TECHNICAL FIELD

The present invention relates to the field of mechanical fatigue testing.

BACKGROUND

Rolling contact fatigue failure is one of the main causes of mechanical part failure. Statistically, more than about 80% of mechanical parts, such as shafts, gears, bearings, blades and springs, fall within contact fatigue breakage, and have no significant deformation before breakage, so fatigue breakage often causes significant accidents. Hence, accurate acquisition of material fatigue performance is one of the key ways to solve the problems of base part, base process and base material falling.

A variety of rolling contact fatigue testers satisfying different test requirements are pushed out by the domestic and outdoor related development mechanism and enterprise, but there are many disadvantages, mainly representing: device stability and reliability are not high; only a single target test is possible, and the test efficiency is low; the test environment is harsh, the person needs to have a long-term value, and the labor intensity is high, and the participation in the test environment is not high; the failure condition requires human subjective judgment after stopping, and the continuous test operation of the device cannot be realized, so that the material contact fatigue intensity data cannot be accurately acquired, thereby severely constraining the establishment of the corresponding material performance base database.

SUMMARY

The present invention aims at the problems that the existing rolling contact fatigue tester cannot quantify and evaluate fatigue failure, and cannot accurately obtain material contact fatigue data, and provides a fatigue state monitoring and quantification evaluation system based on a machine vision technology, and the system can quantify and evaluate the fatigue failure state of a roller test specimen through an image processing technology or the like, and can obtain data of the material contact fatigue failure.

The technical solution of an embodiment of the present invention is provided an intelligent rolling contact fatigue testing system, wherein mainly including a main testing system, a loading system and a subsidiary testing system.

The main testing system and the subsidiary testing system are provided on a same experimental platform.

The main testing system mainly includes a main testing system base, a main testing shaft driving servo motor, a main testing box, a main testing system moving slider, a main testing system moving rail and a main testing box base.

The main testing box mainly includes a main shaft A, two sealing end caps, a box body and a sensor race A. The main shaft A is provided in the box body by using a bearing. Two ends of the box body are closed by sealing end covers with oil sealing. Two ends of the main shaft A pass through the sealing end covers at two ends of the box body, and one end of the main shaft A connects the main testing shaft driving servo motor, and the other end of the main shaft A is provided with a roller test specimen.

The sensor race A is provided on one of the sealing end covers. An acceleration sensor is provided on the sensor race A. A bottom of the main testing box is fixed on the main testing system base. The main testing system base is provided on the main testing system moving rail by using the main testing system moving slider. The main testing system moving rail is fixed on the experimental platform. A direction of the main testing box along the main testing system moving rail to slide is perpendicular to an axial direction of the main shaft A.

The subsidiary testing system includes a subsidiary testing box, a subsidiary testing piece, a subsidiary testing box base and a subsidiary testing shaft driving servo motor.

The subsidiary testing box mainly includes a main shaft B, two sealing end caps and a box body. The main shaft B is provided in the box body by using a bearing. Two ends of the box body are closed by sealing end covers with oil sealing. Two ends of the main shaft B pass through the sealing end covers at two ends of the box body, and one end of the main shaft B connects the subsidiary testing shaft driving servo motor and the other end of the main shaft B is provided with the subsidiary testing piece. The subsidiary testing box is fixed on the experimental platform. A shape and size of the subsidiary testing piece are the same as the roller test specimen.

The loading system mainly includes a servo cylinder driven by a driving motor. A mounting base of the servo cylinder is fixed on one side of the main testing system. A pressure sensor is installed at a telescopic end of the servo cylinder. The pressure sensor is in contact with the main testing box. When the servo cylinder pushes the main testing box to move along the main testing system moving rail, the pressure sensor measures a load loaded on the main testing box. In the experiment, the loading system pushes the main testing box such that the subsidiary testing piece contacts the roller test specimen.

In an exemplary embodiment, the experimental platform includes a testing machine base. A main body part of the testing machine base is a cabinet. A lower end of the cabinet is provided with a pulley, and an upper surface of the cabinet is a main/subsidiary testing box body base. The main/subsidiary testing box body base is a horizontal platform.

