A medium and heavy truck axle housing bench test fixture

Abstract

The application discloses a medium and heavy truck axle housing bench test clamp, relates to the technical field of axle housing bench test, and is used for vertical bending static strength test of simulating multiple working conditions of an axle housing. The clamp comprises a lower support assembly, a pressurizing actuating assembly, a loading column, a clamping unit, an eccentric load adjusting unit and a locking assembly. The conventional detection mode, the eccentric load detection mode and the longitudinal slope detection mode are integrated in the same clamp through the circumferential sliding self-adaptive function of the clamping unit, the transverse position adjusting function of the eccentric load adjusting unit and the locking function of the locking assembly. The conventional detection mode can simulate the flat and straight road condition. The eccentric load detection mode simulates the asymmetric stress state of the cargo eccentric load. The longitudinal slope detection mode simulates the stress state of the vehicle on the uphill or downhill road. The three modes improve the diversity of the bench test and the coverage degree of the actual working conditions, and cooperate with the locking assembly to ensure the accuracy and reliability of the test loading.

Description

Technical Field

[0001] This invention relates to the field of axle housing test bench technology, and more particularly to a test fixture for medium and heavy-duty truck axle housings. Background Technology

[0002] As the core load-bearing component of the drive axle, the axle housing of medium and heavy-duty trucks bears the vertical loads from the vehicle body and cargo, as well as the torsional loads caused by uneven road surfaces. The vertical bending static strength of the axle housing is a key indicator for evaluating its safety and reliability, directly affecting the driving safety and service life of the entire vehicle.

[0003] Currently, static bending strength tests are conducted on axle housings of medium and heavy-duty trucks using a bench test. The tests employ a simply supported beam model with "load at both ends," where the loading force is applied to the leaf spring seats of the axle housing, resulting in symmetrical force distribution at both ends. However, actual operating conditions are far more complex than standard tests: vehicles frequently experience uneven cargo loading and stress distribution during operation; long and steep slopes on mountain roads cause the axle housing to bear tilting loads in the longitudinal plane; and uneven road surfaces can also lead to asymmetrical stress distribution on the axle housing.

[0004] Existing standard tests can only simulate ideal conditions such as flat road surfaces and symmetrical loading, failing to cover the complex stress states encountered in actual use. Although some research in the industry has attempted to simulate complex conditions by adding multi-channel loading systems or multi-directional actuators, these solutions are typically expensive, have complex control systems, and are difficult to promote and apply in conventional bench tests. Therefore, there is an urgent need for a bridge shell bench test fixture with a relatively simple structure, controllable cost, and the ability to integrate multiple testing modes, in order to achieve a comprehensive assessment of the vertical bending static strength of the bridge shell under actual complex working conditions.

[0005] Therefore, in order to improve the diversity and coverage of operating conditions of the test, the present invention provides a test fixture for a medium and heavy-duty truck axle housing. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art and to propose a test fixture for a medium and heavy-duty truck axle housing.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a test fixture for a medium and heavy-duty truck axle housing, including a lower support assembly for supporting the axle tubes at both ends of the axle housing after the axle housing is hoisted to the testing station.

[0008] The pressurized actuation assembly is suspended above the testing station via a gantry crane.

[0009] The loading column is fixedly installed at the output end of the pressurization actuation assembly.

[0010] The clamping unit is installed at the two leaf spring seats on the axle housing to clamp the leaf spring seats and adapt to changes in the angle of the axle housing.

[0011] An off-center load adjustment unit is installed on the clamping unit and is used to adjust the lateral position of the loading force.

[0012] A locking assembly is used to lock the adjusted positions of the off-center load adjustment unit and the clamping unit.

[0013] The medium and heavy-duty truck axle housing test fixture integrates three testing modes: Mode 1, conventional testing mode: the lower support assembly and clamping unit support the axle housing to maintain a horizontal posture, and the off-center load adjustment unit adjusts the loading force to be applied evenly to the axle housing; Mode 2, off-center load testing mode: the axle housing maintains a horizontal posture, and the off-center load adjustment unit adjusts the loading force to be applied eccentrically to the axle housing; Mode 3, longitudinal slope testing mode: the lower support assembly and clamping unit support the axle housing to rotate to an inclined posture in the longitudinal plane, and the loading force is applied evenly to the axle housing.

