Tribotester with Triboelectric Nanogenerator

Abstract

The present invention is intended to describe various friction phenomena that are difficult to distinguish with a general friction testing device, and is a device capable of measuring relatively accurate wear onset time, appearance and size of wear particles, and shape matching conditions on a contact surface, and may include a mechanical module capable of implementing various arrangements and modes of dielectrics and a measuring unit capable of measuring the dielectric installed on the mechanical module in real time.

Description

Technology Field

[0001] The present invention relates to a device for testing the friction of materials in connection with energy harvesting and materials science, and more specifically, to a friction testing device utilizing the characteristics of triboelectricity. Background Technology

[0002] Friction occurs between two surfaces when two objects in relative motion come into contact, and prolonged friction between these surfaces leads to wear. This is a critical issue considered across various industrial sectors, including automotive, machinery, aerospace, biomedical, and micro-nano electromechanical systems.

[0003] Recently, various friction testing devices have been developed to measure these friction characteristics, including pin-on-disk, ball-on-disk, block-on-ring, reciprocating slider, four-ball tester, pin-on-cylinder, and vibratory friction tester. Each device is used differently depending on the application and operating conditions, and is generally utilized to estimate the lifespan of an object by analyzing wear characteristics or to improve dynamic systems.

[0004] However, to help understand the time-series wear characteristics during the wear process, the wear test of the object surface must be analyzed not only after it is completed but also during the test. Methods for analyzing these characteristics include recording normal and tangential forces during the wear test, directly observing the contact area through a transparent material, and monitoring the wear location using the viewport of a 3D laser microscope.

[0005] However, each of these methods has disadvantages and limitations in adequately monitoring the interaction and wear characteristics of contact surfaces. First, it is difficult to clearly measure the onset of wear and the presence of wear material by recording only the interaction force. In particular, this method is difficult to implement without applying high-cost load sensors. Furthermore, second, most materials are not transparent, making it difficult to directly observe the location of wear. Additionally, third, even when using a 3D laser microscope during testing, only a very limited contact area can be measured where wear may not have yet started. These limitations tended to be even more pronounced, especially in friction testing devices including block-on rings and reciprocating slides, where the contact area is much larger than the field of view of the microscope lens. Prior art literature

[0006] Korean Registered Patent No. 10-2533450 The problem to be solved

[0007] The present invention was devised to overcome the aforementioned limitations, and the objective of the present invention is to provide a friction testing device capable of clearly measuring various characteristics of wear using a triboelectric nanogenerator (TENG).

[0008] In addition, the objective of the present invention is to provide a friction test device capable of measuring friction characteristics by utilizing the electron transport effect. means of solving the problem

[0009] The present invention may comprise a friction test device for measuring friction characteristics of one or more dielectric surfaces, comprising: a normal motion unit having an upper dielectric with an attached electrode coupled to its lower end to implement normal motion of the upper dielectric; a horizontal motion unit disposed below the normal motion unit and having a lower dielectric or a single electrode with an attached electrode coupled to its upper end to implement relative motion of the lower dielectric or the single electrode with respect to the upper dielectric in a direction perpendicular to the motion direction of the normal motion unit; and a measuring unit connected to at least one of the electrodes coupled to the normal motion unit and the horizontal motion unit to measure the characteristics of electricity induced by surface contact and separation between the upper dielectric and the lower dielectric or the single electrode generated through the combination of motion of the normal motion unit and the horizontal motion unit.

[0010] In addition, through the combination of the normal motion unit and the horizontal motion unit, at least one of a vertical contact separation mode that implements motion or vibration involving repeated contact and separation of two dielectrics, a sliding mode that implements relative motion of two dielectrics in the horizontal direction, a single electrode mode that implements contact and separation of the dielectrics in the vertical direction or sliding motion in the horizontal direction with respect to the electrode, and a self-supporting triboelectric layer mode that implements electric field change without contact can be implemented.

