Friction test device for simulating polytetrafluoroethylene polymer coatings with different thicknesses

Abstract

The invention discloses a friction test device for simulating polytetrafluoroethylene polymer coatings with different thicknesses in the technical field of friction test devices, which comprises a test box and a lifting frame mounted on the test box, the lifting frame is provided with an air cylinder, and the movable end of the air cylinder drives a friction head; the test box is rotationally connected with a rotating disc, the test device further comprises a first motor for driving the rotating disc to rotate, the rotating disc is rotationally connected with a mounting shaft in the circumferential direction, the end, extending into the rotating disc, of the mounting shaft is fixedly sleeved with a driven gear, and the rotating disc is fixedly provided with a second motor; the second motor drives a driving gear engaged with the multiple driven gears at the same time, the other ends of the multiple mounting shafts are each provided with a test plate coated with a coating, and the multiple test plates alternately rotate to the position under the friction head. The invention provides a friction test device which can simulate surface indentations, side indentations and back-and-forth friction tests of coatings with different thicknesses.

Description

Technical Field

[0001] The invention relates to the technical field of friction test devices, in particular to a friction test device for simulating polytetrafluoroethylene polymer coatings with different thicknesses. Background Art

[0002] According to incomplete statistics, friction and wear consumption accounts for 2% to 7% of my country's national economy each year. Based on my country's GDP of 121 trillion in 2022, 5% of friction and wear consumption will cause nearly 6 trillion in national economic losses. Under normal circumstances, friction and wear failure is the main form of failure of agricultural machinery parts and the main cause of material consumption. Among them, the seizure of gears or bearings is the main reason why the plow shaft of the tiller cannot rotate, which has become a technical issue that agricultural machinery manufacturers focus on.

[0003] Traditional basic components often use liquid lubrication to reduce friction and wear damage. However, liquid lubrication often faces complex elastohydrodynamic lubrication conditions and cannot achieve the expected stable lubrication effect. In order to obtain a stable and long-term lubrication state and effectively extend the service life of basic transmission components, solid self-lubricating materials are gradually replacing liquid lubrication and becoming the new favorite of lubrication systems. Among them, polymers have been widely used in various mechanical parts lubrication systems due to their many excellent properties such as low friction, high wear resistance, and high load-bearing capacity. The new PTFE bearing uses polytetrafluoroethylene (PTFE) as the sliding inner layer, which effectively avoids the high subsequent maintenance costs of liquid lubrication. Its dry lubrication characteristics and long-term stability have the potential to serve in extreme working conditions and can be used in transmission components such as space station robotic arms.

[0004] The bonding performance of the contact interface between the coating and the substrate is closely related to the substrate interface treatment, coating material selection, preparation control conditions, etc. At present, it is mainly identified and analyzed through indentation experiments and scratch experiments. The indentation experiment includes surface indentation and side indentation. The bonding performance is calibrated mainly by testing parameters such as coating hardness, Young's modulus, indentation depth, lateral displacement and minimum failure friction. However, the determination of layer thickness often relies on experience to set, and the specific influence mechanism of layer thickness on bonding performance has not been revealed. The coupling mechanism of layer thickness, material parameters, and friction coefficient on friction force has not been thoroughly studied. To this end, the present application provides a friction test device that simulates polytetrafluoroethylene polymer coatings of different thicknesses, and studies the distribution of coating stress fields under different coating thicknesses, in order to provide a reference test basis for the influence mechanism of stress field changes caused by friction. Summary of the invention

[0005] The present invention aims to provide a friction test device for simulating polytetrafluoroethylene polymer coatings of different thicknesses, so as to study the stress field distribution of the coatings under different coating thicknesses.