[0014] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, the clamping unit includes a clamping group disposed outside two leaf spring seats. The clamping group includes two clamping blocks distributed vertically, which are detachably fixedly connected by bolts.

[0015] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, a set of pads is movably arranged on the clamping assembly. The set of pads includes two contact pads distributed vertically for clamping the leaf spring seat of the axle housing. The contact surface of the pads forms a conformal fit with the surface of the leaf spring seat, and the edge of the contact end is provided with a chamfered structure.

[0016] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, the top walls of the two upper clamping blocks of the clamping assembly are fixedly connected to an inverted U-shaped clamping frame.

[0017] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, the off-center load adjustment unit includes a movable sleeve that is fitted onto the outside of the loading column. The movable sleeve includes a cylindrical part that slides up and down with the loading column and a connecting part that is fixed to the bottom wall of the cylindrical part.

[0018] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, the top wall of the inverted U-shaped clamping frame is provided with guide grooves facing left and right, allowing the connecting part to slide laterally left and right.

[0019] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, the locking assembly includes a locking part one, which includes a first locking pin fixedly connected to the bottom wall of the loading column. A first adjustment hole is provided on the movable sleeve to accommodate and allow the first locking pin to pass through.

[0020] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, the top wall of the inverted U-shaped clamping frame is provided with multiple first locking holes along the left and right directions. The first locking holes and the first locking pins form a selective insertion fit to lock the lateral position of the movable sleeve relative to the inverted U-shaped clamping frame.

[0021] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, the locking assembly further includes a second locking part. The second locking part includes a cantilever rod that is fixedly connected to the outer wall of the loading column and is symmetrically distributed on the left and right. A connecting rod slides through the vertical section of the inverted U-shaped clamping frame. A second locking pin is fixedly connected to the bottom end of the connecting rod. The top end of the connecting rod and the bottom wall of the cantilever rod form a sliding fit.

[0022] In the aforementioned test fixture for a medium- and heavy-duty truck axle housing, a second adjustment hole is provided in the middle of the upper clamping block of the clamping assembly to accommodate and allow the second locking pin to pass through; a plurality of second locking holes are provided on the upper contact pad, and the second locking holes and the second locking pin form a selective insertion fit to lock the circumferential position of the upper contact pad relative to the upper clamping block.

[0023] Compared with existing technologies, the advantages of this invention are: this solution integrates the conventional detection mode, the off-center load detection mode and the longitudinal slope detection mode into the same fixture by means of the circumferential sliding adaptive function of the clamping unit, the lateral position adjustment function of the off-center load adjustment unit and the locking function of the locking component.

[0024] The standard testing mode can simulate flat road conditions; the off-center load testing mode uses the movable sleeve to move laterally along the guide groove to achieve eccentric loading of the axle housing, simulating asymmetrical force states such as off-center loading of cargo; the longitudinal slope testing mode uses the rotary drive unit to drive the axle housing to rotate around the axis of the axle tube to a preset tilt angle, simulating the force state of the vehicle on uphill or downhill roads.

[0025] The three modes enhance the diversity of bench tests and the coverage of actual working conditions. They also work in conjunction with the locking assembly to achieve simultaneous locking of locking part one and locking part two at one time, ensuring the accuracy and reliability of test loading. Attached Figure Description

[0026] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0027] Figure 1 This is a schematic diagram of the overall structure;

[0028] Figure 2 A partial cross-sectional front view of the clamping unit, the off-center load adjustment unit, and the locking assembly;

[0029] Figure 3 This is a three-dimensional cross-sectional view of the locking assembly before it is locked.

[0030] Figure 4 This is a three-dimensional cross-sectional view of a portion of the locking assembly after it has been locked.

[0031] Figure 5 This is a left-side view of a partial structural cross-section of the clamping unit;

[0032] Figure 6 A schematic diagram of the clamping unit and the off-center load adjustment unit in the off-center load detection mode;

[0033] Figure 7 This is a schematic diagram of the clamping unit and the off-center load adjustment unit in the longitudinal slope detection mode.