[0011] In addition, the device includes a base on which the dielectric is arranged and a fixing jig for fixing the dielectric on the base, and the number and arrangement of the dielectric can be changed by changing the fixing jig.

[0012] In addition, the above-mentioned fixed jig can form a connector when installed on the base.

[0013] In addition, the base includes an upper base on which an upper dielectric is installed and a lower base on which a lower dielectric is installed, and the upper base and the lower base can each be coupled to the normal motion part and the horizontal motion part.

[0014] In addition, the normal motion member may include a plurality of rod-shaped rods that transmit a load, an elastic member formed on the rods, and a linear guide that fixes the load direction of the rods in a unidirectional manner and transmits the load to the rods through the elastic member.

[0015] Additionally, the normal motion unit includes an upper control arm coupled to all the linear guides and a lower control arm coupled to the ends of all the rods, and the lower control arm can be connected to the upper base.

[0016] In addition, the plurality of rods may be installed symmetrically with respect to the center of the upper control arm and the lower control arm, and the center of the upper base may be installed to coincide with the center of the lower control arm.

[0017] In addition, the area formed by the plurality of rods may be larger than the area of ​​the upper base.

[0018] In addition, the above measuring unit can measure electrical characteristics including no-load voltage or short-circuit current. Effects of the invention

[0019] The friction test device according to the present invention can describe various friction characteristic phenomena, such as the accurate wear onset time, which is generally difficult to distinguish, the appearance and size of wear particles, and shape matching conditions on the contact surface.

[0020] In addition, the friction test device according to the present invention has the advantage of enabling on-site measurement at the nanoscale through the electron transport effect, and thereby further enabling measurement of friction characteristics at the micro and macro scales.

[0021] In addition, the friction test device according to the present invention has the advantage of being applicable to various environmental conditions, such as dry or lubricated environments.

[0022] In addition, the friction test device according to the present invention has the advantage of being able to measure mechanical or electrical output variables of materials, such as bulk or thin film states, regardless of thickness.

[0023] In addition, the friction test device according to the present invention has the advantage of simultaneously measuring electrical output variables, enabling real-time on-site measurement under various electrical impedance operating conditions. Brief explanation of the drawing

[0024] FIG. 1 is a schematic diagram showing the configuration of a friction test device according to the present invention. FIG. 2 is a schematic diagram showing friction test modes according to various embodiments of the present invention. FIG. 3 is a perspective view of a mechanical module of a friction test device according to an embodiment of the present invention. FIG. 4 is an exploded view of the mechanical module of a friction test device according to an embodiment of the present invention. Specific details for implementing the invention

[0025] Hereinafter, the technical concept of the present invention will be explained in more detail using the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical concept of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all aspects of the technical concept of the present invention; thus, it should be understood that various modifications capable of replacing them may exist at the time of filing this application.

[0026] FIG. 1 briefly illustrates the main modules of a friction test device according to the present invention. FIG. 1a briefly illustrates the mechanical module, and a detailed description is provided in FIG. 2 and FIG. 3.

[0027] FIG. 1b schematically illustrates the operating mechanism of the mechanical module of the friction test device according to the present invention. The type of interatomic interaction depicted is based on the interaction between two different materials and triboelectricity (TE). TE refers to the process of harvesting energy through contact between two surfaces with different electrical properties. More specifically, TE is generated by mechanical contact, relative motion, and friction between surfaces with different molecular polarities. These polarities originate from the electronegativity of the atoms constituting the contact surfaces. Consequently, electrons move between different types of molecules, and triboelectricity is induced through contact between surfaces with different electrical properties. Additionally, electrostatic forces are generated between the molecules, causing the two surfaces to attract each other.

[0028] FIG. 1c briefly illustrates a measurement unit of a friction test device according to the present invention. The measurement unit may include an electric meter (R). The electric meter can measure electrical characteristics including no-load voltage (VOC) and short-circuit current (ISC). At this time, the measurement unit can post-process the measured output variables to display the no-load voltage (VOC), short-circuit current (ISC), and Q on a device such as a personal computer as shown in FIG. 1e.

