Rotary friction power-up device

Abstract

The invention relates to the technical field of tribology in mechanical engineering, in particular to a rotating friction power-up device which comprises a rotating part, a transmission shaft, a conductive slip ring, a liquid pool, a friction part and a supporting part, one end of the transmission shaft is fixed to the rotating part, and the other end of the transmission shaft is fixed to the liquid pool; a fixing seat for fixing a test piece is arranged in an inner cavity of the liquid pool; a rotor of the conductive slip ring is fixed on the transmission shaft in a sleeving manner; a stator of the conductive slip ring is fixed by the supporting part; the friction part is fixedly connected with the supporting part, and the friction part is arranged above the fixed seat; an auxiliary electrode is fixed on the friction part, a reference electrode is fixed in an inner cavity of the liquid pool, and the fixed seat is connected with a working electrode; the auxiliary electrode is electrically connected with the electrochemical workstation, the reference electrode and the working electrode are electrically connected to a rotor of the conductive slip ring, and a stator of the conductive slip ring is electrically connected to the electrochemical workstation. According to the device provided by the embodiment of the invention, the influence of electromagnetic coupling on the electrode potential can be reduced while wire winding is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of tribology in mechanical engineering, and in particular to a rotary friction electrification device. Background Art

[0002] The triboelectrochemical phenomenon refers to the application of an external electric field on the friction interface, which affects the physical and chemical properties, surface properties, and environmental atmosphere of the friction pair surface and interface, thereby changing the friction coefficient and wear state. On a macro scale, a friction and wear tester is usually used to measure the friction and load of two material surfaces during sliding; for example, a rotary friction and wear tester can measure continuous friction and speed data, which is suitable for evaluating the wear resistance and stability of materials under continuous rotation conditions.

[0003] The power-on method of rotary friction motion faces great challenges, mainly because when the test piece is connected to the working electrode, the rotary motion may cause the wire to be entangled. In the related art, a friction and wear tester that can reduce the probability of wire entanglement is provided. Figure 1 , the related art adopts a friction pair layout of three evenly distributed ceramic balls 1 and a metal disk 9. The fixture with three ceramic balls 1 is fixed on the metal disk 8, connected to the motor shaft 3 through the coupling 2, and the auxiliary electrode is fixed on the flange and connected to the auxiliary electrode through the brush device 4 to ensure power supply to the rotating auxiliary electrode. In other words, the related art adopts the upper motor, and the three ceramic balls 1 are driven to rotate by the motor, so that the ceramic balls 1 can achieve friction charging with the workpiece placed in the metal disk 8.

[0004] Although the method in the related art can solve the problem of wire winding to a certain extent, since its brush is connected to the motor shaft, there may be coupling between the electrode field strength of the brush and the auxiliary electrode, which will interfere with the accurate control of the working electrode potential.

[0005] Therefore, how to reduce the impact of electromagnetic coupling on electrode potential while avoiding wire entanglement is an urgent problem to be solved. Summary of the invention

[0006] Based on this, it is necessary to provide a rotating friction charging device that can avoid wire entanglement and reduce the impact of electromagnetic coupling on electrode potential in order to address the above technical problems.

[0007] In a first aspect, the present application provides a rotary friction charging device, the device comprising a rotating part, a transmission shaft, a conductive slip ring, a liquid pool, a friction part and a supporting part, wherein:

[0008] One end of the transmission shaft is fixed to the rotating part, and the other end of the transmission shaft is fixed to the liquid pool;

[0009] The inner cavity of the liquid pool is provided with a fixing seat for fixing the test piece;

[0010] The rotor of the conductive slip ring is sleeved on the transmission shaft and fixed, and the stator of the conductive slip ring is fixed by the support part;

[0011] The friction part is fixedly connected to the support part, and the friction part is placed above the fixing seat;

[0012] The friction part is fixed with an auxiliary electrode, the inner cavity of the liquid pool is fixed with a reference electrode, and the fixing seat is connected with a working electrode; the auxiliary electrode is electrically connected to an electrochemical workstation, the reference electrode and the working electrode are both electrically connected to the rotor of the conductive slip ring, and the stator of the conductive slip ring is electrically connected to the electrochemical workstation.

[0013] In one of the embodiments, the fixing seat is coaxially fixed with the liquid pool on the bottom surface of the inner cavity of the liquid pool, and the outer bottom end of the liquid pool is coaxially fixed with the transmission shaft.

[0014] In one embodiment, the friction part includes a friction ball, a ball holder and a joint, wherein:

[0015] The joint is fixed to the ball holder, the ball holder is fixed to the supporting part, and the rubbing ball is fixed to the ball holder.