[0034] In the diagram: 1. Lower support assembly; 2. Pressurization actuation assembly; 3. Loading column; 4. Clamping unit; 41. Clamping group; 42. Pad group; 43. Inverted U-shaped clamping frame; 5. Off-center load adjustment unit; 51. Movable sleeve; 511. Cylindrical part; 512. Connecting part; 52. Guide groove; 6. Locking assembly; 61. Locking part one; 611. First locking pin; 612. First adjusting hole; 613. First locking hole; 62. Locking part two; 621. Cantilever rod; 622. Connecting rod; 623. Second locking pin; 624. Second adjusting hole; 625. Second locking hole. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Reference Figure 1 A test fixture for a medium and heavy-duty truck axle housing is used to conduct vertical bending static strength tests on axle housings under multiple working conditions. It includes a lower support assembly 1, a pressurization actuation assembly 2, a loading column 3, a clamping unit 4, an off-center load adjustment unit 5, and a locking assembly 6.

[0037] The lower support assembly 1 supports the shaft tubes at both ends of the bridge shell after it has been hoisted to the testing station. The pressurization actuation assembly 2 is suspended above the bridge shell testing station via a movable truss (specifically, a gantry transverse drive mechanism, not shown in the figure) to provide the vertical loading force required for the test. The pressurization actuation assembly 2 can employ an electro-hydraulic servo actuator or other device capable of providing controllable static loading. The loading column 3 is fixedly installed at the output end of the pressurization actuation assembly 2 to transmit the loading force generated by the pressurization actuation assembly 2 to the clamping unit 4 below.

[0038] Clamping unit 4 is installed at the two leaf spring seats of the axle housing. Its function is to clamp the leaf spring seats and adapt to changes in the angle of the axle housing. Off-center load adjustment unit 5 is installed on clamping unit 4 and is used to adjust the lateral position of the loading force. Locking assembly 6 is used to lock the adjustment positions of off-center load adjustment unit 5 and clamping unit 4 to ensure the stability and accuracy of the loading force during the test.

[0039] The heavy-duty truck axle housing test fixture in this embodiment integrates three testing modes: conventional testing mode, off-center load testing mode, and longitudinal slope testing mode. It can simulate the stress state of the axle housing under various actual working conditions, significantly improving the diversity and accuracy of the test.

[0040] Reference Figures 1 to 2 The lower support assembly 1 includes a lower axle tube support and an upper axle tube cap mounted on the lower axle tube support, which are detachably fixedly connected. A sliding seat (not shown in the figure) is slidably installed between the lower axle tube support and the upper axle tube cap. This sliding seat has the freedom to slide along the axle tube axis to accommodate the slight lateral elongation of the axle housing during stress and avoid additional stress. A axle tube bushing, which is sleeved on the outer wall of the axle tube of the axle housing, is circumferentially slidably installed on the sliding seat to accommodate the rotation of the axle housing around the axle tube axis at a certain angle, thereby simulating the tilting posture of the vehicle under uphill or downhill conditions.

[0041] It should be noted that the axle housing rotates at a certain angle around the axis of the shaft tube by a rotary drive unit (not shown in the figure) installed on the inspection station and symmetrically arranged on the outside of the axle housing. The rotary drive unit drives the end of the axle housing shaft tube, thereby driving the entire axle housing to deflect at a certain angle around the axis of the shaft tube. During the deflection, the shaft tube bushing slides adaptively on the sliding seat in a circumferential direction.

[0042] Reference Figures 1 to 3 The clamping unit 4 includes a clamping assembly 41 disposed outside the two leaf spring seats. The clamping assembly 41 includes two clamping blocks distributed vertically, which are detachably fixedly connected by bolts to facilitate the installation and removal of the axle housing. The top walls of the two upper clamping blocks are jointly fixedly connected to an inverted U-shaped clamping frame 43.

[0043] A pad assembly 42 is movably mounted on the clamping assembly 41. This pad assembly 42 includes two contact pads distributed vertically for directly clamping the leaf spring seat of the axle housing. The contact surfaces of the two contact pads form a contour fit with the surface of the leaf spring seat; that is, the contact surfaces of the contact pads are designed to conform to the specific shape of the leaf spring seat to reduce contact stress. Simultaneously, the contact edges of the contact pads are chamfered to eliminate stress concentration.