[0029] FIG. 1d briefly illustrates a data acquisition (DAQ) module that transmits measured electrical and mechanical data to a PC. Depending on the experimental conditions, input mechanical variables such as normal force (FN), reciprocating speed (V), and load application time (t) can be applied to the system using a programmable controller and an actuator. For example, the tangential force output mechanical variable of the contact surface can be measured using a load cell and an analog-to-digital (A / D) card and monitored via a personal computer.

[0030] FIG. 2 shows a mechanical module (10) of a friction test device according to the present invention. As illustrated, the mechanical module (10) implements friction on the surface of one or more dielectrics (1) and may largely include a normal motion part (100) and a horizontal motion part (200).

[0031] At this time, the machine module (10) can implement at least one of the following modes, or a combination of modes, through the arrangement of the dielectric (1), the motion combination of the normal motion unit (100) and the horizontal motion unit (200), a vertical contact separation mode that implements motion or vibration in which two dielectrics (1) are repeatedly contacted and separated, a sliding mode that implements relative motion of two dielectrics (1) in the horizontal direction, a single electrode mode that implements contact and separation of the dielectric with respect to the electrode in the vertical direction or sliding motion in the horizontal direction, and a self-supporting triboelectric layer mode that implements electric field change in a non-contact manner.

[0032] To explain in more detail, referring to FIG. 3, FIG. 3a briefly illustrates a vertical contact separation mode. In the vertical contact separation mode, two different dielectrics are provided vertically, and electricity is generated from the potential difference that occurs when the two surfaces are separated by a predetermined distance from the contact between the two surfaces caused by the mechanical energy of the vertical movement or vibration of the normal motion part (100). At this time, electrodes are attached to the other side of the contacting surfaces of each of the two dielectrics, and electrical characteristics can be measured through this.

[0033] FIG. 3b briefly illustrates the sliding mode. The dielectric arrangement of the sliding mode starts in the same way as the vertical contact separation mode described above, and electrical characteristics can be measured through the potential difference generated on two surfaces that slide and come into contact by the mechanical energy of the horizontal movement or horizontal vibration of the horizontal movement part (200).

[0034] FIG. 3c briefly illustrates a single electrode mode. In the single electrode mode, one electrode is first grounded, and the operation of contacting or separating a dielectric material over the electrode is implemented. At this time, the local electric field distribution within the device changes due to the contact or separation between the dielectric material and the electrode. As a result, electron movement occurs between the two electrodes to balance the potential between the device electrode and the reference electrode. The single electrode mode has the advantage that the movement of the object is not restricted. That is, the single electrode mode has the advantage of allowing experiments to be performed by combining the normal motion unit (100) and the horizontal motion unit (200), or using surrounding objects or human skin as the dielectric material.

[0035] Figure 3d briefly illustrates a self-supporting triboelectric layer mode. The self-supporting triboelectric layer mode may not be limited to a single arrangement. For example, as illustrated, two electrodes are arranged laterally, and the self-supporting triboelectric layer slides while covering a portion of the electrodes. Similar to the first configuration, the movement of the self-supporting triboelectric layer or the object causes a change in the electric field between the electrodes, thereby inducing a flow of charge. As another example, two electrodes are arranged facing each other vertically, and the self-supporting triboelectric layer moves up and down between the two electrodes. This vertical movement of the self-supporting triboelectric layer induces an alternating electric field, and to balance this electric field, an electron flow occurs between the two electrodes. The self-supporting triboelectric layer mode can generate electricity through non-contact movement because the triboelectric layer does not need to maintain contact with the electrodes during the sliding process.

