Gearbox housing fatigue life detection device and method

Abstract

The present application relates to a gearbox housing fatigue life detection device and method, which belongs to the field of gearbox housing fatigue test technology, including a support platform, on which a mounting seat for cantilever mounting the gearbox housing is provided; a loading member, which is arranged on the support platform, and a connecting frame for connecting the gearbox housing is threadedly connected to the loading shaft of the loading member, and the loading shaft is provided with a limiting surface facing the connecting frame; a pre-tightening member, which is arranged between the limiting surface and the connecting frame, and is used to provide axial pre-tightening force to tighten the connecting frame, and the pre-tightening member is provided with an inclined surface. The pre-tightening members are used in pairs, and when used, the inclined surfaces on the pre-tightening members are relatively fitted together, and the relative positions of the inclined surfaces of the two pre-tightening members are adjusted to abut the limiting surface and the connecting frame respectively. The device of the present application can ensure a stable connection between the gearbox housing and the loading member to effectively transfer the load and realize the fatigue strength assessment of the gearbox housing.

Description

Technical Field

[0001] The present application relates to the technical field of gearbox housing fatigue testing, and in particular to a gearbox housing fatigue life detection device and method. Background Art

[0002] As the power density of automotive diesel engines increases, the cylinder pressure and piston linear speed also increase significantly. This leads to an increase in the tensile stress on the connecting rod and a faster frequency of change, which in turn makes the vibration excitation of the transmission housing increasingly stronger. Special equipment is needed to perform fatigue tests on the transmission housing.

[0003] Currently, gearbox housing fatigue strength analysis is mostly based on FEA simulation. However, the simulation model assumptions differ significantly from actual conditions, making model accuracy difficult to verify. A few fatigue tests are performed using testing machines, such as the one disclosed in Publication No. CN202956276U.

[0004] However, since the force-applying systems of currently known testing machines are generally composed of a force-applying cylinder or hydraulic cylinder, a control system, and a force sensor, the force value of the load required for the test is relatively large. How to ensure a stable connection between the gearbox housing and the loading part to effectively transfer the load is a problem that needs to be solved urgently. Therefore, it is necessary to provide a gearbox housing fatigue life detection device and method. Summary of the Invention

[0005] In response to the shortcomings or one of the shortcomings of the above-mentioned background technology, the embodiments of the present application provide a gearbox housing fatigue life detection device and method, which can ensure a stable connection between the gearbox housing and the loading part to effectively transfer the load and realize the gearbox housing fatigue strength assessment.

[0006] In a first aspect, an embodiment of the present application provides a gearbox housing fatigue life detection device, comprising:

[0007] a support platform on which a mounting seat for cantilever mounting the gearbox housing is provided;

[0008] A loading member is provided on the support platform, wherein a connecting frame for connecting to a gearbox housing is threadedly connected to a loading shaft of the loading member, and a limiting surface facing the connecting frame is provided on the loading shaft;

[0009] A pre-tightening member is arranged between the limiting surface and the connecting frame, and is used to provide axial pre-tightening force to tighten the connecting frame. The pre-tightening member is provided with an inclined surface. The pre-tightening members are used in pairs. When in use, the inclined surfaces on the pre-tightening members are relatively fitted together. The relative positions of the inclined surfaces of the two pre-tightening members are adjusted to abut the limiting surface and the connecting frame respectively.

[0010] In the first aspect, in some embodiments, the preload member is an annular gasket, and the inclined surface is located at one end of the annular gasket and rises in a spiral along the circumference of the annular gasket.

[0011] In the first aspect, in some embodiments, the loading shaft of the loader has a large diameter shaft section and a small diameter shaft section, the small diameter shaft section is provided with a thread for installing the connecting frame, and the limiting surface connects the large diameter shaft section and the small diameter shaft section.

[0012] On the first aspect, in some embodiments, the connecting frame includes a sleeve for connecting the loading shaft, and a connecting plate connected to the sleeve, and an L-shaped block is symmetrically installed at one end of the gearbox housing away from the mounting seat, and the connecting plate is fixedly connected to the L-shaped block.

[0013] In the first aspect, in some embodiments, a column for mounting the loader is provided on the support platform, the mounting seat is L-shaped, and a strip hole for mounting a fastener is provided on the mounting seat.