In an exemplary embodiment, a box body of the main testing box includes a box cover A, a box cover plate A and a lower box body A. The lower box body A is hollow, and two ends of the lower box body A have a main shaft hole. The main shaft A, a bearing NJ314A and a bearing NJ310A are provided inside the lower box body A.

An upper end opening of the lower box body A is closed by the box cover A. the box cover A is provided with an inspection hole. The inspection hole is closed by the box cover plate A.

An outer ring of the bearing NJ314A and an outer ring of the bearing NJ310A are fixed in the lower box body A. The main shaft A passes through and is fixed on an inner ring of the bearing NJ314A and an inner ring of the bearing NJ310A.

One sealing end cap at left side of the two sealing end caps of the main testing box includes a skeleton oil seal IA and a left end cover A. A left side of the main shaft A passes through a central hole of the left end cover A. The left end cover A closes a main shaft hole on a left side of the lower box body A. One side of the left end cover A faces an inside of the main testing box is provided with the skeleton oil seal IA. The main shaft A passes through the skeletal oil seal IA.

One sealing end cap at right side of the two sealing end caps of the main testing box includes a skeleton oil seal IIA and a right end cover A. A right side of the main shaft A passes through a central hole of the right end cover A. The right end cover A closes a main shaft hole on a right side of the lower box body A. One side of the right end cover A faces an inside of the main testing box is provided with a skeleton oil seal IIA. The main shaft A passes through the skeleton oil seal IIA.

The main shaft A is provided with a roller test specimen by a shaft end connector A and a roller coupon mounting seat A. The shaft end connector A is a rotary body, which is sheathed at one end of the main shaft A by means of a keyway connection. the shaft end connector A rotates with the main shaft A. The roller coupon mounting seat A is a rotary body, and one end of the roller coupon mounting seat A is connected to an end surface of the shaft end connector A by a bolt IIIA and the other end of the roller coupon mounting seat A fixes the roller test specimen.

The box body of the subsidiary testing box includes a box cover B, a box cover plate B and a lower box body B. The lower box body B is hollow, and two ends of the lower box body B have a main shaft hole. A main shaft B, a bearing NJ314B and a bearing NJ310B are provided inside the lower box body B.

An upper end opening of the lower box body B is closed by the box cover B. the box cover B has an inspection hole. The inspection hole is closed by the box cover plate B.

An outer ring of the bearing NJ314B and an outer ring of the bearing NJ310B are fixed in the lower box body B. The main shaft B passes through and is fixed on an inner ring of the bearing NJ314B and an inner ring of the bearing NJ310B.

One sealing end cap at left side of the two sealing end caps of the subsidiary testing box includes a skeletal oil seal IB and a left end cover B. A left side of the main shaft B passes through a central hole of the left end cover B. The left end cover B closes a main shaft hole on a left side of the lower box body B. One side of the left end cover B facing an inside of the subsidiary testing box is provided with a skeletal oil seal IB. the main shaft B passes through the skeletal oil seal IB.

One sealing end cap at right side of the two sealing end caps of the subsidiary testing box includes a skeletal oil seal IIB and a right end cover B. A right side of the main shaft B passes through a central hole of the right end cover B. The right end cover B closes a main shaft hole on a right side of the lower box body B. One side of the right end cover B facing an inside of the subsidiary testing box is provided with a skeletal oil seal IIB. The main shaft B passes through the skeletal oil seal IIB.

The main shaft B is provided with a subsidiary testing piece by a shaft end connector B and a roller coupon mounting seat B. The shaft end connector B is a rotary body, which is sheathed at one end of the main shaft B by means of a keyway connection. The shaft end connector B rotates with the main shaft B. The roller coupon mounting seat B is a rotary body, and one end of the roller coupon mounting seat B is connected to an end surface of the shaft end connector B by a bolt IIIB and the other end of the roller coupon mounting seat B is fixed to the subsidiary testing piece.

In an exemplary embodiment, the intelligent rolling contact fatigue testing system further includes a control box. The subsidiary testing shaft driving servo motor and the main testing shaft driving servo motor are controlled by the control box.

