CN217484008U - Bending-twisting micro-motion damage test device based on lead screw displacement control - Google Patents

Abstract

The utility model discloses a turn round fine motion damage test device based on lead screw control displacement. The system comprises a test piece clamping system, a bending load applying system and a torsion load applying system. In a bending load applying system, the closed screw mechanisms are symmetrically arranged, so that the symmetrical cyclic bending fatigue load loading is realized. The bending alternating load and the common normal load are loaded through the symmetrical screw rod mechanisms, the variable can be accurately controlled, the experiment repeatability is good, and therefore quantitative experiments can be carried out. The testing machine has small amplitude and good stability, can directly control the speed, the acceleration, the lead and the stroke of the lead screw by using computer software, and is convenient to operate and easy to control. The tester is convenient to assemble and disassemble, can be matched with other fatigue testers for use, and has wide universality.

Description

A bending-torsional fretting damage test device based on screw-controlled displacement

technical field

The utility model relates to the field of material strength and tribological properties, in particular to a fretting test device for materials.

Background technique

Fretting damage is a damage method that exists in mechanical parts that are close to static fit. The fretting damage is defined as: under the action of a certain normal load, two surfaces in contact with each other have a relative movement with a very small amplitude (relative vibration amplitude < 300 μm), causing damage to the contact surface. According to the different damage modes, it can be divided into three categories: fretting fatigue, fretting wear and fretting corrosion (fretting corrosion phenomenon is relatively rare, usually not considered). (1) Fretting fatigue refers to the phenomenon that the contact interface undergoes a slight relative movement due to different deformations of the contact body due to the external alternating fatigue stress, which promotes the early initiation and accelerated expansion of fatigue cracks, resulting in premature failure and damage of components. (2) Fretting wear refers to the fact that the fretting produces fine wear debris between the contact surfaces, and the color of the oxidized wear debris is different from the color of the material of the fretting parts, so there is no "fretting spot" in the damaged area. It is an important sign to distinguish normal wear from fretting wear. During the development of fretting damage, fretting wear and fretting fatigue may occur, but their damage rates are different. Fretting injury is also known as "industrial cancer". However, due to the complexity of the problem and the singleness of the research equipment, there are few experimental studies on this.

The main difficulties of the currently reported fretting damage test devices are the measurement of the variation in the experiment, and the difficulty of quantitative research very accurately. Therefore, the study of fretting damage test devices and experimental methods that can precisely control variables and have good repeatability has a certain guiding role in the design of parts and components in related fields.

Utility model content

According to the above problems, a bending-torsional fretting damage test system and its experimental method based on screw-controlled displacement are studied, which can realize three different contact methods of point, line and surface to meet the requirements of various actual situations. The magnitude and frequency of the load can also be precisely controlled with good repeatability, enabling quantitative research.

In order to achieve the above-mentioned purpose of the utility model, the technical scheme adopted by the utility model is:

The utility model provides a bending-torsional fretting damage test device based on the control displacement of a lead screw. The test device mainly includes the following systems: a specimen clamping system, a bending load applying system and a torsional load applying system.

The specimen clamping system includes: a base, a micro-movement support, a micro-motion support, a micro-motion support base, a three-jaw chuck, and an upper bracket.

Wherein, the micro-motion bracket, the micro-motion support base and the three-jaw chuck are fixed on the base by screw connection, the upper bracket is fixed on the micro-motion support by screw connection, and the micro-motion support is The screw connection is fixed on the micro-movement support base. The lower end of the specimen is fixed by a three-jaw chuck.

The bending load application system includes: a stepping motor, a lead screw, a linear guide rail, a slider, and a micro-motion pad.

Wherein, the micro-motion pad is connected to the slider through a ball hinge, the slider is connected to the linear guide rail, the linear guide rail is fixed on the micro-motion support, and the lead screw is connected to the The sliding block transmits motion through rolling friction, so that the sliding block can move along the linear guide in the order of microns, and the stepper motor is connected with the lead screw.

The torsional load application system includes: a stepping motor, a coupling, a torque sensor, and an upper clamp.

Wherein, the stepping motor is fixed on the upper bracket, the coupling is connected with the motor, the torque sensor and the coupling are connected by magnetic force, and the upper clamp is connected with the coupling The shaft is connected by a key and used to clamp the test piece.

The test device is controlled by a computer control system, including: a computer, a controller, and a driver.

Wherein, the computer is connected with the controller, the controller is connected with the driver, and the driver is connected with the stepping motor. The signal transmission process is: generating a signal through the software on the computer to make the controller drive the driver, and then drive the stepper motor, and finally the controller receives the feedback from the stepper motor and the sensor, After data processing the data is transferred to the computer.

This program also has the following features:

First, the lead screw, slider and linear guide are sealed with stainless steel casing to make it a dustproof and waterproof module.

Second, there are two groups of the micro-moving pads, sliders, linear guide rails, and lead screws, which are symmetrically arranged on both sides of the specimen, and their motions are transmitted symmetrically by the stepping motor through the ball screw to realize symmetrical circulation. Bending fatigue load loading.