[0014] In a first aspect, in some embodiments, the loading member is a loading cylinder driven by a hydraulic oil source, and the loading cylinder is connected to a cooling mechanism for regulating the temperature of the hydraulic oil source;

[0015] The cooling mechanism includes a refrigerated water circuit and a chiller. The chiller exchanges heat with the refrigerated water circuit through a first heat exchanger. The refrigerated water circuit exchanges heat with a hydraulic oil source in a loading cylinder through a second heat exchanger.

[0016] In the first aspect, in some embodiments, the refrigerated water circuit includes a water tank connected to the inlet of the first heat exchanger and the outlet of the second heat exchanger, and a temperature control valve connected to the outlet of the first heat exchanger and the inlet of the second heat exchanger, the temperature control valve is connected to the water tank through a bypass, and a water pump is arranged between the temperature control valve and the second heat exchanger.

[0017] On the first aspect, in some embodiments, the cooling mechanism further includes a controller and a temperature sensor connected to the controller, the temperature sensor is arranged between the water pump and the second heat exchanger, and the controller is used to adjust the opening of the temperature control valve and the power of the water pump.

[0018] In a second aspect, an embodiment of the present application provides a method for detecting fatigue life of a transmission housing, using the transmission housing fatigue life detection device as described in any one of the above, the method comprising:

[0019] The connecting frame is threadedly connected to the loading shaft of the loading member, and the pre-tightening members are arranged in pairs between the connecting frame and the limiting surface, and the inclined surfaces on the two pre-tightening members are relatively fitted together;

[0020] Connect the connecting frame to the support platform, and apply a set tension to the loading shaft through the loading member to tighten the connecting frame on the thread of the loading shaft;

[0021] By adjusting the relative positions of the inclined surfaces of the two pre-tightening members to respectively abut against the limiting surface and the connecting frame, and then unloading the set tension, the connecting frame is separated from the support platform;

[0022] A gearbox housing is cantilevered on the mounting seat of the support platform, and one end of the gearbox housing away from the mounting seat is fixedly mounted to the connecting frame;

[0023] An alternating load of preset amplitude and frequency is applied to the gearbox housing through a loading member to obtain the life of the gearbox housing under the preset amplitude and frequency.

[0024] In a second aspect, in some embodiments, applying an alternating load of a preset amplitude and frequency to the gearbox housing by a loading member to obtain the life of the gearbox housing at the preset amplitude and frequency includes:

[0025] Arrange sensors on the gearbox housing to obtain data on the load on the gearbox housing that changes over time when the vehicle is traveling on a typical road;

[0026] The data is processed and divided into load levels and operating times to obtain the operating time of the transmission housing under each load level on a typical road.

[0027] Apply alternating loads corresponding to the load levels to the gearbox housing through the loading component to obtain the life of the gearbox housing under each load level;

[0028] Calculate the fatigue damage of the gearbox housing under a typical road cycle based on the operating time under each load level and the life of the gearbox housing under each load level;

[0029] Based on the fatigue damage of the gearbox housing under a typical road cycle, the number of cycles that the gearbox housing can undergo under the typical road conditions is calculated to reflect the life of the gearbox housing.

[0030] The beneficial effects of the technical solution provided by this application include:

[0031] An embodiment of the present application provides a gearbox housing fatigue life detection device and method, which includes a support platform provided with a mounting seat for cantilever mounting the gearbox housing; a loading member provided on the support platform, a loading shaft of the loading member being threadedly connected to a connecting frame for connecting the gearbox housing, and a limiting surface facing the connecting frame provided on the loading shaft; a pre-tightening member provided between the limiting surface and the connecting frame for providing an axial pre-tightening force to tighten the connecting frame, a bevel provided on the pre-tightening member, and the pre-tightening members are used in pairs, and when in use, the bevels on the pre-tightening members are relatively fitted together, and the relative positions of the bevels of the two pre-tightening members are adjusted to abut the limiting surface and the connecting frame respectively.

[0032] Therefore, the transmission case and the loading component are securely connected to effectively transfer loads. Specifically, the connecting frame is threaded onto the loading shaft, and paired preload members are installed between the limiting surface on the loading shaft and the connecting frame. By adjusting the relative positions of the inclined surfaces of the two preload members, the preload member elevations can be adjusted to abut the limiting surface and the connecting frame, respectively, thereby providing an axial preload to secure the connecting frame. During fatigue testing, the axial preload force is greater than the extrusion force applied to the connecting frame, preventing the connecting frame from loosening. This ensures a secure connection between the transmission case and the loading component, effectively transferring loads and enabling fatigue strength assessment of the transmission case. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 A schematic structural diagram of a device according to an embodiment of the present application;

