Device and method for detecting fatigue life of gearbox shell

Abstract

The invention relates to a gearbox shell fatigue life detection device and method, and belongs to the technical field of gearbox shell fatigue tests.The gearbox shell fatigue life detection device comprises a supporting table which is provided with an installation base used for cantilever installation of a gearbox shell; the loading piece is arranged on the supporting table, a loading shaft of the loading piece is in threaded connection with a connecting frame used for being connected with a gearbox shell, and the loading shaft is provided with a limiting face facing the connecting frame; the pre-tightening pieces are arranged between the limiting face and the connecting frame and used for providing axial pre-tightening force to fasten the connecting frame, inclined faces are arranged on the pre-tightening pieces, the pre-tightening pieces are used in pairs, the inclined faces on the pre-tightening pieces are oppositely attached when the pre-tightening pieces are used, and the limiting face and the connecting frame are connected in an abutting mode by adjusting the relative positions of the inclined faces of the two pre-tightening pieces. The device can ensure the stable connection between the gearbox shell and the loading piece so as to effectively transmit the load, and achieves the fatigue strength examination of the gearbox shell.

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, resulting in an increase in the tensile pressure on the connecting rod and a faster frequency of change, which makes the vibration excitation of the gearbox housing stronger and stronger, requiring the use of special equipment to perform fatigue tests on the gearbox housing.

[0003] At present, the fatigue strength of gearbox housing is mostly analyzed based on FEA simulation, but the simulation model assumptions are very different from the actual conditions, and it is difficult to verify the model accuracy. There are also a few that use testing machines for fatigue testing, such as the testing machine disclosed in the announcement number CN202956276U.

[0004] However, since the force application systems of currently known testing machines are generally composed of a force cylinder or a 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 view of 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 of a gearbox housing is provided;

[0008] A loading member, which is arranged on the support platform, 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 arranged on the loading shaft;

[0009] A pre-tightening member is arranged between the limiting surface and the connecting frame, and is used to provide an 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 disposed on the support platform, the mounting seat is L-shaped, and a strip hole for mounting a fastener is disposed 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 adjusting 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, and the refrigerated water circuit exchanges heat with a hydraulic oil source in a loading cylinder through a second heat exchanger.

[0016] On the first aspect, in some embodiments, the refrigeration 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] In 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 gearbox housing fatigue life detection method, using a gearbox 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 preload members are arranged in pairs between the connecting frame and the limiting surface, and the inclined surfaces on the two preload members are relatively fitted;

[0020] Connect the connecting frame to the support table, and apply a set tension to the loading shaft through the loading member so that the connecting frame is tightened on the thread of the loading shaft;

[0021] The relative positions of the inclined surfaces of the two pre-tightening members are adjusted to respectively abut against the limiting surface and the connecting frame, and then the set tension is unloaded to separate the connecting frame from the supporting 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 on the connecting frame;

[0023] An alternating load with a 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 through a loading member to obtain the life of the gearbox housing at the preset amplitude and frequency includes:

[0025] Sensors are arranged on the gearbox housing to obtain data on the load on the gearbox housing changing over time when the vehicle is traveling on a typical road;

[0026] The data is processed, divided into load levels and operating time, and the operating time of the gearbox housing under each load level on a typical road is obtained;

[0027] Applying alternating loads corresponding to the load levels to the gearbox housing through a loading member 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 a typical road is calculated to reflect the life of the gearbox housing.

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

[0031] The embodiment of the present application provides a gearbox housing fatigue life detection device and method, which includes a support platform on which is provided a mounting seat for cantilever mounting the gearbox housing; a loading member arranged on the support platform, a loading shaft of the loading member being threadedly connected with a connecting frame for connecting the gearbox housing, and the loading shaft being provided with a limiting surface facing the connecting frame; a pre-tightening member arranged between the limiting surface and the connecting frame, and used for providing an axial pre-tightening force to tighten the connecting frame, the pre-tightening member being provided with an inclined surface, and the pre-tightening members being used in pairs, and when in use, the inclined surfaces on the pre-tightening members are arranged in relative contact, 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.

