Patent Description:
The present application relates to the technical field of mechanical design and manufacturing, and in particular to a method for a fatigue test assessment for a fatigue test assessment for carrying out a fatigue test assessment on a suspension point of a cylinder block.

A cylinder block, that is, a main body of an engine, connects each cylinder with a crankcase. The cylinder block is a support framework for installing pistons, crankshafts, other parts and accessories.

An engine suspension system is mainly used to reduce a vibration transmitted by power assembly to a vehicle body, so as to improve riding comfort and ensure that the engine assembly is always at a correct position, control a displacement of engine assembly and avoid dynamic interference between the engine assembly and the peripheral parts, which may cause damage to the engine assembly or the parts.

During use, it is found that a point on the cylinder block corresponding to a mounting position of the suspension system (that is, "a suspension point of a cylinder block", referred to as "suspension point") is susceptible to damage. However, in the conventional technology, there is no mature and applicable system and method for carrying out a fatigue assessment on the suspension point of the cylinder block. And it is impossible to assess whether the structural strength of the suspension point of the cylinder block meets the use requirements during a stage of the parts testing.

Among the prior arts, the patent of <CIT> discloses a multiaxis fatigue test rack, including portal frame, Y to reaction frame, Y to loading actuator, X to reaction frame, X to loading actuator, translation load bar, Z to loading actuator and workpiece to be tested interfacing apparatus, Z suspends in midair to the loading actuator is vertical on the portal frame, Y to the tail end of loading actuator with Y connects to the reaction frame, Y to the loading end of loading actuator with the translation load bar is connected, X to the tail end of loading actuator with X connects to the reaction frame, X to the loading end of loading actuator with the one end of translation load bar is connected, the other end of translation load bar with workpiece to be tested interfacing apparatus connects. The patent of <CIT> discloses a test combined bench for a full-frame type auxiliary frame, and is capable of carrying out bench tests in various directions conveniently and efficiently. The test combined bench for the full-frame type auxiliary frame is characterized by comprising a stabilizer bar, a front lower swing arm, an auxiliary frame, an adapter plate, an angle adjustable support, a test plate and a cylinder of an electro-hydraulic servo test system which can selectively form a longitudinal force fatigue test bench, a lateral force fatigue test bench, a steering engine mounting point fatigue test bench, an engine suspending bracket fatigue test bench or a stabilizer bar support fatigue test bench. Another patent of <CIT> discloses an elastic component large-load fatigue test device, a test method and an installation method. The elastic component large-load fatigue test device includes a test device pedestal, four stand columns and a movable beam, one end of each stand column is arranged on the test device pedestal, the other end penetrates through the movable beam and the movable beam can move back and forth vertically along the stand column, and the test device pedestal,; a fixed platform used for fixing an elastic component clamp is also arranged on the test device pedestal, a vertical loading oil cylinder mechanism with a sensor is arranged on the movable beam. Therefore, those skilled in the art have a strong desire to carry out the fatigue assessment on the suspension point of the cylinder block to assess whether the structural strength of the suspension point of the cylinder block meets the use requirements in the stage of the parts testing.

An object of the present application is to provide a method according to claim <NUM> for a fatigue test assessment, which can carry out a fatigue assessment on a suspension point of a cylinder block to assess whether the structural strength of the suspension point of the cylinder block meets the use requirements in a stage of the parts testing.

Preferably, in the above method, a fluorescence flaw detection method is used to determine the damage position, and the damage position includes a crack part.

Preferably, in step b of the above method, the preset direction includes:.

Preferably, in step b of the above method, loads in different preset directions are sequentially applied.

Preferably, in the above method, a cycle cardinality of the dynamic load is <NUM> million times. And/or, a calibration load of the static load is calculated in advance based on a suspension mode of the power assembly of the whole vehicle.

Preferably, in the above method, whether the suspension point damages is determined by monitoring an anomalous change of displacement amplitude of the suspension point.

Preferably, in the above method, a passing method is taken as an assessment criterion, and the passing method is that a preset number of cylinder block samples is taken as a group, and if all the cylinder block samples in the group have completed a process of the loading application in step b without damage, then the cylinder block samples are determined to meet the strength target.