[0035] Figure 2 A schematic structural diagram of the device according to another embodiment of the present application from another perspective;

[0036] Figure 3 This is a schematic structural diagram of a pre-tightening member according to an embodiment of the present application;

[0037] Figure 4 This is a schematic diagram of the cooperation between two pre-tightening members in an embodiment of the present application;

[0038] Figure 5 This is a schematic diagram of the installation of the pre-tightening member according to an embodiment of the present application;

[0039] Figure 6 This is a schematic structural diagram of a connecting frame according to an embodiment of the present application;

[0040] Figure 7This is a schematic structural diagram of an L-shaped block according to an embodiment of the present application;

[0041] Figure 8 This is a schematic structural diagram of a mounting base according to an embodiment of the present application;

[0042] Figure 9 This is a schematic diagram of the principle of the cooling mechanism of an embodiment of the present application.

[0043] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0044] 1. Support platform; 2. Mounting seat; 21. Strip hole; 3. Loading member; 31. Loading shaft; 32. Limiting surface; 4. Connecting frame; 41. Sleeve; 42. Connecting piece; 5. Pre-tightening member; 51. Inclined surface; 6. L-shaped block; 7. Column;

[0045] 8. Chiller; 9. First heat exchanger; 10. Second heat exchanger; 11. Water tank; 12. Temperature control valve; 13. Water pump; 14. Temperature sensor; 15. Controller. DETAILED DESCRIPTION

[0046] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0047] In response to the shortcomings or one of the shortcomings of the above-mentioned background technology, the embodiments of the present application provide a gearbox housing fatigue life detection device and method, which can ensure a stable connection between the gearbox housing and the loading part to effectively transfer the load and realize the gearbox housing fatigue strength assessment.

[0048] See also Figures 1 to 9 As shown, a first aspect of an embodiment of the present application provides a gearbox housing fatigue life detection device, comprising:

[0049] A support platform 1, on which a mounting base 2 for cantilever mounting the gearbox housing is provided;

[0050] The loading member 3 is arranged on the support platform 1. The loading shaft 31 of the loading member 3 is threadedly connected to a connecting frame 4 for connecting to the gearbox housing. The loading shaft 31 is provided with a limiting surface 32 facing the connecting frame 4;

[0051] The pre-tightening member 5 is arranged between the limiting surface 32 and the connecting frame 4, and is used to provide axial pre-tightening force to tighten the connecting frame 4. The pre-tightening member 5 is provided with an inclined surface 51. The pre-tightening members 5 are used in pairs. When in use, the inclined surfaces 51 on the pre-tightening members 5 are relatively fitted together. By adjusting the relative positions of the inclined surfaces 51 of the two pre-tightening members 5, they can respectively abut the limiting surface 32 and the connecting frame 4.

[0052] A mounting base 2 is installed on the support platform 1 of the gearbox housing fatigue life detection device in the embodiment of the present application. The mounting base 2 can realize cantilever installation of the gearbox housing, simulating the suspended use state of the gearbox housing in the vehicle. The loading member 3 is connected to the end of the gearbox housing through the connecting frame 4 to realize load transfer, so as to perform fatigue strength assessment of the gearbox housing.

[0053] In order to ensure a firm connection between the gearbox housing and the loading member 3 so as to effectively transfer the load, the connecting frame 4 is threadedly connected to the loading shaft 31, and a pair of pre-tightening members 5 are installed between the limiting surface 32 on the loading shaft 31 and the connecting frame 4. By adjusting the relative position of the inclined surfaces 51 of the two pre-tightening members 5, the elevation of the pre-tightening members 5 can be adjusted to respectively abut the limiting surface 32 and the connecting frame 4, thereby providing axial pre-tightening force to tighten the connecting frame 4.

[0054] During the fatigue test, the axial preload force is greater than the extrusion force on the connecting frame 4. Therefore, the connecting frame 4 will not loosen, and a stable connection between the gearbox housing and the loading part 3 can be ensured to effectively transfer the load and realize the fatigue strength assessment of the gearbox housing.

[0055] For example, the connecting frame 4 is threadedly connected to the loading shaft 31 of the loading member 3, and the pre-tightening members 5 are arranged in pairs between the connecting frame 4 and the limiting surface 32, with the inclined surfaces 51 on the two pre-tightening members 5 being relatively fitted together;

[0056] The connecting frame 4 is fixedly connected to the support platform 1 through the mounting block. A pulling force of 500 kN is applied to the loading shaft 31 through the loading member 3. The connecting frame 4 is tightened on the thread of the loading shaft 31. At this time, the gap between the top of the connecting frame 4 and the limiting surface 32 becomes larger.