[0032] Therefore, the gearbox housing and the loading part can be firmly connected to effectively transfer the load, that is, the connecting frame is threadedly connected to the loading shaft, and a pair of preloaded parts are installed between the limit surface on the loading shaft and the connecting frame. By adjusting the relative positions of the inclined surfaces of the two preloaded parts, the elevation of the preloaded parts can be adjusted to respectively abut the limit surface and the connecting frame, thereby providing an axial preload to tighten the connecting frame. During the fatigue test, the axial preload is greater than the extrusion force on the connecting frame, and the connecting frame will not loosen, which can ensure a firm connection between the gearbox housing and the loading part to effectively transfer the load and achieve the gearbox housing fatigue strength assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 creative work.

[0034] Figure 1 A schematic diagram of the structure of the 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 A schematic diagram of the cooperation between two pre-tightening members of an embodiment of the present application;

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

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

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

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

[0042] Fig. 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 listed 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. Preload 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] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0047] In view of 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, the first aspect of the embodiment of the present application provides a gearbox housing fatigue life detection device, comprising:

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

[0050] A loading member 3 is disposed on the support platform 1, a loading shaft 31 of the loading member 3 is threadedly connected with a connecting frame 4 for connecting to a gearbox housing, and a limiting surface 32 facing the connecting frame 4 is disposed on the loading shaft 31;

[0051] The pre-tightening member 5 is arranged 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 in use, 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 abut the limiting surface 32 and the connecting frame 4 respectively.

[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 to simulate 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 stable connection between the gearbox housing and the loading member 3 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 loader 3 can be ensured to effectively transfer the load and realize the fatigue strength assessment of the gearbox housing.

[0055] Exemplarily, the connecting frame 4 is threadedly connected to the loading shaft 31 of the loading member 3, and the preload members 5 are arranged in pairs between the connecting frame 4 and the limiting surface 32, and the inclined surfaces 51 on the two preload members 5 are relatively fitted;

[0056] The connecting frame 4 is fixedly connected to the support platform 1 through the mounting block, and a 500KN pulling force is applied to the loading shaft 31 through the loading member 3, and 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] The relative positions of the two pre-tightening members 5 are moved, the relative positions of the inclined surfaces 51 of the two pre-tightening members 5 are changed, and the height of the upper pre-tightening member 5 is changed to adapt to the gap. That is, the two pre-tightening members 5 are respectively in contact with the limiting surface 32 and the top of the connecting frame 4, and then the 500KN pulling force is removed, the mounting block is disassembled, and the connecting frame 4 is separated from the support platform 1, so that the pre-tightening member 5 can generate a large axial force to fasten the connecting frame 4 to the thread of the loading shaft 31, so that the connecting frame 4 will not be displaced.

[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 rises in a spiral along the circumference of the annular gasket.

[0059] The preload member 5 of the embodiment of the present application is an annular pad, one end of which is a plane and the other end is an inclined surface 51, and the inclined surface 51 rises in a spiral along the circumference of the annular pad. During installation, the annular pads are used in pairs, and the two annular pads are sleeved on the loading shaft 31 of the loading member 3, and the inclined surfaces 51 fit each other. Since the inclined surfaces 51 rise in a spiral along the circumference, the height of the upper annular pad can be adjusted by rotating the two annular pads 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 radially penetrating through hole is provided on the annular gasket, and a rod can be inserted into the through hole, thereby facilitating the annular gasket to rotate through 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 a loading shaft 31 of a loading member 3 of the gearbox housing fatigue life detection device has a large diameter shaft section and a small diameter shaft section, a thread for installing a connecting frame 4 is provided on the small diameter shaft section, and a limiting surface 32 connects the large diameter shaft section and the small diameter shaft section.

