CN104297079B - A kind of end tooth structure jogging fatigue experimental device and test method - Google Patents

Abstract

The invention discloses an end tooth structure fretting fatigue test device and a test method, wherein the test device includes a concave tooth fixing component, a convex tooth clamping component and a normal force loading component, and the concave tooth fixing component realizes the fixing of the concave tooth test piece. The convex tooth clamping assembly realizes the loading of the convex tooth test piece, and the normal force loading assembly realizes the application of horizontal load. The horizontal loading device of the fretting fatigue test adopts a symmetrical structure layout, and the load is realized by a hydraulic loading system. The hydraulic loading system adopts a closed force It is a frame structure with no external force output, which does not affect the vertical loading of the fatigue testing machine. The concave tooth test piece is subjected to preload in the horizontal direction, and the vertical direction is pressed by the concave tooth pressure plate to ensure that the horizontal The direction of loading remains unchanged. The present invention can approximately simulate the force condition of the end teeth in the actual working environment, cooperate with the ordinary single-axis fatigue testing machine, and can carry out the fretting fatigue test of the end tooth structure simulation parts, and reduce the experiment cost.

Description

A fretting fatigue test device and test method for an end tooth structure

Technical field:

The invention relates to an end tooth structure fretting fatigue test device and a test method, which belong to the technical field of life evaluation tests of materials and structural parts.

Background technique:

The end-tooth structure is widely used in aeromechanical turbine engine transmission spindles and transmission devices of various high-speed, large-scale and heavy-duty mechanical equipment. It has the advantages of fewer transmission teeth, compact structure, and high load-bearing capacity. Among them, the fretting fatigue between the mating contact surfaces of the concave and convex teeth will lead to a significant decrease in fatigue life. However, it is difficult to conduct fretting fatigue test research on three-dimensional structural parts of end teeth, mainly because of two technical problems: (1) the end tooth structure needs to be processed by a special gear grinding machine, and the processing cost of three-dimensional structural parts is too high; (2) For the fatigue test of three-dimensional structural parts, it is necessary to consider the actual stress of the end tooth structure, mainly including axial preload, torque and centrifugal force. If it is necessary to completely simulate the stress of its real three-dimensional structure, a rotation test is required In the non-rotating test, when considering the preload and torque alone, it is also necessary to use a multi-axis fatigue testing machine. In the prior art, the cost of a biaxial fretting fatigue testing machine capable of realizing the above functions is relatively high.

In order to reduce the test cost, it is necessary to perform equivalent stress on the three-dimensional structure of the end teeth, and use equivalent simulation parts to carry out fretting fatigue tests. For the test, a special loading device that can simulate the above loading effects at the same time is needed.

The existing loading device for fretting fatigue test with uniaxial fatigue testing machine mostly adopts the loading ring structure and loads through bolts, but the driving force of the thread loading scheme is small, and various factors such as vibration during the fatigue process are likely to cause the thread The connection is loose, causing a change in the loading normal force. In addition, the existing fretting test auxiliary devices are mostly used for the design of standard test pieces, so it is necessary to design a special loading device for the fretting of the end tooth structure.

Invention content:

The invention provides a fretting fatigue test device and a test method for an end tooth structure capable of cooperating with a common uniaxial tension-compression fatigue testing machine to carry out a two-way loading fretting fatigue test of an end tooth simulation structural member.

The present invention adopts the following technical scheme: a fretting fatigue test device for end tooth structure, including a concave tooth fixing component, a convex tooth clamping component and a normal force loading component, wherein:

The concave tooth fixing assembly includes an upper clamp body and a concave tooth test piece and a concave tooth pressure plate installed on the upper clamp body. The upper clamp body includes a hollow lower part and an upper part above the lower part. The lower part is formed with Rectangular holes running through the front, rear and lower surfaces of the lower part. The upper clamp body is symmetrically provided with rectangular sliding grooves on the left and right sides of the rectangular hole. The concave tooth test piece is placed in the rectangular sliding grooves and slides along the rectangular The groove slides freely in the horizontal direction. The concave tooth pressure plate is placed in the rectangular sliding groove and the bottom surface of the concave tooth pressure plate is pressed against the top surface of the concave tooth test piece. The upper clamp body is located directly above the rectangular sliding groove. M10 compression bolts for tight concave tooth pressure plate;

The convex tooth clamping assembly includes a lower clamp body, a convex tooth test piece installed on the lower clamp body, a wedge block and a convex tooth positioning cover, and the convex tooth clamping assembly is placed in the rectangular hole of the upper clamp body, On the left and right side walls of the lower clamping body, grooves are symmetrically arranged opposite to the rectangular sliding groove, the convex tooth test piece is placed in the groove, the wedge-shaped block is placed in the groove, and the top surface of the wedge-shaped block Closely attached to the bottom surface of the convex tooth test piece, the thickness of the convex tooth test piece is smaller than the thickness of the lower clamp body, and the convex tooth positioning cover plate consists of two, which are respectively installed in front of the lower clamp body and the convex tooth test piece On the upper surface and the rear surface of the lower clamp body, there is a slot running through the front and rear surfaces of the lower clamp body at a position along the central axis of the lower clamp body;

The normal force loading assembly includes a hydraulic cylinder, a flange welded integrally with the hydraulic cylinder, a hydraulic cylinder piston rod arranged in the hydraulic cylinder, a flange pull rod, and a support seat for supporting the flange thereon. The end of the cylinder piston rod extends beyond the flange and the end of the hydraulic cylinder piston rod abuts against the toothed test piece so that the toothed tooth test piece can slide freely along the horizontal direction of the rectangular sliding groove. The piece is in contact with the convex tooth test piece and pressed, and the upper clamp body is fixed with the support base.