Preferably, in the above method, the method for the fatigue test assessment is operated at a four-pillar test bench, which is driven by hydraulic pressure.

It can be seen from the above technical solution that the method for the fatigue test assessment according to the present application can carry out the fatigue test assessment on the suspension point of the cylinder block during the stage of the parts testing, and accurately assess whether the structural strength of the suspension point of the cylinder block meets the requirements, so as to predict and avoid the occurrence of the fracture of the suspension point of the cylinder block in advance, and control the validity of the whole vehicle test.

To illustrate technical schemes according to the embodiments of the present application or in the conventional technology more clearly, the drawings to be used in the description of the conventional technology or the embodiments are described briefly hereinafter. Apparently, the drawings described hereinafter are only some embodiments of the present application, and other drawings may be obtained by those skilled in the art based on those drawings without creative effort.

A method for a fatigue test assessment is disclosed according to the present application, which can carry out a fatigue assessment on a suspension point of a cylinder block to assess whether the structural strength of the suspension point of the cylinder block meets the use requirements in a stage of the parts testing.

Technical solutions of embodiments of the present application are clearly and completely described hereinafter in conjunction with the drawings of the embodiments of the present application. Apparently, the embodiments described in the following are only some embodiments of the present application, rather than all embodiments. Any other embodiments obtained by those skilled in the art based on the embodiments in the present application without any creative work fall in the scope of protection of the present application.

Referring to <FIG>, <FIG> is a schematic structural view when a suspension point of a cylinder block is loaded in an X direction in a method for a fatigue test assessment according to an embodiment of the present application; <FIG> is a schematic structural view when the suspension point of the cylinder block is loaded in a Z direction in a method for a fatigue test assessment according to the embodiment of the present application; and <FIG> is a schematic structural view when the suspension point of the cylinder block is loaded in a Y direction in a method for a fatigue test assessment according to the embodiment of the present application.

The method for the fatigue test assessment according to the embodiment of the present application is used for carrying out a fatigue test assessment on the suspension point (a front suspension point) of the cylinder block, which includes:.

It can be seen that the method for the fatigue test assessment for the suspension point of the cylinder block is provided according to the embodiment of the present application, which can carry out the fatigue test assessment on the suspension point of the cylinder block during the stage of the parts testing, and accurately assess whether the structural strength of the suspension point of the cylinder block meets the requirements, so as to predict and avoid the occurrence of the fracture of the suspension point of the cylinder block in advance, and control the validity of the whole vehicle test.

Further, the method for the fatigue test assessment further includes:.

Specifically, in step b, a loading test is carried out on the suspension point of the cylinder block in three directions, that is, the "preset direction" includes an X direction, a Y direction and a Z direction, which are perpendicular to each other (taking the cylinder block sample <NUM> as a reference).

In an embodiment, the loading mode used in step b is a uniaxial loading, that is, the loads in different preset directions are sequentially applied. And the loading mode is shown in <FIG>, <FIG>.

In an embodiment, the cylinder block sample <NUM> is fixed by a tooling support <NUM>, and a rear end of the cylinder block sample <NUM> is connected with a hydraulic actuator to apply the load. When a test load is applied on the suspension point of the cylinder block in different directions, the tooling support <NUM> may adopt the same structure, or a pair of tooling supports <NUM> may be used for different fixed modes of the cylinder block sample <NUM>. It should be noted that each time the cylinder block sample <NUM> is fixed, the suspension point thereof is fixed according to the installation mode of the power assembly.

In an embodiment, in step b, the load applied to the suspension point of the cylinder block includes a dynamic load that is cyclically loaded and a static load that is singly loaded in static. A cycle cardinality of the dynamic load is <NUM> million times. And a calibration load of the static load is calculated in advance based on a suspension mode of the power assembly of the whole vehicle.