[0044] When the upper and lower contact pads are combined, their outer peripheral walls are cylindrical; correspondingly, when the upper and lower clamping blocks are combined, their inner peripheral walls are cylindrical. Both the upper and lower clamping blocks have arc-shaped slides on their inner peripheral walls, which connect to form a circular guide rail, allowing the upper and lower contact pads to slide freely in the circumferential direction on the clamping blocks.

[0045] With the above structure, when the bridge shell tilts in the longitudinal slope detection mode, the contact pad can rotate freely along the circular guide rail, thereby adaptively following the angle change of the bridge shell.

[0046] Reference Figures 1 to 3 The off-center load adjustment unit 5 includes a movable sleeve 51 sleeved and installed outside the loading column 3. The movable sleeve 51 includes a cylindrical part 511 that slides vertically with the loading column 3 and a connecting part 512 fixed to the bottom wall of the cylindrical part 511. The top wall of the inverted U-shaped clamping frame 43 has a guide groove 52 facing left and right, allowing the connecting part 512 to slide laterally. The movable sleeve 51 and the inverted U-shaped clamping frame 43 form a sliding pair through the connecting part 512. When the pressure actuation assembly 2 is driven by the movable truss, and the movable sleeve 51 is driven to move left and right along the guide groove 52, it can adapt to the lateral displacement generated, thereby adapting to the lateral position change of the loading force acting on the leaf spring seat and realizing off-center load adjustment.

[0047] It should be noted that the movable truss drives the overall lateral displacement of the pressurization actuation assembly 2, which in turn causes the loading column 3 and the movable sleeve 51 to move laterally relative to the inverted U-shaped clamping frame 43.

[0048] Reference Figures 1 to 5 The locking assembly 6 includes a first locking part 61 and a second locking part 62. The first locking part 61 is used to lock the lateral position of the movable sleeve 51 relative to the inverted U-shaped clamping frame 43. Specifically, the first locking part 61 includes a first locking pin 611 fixedly connected to the bottom wall of the loading column 3. The movable sleeve 51 has a first adjusting hole 612 for accommodating and allowing the first locking pin 611 to pass through. The top wall of the inverted U-shaped clamping frame 43 has multiple first locking holes 613 along its left-right orientation, which selectively engage with the first locking pin 611. When the movable sleeve 51 moves to the target lateral position, the first locking pin 611 inserts into the corresponding first locking hole 613, thereby locking the movable sleeve 51 in the corresponding position of the inverted U-shaped clamping frame 43.

[0049] Locking part 2 62 is used to lock the circumferential position of the contact pad block relative to the clamping block. Specifically, locking part 2 62 includes a cantilever rod 621 fixedly connected to the outer wall of the loading column 3 and symmetrically distributed on both sides. The vertical section of the inverted U-shaped clamping frame 43 slides through a connecting rod 622 in the vertical direction. The bottom end of the connecting rod 622 is fixedly connected to a second locking pin 623, and the top end of the connecting rod 622 forms a sliding fit with the bottom wall of the cantilever rod 621.

[0050] The upper clamping block of the clamping assembly 41 has a second adjustment hole 624 in the middle for accommodating and allowing the second locking pin 623 to pass through. The upper contact pad has multiple second locking holes 625, which selectively engage with the second locking pin 623. When the contact pad rotates to the target circumferential position, the second locking pin 623, driven by the cantilever rod 621 and connecting rod 622, inserts into the corresponding second locking hole 625, thereby locking the upper contact pad relative to the circumferential position of the upper clamping block.

[0051] It should be noted that the structures bearing high pressure stress, such as the loading column 3, the inverted U-shaped clamp 43, the movable sleeve 51, and the cantilever rod 621, are made of 40Cr or 42CrMo alloy steel. Their strength can meet the maximum load of the static strength test, and their deformation under the maximum load is less than one-tenth of the elastic deformation of the bridge shell itself.