Further, the hydraulic cylinder includes a first hydraulic cylinder and a second hydraulic cylinder located on the left and right sides of the upper clamp body, and the flange includes a first flange welded to the right end of the first hydraulic cylinder and a flange welded to the second The second flange at the left end of the hydraulic cylinder, the flange tie rod is connected between the first flange and the second flange.

Further, there are four flange rods in total.

Further, the lower end of the slot extends to a position consistent with the level of the lower end of the convex tooth test piece.

Further, the top surface of the concave tooth test piece and the bottom surface of the concave tooth pressure plate are both in a horizontal state.

Further, the lower wall surface of the groove provided on the lower clamp body is an inclined surface, and the bottom surface of the wedge-shaped block is in the shape of an inclined surface matching the lower wall surface of the groove.

Further, the convex tooth clamping assembly also includes M5 cover plate bolts and M5 nuts for installing the convex tooth positioning cover plate on the lower clamp body, and M6 fastening screws for fastening the wedge block and the lower clamp body together. screw.

The present invention adopts the following technical scheme: a test method for a terminal tooth structure fretting fatigue test device, which includes the following steps:

(a) A uniaxial fatigue testing machine is provided, and the terminal tooth structure fretting fatigue testing device is installed on the uniaxial fatigue testing machine, and the uniaxial fatigue testing machine includes a testing machine that clamps the upper end of the upper clamp body The chuck, the upper beam of the testing machine connected with the upper chuck of the testing machine, the lower chuck of the testing machine clamping the lower end of the lower chuck body, the load sensor, the servo actuator and the displacement sensor located under the lower chuck of the testing machine, will The upper clamp body and the normal force loading component are connected with the upper chuck of the testing machine as a whole, and the upper beam of the testing machine is raised, and the normal force loading component rises together with the upper clamp body and the upper beam of the testing machine;

(b) Assemble the convex tooth clamping assembly, and assemble the front and rear two convex tooth positioning covers on the lower clamp body through M5 cover bolts and M5 nuts. At this time, the M5 cover bolts are not tightened, and the convex tooth test piece Put it in the groove, place the wedge block in the groove and the top surface of the wedge block is close to the bottom surface of the convex tooth test piece, and tighten the M5 cover plate bolts and M6 fastening screws at the same time, so that the convex tooth test piece and the lower clamp Fasten them together, and finally loosen the M5 cover bolts and M5 nuts;

(c) Place the convex tooth clamping assembly assembled in step (b) in the rectangular hole of the upper clamping body, and slowly adjust the remote pressure regulating valve on the electric control cabinet to control the pressure of the hydraulic cylinder in the horizontal direction to make the piston rod of the hydraulic cylinder slow down. Stretch out of the flange and press it onto the concave tooth test piece, observe the reading of the precision pressure gauge connected to the hydraulic cylinder on the electric control cabinet, and gradually increase the pressure until the predetermined load value;

(d) Tighten the M10 compression bolt located in the upper clamp body, so that the concave tooth pressure plate presses the top surface of the concave tooth test piece, and the bottom surface of the concave tooth test piece is in close contact with the bottom of the rectangular sliding groove of the upper clamp body to ensure that the concave tooth The test piece is in a horizontal state;

(e) Lower the upper beam of the testing machine so that the lower end of the lower clamp body falls into the lower chuck of the testing machine, clear the load sensor of the fatigue testing machine, eliminate the initial load caused by the weight of the testing device itself, and then clamp the lower clamp of the testing machine Head, set the control program of the testing machine to the load control mode, control the servo actuator of the testing machine, make the fatigue testing machine move downward, apply initial tension to the convex tooth, observe the reading of the load sensor, when the reading of the load sensor reaches the fatigue test Pause loading when the average value of the load is reached, where the size of the fatigue load is measured by the load sensor, and the movement stroke of the servo actuator is measured by the displacement sensor;

(f) Control the fatigue program module of the testing machine control program, set the average value and amplitude of the fatigue load, and start the fretting fatigue test;

(g) The up and down movement of the lower chuck of the testing machine causes the convex tooth test piece to move up and down, and the concave tooth test piece remains fixed under the joint action of the normal preload in the horizontal direction and the concave tooth pressure plate, so it is consistent with the convex tooth test piece The upper end of the connected lower clamp body will produce a slight deformation toward the center, so that a small relative slip occurs between the tooth mating surfaces of the concave tooth test piece and the convex tooth test piece, that is, fretting wear. After a certain number of cycles , fretting fatigue cracks can appear.

The present invention has following beneficial effects:

(1) In the test device of the present invention, the axial pretightening force of the three-dimensional structure of the end tooth is simulated by the load in the horizontal direction, and the torque load of the end tooth is simulated by the load in the vertical direction, and the test device of the present invention can simulate the end tooth under the actual working environment. The stress situation can be approximated to replace the three-dimensional fatigue test of the end tooth, which greatly saves the cost of the test piece; using the test device of the present invention, the fretting fatigue test of the end tooth structure simulation piece can be carried out with the cooperation of the uniaxial fatigue testing machine. There is no need to introduce biaxial fatigue testing machine, which reduces the test cost;

(2) Use four M10 compression bolts to press on the concave tooth pressure plate, and then press the concave tooth pressure plate to the concave tooth test piece, which can ensure that the concave teeth will not warp when they are subjected to the downward force of the convex teeth. That is to say, it will not change the assembly position relationship between the concave teeth and the convex teeth, so that it will not affect the direction of the force exerted by the piston rod of the hydraulic cylinder in the horizontal direction; at the same time, the smooth chute of the upper clamp body and the smooth bottom surface of the concave tooth pressure plate can ensure that the concave teeth The test piece slides left and right. When the hydraulic cylinder piston rod exerts force on the concave tooth test piece, it only provides horizontal load. The horizontal hydraulic loading system adopts a closed force system frame structure, and there is no external force output in the horizontal direction, which will not affect Loading of vertical fatigue testing machine;

(3) The application of normal pretightening force in the horizontal direction is realized by hydraulic loading system. Hydraulic loading can provide stable and continuous load, which can provide greater driving force than ordinary bolt loading, and will not be applied due to vibration during the fatigue process. When the load changes, the left and right hydraulic cylinders use two independent hydraulic lock control elements to ensure the stability of the pressure. The left and right overall rigid body displacement of the concave tooth and convex tooth assembly caused by the back-and-forth flow;

(4) The lower clamp is provided with slots, and the rigidity of the lower clamp can be controlled by using different slot sizes, and the fretting fatigue conditions of the end tooth structure can be simulated under different materials, different structural forms and different working environments.