[0006] To achieve the above object, the present invention provides the following technical solutions: A friction test device for simulating polytetrafluoroethylene polymer coatings with different thicknesses, comprising a test chamber and a lifting frame mounted on the test chamber. The lifting frame is provided with a cylinder, and the movable end of the cylinder drives a friction head that moves horizontally; the test chamber is rotatably connected to a rotating disk with an air structure inside, and further includes a first motor for driving the rotating disk to rotate. The rotating disk is rotatably connected with a plurality of mounting shafts extending into the inside of the rotating disk along the circumferential direction. One end of the mounting shaft extending into the rotating disk is fixedly sleeved with a driven gear. The rotating disk is fixedly provided with a second motor, and the second motor drives a driving gear that meshes with a plurality of driven gears simultaneously. The other ends of the plurality of mounting shafts are respectively mounted with test plates coated with polytetrafluoroethylene polymer coatings with different thicknesses, and the plurality of test plates alternately rotate to directly below the friction head.

[0007] The working principle and beneficial effects of the present invention: The second motor locks a plurality of driven gears through the driving gear, that is, locks all the mounting shafts and test plates in a stationary state. When conducting a test, at this time, one of the test plates is in a horizontal state and is directly below the friction head. The lifting frame drives the cylinder and the friction head to descend, and the friction head presses down on the coating on the test plate for a front indentation test. Subsequently, the cylinder is used to push the friction head to conduct a back-and-forth scraping test on the coating of the test plate.

[0008] The lifting frame drives the cylinder and the friction head to rise, and the friction head disengages from the coating. Then, the second motor drives the driving gear to rotate, and the driving gear drives a plurality of mounting shafts to rotate through a plurality of driven gears. The rotation of the mounting shafts drives the test plate to rotate to a vertical state, so that the side surface of the test plate rotates to directly below the friction head. The lifting frame drives the cylinder and the friction head to descend, and the friction head presses down on the coating on the test plate for a side indentation test. Subsequently, the friction head disengages from the test plate, and the mounting shafts rotate to drive all the test plates to rotate to a horizontal state. The first motor drives the rotating disk to rotate, so that the next test plate coated with a different thickness rotates to directly below the friction head, and the above operations are repeated.

[0009] The present application provides a friction test device that can simulate surface indentation, side indentation, and back-and-forth friction tests of coatings with different thicknesses. Moreover, it can automatically switch test plates with polytetrafluoroethylene polymer coatings of different thicknesses for rapid testing.

[0010] Optimally, the first motor and the second motor are both servo motors. The servo motor has a reliable self-locking ability, thus locking a plurality of test plates in a stationary state, and has a forward and reverse rotation function.

[0011] Optimally, the number of test plates is 2 to 5. Multiple tests of coatings with different thicknesses can be carried out by using 2 to 5 test plates.

[0012] Optimally, the test box is fixed with an electric push rod for pushing the lifting frame to move up and down. The electric push rod is used to push the lifting frame to move up and down.

[0013] Optimized, the test box is provided with a blowing sleeve and a cleaning hole, the friction head is alternately inserted into the blowing sleeve and the cleaning hole; the blowing sleeve is provided with a plurality of high-pressure nozzles, the cleaning hole is fixedly sleeved with a cloth bag; the movable end of the first motor is fixedly provided with a first gear, the test box is rotatably connected with a rotating shaft, the rotating shaft is fixedly sleeved with a second gear meshing with the first gear, the rotating shaft is fixedly sleeved with a cam, the test box is fixedly provided with a first friction plate, the test box is also vertically slidably connected with a second friction plate abutting the cam, the second friction plate slides up and down to cooperate with the first friction plate to rub the cloth bag.