[0057] By moving the two preload members 5 relative to each other, their inclined surfaces 51 change relative position, and the height of the upper preload member 5 changes to accommodate the gap. That is, the two preload members 5 abut the limiting surface 32 and the top of the connecting frame 4, respectively. The 500 kN tension is then removed, and the mounting block is disassembled, separating the connecting frame 4 from the support platform 1. This allows the preload members 5 to generate a large axial force to secure the connecting frame 4 to the threads of the loading shaft 31, preventing displacement of the connecting frame 4.

[0058] In some optional embodiments, see Figures 1 to 9As shown, an embodiment of the present application provides a gearbox housing fatigue life detection device, wherein the preload member 5 of the gearbox housing fatigue life detection device is an annular gasket, and the inclined surface 51 is located at one end of the annular gasket and spirally rises along the circumference of the annular gasket.

[0059] The preload member 5 of the present embodiment is an annular spacer with a flat surface at one end and an inclined surface 51 at the other end. The inclined surface 51 spirals upward along the circumference of the spacer. During installation, the annular spacers are used in pairs. The two annular spacers are mounted on the loading shaft 31 of the loading member 3, and the inclined surfaces 51 fit together. Because the inclined surfaces 51 spiral upward along the circumference, the height of the upper annular spacer can be adjusted by rotating the two annular spacers relative to each other to adapt to the gap between the limiting surface 32 and the connecting frame 4.

[0060] It should be noted that the height of the circumferential spiral rise of the inclined surface 51 is relatively small. When the two annular gaskets used in a pair are squeezed, the inclined surfaces 51 between the two annular gaskets can be self-locked with each other under the action of friction and will not cause mutual twisting movement.

[0061] Furthermore, in order to facilitate the adjustment of the position of the annular gasket, a radial through hole is provided on the annular gasket, and the through hole can be inserted into the rod, thereby facilitating the rotation of the annular gasket by the rod to adjust the position.

[0062] In some optional embodiments, see Figures 1 to 9 As shown, an embodiment of the present application provides a gearbox housing fatigue life detection device, wherein the loading shaft 31 of the loading part 3 of the gearbox housing fatigue life detection device has a large diameter shaft section and a small diameter shaft section, the small diameter shaft section is provided with a thread for installing the connecting frame 4, and the limiting surface 32 connects the large diameter shaft section and the small diameter shaft section.

[0063] In the embodiment of the present application, the loading shaft 31 of the loading member 3 is provided with a shoulder, forming a coaxially arranged large-diameter shaft section and a small-diameter shaft section. The small-diameter shaft section is provided with threads for mounting the connecting frame 4. The annular surface at the shoulder forms a limiting surface 32, which connects the large-diameter shaft section and the small-diameter shaft section. After the preload member 5 is sleeved on the small-diameter shaft section, the connecting frame 4 is installed via threads. The preload member 5 cooperates with the limiting surface 32 to circumferentially limit the connecting frame 4. In other embodiments, a fixing ring can be welded to the loading shaft 31 to form the limiting surface 32 facing the connecting frame 4.

[0064] In some optional embodiments, see Figures 1 to 9As shown, an embodiment of the present application provides a gearbox housing fatigue life detection device, wherein the connecting frame 4 of the gearbox housing fatigue life detection device includes a sleeve 41 for connecting the loading shaft 31, and a connecting piece 42 connected to the sleeve 41, and an L-shaped block 6 is symmetrically installed at one end of the gearbox housing away from the mounting seat 2, and the connecting piece 42 is fixedly connected to the L-shaped block 6.

[0065] The connecting frame 4 of the embodiment of the present application includes a sleeve 41 with an internal thread, a connecting piece 42 is welded or integrally formed on the sleeve 41, and a mounting hole is provided on the connecting piece 42. When in use, a group of L-shaped blocks 6 are symmetrically installed on the gearbox housing in advance through fasteners, and the connecting piece 42 is fixedly connected to the group of symmetrically arranged L-shaped blocks 6 through fasteners.

[0066] Exemplarily, the L-shaped block 6 in this embodiment includes an L-shaped plate, which is provided with mounting holes for installing fasteners to connect to the gearbox housing in the front and rear directions. The L-shaped plate is integrally formed with an end block arranged perpendicular to the L-shaped plate, and the top surface of the end block is provided with mounting holes for installing fasteners to fix the connecting piece 42 in the upper and lower directions. A triangular reinforcing rib is integrally formed between the end block and the connecting piece 42.