Description of drawings:

Fig. 1 is a schematic diagram of the overall structure of the end tooth structure fretting fatigue test device of the present invention.

Fig. 2 is a cross-sectional view of the fretting fatigue test device for the end tooth structure shown in Fig. 1 .

FIG. 3 is a schematic structural view of the upper clamping body in the concave tooth fixing assembly in FIG. 1 .

FIG. 4 is a schematic structural diagram of the convex tooth clamping assembly in FIG. 1 .

FIG. 5 is a schematic top view of the convex tooth clamping assembly in FIG. 4 .

FIG. 6 is a schematic left view of the convex tooth clamping assembly in FIG. 4 .

FIG. 7 is a schematic cross-sectional view along the direction A-A of the convex tooth clamping assembly in FIG. 5 .

Fig. 8 is a schematic diagram of the hydraulic system of the normal force loading assembly of the test device of the present invention.

Fig. 9 is a schematic diagram of the fretting fatigue test device for the end tooth structure of the present invention assembled on the uniaxial fatigue testing machine.

in:

1-concave tooth fixing assembly; 11-concave tooth test piece; 110-first concave tooth test piece; 111-second concave tooth test piece; 12-upper clamp body; 120-lower part; 121-upper part; ;13-M10 compression bolt; 14-concave tooth pressure plate; 140-first concave tooth pressure plate; 141-second concave tooth pressure plate; 2-convex tooth clamping assembly; 21-convex tooth test piece; 210-first convex Tooth test piece; 211-second convex tooth test piece; 22-lower clamp body; 23-wedge block; 230-first wedge block; 231-second wedge block; 24-M6 fastening screw; 25-convex tooth positioning Cover plate; 250-first convex tooth positioning cover plate; 251-second convex tooth positioning cover plate; 26-M5 cover plate bolt; 27-M5 nut; 28-slot; 3-normal force loading component; 31- Hydraulic cylinder; 310-the first hydraulic cylinder; 311-the second hydraulic cylinder; 32-hydraulic cylinder piston rod; 320-the first hydraulic cylinder piston rod; 321-the second hydraulic cylinder piston rod; 33-support seat; 330-the first 1 support seat; 331-second support seat; 34-M8 fixing screw; 35-flange tie rod; 36-flange; 360-first flange; 361-second flange; 37-M14 nut; 41-test 42-Load sensor; 43-Clamp on the test machine; 44-Clamp on the test machine; 45-Servo actuator; 46-Displacement sensor.

detailed description:

Please refer to FIG. 1 to FIG. 7 , the end tooth structure fretting fatigue test device of the present invention includes a concave tooth fixing component 1 , a convex tooth clamping component 2 and a normal force loading component 3 .

The concave tooth fixing assembly 1 includes an upper clamp body 12 and a concave tooth test piece 11 installed on the upper clamp body 12, an M10 compression bolt 13 and a concave tooth pressure plate 14, wherein the upper clamp body 12 includes a hollow lower part 120 and a lower part. The upper part 121 above 120, wherein the upper end of the upper part 121 can be clamped on the upper chuck 43 of a common uniaxial fatigue testing machine, and is integrated with the upper crossbeam 41 of the testing machine, and can be raised and lowered in the vertical direction thereupon. The lower part 120 is formed with a rectangular hole 122 penetrating through the front, rear and lower surfaces of the lower part 120 . A rectangular sliding groove (not marked) is respectively arranged on the left and right sides of the rectangular hole 122 on the upper clamp body 12, which are respectively a left rectangular sliding groove and a right rectangular sliding groove, wherein the left rectangular sliding groove and the right rectangular sliding groove are along the The left and right symmetrical planes of the upper clamp body 12 are symmetrically distributed, and the bottoms of the left rectangular sliding groove and the right rectangular sliding groove are at the same horizontal position, thereby ensuring the symmetry of the test loading. The concave tooth test piece 11 includes a first concave tooth test piece 110 and a second concave tooth test piece 111 respectively arranged in the left rectangular sliding groove and the right rectangular sliding groove, wherein the first concave tooth test piece 110 and the second concave tooth test piece 110 The test piece 111 can slide freely in the horizontal direction in the left rectangular sliding groove and the right rectangular sliding groove respectively. The concave tooth pressure plate 14 includes the first concave tooth pressure plate 140 arranged in the left rectangular sliding groove and pressed on the first concave tooth test piece 110 by the M10 compression bolt 13, and the first concave tooth pressure plate 140 which is arranged in the right rectangular sliding groove and passed the M10 The compression bolt 13 is pressed against the second concave tooth pressure plate 141 above the second concave tooth test piece 111 . There are four M10 compression bolts 13, which are arranged on the lower clamp body 12 and are located directly above the rectangular sliding groove, two of which are pressed on the top of the first concave tooth pressure plate 140, and the other two are pressed on the second concave tooth pressure plate 140. Above the tooth pressure plate 141, the first concave tooth pressure plate 140 and the first concave tooth test piece 110 are pressed together by the M10 compression bolt 13, and the second concave tooth pressure plate 141 and the second concave tooth test piece 111 are pressed together. Together, it can ensure that the concave tooth test piece 11 remains horizontal when it is subjected to a vertical downward load. At the same time, the top surface of the concave tooth test piece 11 and the bottom surface of the concave tooth pressure plate 14 are both in a horizontal state, and the surface finish is relatively high. The friction contact surface can ensure that the normal load in the horizontal direction is not affected by the compression of the M10 compression bolt 13.