[0063] The loading shaft 31 of the loading member 3 of the embodiment of the present application is provided with a shaft shoulder, forming a coaxially arranged 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, the annular surface at the shaft shoulder forms a limiting surface 32, the limiting surface 32 connects the large diameter shaft section and the small diameter shaft section, after the preload 5 is sleeved on the small diameter shaft section, the connecting frame 4 is installed by thread, and the connecting frame 4 can be circumferentially limited by the cooperation between the preload 5 and the limiting surface 32. In some other embodiments, a fixing ring can be welded on the loading shaft 31, and the limiting surface 32 facing the connecting frame 4 is formed by the fixing ring.

[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 a connecting frame 4 of the gearbox housing fatigue life detection device includes a sleeve 41 for connecting a 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 opened 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 from front to back, and an end block is integrally formed on the L-shaped plate and is arranged perpendicular to the L-shaped plate, and mounting holes for installing fasteners to fix the connecting plate 42 are penetrated from top to bottom on the top surface of the end block, and a triangular reinforcing rib is integrally formed between the end block and the connecting plate 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, a mounting seat 2 is L-shaped, and a strip hole 21 for installing a fastener is provided on the mounting seat 2.

[0068] Four columns 7 distributed in a rectangular shape are fixedly mounted on the support platform 1 of the embodiment of the present application, and a loading member 3 is mounted on the column 7. After installation, the gearbox housing is located below the loading member 3, so that the loading member 3 can apply an axial load to impact the gearbox housing. Furthermore, a strip hole 21 for fastener installation is provided on the mounting seat 2. When the fastener is installed to connect the support platform 1, the strip hole 21 is convenient for adjusting the position of the mounting seat 2 to adjust the position of the gearbox housing.

[0069] Exemplarily, the mounting base 2 in this embodiment is L-shaped, including a bottom plate and a vertical plate, the strip hole 21 is located on the bottom plate, the thickness of the vertical plate gradually becomes thicker in the direction close to the bottom plate, and the vertical plate is provided with mounting holes, which can effectively support the installed gearbox housing, and triangular reinforcing ribs are integrally formed between the bottom plate and the vertical plate. The angle between the mounting surface on the vertical plate and the top surface of the bottom 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 a hydraulic oil source in a 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 member 3 may adopt an electro-hydraulic servo actuator, and the cooling mechanism includes a refrigerated water circuit and a chiller 8. The refrigerated water circuit exchanges heat with the refrigerated water circuit through a first heat exchanger 9 to achieve cooling of the refrigerated water circuit, and the refrigerated water circuit exchanges heat with the hydraulic oil source in the loading cylinder through a second heat exchanger 10 to achieve cooling of the hydraulic oil source in the loading cylinder. By way of example, the chiller 8 may adopt an industrial chiller 8, and use a Freon circuit to cool the refrigerated 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 a cooling water circuit of the gearbox housing fatigue life detection device comprises a water tank 11 connected to an inlet of a first heat exchanger 9 and an outlet of a 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 being connected to the water tank 11 via a bypass, and a water pump 13 being arranged 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. The opening of the proportional valve can be adjusted to control the water flow from the water tank 11 to the water pump 13 through the bypass. The cooling water passing through the first heat exchanger 9 is cooled by the chiller 8 and then 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 refrigeration water circuit to provide chilled water, and a circulation is formed with the second heat exchanger 10. The variable frequency pump is used to drive the water flow, and the opening is adjusted by the proportional valve 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 refrigeration 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, the second aspect of the embodiment of the present application provides a gearbox housing fatigue life detection method, using a gearbox housing fatigue life detection device as described in any of the above embodiments, the method includes:

[0079] 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;

[0080] Connect the connecting frame 4 to the supporting 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 supporting platform 1;

[0082] The gearbox housing is cantilever mounted 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;

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

[0084] The preload member 5 of the embodiment of the present application is an annular gasket with a spiral bevel 51. When in use, the spiral bevels 51 of the two annular gaskets are first pressed tightly against each other 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 bevel 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 does not move, and there is no relative displacement between the loading shaft 31 and the connecting frame 4.