[0067] In some optional embodiments, see Figures 1 to 9 As shown, an embodiment of the present application provides a gearbox housing fatigue life detection device, wherein a support platform 1 of the gearbox housing fatigue life detection device is provided with a column 7 for installing a loader 3, the mounting seat 2 is L-shaped, and a strip hole 21 for installing a fastener is provided on the mounting seat 2.

[0068] The support platform 1 of the present embodiment is fixedly mounted with four rectangularly arranged columns 7. Loading members 3 are mounted on these columns. After installation, the transmission housing is positioned below the loading members 3, facilitating the loading members 3 applying axial loads to the transmission housing. Furthermore, the mounting base 2 is provided with strip-shaped holes 21 for fastener installation. These holes facilitate adjustment of the mounting base 2, and thus the position of the transmission housing, when fasteners are attached to the support platform 1.

[0069] For example, the mounting base 2 in this embodiment is L-shaped, including a base plate and a vertical plate. The strip hole 21 is located on the base plate. The thickness of the vertical plate gradually becomes thicker as it approaches the base plate. The vertical plate is provided with mounting holes, which can effectively support the installed gearbox housing. Triangular reinforcing ribs are integrally formed between the base plate and the vertical plate. The angle between the mounting surface on the vertical plate and the top surface of the base plate is related to the layout of the gearbox housing. By setting the size of the angle in advance, the force on the housing can be ensured to be consistent with the environment of the entire vehicle.

[0070] In some optional embodiments, see Figures 1 to 9As shown, the embodiment of the present application provides a gearbox housing fatigue life detection device, wherein the loading component 3 of the gearbox housing fatigue life detection device is a loading cylinder driven by a hydraulic oil source, and the loading cylinder is connected to a cooling mechanism for adjusting the temperature of the hydraulic oil source;

[0071] The cooling mechanism includes a refrigerated water circuit and a chiller 8 . The chiller 8 exchanges heat with the refrigerated water circuit through a first heat exchanger 9 . The refrigerated water circuit exchanges heat with the hydraulic oil source in the loading cylinder through a second heat exchanger 10 .

[0072] The loading component 3 of the embodiment of the present application is a loading cylinder driven by a hydraulic oil source. The loading cylinder is connected to a cooling mechanism for adjusting the temperature of the hydraulic oil source. The cooling mechanism can cool the hydraulic oil source in the loading cylinder to ensure continuous and stable operation of the loading cylinder.

[0073] By way of example, in this embodiment, the loading element 3 may employ an electro-hydraulic servo actuator. The cooling mechanism includes a chilled water circuit and a chiller 8. The chilled water circuit exchanges heat with the refrigerated water circuit via a first heat exchanger 9 to cool the chilled water circuit. The chilled water circuit then exchanges heat with the hydraulic oil source within the loading cylinder via a second heat exchanger 10 to cool the hydraulic oil source within the loading cylinder. By way of example, the chiller 8 may employ an industrial chiller 8 that utilizes a Freon circuit to cool the chilled water circuit.

[0074] In some optional embodiments, see Figures 1 to 9 As shown, an embodiment of the present application provides a gearbox housing fatigue life detection device, wherein the cooling water circuit of the gearbox housing fatigue life detection device includes a water tank 11 connected to the inlet of the first heat exchanger 9 and the outlet of the second heat exchanger 10, and a temperature control valve 12 connected to the outlet of the first heat exchanger 9 and the inlet of the second heat exchanger 10. The temperature control valve 12 is connected to the water tank 11 through a bypass, and a water pump 13 is provided between the temperature control valve 12 and the second heat exchanger 10.

[0075] The temperature control valve 12 of the embodiment of the present application adopts a proportional valve, and the water pump 13 adopts a variable frequency pump. By adjusting the opening of the proportional valve, the water flow from the water tank 11 to the water pump 13 through the bypass can be controlled. The cooling water passing through the first heat exchanger 9 is cooled by the chiller 8 and merged with the cooling water passing through the bypass, thereby adjusting the temperature of the cooling water flowing to the second heat exchanger 10. On the other hand, the power of the water pump 13 can be adjusted, such as by adjusting the speed of the water pump 13 to change the power, and the temperature of the hydraulic oil source can be regulated by controlling the cooling water flow rate.