[0036] FIG. 4 shows a disassembled view of a mechanical module (10) of a friction test device according to an embodiment of the present invention. The mechanical module (10) may largely include a normal motion unit (100) that implements normal motion of the dielectric and a horizontal motion unit (200) that implements relative motion of the dielectric in a direction perpendicular to the normal motion unit (100).

[0037] To explain in more detail, the normal motion unit (100) and the horizontal motion unit (200) may each include a base (110, 210) on which a dielectric (1) or an electrode (2) is arranged, and a fixing jig (211) for fixing the dielectric (1) or the electrode (2) on the base (110, 210). At this time, the base (110, 210) may include an upper base (110) connected to the normal motion unit (100) and a lower base (210) connected to the horizontal motion unit (200). In addition, the fixing jig (211) may each include an upper fixing jig (230) and a lower fixing jig (211) for fixing an upper dielectric (1-1) or an upper electrode (2-1) and a lower dielectric (1-2) or a lower electrode (2-2). The upper fixing jig (230) and the lower fixing jig (211) can be replaced and can be varied in various ways depending on the shape and arrangement of the dielectric or electrode to be installed.

[0038] At this time, the fixing jig (211) may be installed to form a connection port in which an electrode pin (3) can be interposed so that the measuring part and the dielectric (1) are electrically connected. For example, as illustrated, the fixing jig (211) may be divided into several parts and assembled on the base (110, 210) respectively to fix the dielectric (1) or the electrode (2) and at the same time form the connection port between the separated fixing jigs (211).

[0039] Additionally, the normal motion unit (100) may include a normal guide (120) and an actuator (121). The normal guide (120) can implement up-and-down movement by receiving power from the actuator (121). Furthermore, the normal motion unit (100) may further include a normal arm (112) for changing the direction of the contact surface of the dielectric (1) and a normal stage (113) so that the normal arm (112) can be coupled to the normal guide (120). For example, the normal arm (112) may be formed as an 'L'-shaped block so that the contact surface of the dielectric (1) can be set to face downward. Of course, the normal arm (112) can be replaced in various forms to set up friction tests of various modes.

[0040] Additionally, the normal motion unit (100) may include a plurality of rod-shaped rods (133) that transmit a load, an elastic member (134) formed on the rods (133), and a linear guide (135) that fixes the load direction of the rods (133) in a unidirectional manner and transmits the load to the rods (133) through the elastic member (134), and may include an upper control arm (131) coupled to all the linear guides (135) and a lower control arm (132) coupled to the ends of all the rods (133).

[0041] More specifically, the plurality of rods (133) serve to uniformly transmit the load received from the normal guide (120). At this time, one end of the rod (133) is connected to the linear guide (135), and the elastic part (134) can be connected to wrap around the rod (133). Subsequently, the upper control arm (131) is connected to the linear guide (135), and the other end of the rod (133) can be connected to the lower control arm (132). At this time, the elastic part (134) can perform an elastic role between the linear guide (135) and the lower control arm (132). For example, as illustrated, four rods (133) are installed at each vertex of the lower control arm (132) so as to be symmetrical from the center to apply a load, and the center of the lower control arm (132) can be connected to coincide with the center of the upper base (110). At this time, the lower control arm (132) may be in the shape of an 'x'. In addition, it is preferable that the area formed by the four rods (133) be larger than the upper base (110). Through this, the load transmitted to each rod (133) can be individually adjusted to apply a uniform load to the upper base (110).

[0042] Additionally, the normal motion unit (100) may further include a load measuring unit (140) interposed between the upper control arm (131) and the normal arm (112) to detect and measure a load. The load measuring unit (140) may include a mechanical load cell to help control the normal force applied to the upper dielectric (1-1).

[0043] Additionally, the horizontal motion unit (200) may include a horizontal guide (220) and an actuator (221). In the illustrated embodiment, the horizontal motion unit (200) can move the lower base (210) and the lower dielectric (1-2) by operating the stage (222) in a single direction. As another example, the horizontal motion unit (200) may be in a replaceable form, and it is understood that various friction test modes can be implemented by installing a device that implements rotational motion around a normal axis or a device that implements rotational motion around a horizontal axis.