[0052] The specific procedure for performing a vertical bending static strength test using the fixture of this embodiment is as follows:

[0053] Preparation before the test: Hoist the bridge housing to be tested to the testing station, connect the shaft tubes at both ends of the bridge housing to the shaft tube bushings of the lower support assembly 1, and lock them in place using the upper shaft tube cap and the lower shaft tube support. At this time, the centerline of the loading column 3 is aligned with the longitudinal centerline of the bridge housing.

[0054] In the initial state, the pressurizing actuation assembly 2 is suspended above the testing station via a movable truss. The loading column 3, clamping unit 4, off-center load adjustment unit 5, and locking assembly 6 are in a raised position along with the pressurizing actuation assembly 2, maintaining a sufficient safe distance from the bridge shell already in place below, facilitating the hoisting and alignment of the bridge shell. The upper and lower clamping blocks are in a separated state, and the two contact pads of the pad assembly 42 are respectively housed within the upper and lower clamping blocks.

[0055] The movable truss drives the pressurized actuation assembly 2 and the clamping unit 4 to slowly descend until the upper contact pad in the upper clamping block forms a preliminary fit with the upper surface of the leaf spring seat. Then, the lower clamping block is placed in the corresponding position below the leaf spring seat so that the lower contact pad in the lower clamping block contacts the lower surface of the leaf spring seat and is tightened and fixed with bolts.

[0056] Select the appropriate detection mode according to the purpose of the experiment:

[0057] If routine testing is performed, such as Figure 1 The position of the pressurizing actuation assembly 2 is adjusted by the movable truss, causing the loading column 3 and the movable sleeve 51 to slide adaptively in the guide groove 52, so that the movable sleeve 51 is located in the center position of the inverted U-shaped clamping frame 43. The rotary drive unit drives the end of the axle housing shaft tube to drive the entire axle housing to rotate, so that the axle housing is in a horizontal state on the horizontal road surface, and the upper and lower contact pads of the clamping axle housing leaf spring seat adaptively slide on the corresponding upper and lower clamping blocks.

[0058] The output of the pressurized actuation assembly 2 drives the loading column 3 to move downwards for locking. The locking structure is simple and the locking action is convenient. Figures 3 to 4 The movable sleeve 51 is locked in the centered position by locking part 61: the loading column 3 moves down, causing the first locking pin 611 to pass through the first adjusting hole 612 and then insert into the corresponding first locking hole 613. The contact pad is locked in the centered position by locking part 62: the loading column 3 simultaneously causes the second locking pin 623 to move down, pass through the second adjusting hole 624 and then insert into the corresponding second locking hole 625. After the locking operation is completed, the rotary drive unit is disconnected from the end of the shaft tube.

[0059] The output end of the pressurization actuation assembly 2 drives the loading column 3 to continue to move down to perform a routine static strength test on the pressurization. At this time, the loading force is uniformly applied to the two leaf spring seats of the axle housing, and the forces at both ends are symmetrical, simulating conventional conditions such as straight highways and urban roads.

[0060] If off-center load detection is performed, such as Figure 6 The position of the pressurizing actuation assembly 2 is adjusted by the movable truss, which drives the loading column 3 and the movable sleeve 51 to slide adaptively in the guide groove 52, so that the off-center load adjustment unit 5 is adjusted to an off-center position, that is, the movable sleeve 51 slides to the left or right along the guide groove 52 to the preset off-center load position. The rotary drive unit drives the end of the axle housing tube to drive the entire axle housing to rotate, so that the axle housing is in a horizontal state on the horizontal road surface, and the upper and lower contact pads of the clamping axle housing leaf spring seat adaptively slide on the corresponding upper and lower clamping blocks.

[0061] The output end of the pressure actuation assembly 2 drives the loading column 3 to move downward to perform a locking operation. Locking part 1 61 locks the movable sleeve 51 in the off-center position, and locking part 2 62 locks the contact pad and clamping block in the center position. After the locking operation is completed, the rotary drive unit is disconnected from the end of the shaft tube.

[0062] The output end of the pressurization actuation assembly 2 drives the loading column 3 to continue to move down to perform a static strength test for off-center load detection. At this time, the loading force is applied eccentrically to the axle housing, and the load on one end of the leaf spring seat is greater than that on the other end, forming an asymmetrical loading, simulating the asymmetrical force state of the vehicle caused by the off-center loading of the cargo. The simulation scenario is the shift of the cargo center of gravity or a single-sided concave road surface.