[0014] After completing a test plate scraping experiment, the friction head and the polytetrafluoroethylene polymer coating rub back and forth, and a lot of polytetrafluoroethylene polymer powder will stick to the friction head, so the powder needs to be cleaned up. The purpose is to ensure the accuracy, repeatability and data reliability of the friction test and maintain the consistency of the contact state of the friction pair. At this time, the cylinder drives the friction head to move to the top of the blowing sleeve, and the lifting frame descends to drive the friction head into the blowing sleeve. First, high-pressure gas is sprayed through multiple high-pressure nozzles in the blowing sleeve to flush out most of the powder on the friction head. Then the lifting frame moves upward to drive the friction head to separate from the blowing sleeve. The cylinder drives the friction head to move to the top of the blowing sleeve. The first motor drives the rotating disk to rotate, so that the next test plate coated with different thicknesses rotates to the bottom of the friction head. In this process, the first motor drives the first gear to rotate, and the second gear drives the rotating shaft to rotate. The rotation drives the cam to rotate rapidly. The cam reciprocates to squeeze the second friction plate to slide up and down, and cooperates with the first friction plate to repeatedly rub the cloth bag, so that the cloth bag generates static electricity. Then the lifting frame descends to drive the friction head into the cloth bag, and uses static electricity to absorb the residual powder that has not been cleaned up by the friction head. After cleaning, the friction head continues to perform friction tests on the next test plate with different coating thicknesses.

[0015] Optimally, the first friction plate and the second friction plate are both provided with a plurality of rubber protrusions, and the rubber protrusions are used for friction, so that the cloth bag generates better static electricity.

[0016] Preferably, the cloth bag is a non-woven cloth bag. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the friction test device in Example 1; Figure 2 for Figure 1 Schematic diagram of the internal structure of the rotating disk; Figure 3Schematic structural diagram when the front friction test is carried out on the test plate; Figure 4 Schematic structural diagram when the side friction test is carried out on the test plate; Figure 5 Schematic structural diagram of the friction test device in Embodiment 2; Figure 6 For Figure 5 Schematic structural diagram when the friction head is blown and cleaned in; Figure 7 For Figure 5 Schematic structural diagram when static electricity is generated by the friction of the cloth sleeve bag in; Figure 8 Schematic structural diagram when the friction head adsorbs powder. Specific embodiments

[0018] The following is further detailed through specific embodiments: The reference numerals in the accompanying drawings of the specification include: first motor 1, electric push rod 2, cylinder 3, lifting frame 4, friction head 5, test plate 6, mounting shaft 7, rotating disk 8, driven gear 9, driving gear 10, second motor 11, test chamber 12, blowing sleeve 13, high-pressure nozzle 14, cloth sleeve bag 15, cam 16, first friction plate 17, second friction plate 18.

[0019] In the following statements, orientation terms such as "left", "right", "up", "down", etc. are based on the orientation shown in the figure. In practice, if the corresponding structure changes in the same direction based on the orientation and the relative position remains unchanged, it does not affect the implementation of the solution.

[0020] Embodiment 1: A friction test device for simulating polytetrafluoroethylene polymer coatings with different thicknesses, as Figure 1 shown, includes a test chamber 12 and a lifting frame 4 mounted on the test chamber 12, and the lifting frame 4 is lifted by an electric push rod 2.

[0021] The lifting frame 4 is fixedly provided with a cylinder 3, and the movable end of the cylinder 3 drives a horizontally moving friction head 5; the right side of the test chamber 12 is rotatably connected with a rotating disk 8 with an air structure inside, and the test chamber 12 is fixedly provided with a first motor 1 for driving the rotating disk 8 to rotate. As Figure 2As shown in the figure, the rotating disk 8 is rotationally connected along the circumferential direction with two mounting shafts 7 extending into the interior of the rotating disk 8. One end of each mounting shaft 7 extending into the rotating disk 8 is fixedly sleeved with a driven gear 9. The rotating disk 8 is fixedly provided with a second motor 11, and the second motor 11 drives a driving gear 10 that meshes with the two driven gears 9 simultaneously. The other ends of the two mounting shafts 7 are respectively fixedly installed with test plates 6 coated with polytetrafluoroethylene polymer coatings of different thicknesses, and the two test plates 6 alternately rotate to directly below the friction head 5. The first motor 1 and the second motor 11 are both servo motors. The servo motor has a reliable self-locking ability and has a forward and reverse rotation function.