[0076] In some optional embodiments, see Figures 1 to 9As shown, an embodiment of the present application provides a gearbox housing fatigue life detection device, the cooling mechanism of the gearbox housing fatigue life detection device also includes a controller 15 and a temperature sensor 14 connected to the controller 15, the temperature sensor 14 is arranged between the water pump 13 and the second heat exchanger 10, and the controller 15 is used to adjust the opening of the temperature control valve 12 and the power of the water pump 13.

[0077] The temperature control valve 12 of the embodiment of the present application adopts a proportional valve, and the water pump 13 adopts a variable frequency pump. The chiller 8 is used to cool the refrigerated water circuit to provide chilled water, forming a circulation with the second heat exchanger 10, and the variable frequency pump is used to drive the water flow. The proportional valve is used to adjust the opening to control the water temperature. Based on the opening of the proportional valve and the power of the variable frequency pump, the controller 15 can control the refrigerated water temperature through a double-loop fuzzy PID, thereby controlling the hydraulic oil source temperature and maintaining thermal stability.

[0078] See also Figures 1 to 9 As shown, a second aspect of the embodiment of the present application provides a gearbox housing fatigue life detection method, using the gearbox housing fatigue life detection device as described in any of the above embodiments, the method includes:

[0079] The connecting frame 4 is screwed to the loading shaft 31 of the loading member 3. The pre-tightening members 5 are arranged in pairs between the connecting frame 4 and the limiting surface 32. The inclined surfaces 51 on the two pre-tightening members 5 are relatively fitted together.

[0080] Connect the connecting frame 4 to the support platform 1, and apply a set tension to the loading shaft 31 through the loading member 3 so that the connecting frame 4 is tightened on the thread of the loading shaft 31;

[0081] By adjusting the relative positions of the inclined surfaces 51 of the two pre-tightening members 5 to respectively abut against the limiting surface 32 and the connecting frame 4, and then unloading the set tension, the connecting frame 4 is separated from the support platform 1;

[0082] The gearbox housing is cantilevered on the mounting base 2 of the support platform 1, and the end of the gearbox housing away from the mounting base 2 is fixed to the connecting frame 4;

[0083] An alternating load of preset amplitude and frequency is applied to the gearbox housing by the loading member 3 to obtain the life of the gearbox housing under the preset amplitude and frequency.

[0084] The preload member 5 of the embodiment of the present application is an annular gasket with a spiral inclined surface 51. When in use, the spiral inclined surfaces 51 of the two annular gaskets are first pressed tightly together and installed between the limiting surface 32 and the connecting frame 4. Then, the bottom end of the connecting frame 4 is fixed and a tensile force of 500KN is applied to the connecting frame 4 to increase the gap between the connecting frame 4 and the limiting surface 32. Then, the two annular gaskets are twisted along the spiral inclined surface 51, and the height of the upper annular gasket is adjusted to adapt to the gap. Then, the force of 500KN is removed, so that the connecting frame 4 squeezes the surface of the annular gasket, so that the annular gasket will not move, and the loading shaft 31 and the connecting frame 4 will not have relative displacement.

[0085] During the fatigue test, the axial preload force is greater than the extrusion force on the connecting frame 4. Therefore, the connecting frame 4 will not loosen, and a stable connection between the gearbox housing and the loading part 3 can be ensured to effectively transfer the load and realize the fatigue strength assessment of the gearbox housing.

[0086] It should be noted that since the thickness of the gearbox housing is only 5 to 10 mm, it is difficult to withstand a tensile force of 500 kN, so auxiliary tooling needs to be designed. In this embodiment, it is connected to the support platform 1 through a mounting block with a thickness of 20 mm. A tensile force of 500 kN is used to tighten the connecting frame 4 on the loading shaft 31, and then the annular gasket is rotated until there is no gap, and then the force is unloaded and locked.

[0087] In the second aspect, in some optional embodiments: see Figures 1 to 9 As shown, an embodiment of the present application provides a gearbox housing fatigue life detection method, in which an alternating load of a preset amplitude and frequency is applied to the gearbox housing by a loading member 3 to obtain the life of the gearbox housing at the preset amplitude and frequency, including:

[0088] Arrange sensors on the gearbox housing to obtain data on the load on the gearbox housing that changes over time when the vehicle is traveling on a typical road;

[0089] The data is processed and divided into load levels and operating times to obtain the operating time of the transmission housing under each load level on a typical road.