[0044] Additionally, the machine module (10) may further include a leveling unit (300) for adjusting the level of the entire device. For example, as illustrated, the leveling unit (300) may include a ground contact unit (310) installed at the bottom of the machine module (10) and in contact with the ground, and a leveling screw (320) that penetrates through each vertex of the leveling unit (300), is connected to the ground contact unit (310), and can adjust the height. Explanation of the symbols

[0045] 1 : Dielectric 2 : Electrode 3 : Electrode pin 10: Machine Module 100 : Normal motion part 110: Upper base 111: Upper jig 112 : Normal Rock 113 : Normal Stage 114 : Central axis 120 : Normal guide 121 : Actuator 131: Upper control arm 132: Lower control arm 133 : Load 134 : Elastic part 135 : Linear guide 140: Load measuring section 200 : Horizontal movement unit 210: Lower base 211: Lower fixing jig 220 : Horizontal guide 221 : Actuator 222 : Horizontal stage 230 : Upper fixing jig 300: Leveling section 310: Ground contact section 320 : Adjustment screw

Claims

Claim 1 A friction test device for measuring friction characteristics of one or more dielectric surfaces, comprising: a normal motion unit having an upper dielectric with an attached electrode coupled to its lower end to implement normal motion of the upper dielectric; a horizontal motion unit disposed below the normal motion unit and having a lower dielectric or a single electrode with an attached electrode coupled to its upper end to implement relative motion of the lower dielectric or the single electrode with respect to the upper dielectric in a direction perpendicular to the motion direction of the normal motion unit; and a measuring unit connected to at least one of the electrodes coupled to the normal motion unit and the horizontal motion unit to measure the characteristics of electricity induced by surface contact and separation between the upper dielectric and the lower dielectric or the single electrode generated through the combination of motion of the normal motion unit and the horizontal motion unit. Claim 2 A friction test apparatus according to claim 1, which implements at least one of the following through a combination of motions of the normal motion unit and the horizontal motion unit: a vertical contact separation mode that implements motion or vibration in which two dielectrics repeatedly contact and separate; a sliding mode that implements relative motion of two dielectrics in the horizontal direction; a single electrode mode that implements vertical contact and separation or horizontal sliding motion of the dielectrics with respect to the electrode; and a self-supporting triboelectric layer mode that implements electric field change without contact. Claim 3 A friction test apparatus according to claim 1, comprising a base on which the dielectric is arranged and a fixing jig for fixing the dielectric on the base, wherein the number and arrangement of the dielectric can be changed by changing the fixing jig. Claim 4 A friction test device characterized in that, in paragraph 3, the fixed jig forms a connector when installed on the base. Claim 5 In paragraph 3, the base comprises an upper base on which an upper dielectric is installed and a lower base on which a lower dielectric is installed, and the upper base and the lower base are each coupled to the normal motion part and the horizontal motion part, respectively, in a friction test device. Claim 6 In claim 5, the normal motion part comprises a plurality of rod-shaped rods that transmit a load, an elastic part formed on the rods, and a linear guide that fixes the load direction of the rods in a unidirectional manner and transmits the load to the rods through the elastic part, forming a friction test device. Claim 7 In claim 6, the normal motion unit comprises an upper control arm coupled to all linear guides and a lower control arm coupled to the ends of all rods, and the lower control arm is a friction test device connected to the upper base. Claim 8 A friction test device according to claim 7, wherein the plurality of rods are installed symmetrically with respect to the center of the upper control arm and the lower control arm, and the center of the upper base is installed to coincide with the center of the lower control arm. Claim 9 A friction test device according to claim 8, characterized in that the area formed by the plurality of rods is larger than the area of ​​the upper base. Claim 10 In claim 1, the measuring unit is a friction test device that measures electrical characteristics including no-load voltage or short-circuit current.

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