The convex tooth clamping assembly 2 includes a lower clamp body 22, a convex tooth test piece 21 installed on the lower clamp body 22, a wedge block 23, an M6 fastening screw 24, a convex tooth positioning cover plate 25, an M5 cover plate bolt 26 and an M5 nut 27. The left and right side walls of the lower clamp body 22 are respectively inwardly recessed to form grooves, which are symmetrical left and right grooves, wherein the lower walls of the left groove and the right groove are sloped. The convex tooth test piece 21 includes a first convex tooth test piece 210 and a second convex tooth test piece 211 respectively arranged in the grooves on the left and right sides, wherein the first convex tooth test piece 210 and the second convex tooth test piece 211 are bilaterally symmetrical The arrangement on the lower clamp body 22 can ensure that no additional bending moment and torque are generated during the loading test. The wedge block 23 includes a first wedge block 230 installed in the left groove and located below the first convex tooth test piece 210 to connect the first convex tooth test piece 210 with the lower clamp body 22 and a first wedge block 230 installed on the right side. The second wedge-shaped block 231 in the groove and below the second convex tooth test piece 211 is used to connect the second convex tooth test piece 211 with the lower clamp body 22 . Wherein the bottom slope of the first wedge-shaped piece 230 matches the lower wall of the left groove, the bottom slope of the second wedge-shaped piece 231 matches the bottom wall of the right groove, and the first wedge-shaped piece 230 and the second wedge-shaped piece 231 are both The M6 fastening screw 24 is threadedly fixed on the lower clamp body 22 . The thickness of the lower clamp body 22 is greater than the thickness of the convex tooth test piece 21, which can ensure that the lower clamp body 22 has sufficient strength and rigidity. The assembly and positioning of the front and rear thickness directions of the lower clamp body 22 and the convex tooth test piece 21 is realized by the convex tooth positioning cover plate 25, wherein the convex tooth positioning cover plate 25 includes a front surface mounted on the lower clamp body 22 and the convex tooth test piece 21 The first convex tooth positioning cover plate 250 on the top and the second convex tooth positioning cover plate 251 installed on the lower clamp body 22 and the rear surface of the convex tooth test piece 21. The first convex tooth positioning cover plate 250 and the second convex tooth positioning cover plate 251 are symmetrically placed on the convex tooth test piece 21 front and back, which can ensure that the thickness direction symmetry plane of the convex tooth test piece 21 coincides with the thickness direction symmetry plane of the lower clamp body 22 . The first convex tooth positioning cover plate 250 , the second convex tooth positioning cover plate 251 and the lower clamp body 22 are fixedly connected by M5 cover plate bolts 26 and M5 nuts 27 .

On the upper surface of the lower clamp body 22, along the central axis, there is an elongated slot 28 that runs through the front and rear surfaces of the lower clamp body 22, wherein the lower end of the slot 28 extends to the level of the lower end of the convex tooth test piece 21. unanimous. Through the slot 28, it can be ensured that the upper half of the lower clamp body 22 is slightly deformed in the horizontal direction when loading, that is, the mating surface of the concave tooth test piece 11 and the convex tooth test piece 21 will produce a small relative slip, that is, a slight In order to generate dynamic wear, applying alternating cyclic fatigue loads to the lower clamp body 22 can generate reciprocating fretting wear fatigue on the contact surface of the concave teeth and the convex teeth. By selecting the lower clamp body 22 with slots 28 of different sizes, the end tooth fretting fatigue test in different contact conditions can be realized.

The assembly sequence of the convex tooth clamping assembly 2 is as follows: first, through four sets of M5 cover plate bolts 26 and M5 nuts 27, the convex tooth positioning cover 25 is placed on the lower clamp body 22, the M5 nut 27 is not tightened, and the convex tooth positioning cover There is a gap in the thickness direction between the plate 25 and the lower clamp body 22. At this time, the convex tooth test piece 21 is placed in the groove of the lower clamp body 22, and then the wedge block 23 is connected to the lower clamp by M6 fastening screws 24. Specifically on 22, gradually tighten the M5 nut 27 and M6 fastening screw 24, while ensuring that the convex tooth test piece 21 coincides with the symmetrical plane of the lower clamp body 22 in the thickness direction, the two are tightly connected; wherein the M6 fastening screw 24 and the wedge-shaped Spring washers are placed between the blocks 23, which can prevent the threaded connection from loosening during the fatigue process and ensure the tight connection between the convex tooth test piece 21 and the lower clamp body 22.