[0016] In one embodiment, the ball holder includes a base and a ball holder cage, wherein:

[0017] The friction ball is fixed to the base, the ball holder is arranged outside the friction ball, and the ball holder is detachably connected to the base;

[0018] The ball cage has an opening at one end away from the base, and the friction balls protrude from the opening end of the ball cage.

[0019] In one of the embodiments, one end of the joint away from the base is connected to a force sensor, and the joint is capable of bearing a vertical load force provided externally.

[0020] In one embodiment, the support portion includes a fixed base and a support rod, wherein:

[0021] The support rod is fixed to the fixed base, the support rod is vertically arranged and the support rod is higher than the top of the liquid pool;

[0022] The joint is connected to the support rod via a displacement assembly, and the displacement assembly can drive the joint to move closer to or away from the fixing seat in a vertical direction.

[0023] In one embodiment, the support portion further comprises a support frame, wherein:

[0024] The support frame is fixedly connected to the fixed base;

[0025] The support frame is fixedly connected to the stator of the conductive slip ring.

[0026] In one embodiment, the support frame comprises support legs and a fixing ring, wherein:

[0027] The supporting legs are fixed to the fixing base, and at least two supporting legs are provided;

[0028] The fixing ring is sleeved on the outside of the conductive slip ring, and the fixing ring is fixedly connected to each of the supporting legs;

[0029] The support frame is not higher than the stator of the conductive slip ring.

[0030] In one embodiment, the fixing seat is an annular clamp, and the connecting ends of the annular clamp are connected by bolts.

[0031] In one embodiment, the liquid pool can contain electrolyte.

[0032] In the above-mentioned rotating friction charging device, when the specimen is fixed on the fixed seat, the rotating part can drive the rotor, the liquid pool and the fixed seat of the conductive slip ring to rotate in the circumferential direction through the transmission shaft; at the same time, the friction part is placed above the fixed seat, and the specimen can achieve friction with the friction part when being driven to rotate. Since the auxiliary electrode is fixed to the friction part, and the friction part does not participate in the rotation, the wire of the auxiliary electrode does not participate in the rotational motion, thereby avoiding entanglement with the remaining wires; since the reference electrode is fixed in the inner cavity of the liquid pool, the working electrode is fixed to the fixed seat, and the reference electrode and the working electrode are both connected to the electrochemical workstation through the conductive slip ring; therefore, during the rotation process, the stator of the conductive slip ring does not participate in the rotation, and the rotor of the conductive slip ring is driven to rotate by the transmission shaft; that is, the wire between the electrochemical workstation and the stator of the conductive slip ring does not participate in the rotational motion, thereby avoiding the problem of wire entanglement; and the wires connecting the reference electrode and the working electrode to the rotor of the conductive slip ring participate in the rotational motion synchronously, and the wires of the two are independent of each other, thereby avoiding the problem of wire entanglement.

[0033] Furthermore, in the device of the present application, the auxiliary electrode is fixed on the fixed friction part. Therefore, the auxiliary electrode is not directly connected to the motor shaft, and there will be no mutual coupling between the electric field of the auxiliary electrode and the electric field of the motor. Therefore, in the device of the present application, the electromotive force of the working electrode can be more accurately regulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of a friction charging device in the related technology.

[0035] FIG. 2 is a schematic diagram of the overall structure of the friction charging device in an embodiment of the present application.

[0036] FIG. 3 is a schematic diagram showing the fixing state of the conductive slip ring and the fixing frame.

[0037] FIG. 4 is a schematic diagram showing the structure of the liquid pool and the fixing seat.

[0038] FIG. 5 is a schematic diagram showing the structure of the friction portion.

[0039] FIG. 6 is a schematic diagram showing the principle of hydration.

[0040] FIG. 7 is a schematic diagram showing the principle of triboelectrochemical reaction.

[0041] Figure numerals: 1, rotating part; 2, transmission shaft; 3, conductive slip ring; 31, rotor; 32, stator; 33, anti-rotation plate; 4, liquid pool; 41, fixed seat; 5, test piece; 6, friction part; 61, ball holder; 611, base; 612, ball holder cage; 613, positioning hole; 62, friction ball; 63, joint; 7, supporting part; 71, fixed base; 72, supporting frame; 721, supporting leg; 722, fixing ring; 723, anti-rotation pin; 8A, auxiliary electrode; 8B, working electrode; 8C, reference electrode; 9, electrochemical workstation. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0043] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0044] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0046] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0047] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0048] Referring to Fig. 2 to Fig. 4, a rotary friction charging device provided in one embodiment of the present application comprises a rotating part 1, a transmission shaft 2, a conductive slip ring 3, a liquid pool 4, a friction part 6 and a support part 7; wherein one end of the transmission shaft 2 is fixed to the rotating part 1, and the other end of the transmission shaft 2 is fixed to the liquid pool 4; the inner cavity of the liquid pool 4 is provided with a fixing seat 41 for fixing the test piece 5. The rotor 31 of the conductive slip ring 3 is sleeved on the transmission shaft 2 and fixed, and the stator 32 of the conductive slip ring 3 is fixed by the support part 7; the friction part 6 is fixedly connected to the support part 7, and the friction part 6 is placed above the fixing seat 41.