[0090] Applying alternating loads corresponding to the load levels to the gearbox housing through the loading member 3 to obtain the life of the gearbox housing under each load level;

[0091] Calculate the fatigue damage of the gearbox housing under a typical road cycle based on the operating time under each load level and the life of the gearbox housing under each load level;

[0092] Based on the fatigue damage of the gearbox housing under a typical road cycle, the number of cycles that the gearbox housing can undergo under the typical road conditions is calculated to reflect the life of the gearbox housing.

[0093] The gearbox housing fatigue life detection method of the embodiment of the present application is based on Miner damage theory to achieve gearbox housing fatigue strength assessment.

[0094] According to Miner's theory D = n / N, under a single constant amplitude load, the damage D can be calculated by the formula, where n is the number of cycles of the constant amplitude load and N is the fatigue life corresponding to the stress level S.

[0095] Miner damage is based on the Palmgren-Miner linear cumulative damage criterion. This theory states that fatigue damage accumulates linearly under cyclic loading, with individual stresses independent and uncorrelated. When the accumulated damage reaches a certain value, fatigue failure of the specimen or component occurs.

[0096] The basic assumptions of Miner's theory include: within each load block, the load must be symmetrically cyclic, meaning the mean stress is zero; at any given stress level, the rate of cumulative damage is constant and independent of the loading history; and the loading sequence does not affect fatigue life. During gearbox operation, the rate of cumulative damage is independent of the loading history and depends only on the number and magnitude of cyclic stresses.

[0097] Based on the above damage theory, the test method of this application is as follows:

[0098] 1. Stress collection

[0099] Strain gauges are arranged on the gearbox housing to follow the movement of the road vehicle. The strain load signal during the test is measured and processed to obtain the stress spectrum under different road spectra.

[0100] 2. Signal processing

[0101] The data is processed according to the four-peak rain count method, as follows, to obtain the operating time at different load levels.

[0102] Assume that the results of typical road driving are as follows: 20 hours of operation at load level 1 (0-20 kN), 30 hours of operation at load level 2 (20-40 kN), 30 hours of operation at load level 3 (40-60 kN), and 20 hours of operation at load level 4 (60-80 kN).

[0103] Load level Runtime 1 0-20KN a 20h 2 20-40KN b 30h 3 40-60KN c 30h 4 60-80KN d 20h

[0104] 3. Lifespan results

[0105] Previously, designers simulated each load level in the ABAQUS finite element model to obtain the life under each load. However, this was based on the material's SN curve and did not consider the impact of structural internal stress on the life. Therefore, the gearbox housing fatigue test bench of this application was built, which can obtain the life under each load level while considering the structural internal stress.

[0106] On the fatigue test bench, different load amplitudes (corresponding to the minimum and maximum values ​​of the load level) and frequencies (which can be given based on the impact frequency of the actual vehicle and design experience) are set according to the load level, and fatigue tests are carried out to understand its life as follows:

[0107] Load level life 1 0-20KN A 6000h 2 20-40KN B 5000h 3 40-60KN C 4000h 4 60-80KN D 3000h

[0108] The fatigue life is as follows:

[0109] Fatigue damage: d = (a / A) + (b / B) + (c / C) + (d / D)

[0110] After calculation, the fatigue damage under a typical road cycle is 0.0235, that is, the gearbox housing will reach the end of its service life after running 1 / 0.0235≈42.5 times.

[0111] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and 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, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0112] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0113] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A gearbox housing fatigue life detection method, using a gearbox housing fatigue life detection device, characterized in that: The device comprises: A support platform (1) having a mounting seat (2) for cantilever mounting a gearbox housing provided thereon; A loading member (3) is arranged on the support platform (1), a connecting frame (4) for connecting to a gearbox housing is threadedly connected to a loading shaft (31) of the loading member (3), and a limiting surface (32) facing the connecting frame (4) is provided on the loading shaft (31); A pre-tightening member (5) is provided between the limiting surface (32) and the connecting frame (4) and is used to provide an axial pre-tightening force to tighten the connecting frame (4). The pre-tightening member (5) is provided with an inclined surface (51). The pre-tightening members (5) are used in pairs. When used, the inclined surfaces (51) on the pre-tightening members (5) are relatively fitted together. The relative positions of the inclined surfaces (51) of the two pre-tightening members (5) are adjusted to respectively abut against the limiting surface (32) and the connecting frame (4). The method comprises: The connecting frame (4) is threadedly connected to the loading shaft (31) of the loading member (3), and the pre-tightening members (5) are arranged in pairs between the connecting frame (4) and the limiting surface (32), and the inclined surfaces (51) on the two pre-tightening members (5) are relatively fitted; Connecting the connecting frame (4) to the support platform (1), applying a set tension to the loading shaft (31) through the loading member (3) so that the connecting frame (4) is tightened on the thread of the loading shaft (31); By adjusting the relative positions of the inclined surfaces (51) of the two pre-tightening members (5) to respectively abut against the limiting surface (32) and the connecting frame (4), and then unloading the set tension, the connecting frame (4) is separated from the support platform (1); A gearbox housing is cantilevered on the mounting seat (2) of the support platform (1), and one end of the gearbox housing away from the mounting seat (2) is fixedly mounted on the connecting frame (4); An alternating load of preset amplitude and frequency is applied to the gearbox housing by a loading member (3) to obtain the life of the gearbox housing at the preset amplitude and frequency.