The normal force loading assembly 3 includes a hydraulic cylinder 31 , a hydraulic cylinder piston rod 32 , a support seat 33 , an M8 fixing screw 34 , a flange tie rod 35 , a flange 36 welded integrally with the hydraulic cylinder, and an M14 nut 37 . The hydraulic cylinder 31 includes a first hydraulic cylinder 310 and a second hydraulic cylinder 311 positioned on the left and right sides of the upper clamping body 12, wherein the right end of the first hydraulic cylinder 310 and the left end of the second hydraulic cylinder 311 are respectively welded with a first hydraulic cylinder. The flange 360 and the second flange 361, the first flange 360 is spaced apart from the left side of the upper clamp body 12, and the second flange 361 is spaced apart from the right side of the upper clamp body 12. The support seat 33 includes a first support seat 330 for placing the first flange 360 and a second support seat 331 for placing the second flange 361, while the lower left end of the upper clamp body 12 is placed on the first support seat 330 And the M8 fixing screw 34 is fixed together with the first supporting base 330 , the lower right end of the upper clamp body 12 is placed on the second supporting base 331 and fixed together with the second supporting base 331 through the M8 fixing screw 34 . The hydraulic cylinder piston rod 32 includes a first hydraulic cylinder piston rod 320 disposed in the first hydraulic cylinder 310 and a second hydraulic cylinder piston rod 321 disposed in the second hydraulic cylinder 311 . The axes of the first hydraulic cylinder piston rod 320 and the second hydraulic cylinder piston rod 321 are along the horizontal direction and pass through the assembly center of the concave tooth test piece 11 and the convex tooth test piece 21 . The flange rods 35 include four connecting the first flange 360 and the second flange 361 through M14 nuts 37 . In the present invention, the normal force is loaded by the normal force hydraulic system, which can provide a sustained and stable large driving force. The horizontal normal force is loaded to the concave tooth test piece 11, and its reaction force is transmitted to the flange by the hydraulic cylinder, and finally It is transmitted to four flange tie rods to form a complete closed force system frame structure in the horizontal direction. The schematic diagram of the hydraulic system, please refer to Figure 8, in which the normal force hydraulic system passes through the remote pressure regulating valve, pilot pressure reducing valve, three-position four-way electromagnetic reversing valve, superimposed hydraulic control check valve and superimposed one-way throttle valve The composed hydraulic lock control element is controlled to ensure the stability of the oil pressure in the rodless cavity (Cavity A) of the hydraulic cylinder 31, and to provide a continuous and stable load to the outside. Compared with the traditional thread loading method, it can overcome the small driving force of the thread loading. And the phenomenon that the vibration causes the loosening load of the threaded connection to drop during the fatigue process.

When loading through the normal force loading assembly 3 in the horizontal direction, in order to ensure that the horizontal loading device will not generate additional force in the horizontal direction on the upper clamp body 12, four flange pull rods 35 are used to connect the first flange 360 and the second flange 360 The flange 361 is directly connected by the M14 nut 37, and the hydraulic cylinder 31, the flange 36, the hydraulic cylinder piston rod 32 and the flange tie rod 35 form a closed force system frame structure as a whole. Therefore, the horizontal thrust received by the first hydraulic cylinder 310 and the second hydraulic cylinder 311 on both sides in the frame structure of the entire closed force system will be shared by the four flange tie rods 35, and the two ends of each tie rod will receive equal and large horizontal pull forces. The balance state is maintained by the action, which ensures that the normal load provided by the hydraulic cylinder is stably applied to the concave tooth test piece 11, and at the same time, there is no external force output in the horizontal direction.

The test device of the present invention applies a load in the horizontal direction to simulate the axial pretightening force load of the end tooth, and a fatigue load in the vertical direction to simulate the equivalent load of the end tooth torque, and the two-way loads are perpendicular to each other. The lower clamp is specifically provided with slots to provide a fretting wear environment, so as to assess the fretting wear fatigue of the mating surface of the concave and convex teeth.

The upper end of the upper clamp body can be clamped on the upper chuck of a common uniaxial fatigue testing machine, and can be lifted in the vertical direction along with the upper beam of the testing machine, which is convenient for its assembly and disassembly or position adjustment during the test. The normal force loading component is integrated with the upper clamp body, and will not cause additional force on the ordinary fatigue testing machine in the horizontal direction.

Please refer to Figures 1 to 8 and in combination with Figure 9, the specific steps of the test method using the above-mentioned terminal tooth structure fretting fatigue test device are as follows:

(a) A uniaxial fatigue testing machine is provided, and the end tooth structure fretting fatigue testing device is installed on the uniaxial fatigue testing machine. The upper beam 41 of the testing machine connected with the upper clamp 43, the lower clamp 44 of the testing machine clamping the lower end of the lower clamp body 22, the load sensor 42, the servo actuator 45 and the displacement sensor located below the lower clamp 44 of the testing machine 46. Clamp the upper end of the upper part 121 of the upper clamp body 12 in the upper chuck 43 of the uniaxial fatigue testing machine, connect the upper clamp body 12 and the normal force loading assembly 3 with the upper chuck 43 of the testing machine, and lift the test The crossbeam 41 on the machine, the normal force loading assembly 3 in the horizontal direction rises together with the upper clamp body 12 and the upper crossbeam 41 of the testing machine;

Loosen the four M10 compression bolts 13, place the first concave tooth test piece 110 and the second concave tooth test piece 111 respectively in the left and right rectangular sliding grooves of the upper clamp body 12, and gently push the first tooth left and right. The concave tooth test piece 110 and the second concave tooth test piece 111 ensure that they can move left and right in the horizontal direction in the left and right rectangular sliding grooves respectively, and then the first concave tooth pressing plate 140 and the second concave tooth pressing plate 141 are respectively placed on the Adjust the approximate position above the first concave tooth test piece 110 and the second concave tooth test piece 111 in the left and right rectangular sliding grooves;

