaft being measured.

6. The fatigue strength testing device according to claim 1, characterized in that: The force-bearing mounting unit also includes two connecting base plates, which are respectively installed on the side of the mounting base away from the force-applying part. The mounting base is connected to the power unit through the connecting base plates.

7. The fatigue strength testing device according to claim 6, characterized in that: The connecting base plate and the mounting base are connected by bolts, welding, riveting, or integral molding.

8. The fatigue strength testing device according to claim 1, characterized in that: The power unit includes a power application component and a power fixing component. The power fixing component fixes one of the mounting seats in position, and the power application component drives the other mounting seat to apply periodically varying pressure or tension in the direction of the line connecting the two mounting seats. The measured shaft extends along its own shaft direction and includes a first region, a second region, a third region and a fourth region in sequence. The first region and the third region correspond to the two force-applying parts of one of the mounting seats, and the second region and the fourth region correspond to the two force-applying parts of the other mounting seat. When the power application component applies pressure, the first region and the third region are subjected to pressure in a first preset direction, and the second region and the fourth region are subjected to a reverse force in a second preset direction. When the power application component applies a pulling force, the first region and the third region are subjected to a pulling force in the second preset direction, and the second region and the fourth region are subjected to a reverse force in the first preset direction.

9. The fatigue strength testing device of any one of claims 1-8, wherein: the force receiving mounting unit is made of aluminum alloy, iron, steel or magnesium alloy.

10. A detection system comprising the fatigue strength testing device according to any one of claims 1 to 9, characterized in that a data collection computer is further included, and the data collection computer is in communication connection with the fatigue strength testing device to obtain test data, wherein the test data at least includes driving parameters of the power unit.

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