CN110006635B

CN110006635B - Double-shaft loading fatigue testing machine

Info

Publication number: CN110006635B
Application number: CN201910167043.1A
Authority: CN
Inventors: 陈高升; 赖亮庆; 尹建伟; 冯林兆; 苏正涛; 刘嘉
Original assignee: AECC Beijing Institute of Aeronautical Materials
Current assignee: AECC Beijing Institute of Aeronautical Materials
Priority date: 2019-03-05
Filing date: 2019-03-05
Publication date: 2021-03-26
Anticipated expiration: 2039-03-05
Also published as: CN110006635A

Abstract

The invention relates to a biaxial loading fatigue testing machine, which is characterized in that: the base (1) is respectively fixedly connected with the variable frequency motor (2), the frequency converter (3) and the protective cover (4), the static moment torsion shaft (5) is connected with the base (1) through a locking nut (18), two ends of an angle adjusting connecting rod (17) are respectively connected with the static moment torsion shaft (5) and a connecting rod assembly (16), and one end of the connecting rod assembly (16) is connected with the base (1) through a bolt; one end interface of the test part (8) is fixedly connected with the static torque torsion shaft (5), the other end interface is fixedly connected with the dynamic torque torsion shaft (15), the dynamic torque torsion shaft (15) is connected with the machine base (1) through a ball bearing (7), and the test part is limited and fixed through a dustproof lock nut (6); one end of the rocker (14) is connected with the dynamic torque torsion shaft (15). The invention reduces the technical requirements and complexity of the part on the test equipment under the specific multi-axis loading condition, reduces the test cost and shortens the test period.

Description

Double-shaft loading fatigue testing machine

The technical field is as follows:

the invention belongs to a fatigue test technology, and relates to a biaxial loading fatigue testing machine.

Technical background:

the double-shaft loading fatigue testing machine is mainly used for the fatigue test of parts which have symmetrical mounting structures and bear loads in two mutually perpendicular axial directions. The laminated spherical rubber elastic bearing is an important functional component of a helicopter rotor system, and simultaneously bears centrifugal load, torsional load, flapping load and shimmy load, the service life of a part is a key technical assessment index, fatigue tests are carried out on the part by simultaneously considering the complex load, and very high requirements are often provided for test equipment and technology. The support bearing for the helicopter tail rotor system is a symmetrical mounting structure, mainly bears mutually perpendicular torsional load and swinging (shimmy) load, is suitable for fatigue verification by adopting a simplified double-shaft fatigue testing machine in a bearing mode, and can greatly reduce the testing cost and the development period.

The invention content is as follows:

the purpose of the invention is: the double-shaft loading fatigue testing machine is simple in structure, low in cost, convenient to install and maintain and long in service life.

The technical scheme of the invention is as follows: a biaxial loading fatigue tester comprising: the device comprises a base 1, a variable frequency motor 2, a frequency converter 3, a protective cover 4, a static torque torsion shaft 5, a dustproof lock nut 6, a ball bearing 7, a test part 8, a cam connecting rod 9, a needle bearing 10, a cam disc 11, an inertia mass wheel 12, a pin 13, a rocker 14, a dynamic torque torsion shaft 15, a connecting rod assembly 16, an angle adjusting connecting rod 17 and a lock nut 18. The device comprises a base 1, a variable frequency motor 2, a frequency converter 3 and a protective cover 4 which are fixedly connected, wherein a static torque torsion shaft 5 is connected with the base 1 through a locking nut 18, an angle adjusting connecting rod 17 is respectively connected with the static torque torsion shaft 5 and a connecting rod assembly 16, and the other end of the connecting rod assembly 16 is connected with the base 1 through a bolt. One end interface of the test part 8 is fixedly connected with the static torque torsion shaft 5, the other end interface is fixedly connected with the dynamic torque torsion shaft 15, the dynamic torque torsion shaft 15 is connected with the machine base 1 through the ball bearing 7 and is limited and fixed through the dustproof locking nut 6, one end of the rocker 14 is connected with the dynamic torque torsion shaft 15, the other end of the rocker is connected with the cam connecting rod 9 through the needle bearing 10 and the pin 13, the other end of the cam connecting rod 9 is connected with the cam disc 11 through the needle bearing 10, the cam disc 11 is connected with the inertia mass wheel 12, and the inertia mass wheel 12 is connected with the variable frequency motor 2. The static torque torsion shaft 5 is rotated by adjusting the length of the connecting rod assembly 16 to realize static torque angle loading, and the dynamic torque angle loading is realized by combining the dynamic torque torsion shaft 15, the rocker 14, the cam connecting rod 9, the cam disc 11, the inertia mass wheel 12 and the variable frequency motor 2, so that the static torque angle and variable torque angle double-shaft fatigue loading of parts is realized.