(b) Assembling the convex tooth clamping assembly 2: first, the front and rear two convex tooth positioning covers (ie, the first convex tooth positioning cover 250 and the second convex tooth positioning cover 251 ) are connected with four sets of M5 cover bolts 26 and The M5 nut 27 is assembled on the lower clamp body 22, but the M5 cover plate bolt 26 is not tightened, and the two convex tooth test pieces (i.e. the first convex tooth test piece 210 and the second convex tooth test piece 211) are respectively placed on the In the left groove and the right groove formed by the left and right side walls of the lower clamp body 22, two wedge blocks 23 (i.e. the first wedge block 230 and the second wedge block 231) are respectively placed in the left groove and the right groove Among them, the first wedge block 230 is located below the first convex tooth test piece 210 and the M6 fastening screw 24 for fastening the first wedge block 230 and the lower clamp body 12 together is installed on the first wedge block 230, The second wedge block 231 is located below the second protruding teeth test piece 211 and the second wedge block 231 is equipped with an M6 fastening screw 24 for fastening the second wedge block 231 and the lower clamp body 12 together. M5 cover plate bolts 26 to ensure that the convex tooth test piece 21 and the lower clamp body 22 coincide on the symmetrical planes in the front and rear thickness directions, and finally tighten the M6 fastening screws 24 to ensure that the convex tooth test piece and the lower clamp body are tightly fixed, and finally the four Set M5 cover plate bolts 26 and M5 nuts 27 to loosen, but it is not necessary to completely dismantle them. This is because the previous tightening is to locate the front and rear positions in the thickness direction, so as to ensure that the convex tooth test piece 21 and the lower clamp body 22 coincide on the symmetrical plane in the thickness direction of assembly. , but during the test, if the convex tooth positioning cover plate 25 is still tightly pressed on the lower clamp body 22, the micro-deformation effect produced by the slot 28 will be inhibited, that is, the effect of fretting wear will be slowed down or even disappeared.

(c) Place the above-mentioned assembled convex tooth loading assembly 2 in the rectangular hole of the upper clamp body 12, turn the knob switch on the electric control cabinet to control the movement direction of the hydraulic cylinder piston rod 32 to the "pressing" position, and then slowly adjust Control the remote pressure regulating valve of the horizontal hydraulic cylinder on the electric control cabinet, so that the piston rods of the left and right hydraulic cylinders (that is, the first hydraulic cylinder piston rod 320 and the second hydraulic cylinder piston rod 321) slowly extend and compress to the concave tooth test (i.e. the first concave tooth test piece 110 and the second concave tooth test piece 111), and at the same time further push the first concave tooth test piece 110 and the second concave tooth test piece 111 to move to the center until they are installed on the lower clamp body 22. The convex tooth test pieces on the left and right sides (that is, the first convex tooth test piece 210 and the second convex tooth test piece 211) are contacted and pressed together. The specific working principle of the control process is as follows:

In conjunction with the illustration shown in Figure 8, the "tightening" knob (not shown) on the electric control cabinet is the control switch of the electromagnetic directional valve. When the knob is in the "tightening" position, the three-position four-way electromagnetic directional valve and the hydraulic The valve port connected to the rodless cavity (Cavity A) of the cylinder 31 is opened, and the oil inlet port of the hydraulic system is connected with the rodless cavity (Cavity A) of the hydraulic cylinder 31. It is connected with the rod chamber (B chamber) of the hydraulic cylinder, so that the rodless chamber (A chamber) enters the oil, and the rod chamber (B chamber) returns the oil, the hydraulic cylinder piston rod 32 will move to the center, and slowly adjust the electric control cabinet. The two remote pressure regulating valves corresponding to the two hydraulic cylinders (namely the first hydraulic cylinder 310 and the second hydraulic cylinder 311) control the pressure of the pilot pressure reducing valve so that the rodless chambers of the left and right hydraulic cylinders (A Cavity) is continuously filled with oil and pressurized, and the hydraulic cylinder piston rod 32 is slowly stretched out and pressed against the outer end surface of the concave tooth test piece 11 (wherein the first hydraulic cylinder piston rod 320 is pressed against the first concave tooth test piece 110 On the left end face, the second hydraulic cylinder piston rod 321 is pressed to the right end face of the second concave tooth test piece 111), carefully observe the reading of the precision pressure gauge connected with the rodless cavity (Cavity A) on the electric control cabinet. Due to the use of a superimposed control element composed of an electromagnetic reversing valve, a hydraulic control check valve and a one-way throttle valve, the pressure oil in the rodless chamber (A chamber) flows in one direction during the pressurization process, that is, when the direction is not reversing The pressure in the rodless cavity (Cavity A) only increases but does not decrease, so the pressure adjustment process must be slow and uniform until it is adjusted to the predetermined pressure, keep it for 1 to 2 minutes, and observe the readings of the precision pressure gauge to ensure that the pressure remains stable;

(d) Tighten the four M10 compression bolts 13 located in the upper clamp body 12, so that the two concave tooth pressure plates 14 press the top surface of the concave tooth test piece 11, then the bottom surface of the concave tooth test piece 11 and the upper clamp body 12 The bottom of the rectangular sliding groove is kept in close contact to ensure that the concave tooth test piece is in a horizontal state;

(e) Adjust the position of the upper crossbeam 41 of the fatigue testing machine so that the lower end of the lower clamp body 22 enters the jaws of the lower chuck 44 of the testing machine, and first clear the load sensor of the fatigue testing machine to eliminate the initial load caused by the weight of the testing device itself, Then the lower clamp 44 of the testing machine is clamped to the lower end of the lower clamping body 22, the control program of the testing machine is set to the load control mode, the servo actuator 45 of the testing machine is controlled, and the fatigue testing machine is moved downward, and the convex teeth Apply initial tension to the test piece, and suspend loading when the reading of the load cell 46 reaches the average value of the fatigue test load;

(f) Enter the fatigue test program module of the fatigue testing machine control program, set the mean value and amplitude of the fatigue test load, and then start the fretting fatigue test, wherein the fatigue load of the test process is measured by the load sensor 42 , the movement stroke of servo actuator 45 is measured by displacement sensor 46;

(g) The up and down movement of the lower chuck of the fatigue testing machine causes the convex tooth test piece to move up and down, and the concave tooth test piece remains fixed under the combined action of the horizontal pre-tightening force load and the M10 compression bolt, so it is consistent with the convex tooth test piece The upper end of the connected lower clamp body will produce a slight deformation toward the center, so that a small relative slip occurs between the tooth mating surfaces of the concave tooth test piece and the convex tooth test piece, that is, fretting wear. After a certain number of cycles , fretting fatigue cracks can appear.