2. The gearbox housing fatigue life detection method according to claim 1, characterized in that: The pre-tightening member (5) is an annular gasket, and the inclined surface (51) is located at one end of the annular gasket and rises in a spiral along the circumference of the annular gasket.

3. The gearbox housing fatigue life detection method according to claim 1, characterized in that: The loading shaft (31) of the loading member (3) has a large-diameter shaft section and a small-diameter shaft section, the small-diameter shaft section is provided with a thread for mounting the connecting frame (4), and the limiting surface (32) connects the large-diameter shaft section and the small-diameter shaft section.

4. The gearbox housing fatigue life detection method according to claim 1, wherein: The connecting frame (4) includes a sleeve (41) for connecting to the loading shaft (31), and a connecting piece (42) connected to the sleeve (41); an L-shaped block (6) is symmetrically mounted on one end of the gearbox housing away from the mounting seat (2); and the connecting piece (42) is fixedly connected to the L-shaped block (6).

5. The gearbox housing fatigue life detection method according to claim 1, wherein: The support platform (1) is provided with a column (7) for mounting the loading member (3); the mounting seat (2) is L-shaped; and the mounting seat (2) is provided with a strip hole (21) for mounting a fastener.

6. The gearbox housing fatigue life detection method according to claim 1, characterized in that: The loading member (3) is a loading cylinder driven by a hydraulic oil source, and the loading cylinder is connected to a cooling mechanism for regulating the temperature of the hydraulic oil source; The cooling mechanism comprises a refrigerated water circuit and a chiller (8), wherein the chiller (8) exchanges heat with the refrigerated water circuit via a first heat exchanger (9), and the refrigerated water circuit exchanges heat with a hydraulic oil source in a loading cylinder via a second heat exchanger (10).

7. The gearbox housing fatigue life detection method according to claim 6, characterized in that: The refrigeration water circuit comprises a water tank (11) connected to the inlet of the first heat exchanger (9) and the outlet of the second heat exchanger (10), and a temperature control valve (12) connected to the outlet of the first heat exchanger (9) and the inlet of the second heat exchanger (10), wherein the temperature control valve (12) is connected to the water tank (11) via a bypass, and a water pump (13) is provided between the temperature control valve (12) and the second heat exchanger (10).

8. The gearbox housing fatigue life detection method according to claim 7, characterized in that: The cooling mechanism further comprises a controller (15) and a temperature sensor (14) connected to the controller (15), wherein the temperature sensor (14) is arranged between the water pump (13) and the second heat exchanger (10), and the controller (15) is used to adjust the opening of the temperature control valve (12) and the power of the water pump (13).

9. The gearbox housing fatigue life detection method according to claim 1, characterized in that: Applying an alternating load of a preset amplitude and frequency to the gearbox housing through a loading member to obtain the life of the gearbox housing at the preset amplitude and frequency includes: Arrange sensors on the gearbox housing to obtain data on the load on the gearbox housing that changes over time when the vehicle is traveling on a typical road; The data is processed and divided into load levels and operating times to obtain the operating time of the transmission housing under each load level on a typical road. Applying alternating loads corresponding to load levels to the gearbox housing through a loading member (3) to obtain the life of the gearbox housing under each load level; Calculate the fatigue damage of the gearbox housing under a typical road cycle based on the operating time under each load level and the life of the gearbox housing under each load level; Based on the fatigue damage of the gearbox housing under a typical road cycle, the number of cycles that the gearbox housing can undergo under the typical road conditions is calculated to reflect the life of the gearbox housing.

Images