Preferably, the arc surface of the upper end of the static torque torsion shaft 5 has an angle scale, and the static torque angle loading can be realized by adjusting the length of the connecting rod assembly 16 to rotate the static torque torsion shaft 5 to a specified angle.

Preferably, the variable frequency motor 2 is connected with the frequency converter 3, and the rotating speed of the variable frequency motor 2 can be controlled by controlling the frequency of the frequency converter 3, so that the dynamic torque conversion angle loading of parts under different frequency conditions is realized.

Preferably, the axis of the static torque shaft 5 and the axis of the dynamic torque shaft 15 intersect perpendicularly with each other.

Preferably, the fatigue-contributing parts are two parts of identical construction, mounted symmetrically with respect to the axis of the static torque torsion shaft 5 and the dynamic torque torsion shaft 15.

The invention has the technical effects that: the simple double-shaft loading fatigue testing machine greatly reduces the technical requirements and complexity of parts on testing equipment under a specific multi-shaft loading condition, reduces the testing cost, shortens the testing period and can generate greater economic benefits.

Drawings

FIG. 1 is a schematic view of the external structure of the fatigue testing machine of the present invention

FIG. 2 is a front isometric view of the whole internal structure of the fatigue testing machine

FIG. 3 is a schematic isometric view of the whole rear view of the internal structure of the fatigue testing machine of the invention

FIG. 4 is a schematic view of the structure of the moving assembly of the fatigue testing machine of the present invention

FIG. 5 is an exploded view of the moving component of the fatigue testing machine of the present invention

FIG. 6 is a schematic diagram of an example motion assembly

Detailed Description

The invention is further described with reference to the following figures and examples:

the basic external structure of the biaxial loading fatigue testing machine is shown in figure 1, wherein 1 is a machine base, 2 is a variable frequency motor, 3 is a frequency converter, 4 is a protective cover, and a testing machine moving component is arranged in the protective cover.

The testing machine moving assembly is shown in attached figures 3 and 4 and mainly comprises a static moment torsion shaft 5, a dustproof lock nut 6, a ball bearing 7, a test part 8, a cam connecting rod 9, a needle bearing 10, a cam disc 11, an inertia mass wheel 12, a pin 13, a rocker 14, a dynamic moment torsion shaft 15, a connecting rod assembly 16, an angle adjusting connecting rod 17 and a lock nut 18.

The structure of the static torque torsion shaft 5 is designed according to the bearing mode and the interface installation size of the part, the static torque torsion shaft 5 and the dynamic torque torsion shaft 15 are ensured to be vertically crossed when the parts are installed in pairs, angle marking marks are designed on the static torque torsion shaft 5, the angle marking range is not smaller than the limit load actually borne by the part, the static torque torsion shaft has enough rigidity and strength, and deformation in the bearing process and fatigue fracture after long-time fatigue work are prevented.

Calculating the limit dynamic moment loading angle range to be subjected to fatigue according to the fatigue load spectrum of the part, designing the basic structure of the rocker mechanism of the rocker according to the calculated dynamic moment loading angle, determining the design sizes of the cam, the connecting rod and the rocker, and developing the detailed structural design on the basis.

The detailed structural design of the connecting rod assembly 16, the angle adjusting connecting rod 17 and the locking nut 18 is developed, wherein threads at two ends of the connecting rod assembly 16 are mutually reversed threads, the telescopic length is adjusted through the connecting rod assembly 16, the static moment torsion shaft 5 is driven through the angle adjusting connecting rod 17 to realize the control of the static angle, and the locking nut 18 is screwed when the required static moment angle is reached.

And bearings are arranged at two ends of the dynamic torque torsion shaft 15 and the cam connecting rod 9, so that the abrasion of a dynamic part in the fatigue process is reduced, and the service life of the dynamic part is prolonged. Roller bearings are preferably arranged at two ends of the cam connecting rod 9, so that repeated impact in the direction changing process of the rocker 14 can be effectively resisted, and lubricating oil or lubricating grease is applied to the bearings before a fatigue test.