[0022] The second motor 11 locks the two driven gears 9 through the driving gear 10, that is, locks all the mounting shafts 7 and the test plates 6 to remain stationary. When conducting the test, as Figure 3 and Figure 4 shown, the top test plate 6 is in a horizontal state and is directly below the friction head 5. The lifting frame 4 drives the cylinder 3 and the friction head 5 to descend, and the friction head 5 presses down on the coating on the test plate 6 for a front indentation test. Subsequently, the cylinder 3 pushes the friction head 5 to move back and forth to conduct a scraping experiment on the coating of the test plate 6.

[0023] The lifting frame 4 drives the cylinder 3 and the friction head 5 to rise, and the friction head 5 disengages from the coating. Then the second motor 11 drives the driving gear 10 to rotate. The driving gear 10 drives multiple mounting shafts 7 to rotate through the two driven gears 9. The rotation of the mounting shafts 7 drives the test plate 6 to rotate to a vertical state, so that the side surface of the test plate 6 rotates to directly below the friction head 5. The lifting frame 4 drives the cylinder 3 and the friction head 5 to descend, and the friction head 5 presses down on the coating on the test plate 6 for a side indentation test. Subsequently, the friction head 5 disengages from the test plate, and the second motor 11 drives the driving gear 10, the driven gears 9, and the mounting shafts 7 to rotate. The rotation of the mounting shafts 7 drives all the test plates 6 to rotate to the horizontal. The first motor 1 drives the rotating disk 8 to rotate 180 degrees, so that the next test plate 6 coated with a different thickness rotates to directly below the friction head 5, and the above operations are repeated.

[0024] This application provides a friction test device, which can simulate surface indentation, side indentation, and back-and-forth friction tests of coatings with different thicknesses. Moreover, it can automatically switch the test plates 6 with polytetrafluoroethylene polymer coatings of different thicknesses for rapid testing.

[0025] Example 2: As Figure 5 shown, the test chamber 12 is provided with a blowing sleeve and a cleaning hole, and the blowing sleeve is fixedly connected to the test chamber 12. The friction head 5 is alternately inserted into the blowing sleeve and the cleaning hole; the blowing sleeve is provided with a plurality of high-pressure nozzles 14, and the cleaning hole is fixedly sleeved with a cloth sleeve bag 15. The cloth sleeve bag 15 is made of non-woven fabric and has a certain flexibility and stretchability.

[0026] The movable end of the first motor 1 is fixedly provided with a first gear. The test chamber 12 is rotatably connected with a rotating shaft, and the rotating shaft is fixedly sleeved with a second gear meshing with the first gear. The rotating shaft is also fixedly sleeved with a cam 16. The test chamber 12 is fixedly provided with a first friction plate 17. Vertical T-shaped grooves are provided on both opposite sides of the test chamber 12. A second friction plate 18 abutted against the cam 16 is slidably connected between the two T-shaped grooves, and the cam 16 is used to support the second friction plate 18 upward.

[0027] After a test plate 6 has completed a back-and-forth scraping experiment, the friction head 5 and the polytetrafluoroethylene polymer coating rub against each other back and forth, and a lot of polytetrafluoroethylene polymer powder will adhere to the friction head 5. Therefore, it is necessary to clean these powders. The purpose is to ensure the accuracy, repeatability, and data reliability of the friction test and maintain the consistency of the contact state of the friction pair.