In an exemplary embodiment, the intelligent rolling contact fatigue testing system further includes a lubrication system. The lubrication system includes a lubricating oil tank, an oil pump motor, an oil pump and a lubricating oil shell.

The oil pump motor drives the oil pump, so that a lubricating oil of the lubricating oil tank is drawn out, and the lubricating oil tank is provided with the lubricating oil for the main testing system, the loading system and the subsidiary testing system.

An upper end of the lubricating oil shell is open. The lubricating oil shell is located below the roller test specimen. After the lubricating oil in the lubricating oil tank is sprayed into the roller test specimen, the lubricating oil is collected into the lubricating oil shell, and the lubricating oil is reflowed to the lubricating oil tank.

A rolling contact fatigue testing method based on above the intelligent rolling contact fatigue testing system, wherein:

The intelligent rolling contact fatigue testing system includes a testing device. The testing device includes a light source, a CCD camera, and a monitoring assistance device.

The light source is an annular light source. The light source surrounds a lens barrel of the CCD camera.

The monitoring assistance device includes a box body, an oil box, a lubricating oil pipe, a vertical oil baffle plate, an inclined oil baffle plate, and a rotating brush.

The box body is consisted of a top plate, a left side plate, a rear side plate and a front side plate. an opening of lower end of the box body is fastened on the oil box.

The left side plate is provided an open pore. The CCD camera and the light source face an opening of the left side plate.

Two rotating shafts are provided on the rear side plate. The two rotating shafts are direct connected with a transmission shaft of a direct-current machine, and the two rotating shafts are simultaneously driven by the direct-current machine. The two rotating shafts respectively mount a roller test specimen and a rotating brush. The roller test specimen faces the CCD camera.

A lubricating oil shower head and a vertical oil baffle plate are provided on the top plate. The lubricating oil shower head supplies oil by the lubricating oil pipe. The vertical oil baffle plate is located above the roller test specimen, and the vertical oil baffle plate is located between the lubricating oil shower head and the left side plate. One side of the inclined oil baffle plate is connected to the rear side plate. The inclined oil baffle plate is located below the roller test specimen.

When testing, the rolling contact fatigue testing method includes following steps:

1). Using the intelligent rolling contact fatigue testing system so that the roller test specimen and the subsidiary testing piece are in contact with each other and rolling with each other. In this process, a load measured by the pressure sensor and a vibration data measured by the acceleration sensor are recorded.

2). Installing the roller test specimen in the monitoring assistance device after a testing set time is completed, and rotating the roller test specimen simultaneously with the rotating brush in a state in which the lubricating oil is sprayed.

3). Adjusting the CCD camera, and dynamically collecting a surface image of the roller test specimen.

4). Image preprocessing: after adopting an image enhancement algorithm to improve the degree of image sharpening, a bright area is determined by using a threshold algorithm, and a ROI tile is obtained by an area subtracting.

5). Image processing: using an edge template matching algorithm for whole circumferential image splicing of the roller test specimen, using a threshold algorithm to acquire a point etching hole, and performing morphology analysis on an image defect area.

6). Image post-processing: performing connected component analysis on the image defect area, selecting a point etching area according to the feature, calculating an area of the point etching area according to the camera pixel equivalent, and performing quantification evaluation on a fatigue failure state.

The technical effects of the present invention are undisputed, and an intelligent rolling contact fatigue testing system is an important equipment for investigating a key basic component fatigue failure mechanism such as a bearing, a gear and a shaft, and the present invention is directed to the existing rolling contact fatigue testing machine not being able to quantify and evaluate the existing state of fatigue defect on the surface of a roller test specimen. Designed roller coupon surface fatigue defect monitoring systems based on machine vision technology are beneficial to acquire accurate and reliable material contact fatigue data, and have a very important meaning to implement industrial instrumentation, solve problems such as base part, base process, base material falling. Meanwhile, such systems can enhance the development facility and economic facility of key base component businesses such as bearings, gears, shafts, etc.