The dustproof locking nuts 6 play roles in adjusting the position and fixing the dynamic torque torsion shaft 5, after the dynamic torque torsion shaft 5 and the test part 8 are installed and fixed, the dustproof locking nuts 6 at two ends are locked, and the locking torque is suitable for preventing the dynamic torque torsion shaft from moving in the axial direction and flexibly rotating.

Design protection casing 4, inverter motor 2, converter 3 and frame 1's mounting structure, its overall structure focus should be in near the geometric centre of frame 1 as far as possible in the horizontal direction, is favorable to reducing the vibration of tired in-process structure, for reducing the influence of tired in-process vibration to the ground, sets up the damping support in the bottom of frame 1.

During fatigue test, the rotating speed of the variable frequency motor 2 is controlled by adjusting the frequency of the frequency converter 3 so as to control the fatigue frequency of the tested part, the frequency of the frequency converter is gradually increased from 0, and when the sensor for monitoring the rotating speed of the variable frequency motor 2 reaches the required frequency, the frequency of the frequency converter is stopped to be increased. In order to prevent the overall structure from generating excessive vibration, the test frequency should avoid the resonance frequency of the overall structure of the testing machine.

Examples of the embodiments

Embodiment as shown in fig. 6, fig. 6 shows a top-bottom symmetrical installation form of the tail rotor elastic supporting bearing structure, wherein the static moment angle is waving around an X axis, and the variable moment angle is bending around a Y axis. The change range of the static moment angle is-20 degrees to 20 degrees, the motion range of the torque conversion angle is-10 degrees to 10 degrees, and the dynamic biaxial fatigue loading of the 2 tail rotor elastic support bearings under different motion frequencies can be realized through the control of the frequency converter.

Claims

1. A biaxial loading fatigue testing machine is characterized in that: the base (1) is respectively fixedly connected with the variable frequency motor (2), the frequency converter (3) and the protective cover (4), the static moment torsion shaft (5) is connected with the base (1) through a locking nut (18), two ends of an angle adjusting connecting rod (17) are respectively connected with the static moment torsion shaft (5) and a connecting rod assembly (16), and one end of the connecting rod assembly (16) is connected with the base (1) through a bolt; one end interface of the test part (8) is fixedly connected with the static torque torsion shaft (5), the other end interface is fixedly connected with the dynamic torque torsion shaft (15), the dynamic torque torsion shaft (15) is connected with the machine base (1) through a ball bearing (7), and the test part is limited and fixed through a dustproof lock nut (6); one end of a rocker (14) is connected with a dynamic torque torsion shaft (15), the other end of the rocker is connected with a cam connecting rod (9) through a needle bearing (10) and a pin (13), the other end of the cam connecting rod (9) is connected with a cam disc (11) through the needle bearing (10), the cam disc (11) is connected with an inertia mass wheel (12), and the inertia mass wheel (12) is connected with a variable frequency motor (2).

2. The biaxial loading fatigue tester as recited in claim 1, wherein: static moment angle loading is realized by rotating the static moment torsion shaft (5) by adjusting the length of the connecting rod assembly (16), and variable moment angle loading is realized by combining the dynamic moment torsion shaft (15), the rocker (14), the cam connecting rod (9), the cam disc (11), the inertia mass wheel (12) and the variable frequency motor (2), so that static moment angle and variable moment angle double-shaft fatigue loading of parts is realized, the static moment angle is a static bending angle applied to an elastic bearing of the part by the static moment torsion shaft (5), and the moment generated by the static bending angle is static moment.

3. The biaxial loading fatigue tester as recited in claim 1, wherein: an angle scale is arranged on the arc surface of the upper end of the static torque torsion shaft (5), and the static torque angle loading can be realized by adjusting the length of the connecting rod assembly (16) to rotate the static torque torsion shaft (5) to a specified angle.

4. The biaxial loading fatigue tester as recited in claim 1, wherein: the variable frequency motor (2) is connected with the frequency converter (3), and the rotating speed of the variable frequency motor (2) can be controlled by controlling the frequency of the frequency converter (3), so that the dynamic torque-changing angle loading of parts under different frequency conditions is realized.

5. The biaxial loading fatigue tester as recited in claim 1, wherein: the axis of the static torque shaft (5) and the axis of the dynamic torque shaft (15) are perpendicularly crossed with each other.

6. The biaxial loading fatigue tester as recited in claim 1, wherein: two parts with the same specification are used for fatigue tests and are symmetrically arranged relative to the axes of the static torque torsion shaft (5) and the dynamic torque torsion shaft (15).