[0063] It should be noted that different off-center load ratios can be adjusted by changing the lateral offset distance of the movable sleeve 51. In this embodiment, multiple preset off-center load positions (such as 1:1, 1.5:1, 2:1, 3:1, etc.) can be provided by setting multiple first locking holes 613.

[0064] If a longitudinal slope test is performed, such as Figure 7 The position of the pressurizing actuation assembly 2 is adjusted by the movable truss, causing the loading column 3 and the movable sleeve 51 to slide adaptively in the guide groove 52, so that the movable sleeve 51 is located in the center position of the inverted U-shaped clamping frame 43. The rotary drive unit drives the end of the axle housing shaft tube to drive the entire axle housing to rotate, so that the axle housing rotates around the shaft tube axis relative to the horizontal state to a preset tilt angle (such as ±5°, ±10°, ±15°), and the upper and lower contact pads of the clamping axle housing leaf spring seat adaptively slide on the corresponding upper and lower clamping blocks.

[0065] The output end of the pressure actuation assembly 2 drives the loading column 3 to move downward to perform a locking operation. Locking part 1 61 locks the movable sleeve 51 in the center position, and locking part 2 62 locks the contact pad and clamping block in the adjusted circumferential position (i.e., the tilted state). After the locking operation is completed, the rotary drive unit is disconnected from the end of the shaft tube.

[0066] The output end of the pressurization actuation assembly 2 drives the loading column 3 to continue moving downward to perform a static strength test on the longitudinal slope of the pressurized axle housing. At this time, the loading force is uniformly applied to the two leaf spring seats of the inclined axle housing, but due to the inclination of the axle housing itself, there is a longitudinal component of the loading force. The test simulates the force state of the vehicle when driving on an uphill or downhill road surface. The simulation scenarios are longitudinally inclined road surfaces such as mountain roads, overpass ramps, and underground parking garage ramps.

[0067] The output end of the pressurization actuation assembly 2 drives the loading column 3 to continue to move down to perform a routine static strength test on the pressurization. At this time, the loading force is uniformly applied to the two leaf spring seats of the axle housing, and the forces at both ends are symmetrical, simulating conventional conditions such as straight highways and urban roads.

[0068] It should be noted that the tilt angle in this embodiment ranges from ±5° to ±15°, corresponding to a road gradient of approximately 9% to 27%, covering the vast majority of actual road conditions.

[0069] This scheme is designed for axle housings of medium and heavy-duty trucks, where the failure load must be greater than 6 times the full-load axle load. During the aforementioned vertical bending static strength test, the axle housing sample is deemed to have failed when any of the following conditions occur, and the failure load at this time is recorded:

[0070] Fracture failure: The bridge housing exhibits visible penetrating cracks or complete fracture. The fracture surface is typically located in the stress concentration area near the leaf spring seat or in the heat-affected zone of the weld.

[0071] Severe plastic deformation failure: The axle housing undergoes significant overall plastic bending deformation, resulting in a clear inflection point in the load-displacement curve (i.e., the load no longer increases with the increase of displacement, or even decreases), or the amount of deformation exceeds the limit specified in the standard.

[0072] Stiffness degradation failure: During loading, the instantaneous stiffness of the bridge shell (the ratio of load increment to displacement increment) continues to drop to below 50% of the initial stiffness, indicating that the structure has lost its load-bearing capacity.

[0073] It should be noted that before the formal test, preloading to 10% to 20% of the full axle load must be performed 2 to 3 times. The purpose is to: eliminate installation gaps between components; check whether each sliding pair moves smoothly; confirm that the contact pad and leaf spring seat are fully engaged; and check whether the locking assembly becomes loose during loading. If any abnormalities (abnormal noise, jamming, force fluctuations) are found during preloading, the test should be stopped immediately and the cause investigated.