Specifically, when the dynamic load is applied to the suspension point of the cylinder block in a certain preset direction, and when the cycle number of the test is greater than the cycle cardinality of <NUM> million times, then it is considered that the test load level is lower than a load limit of the suspension point of the cylinder block in the preset direction, and the dynamic load test in the preset direction is terminated.

The test load refers to pulsating load amplitude used in an i-th independent test in a group of tests that the total number of subsamples is n.

The cycle cardinality refers to a limit of the cycle number under a fixed load when the fatigue strength is measured. If the limit is exceeded, the test is terminated and it is considered that the sample may never produce fatigue damage under this load.

The fatigue strength refers to resistance of the sample to the fatigue damage, which is expressed by a load level corresponding to a certain fatigue life.

The fatigue life refers to a cycle number that the sample has passed before the fatigue damage under a specified load level.

Specifically, when the load is applied, oil pressure is transmitted to the suspension point of the cylinder block through a hydraulic cylinder, a simulated connecting rod piston group and a simulated shaft, so as to realize the loading on the suspension point of the cylinder block. After being amplified by the hydraulic amplifier, the pulsating hydraulic load acts on the piston directly.

Specifically, the method for a fatigue test assessment takes a passing method as an assessment criterion, and the passing method is that a preset number (for example, three) of cylinder block samples <NUM> is taken as a group, and if all the cylinder block samples <NUM> in the group have completed the process of the loading application in step b without damage, then the cylinder block samples are determined to meet the strength target.

For example, in a preferred embodiment, three cylinder block samples are taken as a group. If the three cylinder block samples have completed the maximum cycle number specified in each direction in the dynamic load assessment process, and the maximum load specified in each direction in the static load assessment process without damage, then the three cylinder block samples are determined to meet the strength target.

Specifically, the method for the fatigue test assessment is carried out on a four-pillar test bench (also known as a four-pillar vibration bench) driven by hydraulic pressure.

As can be seen, the method for the fatigue test assessment according to embodiment of the present application adopts a newly designed loading fatigue test system and method in three directions, which can carry out the fatigue test assessment on the suspension point (the front suspension point) of the cylinder block during the stage of the parts testing, and accurately assess whether the structural strength of the suspension point of the cylinder block meets the requirements, so as to predict and avoid the occurrence of the fracture of the suspension point of the cylinder block in advance, and control the validity of the whole vehicle test.

It should be noted here that the present application does not specifically limit a loading sequence, a loading system and a specific structure of the tooling support <NUM>, and those skilled in the art can carry out a specific implementation according to actual needs.

Finally, it should be noted that the relationship terminologies such as "first", "second" and the like are only used herein to distinguish one entity or operation from another, rather than to necessitate or imply that the actual relationship or order exists between the entities or operations. Moreover, terms "comprising", "including", or any other variant thereof are intended to encompass a non-exclusive inclusion such that processes, methods, articles, or devices that include a series of elements include not only those elements but also those that are not explicitly listed or other elements that are inherent to such processes, methods, articles, or devices. Without limiting more, the elements defined by the statement "comprising one. " do not exclude that there are other identical elements in the process, method, article, or device that includes said elements.

The above embodiments are described in a progressive manner. Each of the embodiments is mainly focused on describing its differences from other embodiments, and references may be made among these embodiments with respect to the same or similar parts.

Claim 1:
A method for a fatigue test assessment for carrying out a fatigue test assessment on a suspension point of a cylinder block of an engine, the suspension point is a position at which the cylinder block is mounted with a suspension system by a bolt and a thread, characterized in that, the method comprises:
in step a, assembling a cylinder block sample (<NUM>) with the suspension system in form of an installation of power assembly at the suspension point, and fixing the suspension point;
in step b, applying a load on the suspension point in a preset direction, wherein the applied load in step b comprises a dynamic load that is cyclically loaded and a static load that is singly loaded in static;
in step c, determining whether the suspension point is damaged or not;
wherein the method further comprises:
in step d, if the suspension point is damaged, determining a damage position, a bolt elongation and torque, and recording a final test data; and
in step e, if the suspension point passes the loading assessment, terminating the fatigue test assessment, measuring the bolt elongation and recording the final test data.