In the test method steps of the above-mentioned terminal tooth structure fretting fatigue test device, due to the combination of the three-position four-way electromagnetic reversing valve and the hydraulic control check valve, the rodless cavity (Cavity A) enters in one direction during the pressurization process. Oil, the one-way oil return of the rod chamber (B chamber), and the hydraulic control check valve will inhibit the backflow of hydraulic oil, so as to ensure the stability of the pressure in the rodless chamber (A chamber), and will not be disturbed by external vibrations. This causes pressure fluctuations in the rodless cavity (Cavity A), which can ensure a constant load in the horizontal direction. In addition, the left and right hydraulic cylinders (namely the first hydraulic cylinder and the second hydraulic cylinder) are controlled by two independent hydraulic control elements, which can ensure that the two pressures will not interfere with each other during the pressurization process, and will not be caused by When there is a small pressure difference in the rodless cavity (Cavity A) of the left and right hydraulic cylinders, the hydraulic oil flows back and forth with each other, which will cause the left and right concave tooth test pieces to move left and right as a whole, causing the rigid body displacement of the test piece assembly structure.

During the hydraulic loading process in the horizontal direction, it is necessary to adjust the opening of the one-way throttle valve to be as small as possible, control the movement speed of the hydraulic cylinder piston rod, keep the hydraulic cylinder loading synchronization in the horizontal direction, and ensure that the hydraulic cylinder piston rod moves toward the center at the same speed. move, and keep the pressure equal. The reaction force produced when the pressure load is applied by the left and right hydraulic cylinders in the horizontal direction is offset by the four flange tie rods 35 in the middle, forming a closed force system frame structure. This loading system has no force on the upper clamp body 12 in the horizontal direction, and only the load generated by the weight of the hydraulic cylinder itself exists in the vertical direction. This load is transmitted to the upper clamp body 12 through the support seat 33, and finally to the upper chuck of the testing machine. 43. Before the fatigue test starts, the load reading of the load cell caused by the weight needs to be cleared to zero.

The transmission path of the fatigue load in the vertical direction during the fatigue process is as follows: when the testing machine applies a tensile load as an example, when the servo actuator 45 of the testing machine moves downward, a downward pulling force is applied to the lower chuck 44 of the testing machine, and the load passes through The lower clamp body 22 is transmitted to the convex tooth test piece 21, the convex tooth test piece 21 is matched with the concave tooth test piece 11, the load is transmitted to the concave tooth test piece 11 through the mating surface, and the concave tooth test piece 11 acts on the upper clamp body 12. Rectangular sliding groove, and transmitted to the upper chuck 43 of the testing machine through the upper clamp body 12, the upper chuck 43 of the testing machine is connected with the load sensor 42, and both are fixed on the upper beam 41 of the testing machine, and the upper beam 41 of the testing machine is locked in the test after the position is adjusted. On the two left and right columns of the machine, the tensile load caused by the downward movement of the servo actuator is finally offset by the pressure on the two middle columns, that is, during the fatigue process, a closed force system structure is formed in the vertical direction.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, some improvements can also be made without departing from the principle of the present invention, and these improvements should also be regarded as the invention. protected range.

Claims (8)