[0074] It should be noted that the loading force, bridge housing deformation, and strain data are monitored in real time during the loading process. Anomaly identification and handling: If the force suddenly drops, it indicates a possible fracture and should be stopped immediately; if the deformation increases abnormally, it indicates the bridge may be entering the plastic yielding stage and should be closely monitored; if there are unusual noises, it indicates possible loose locking or component damage and should be stopped immediately for inspection; if the force-displacement curve shows an inflection point, this point should be recorded as a reference for the failure load.

[0075] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0076] Furthermore, the terms "first," "second," "number one," and "number two" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," "number one," or "number two" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0077] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0078] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A test fixture for a medium- and heavy-duty truck axle housing, characterized in that, include: The lower support assembly is used to support the shaft tubes at both ends of the axle housing after the axle housing is hoisted to the inspection station; The pressurized actuation assembly is suspended above the testing station via a gantry crane; The loading column is fixedly installed at the output end of the pressurization actuation assembly; The clamping unit is installed at the two leaf spring seats of the axle housing to clamp the leaf spring seats and adapt to the angle changes of the axle housing. An off-center load adjustment unit, mounted on the clamping unit, is used to adjust the lateral position of the loading force. A locking assembly is used to lock the adjusted positions of the off-center load adjustment unit and the clamping unit. The medium and heavy-duty truck axle housing test fixture integrates three testing modes: The clamping unit includes a clamping group disposed outside the two leaf spring seats, and the clamping group includes two clamping blocks distributed vertically. The top walls of the two upper clamping blocks of the clamping assembly are fixedly connected to an inverted U-shaped clamping frame. The off-center load adjustment unit includes a movable sleeve that is fitted onto the outside of the loading column; The locking assembly includes a locking part one, which includes a first locking pin fixedly connected to the bottom wall of the loading column. A first adjustment hole is provided on the movable sleeve to accommodate and allow the first locking pin to pass through. The top wall of the inverted U-shaped clamping frame is provided with a plurality of first locking holes along the left and right directions. The first locking holes and the first locking pins form a selective insertion fit to lock the lateral position of the movable sleeve relative to the inverted U-shaped clamping frame. The locking assembly also includes a second locking part, which includes a cantilever rod that is fixedly connected to the outer wall of the loading column and is symmetrically distributed on the left and right. A connecting rod slides through the vertical section of the inverted U-shaped clamping frame. A second locking pin is fixedly connected to the bottom end of the connecting rod. The top end of the connecting rod and the bottom wall of the cantilever rod form a sliding fit. The upper clamping block of the clamping assembly has a second adjustment hole in the middle for accommodating and allowing the second locking pin to pass through; the upper contact pad has a plurality of second locking holes, which selectively insert into the second locking pin to lock the circumferential position of the upper contact pad relative to the upper clamping block. In the normal testing mode, the lower support assembly and clamping unit work together to keep the bridge shell in a horizontal position, and the off-center load adjustment unit adjusts the loading force to be applied evenly to the bridge shell; in the off-center load testing mode, the bridge shell is kept in a horizontal position, and the off-center load adjustment unit adjusts the loading force to be applied eccentrically to the bridge shell; in the longitudinal slope testing mode, the lower support assembly and clamping unit work together to support and adapt to the rotation of the bridge shell to an inclined position in the longitudinal plane, and the loading force is applied evenly to the bridge shell.

2. The test fixture for a medium-heavy truck axle housing according to claim 1, characterized in that, The two clamping blocks are connected by bolts to form a detachable fixed connection.

3. The test fixture for a medium-heavy-duty truck axle housing according to claim 2, characterized in that, The clamping assembly is movably provided with a pad block assembly, which includes two contact pad blocks distributed vertically for clamping the leaf spring seat of the bridge housing. The contact surface of the pad block and the leaf spring seat surface form a conformal fit, and the contact end edge is provided with a chamfer structure.

4. The test fixture for a medium-heavy-duty truck axle housing according to claim 1, characterized in that, The movable sleeve includes a cylindrical part that slides up and down with the loading column and a connecting part that is fixed to the bottom wall of the cylindrical part.

5. The test fixture for a medium-heavy-duty truck axle housing according to claim 1, characterized in that, The top wall of the inverted U-shaped clamping frame is provided with guide grooves facing left and right, allowing the connecting part to slide left and right laterally.

Images