[0028] At this time, the air cylinder 3 drives the friction head 5 to move directly above the blowing sleeve. As Figure 6 shown, the lifting frame 4 descends to drive the friction head 5 into the blowing sleeve. First, high-pressure gas is ejected through multiple high-pressure nozzles 14 in the blowing sleeve to blow off most of the powder on the friction head 5. Then, the lifting frame 4 moves upward to drive the friction head 5 to move upward out of the blowing sleeve. As Figure 7 shown, the air cylinder 3 drives the friction head 5 to move directly above the blowing sleeve, and the first motor 1 drives the rotating disk 8 to rotate, so that the next test plate 6 coated with different thicknesses rotates to directly below the friction head 5. During this process, the first motor 1 drives the first gear to rotate, drives the rotating shaft to rotate through the second gear, and the rotation drives the cam 16 to rotate rapidly. The cam 16 reciprocally presses the second friction plate 18 to slide up and down, and cooperates with the first friction plate 17 to repeatedly rub the cloth sleeve bag 15, so that the cloth sleeve bag 15 generates static electricity. As Figure 8 shown, then the lifting frame 4 descends to drive the friction head 5 into the cloth sleeve bag 15, and the residual powder that has not been cleaned on the friction head 5 is adsorbed by static electricity. After the cleaning is completed, the friction head 5 continues to perform a friction test on the next test plate 6 with a different thickness coating.

[0029] In addition, in order to improve the static electricity adsorption efficiency, the driving time of the rotating shaft by the first motor 1 is prolonged.

[0030] The standard parts used in the present invention can all be purchased from the market. The special-shaped parts can be customized according to the descriptions in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, and welding that are mature in the prior art. The machines, parts, and equipment all adopt conventional models in the prior art, and the circuit connection adopts the conventional connection method in the prior art, which will not be elaborated here.

Claims

1. A friction test device for simulating polytetrafluoroethylene polymer coatings of different thicknesses, comprising a test box and a lifting frame mounted on the test box, characterized in that: The lifting frame is provided with a cylinder, and the movable end of the cylinder drives a horizontally movable friction head; the test box is rotatably connected to a rotating disk with an aerial structure inside, and also includes a first motor that drives the rotating disk to rotate, the rotating disk is rotatably connected to multiple installation shafts extending into the interior of the rotating disk along the circumferential direction, one end of the installation shaft extending into the rotating disk is fixedly sleeved with a driven gear, the rotating disk is fixedly provided with a second motor, the second motor drives a driving gear that meshes with multiple driven gears at the same time, and the other ends of the multiple installation shafts are respectively installed with test plates coated with polytetrafluoroethylene polymer coatings of different thicknesses, and the multiple test plates are alternately rotated to be directly below the friction head.

2. The friction test device for simulating polytetrafluoroethylene polymer coatings of different thicknesses according to claim 1, characterized in that: The first motor and the second motor are both servo motors.

3. The friction test device for simulating polytetrafluoroethylene polymer coatings of different thicknesses according to claim 2, characterized in that: The number of the test plates is 2 to 5.

4. The friction test device for simulating polytetrafluoroethylene polymer coatings of different thicknesses according to any one of claims 1 to 3, characterized in that: The test box is fixedly provided with an electric push rod for pushing the lifting frame up and down.

5. The friction test device for simulating polytetrafluoroethylene polymer coatings of different thicknesses according to claim 4, characterized in that: The test box is provided with a blowing sleeve and a cleaning hole, and the friction head is alternately inserted into the blowing sleeve and the cleaning hole; the blowing sleeve is provided with a plurality of high-pressure nozzles, and the cleaning hole is fixedly sleeved with a cloth bag; the movable end of the first motor is fixedly provided with a first gear, the test box is rotatably connected with a rotating shaft, the rotating shaft is fixedly sleeved with a second gear meshing with the first gear, the rotating shaft is fixedly sleeved with a cam, the test box is fixedly provided with a first friction plate, and the test box is also vertically slidably connected with a second friction plate abutting the cam, and the second friction plate slides up and down to cooperate with the first friction plate to rub the cloth bag.

6. The friction test device for simulating polytetrafluoroethylene polymer coatings of different thicknesses according to claim 5, characterized in that: A plurality of rubber protrusions are provided on the first friction plate and the second friction plate.

7. The friction test device for simulating polytetrafluoroethylene polymer coatings of different thicknesses according to claim 6, characterized in that: The cloth bag is a non-woven cloth bag.

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