Thirdly, the friction pair between the micro-motion pad and the test piece can realize point contact friction pair, line contact friction pair and surface contact friction pair.

The experimental method of the present utility model is as follows, wherein:

In the bending-torsional fretting fatigue experiment, the lower end of the specimen is fixed by a three-jaw chuck, and the upper end of the specimen is connected with the upper fixture, which can provide torsional alternating stress, which is measured by the sensor and transmitted to the computer controller. The bending alternating stress is to press the left and right fretting pads at the appropriate position in the middle of the specimen through the slider to form a point contact pair, a line contact pair or a surface contact pair. The computer sends instructions to the controller to control the speed, lead and stroke of the lead screw, and the lead screw drives the slider to move, so as to realize the cyclic loading of the bending load. The magnitude of the bending load can be controlled by adjusting the acceleration of the lead screw, and the It is measured by the pressure sensor and transmitted to the computer controller.

In the fretting wear experiment, the lower end of the specimen is fixed by a three-jaw chuck, and the upper end is free to form a cantilever beam structure. The fretting pad on the right side of the specimen provides surface contact to directly press the specimen, and the fretting pad on the left side of the specimen is optional point contact or line contact. The normal load is controlled by the acceleration of the left screw and the spring stiffness in the left fretting pad. The load is fed back to the controller through the pressure sensor and then received and displayed by the computer. The micro-amplitude vibration of the specimen loading horizontal direction is provided by the right fretting pad.

Compared with the prior art, the beneficial effects of the present utility model are:

First, through the symmetrical lead screw mechanism, the bending alternating load and the normal normal load can be loaded, which can accurately control the variables, and the experiment repeatability is good, so that quantitative experiments can be carried out. Second, the testing machine has small amplitude and good stability. The speed, acceleration, lead and stroke of the screw can be directly controlled by computer software, which is convenient to operate and control. Third, the testing machine is easy to assemble and disassemble, can be used in conjunction with other fatigue testing machines, and has wide versatility.

Description of drawings

Fig. 1 is the structural representation of the bending-torsional fretting damage testing machine in the utility model;

Fig. 2 is the front view of the bending-torsion fretting damage testing machine in the utility model;

3 is a schematic structural diagram of a micro-motion pad in the utility model;

4 is an exploded view of the micro-moving pad of the present invention;

Fig. 5 is the principle diagram of the utility model device used in the fretting fatigue experiment;

FIG. 6 is a schematic diagram of the device of the utility model used in the fretting wear experiment;

Fig. 7 is the control flow chart of the utility model;

The figure includes: 1. Base, 2. Left micro-motion bracket, 3. Left lower support frame, 4. Upper support frame, 5. Left linear guide rail, 6. Left slider, 7. Left micro-motion pad, 8. Test Parts, 9. Right micro-motion support, 10. Right micro-motion support base, 11. Three-jaw chuck, 12. Left micro-motion support, 13. Left micro-motion support base, 14, No. 1 motor, 15, Left lead screw , 16, Motor No. 3, 17, Coupling, 18, Upper clamp, 19, Right micro-motion pad, 20, Right slider, 21, Right screw, 22, Right linear guide, 23, No. 2 motor, 24 , lower right support frame, 25, back cover of micro-motion pad, 26, pressure ball, 27, spring, 28, micro-motion pad upper cover, 29, micro-motion pad intermediate, 30, pressure sensor, 31, point contact, 32, Line contact, 33, surface contact, 34, micro-motion pad lower cover.

Detailed ways

The present utility model will be further described in complete and clear detail below in conjunction with the accompanying drawings and embodiments of the present utility model, so as to make its purpose, technical solutions and advantages more clear. The specific examples described here are only used to explain the present invention, and are not limited to the present invention.

Referring to Figure 1, Figure 2, Figure 3, Figure 4, Figure 1 is a schematic structural diagram of a bending-torsion fretting damage testing machine in the utility model, Figure 2 is its front view, and Figure 3 is a schematic structural diagram of a fretting pad;

4 is an exploded view of the fretting pad; the present utility model provides a bending-torsion fretting damage test system based on screw-controlled displacement and an experimental method thereof, which mainly include the following systems: a specimen clamping system, a bending Load application system, torsional load application system, computer control system. The motor 14 , the left lead screw 15 , the left linear guide 5 , the left slider 6 and the left micro-motion pad 7 together form a closed lead screw mechanism, which is formed by connecting the stainless steel closed casing, the left linear guide 5 and the motor 14 . The airtight mechanism is fixedly connected with the left micro-movement support 12. The left screw 15 provides power to the left slider 6 through rolling friction in the airtight mechanism, and the left slider 6 is connected to the left linear guide through the moving pair. 5 connection, the left micro-motion pad 7 is connected to the left slider 6 through a ball hinge for fixed connection, and the pressure sensor 30 is installed in the left micro-motion pad 7, wherein the left micro-motion pad 7 can be replaced by replacing the point Contact 31, line contact 32, and surface contact 33 respectively implement point contact/line contact/surface contact tests. There are two groups of the above components, which are installed symmetrically to form the bending load application system. The upper clamp 18 is connected with the motor 16 through the coupling 17, the motor 16 is fixed on the upper support frame 4, and the upper support frame 4 is fixed on the left side by bolts. On the movable bracket 2, the above components together constitute the torsional load application system. The lower end of the test piece 8 is fixed by the three-jaw chuck 11 , and the upper end is fixed by the upper clamp 18 , and the three-jaw chuck 11 is fixedly connected to the base 1 by bolting.