1. A fretting fatigue test device for an end tooth structure, comprising a concave tooth fixing assembly (1), a convex tooth clamping assembly (2) and a normal force loading assembly (3), characterized in that: The concave tooth fixing assembly (1) includes an upper clamp body (12), a concave tooth test piece (11) and a concave tooth pressure plate (14) installed on the upper clamp body (12), and the upper clamp body (12) Comprising a hollow lower part (120) and an upper part (121) above the lower part (120), the lower part (120) is formed with a rectangular hole (122) passing through the front, rear and lower surfaces of the lower part (120), The upper clamp body (12) is symmetrically provided with rectangular sliding grooves on the left and right sides of the rectangular hole (122), and the concave tooth test piece (11) is placed in the rectangular sliding groove and slides freely along the horizontal direction of the rectangular sliding groove , the concave tooth pressure plate (14) is placed in the rectangular sliding groove and the bottom surface of the concave tooth pressure plate (14) is pressed against the top surface of the concave tooth test piece (11), and the upper clamp body (12) is located on the rectangular sliding An M10 pressing bolt (13) for pressing the concave tooth pressure plate (14) is arranged directly above the groove; The convex tooth clamping assembly (2) includes a lower clamp body (22), a convex tooth test piece (21) installed on the lower clamp body (22), a wedge block (23) and a convex tooth positioning cover (25) , the convex tooth clamping assembly (2) is placed in the rectangular hole of the upper clamping body (12), and grooves are symmetrically arranged on the left and right side walls of the lower clamping body (22) opposite to the rectangular sliding groove, The convex tooth test piece (21) is placed in the groove, the wedge block (23) is placed in the groove and the top surface of the wedge block (23) is close to the bottom surface of the convex tooth test piece (21), so The thickness of the convex tooth test piece (21) is less than the thickness of the lower clamp body (22), and the convex tooth positioning cover plate (25) comprises two altogether, which are installed on the lower clamp body (22) and the convex tooth test piece respectively. (21) On the front surface and the rear surface, a slot ( 28); The normal force loading assembly (3) includes a hydraulic cylinder (31), a flange (36) welded integrally with the hydraulic cylinder, a hydraulic cylinder piston rod (32) arranged in the hydraulic cylinder (31), a flange pull rod (35) and the support base (33) that flange (36) is supported thereon, the end of the hydraulic cylinder piston rod (32) extends beyond the flange (36) and the hydraulic cylinder piston rod (32) The end is against the concave tooth test piece (11) so that the concave tooth test piece (11) can slide freely along the horizontal direction of the rectangular sliding groove, and the concave tooth test piece (11) and the convex tooth test piece (21 ) contact and press together, and the upper clamp body (12) and the support seat (33) are fixed together. 2. The end tooth structure fretting fatigue test device according to claim 1, characterized in that: the hydraulic cylinder (31) includes a first hydraulic cylinder (310) and a second hydraulic cylinder (310) located on the left and right sides of the upper clamp body (12). Two hydraulic cylinders (311), the flange (36) includes a first flange (360) welded to the right end of the first hydraulic cylinder (310) and a second flange (360) welded to the left end of the second hydraulic cylinder (311). A flange (361), the flange pull rod (35) is connected between the first flange (360) and the second flange (361). 3. The fretting fatigue test device for end tooth structure according to claim 2, characterized in that there are four flange tie rods (35) in total. 4. The end tooth structure fretting fatigue test device according to claim 1, characterized in that: the lower end of the slot (28) extends to the same level as the lower end of the convex tooth test piece (21) s position. 5. The fretting fatigue test device for end tooth structure according to claim 1, characterized in that: the top surface of the concave tooth test piece (11) and the bottom surface of the concave tooth pressure plate (14) are both in a horizontal state. 6. The end tooth structure fretting fatigue test device according to claim 1, characterized in that: the lower wall surface of the groove set on the lower clamp body (22) is an inclined plane, and the bottom surface of the wedge block (23) It is in the shape of an inclined plane matched with the lower wall of the groove. 7. The end tooth structure fretting fatigue test device according to claim 1, characterized in that: the convex tooth clamping assembly (2) also includes a convex tooth positioning cover (25) installed on the lower clamp body (22) M5 cover plate bolts (26) and M5 nuts (27) and the M6 fastening screws (24) that the wedge block (23) and the lower clamp body (22) are fastened together. 8. A test method for an end tooth structure fretting fatigue test device, characterized in that: comprising the following steps (a) A uniaxial fatigue testing machine is provided, and the terminal tooth structure fretting fatigue testing device is installed on the uniaxial fatigue testing machine, and the uniaxial fatigue testing machine includes the upper end of the clamping body (12) The upper chuck (43) of the testing machine, the upper beam (41) of the testing machine connected with the upper chuck (43) of the testing machine, the lower chuck (44) of the testing machine clamping the lower end of the lower clamp body (22), the load sensor (42), the servo actuator (45) and the displacement sensor (46) located under the lower clamp (44) of the testing machine connect the upper clamp body (12) and the normal force loading assembly (3) to the upper clamp of the testing machine (43) connect as a whole, raise the upper beam (41) of the testing machine, and the normal force loading assembly (3) rises together with the upper clamp body (12) and the upper beam (41) of the testing machine; (b) Assemble the convex tooth clamping assembly (2), and assemble the front and rear two convex tooth positioning covers (25) to the lower clamp body (22) through M5 cover bolts (26) and M5 nuts (27). When the M5 cover plate bolts (26) are not tightened, place the convex tooth test piece (21) in the groove, place the wedge block (23) in the groove and the top surface of the wedge block (23) is close to the The bottom surface of the convex tooth test piece (21), tighten the M5 cover plate bolt (26) and the M6 fastening screw (24) at the same time, so that the convex tooth test piece (21) and the lower clamp body (22) are fastened together, and finally the M5 cover plate bolts (26) and M5 nuts (27) are loosened; (c) Place the convex tooth clamping assembly (2) assembled in step (b) in the rectangular hole of the upper clamping body (12), and slowly adjust the remote pressure regulating valve on the electric control cabinet to control the pressure of the hydraulic cylinder in the horizontal direction , so that the hydraulic cylinder piston rod (32) slowly protrudes out of the flange (36) and is pressed against the concave tooth test piece (11), observe the reading of the precision pressure gauge connected to the hydraulic cylinder on the electric control cabinet, and gradually increase the pressure , until the predetermined load value; (d) Tighten the M10 compression bolt (13) located in the upper clamp body (12), so that the concave tooth pressure plate (14) presses the top surface of the concave tooth test piece (11), and the bottom surface of the concave tooth test piece (11) Keep in close contact with the bottom of the rectangular sliding groove of the upper clamp body (12) to ensure that the concave tooth test piece is in a horizontal state; (e) Lower the upper beam (41) of the testing machine so that the lower end of the lower clamp body (22) falls into the lower chuck (44) of the testing machine, clear the load sensor of the fatigue testing machine, and eliminate the initial load caused by the weight of the testing device itself. load, then clamp the lower chuck (44) of the testing machine, set the testing machine control program to the load control mode, control the testing machine servo actuator (45), make the fatigue testing machine move downwards, and apply initial force to the convex teeth. Tensile force, observe load cell (42) reading, suspend loading when the reading of load cell (46) reaches the mean value of fatigue test load, wherein the size of fatigue load is measured by load cell (42), the servo actuator (45) Movement stroke is measured by displacement sensor (46); (f) Control the fatigue program module of the testing machine control program, set the average value and amplitude of the fatigue load, and start the fretting fatigue test; (g) The up and down movement of the lower chuck of the testing machine causes the convex tooth test piece (21) to move up and down, and the concave tooth test piece (11) is under the joint action of the normal preload in the horizontal direction and the concave tooth pressure plate (14) Keep fixed, so the upper end of the lower clamp body (22) which is integrated with the convex tooth test piece (21) will produce a slight deformation towards the center, so that the concave tooth test piece (11) and the convex tooth test piece (21) teeth A small relative slip occurs between the mating surfaces, that is, fretting wear. After a certain number of cycles, fretting fatigue cracks appear.