[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 loader 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 500KN, so auxiliary tooling needs to be designed. In this embodiment, it is connected to the support platform 1 through a 20mm thick mounting block. A tensile force of 500KN 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 to lock the annular gasket.

[0087] In the second aspect, in some optional embodiments: see Figures 1 to 9 As shown, the embodiment of the present application provides a gearbox housing fatigue life detection method, in which 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, including:

[0088] Sensors are arranged on the gearbox housing to obtain data on the load on the gearbox housing changing over time when the vehicle is traveling on a typical road;

[0089] The data is processed, divided into load levels and operating time, and the operating time of the gearbox housing under each load level on a typical road is obtained;

[0090] Applying an alternating load corresponding to the load level 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 a typical road 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 concept of Palmgren-Miner linear cumulative damage criterion. This theory proposes that under cyclic loads, fatigue damage can be accumulated linearly, and each stress is independent and unrelated to each other. When the accumulated damage reaches a certain value, fatigue failure will occur in the specimen or component.

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

[0097] Based on the above damage theory, exemplary, 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 road vehicles, and the strain load signals during the test are tested and processed to obtain the stress spectra 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 (0-20KN), 30 hours of operation at load level 2 (20-40KN), 30 hours of operation at load level 3 (40-60KN), and 20 hours of operation at load level 4 (60-80KN).

[0103] Load level Run time 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 SN curve of the material and did not consider the impact of structural internal stress on the life. Therefore, a gearbox housing fatigue test bench was built in this application, 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 refer to the impact frequency of the actual vehicle and are given based on 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 the present application, it should be noted that the terms "upper", "lower", etc. 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 the present application and simplifying the description, rather than indicating or implying 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 the present 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 it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present 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 only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such 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 including 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, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0113] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A gearbox housing fatigue life detection device, characterized in that: include: A support platform (1) on which a mounting seat (2) for cantilever mounting a gearbox housing is provided; A loading member (3) is arranged on the support platform (1), a loading shaft (31) of the loading member (3) is threadedly connected to a connecting frame (4) for connecting to a gearbox housing, and a limiting surface (32) facing the connecting frame (4) is arranged on the loading shaft (31); A pre-tightening member (5) is arranged 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 close to each other. The relative positions of the inclined surfaces (51) of the two pre-tightening members (5) are adjusted so as to respectively abut against the limiting surface (32) and the connecting frame (4).

2. The gearbox housing fatigue life detection device according to claim 1, characterized in that: The preload 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 device according to claim 1, characterized in that: The loading shaft (31) of the loading member (3) comprises 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 device according to claim 1, characterized in that: The connecting frame (4) comprises a sleeve (41) for connecting 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 device according to claim 1, characterized in that: 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 device according to claim 1, characterized in that: The loading component (3) 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; The cooling mechanism comprises a refrigeration water circuit and a chiller (8), wherein the chiller (8) exchanges heat with the refrigeration water circuit via a first heat exchanger (9), and the refrigeration 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 device 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); 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 device 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); the temperature sensor (14) is arranged between the water pump (13) and the second heat exchanger (10); the controller (15) is used to adjust the opening of the temperature control valve (12) and the power of the water pump (13).

9. A gearbox housing fatigue life detection method, using the gearbox housing fatigue life detection device according to any one of claims 1 to 8, characterized in that: Methods include: 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 supporting 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) so as 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 supporting platform (1); A gearbox housing is cantilever-mounted on a mounting seat (2) of a support platform (1), and one end of the gearbox housing away from the mounting seat (2) is fixedly mounted on a connecting frame (4); An alternating load with 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.

10. The gearbox housing fatigue life detection method according to claim 9, characterized in that: The step of 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: Sensors are arranged on the gearbox housing to obtain data on the load on the gearbox housing changing over time when the vehicle is traveling on a typical road; The data is processed, divided into load levels and operating time, and the operating time of the gearbox housing under each load level on a typical road is obtained; 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 a typical road is calculated to reflect the life of the gearbox housing.

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