Example 1, when the bending-torsion fretting fatigue test is realized, as shown in FIG. 5 , the lower end of the specimen 8 is fixed by the three-jaw chuck 11, the upper end is fixed by the upper clamp 18, and the fretting pad 7/ 19. The point contact 31, the line contact 32, and the surface contact 33 can be selected for installation according to the experimental idea, and the slider 6/20 can be adjusted to an appropriate initial position through the computer control system. The required parameters are input from the computer software, and the controller is used to control the driver to drive the motor 14/16/23 to apply appropriate bending alternating load and torsional alternating load to the test piece.

The magnitude of the bending alternating load is controlled by the acceleration of the lead screw 15/21 and the stiffness of the spring 27. The magnitude of the load is fed back to the controller through the pressure sensor 30 and then received and displayed by the computer. The load frequency can be directly input by the computer software through Controlling the motors 14/23 is achieved.

The frequency of the torsional alternating load is controlled by the rotational speed of the motor 16, and the magnitude is controlled by the torque of the motor 16. The frequency and magnitude can be measured by selecting an appropriate torsion angle sensor and torque sensor, and then fed back to the controller and then received and displayed by the computer.

Thereby, the bending-torsional fretting fatigue experiment is realized.

Example 2, when the fretting wear experiment is implemented, as shown in Figure 6, the lower end of the test piece 8 is fixed by the three-jaw chuck 11, and the upper end is free to form a cantilever beam structure, and the right fretting pad 19 on the right side of the test piece is selected. The surface contact 33 is installed and the test piece 8 is directly pressed. The left micro-motion pad 7 on the left side of the test piece selects the point contact 31 or the line contact 32 for installation, and the slider 6 is adjusted to the proper initial position through the computer control system. The normal load is controlled by the acceleration of the left screw 15 and the stiffness of the spring 27. The load is fed back to the controller through the pressure sensor 30 and then received and displayed by the computer. The displacement value can be calculated from the pressure sensor reading and the spring elastic coefficient. The load frequency Direct input from computer software may be accomplished by controlling the motor 14 . The micro-amplitude vibration in the horizontal direction of the loading of the specimen is provided by the right micro-movement pad 19 .

So as to realize the fretting wear experiment.

Claims (4)

1. The utility model provides a little moving damage test device of turn round based on lead screw control displacement which characterized in that: the bending and twisting micro-motion damage test device based on lead screw control displacement comprises a base (1), a linear guide rail (5), a sliding block (6), a micro-motion pad (7), a micro-motion support (12), a stepping motor (14), a lead screw (15), a pressure sensor (30), a micro-motion support (2), an upper support frame (4), a motor (16), a coupler (17) and an upper clamp (18);

the stepping motor (14), the lead screw (15), the linear guide rail (5), the sliding block (6) and the micro-motion pad (7) jointly form a closed lead screw mechanism, the lead screw (15) provides power for the sliding block (6) through rolling friction in the closed lead screw mechanism, the sliding block (6) is connected with the linear guide rail (5) through a sliding pair, and the micro-motion pad (7) is connected to the sliding block (6) through a ball hinge; the pressure sensor (30) is arranged in the micro-motion pad (7) and is fixedly connected with the micro-motion support (12), and the micro-motion support (12) is fixed on the base (1) through threaded connection; the stepping motor (14) drives the screw rod (15) to rotate;

the upper clamp (18) is connected with the motor (16) through the coupler (17) to form a transmission system, the motor (16) is fixedly connected to the upper support frame (4), the upper support frame (4) is fixedly connected to the micro-motion support (2) through a bolt, and the micro-motion support (2) is fixed to the base (1) through threaded connection.

2. The bending and twisting fretting damage testing device based on lead screw control displacement according to claim 1, characterized in that: the micro-motion pad (7), the sliding block (6), the linear guide rail (5) and the screw rod (15) are respectively provided with two groups, and the two groups are symmetrically arranged on two sides of the test piece (8).

3. The bending and twisting fretting damage testing device based on lead screw control displacement according to claim 2, characterized in that: the lower end of the test piece is fixed through a three-jaw chuck.

4. The bending and twisting fretting damage test device based on lead screw control displacement according to claim 2, characterized in that: the friction pairs between the micro-motion pad (7) and the test piece (8) are point contact friction pairs, line contact friction pairs and surface contact friction pairs.

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