[0049] Furthermore, an auxiliary electrode 8A is fixed to the friction part 6, a reference electrode 8C is fixed to the inner cavity of the liquid pool 4, and a working electrode 8B is connected to the fixing seat 41; the auxiliary electrode 8A is electrically connected to the electrochemical workstation 9, the reference electrode 8C and the working electrode 8B are both electrically connected to the rotor 31 of the conductive slip ring 3, and the stator 32 of the conductive slip ring 3 is electrically connected to the electrochemical workstation 9.

[0050] In an embodiment of the present application, the rotating part 1 serves as a driving source of the rotating friction charging device; when the specimen 5 is fixed on the fixed seat 41, the rotating part 1 can drive the rotor 31 of the conductive slip ring 3, the liquid pool 4 and the fixed seat 41 to rotate circumferentially through the transmission shaft 2; at the same time, the friction part 6 is placed above the fixed seat 41, and the specimen 5 can achieve friction with the friction part 6 when being driven to rotate. Since the auxiliary electrode 8A is fixed to the friction part 6, and the friction part 6 does not participate in the rotation, the wire of the auxiliary electrode 8A does not participate in the rotational motion, thereby avoiding entanglement with other wires; since the reference electrode 8C is fixed in the inner cavity of the liquid pool 4, the working electrode 8B is fixed to the fixing seat 41, and the reference electrode 8C and the working electrode 8B are both connected to the electrochemical workstation 9 through the conductive slip ring 3; therefore, during the rotation process, the stator 32 of the conductive slip ring 3 does not participate in the rotation, and the rotor 31 of the conductive slip ring 3 is driven to rotate by the transmission shaft 2; that is, the wire between the electrochemical workstation 9 and the stator 32 of the conductive slip ring 3 does not participate in the rotational motion, thereby avoiding the entanglement problem of the wire; and the wires connecting the reference electrode 8C and the working electrode 8B to the rotor 31 of the conductive slip ring 3 participate in the rotational motion synchronously, and the wires of the two are independent of each other, thereby avoiding the entanglement problem of the wire.

[0051] Furthermore, in the device of the present application, the auxiliary electrode 8A is fixed on the friction part 6, and therefore, it is not directly connected to the motor main shaft, and there will be no mutual coupling between the electric field of the auxiliary electrode 8A and the electric field of the motor. Therefore, in the device of the present application, the electromotive force of the working electrode 8B can be more accurately regulated.

[0052] In a possible implementation, the rotating part 1 can be a rotating platform of an existing rotating test device, and the transmission shaft 2 is coaxially fixed with the rotating platform, and the transmission shaft 2 is perpendicular to the rotating platform. For example, the rotating part 1 can be a rotating platform of a friction and wear testing machine.

[0053] In another possible implementation, the rotating part 1 can be an independent rotating platform driven by a driving motor; for example, the rotating part 1 can also be composed of a driving motor, a reducer, a coupling, and a rotating table. The output shaft of the driving motor is coaxially fixed with the input shaft of the reducer, the output shaft of the reducer is coaxially fixed with the rotating table through the coupling, and the transmission shaft 2 is coaxially fixed with the rotating table. Thus, the driving part drives the components fixed to the transmission shaft 2 to realize rotational motion through the transmission shaft 2.

[0054] It should be clear that the rotational motion of the rotating part 1 can be variable speed or uniform speed, that is, the circumferential rotation speed of the rotating part 1 is controllable and adjustable.

[0055] Furthermore, the support portion 7 includes a fixed base 71 and a support frame 72; wherein the fixed base 71 is used to support the rotating friction charging device, and the support frame 72 is used to fix the stator 32 of the conductive slip ring 3, so that when the transmission shaft 2 rotates, the stator 32 and the rotor 31 of the conductive slip ring 3 can remain relatively stable.

[0056] Specifically, in one embodiment, referring to FIG. 2 and FIG. 3 , when the rotating part 1 is a rotating platform of a friction and wear tester, the fixed base 71 is a frame of the friction and wear tester. When the rotating part 1 is a rotating platform driven by an independent driving motor, the fixed base 71 can be a hollow cavity with an open upper end, the lower end of the fixed base 71 is closed, the rotating part 1 is fixedly connected to the bottom end of the fixed base 71 in the hollow cavity of the fixed base 71, and the top end of the rotating platform protrudes from the upper open end of the fixed base 71.

[0057] In one embodiment, referring to Fig. 2 and Fig. 3, the support frame 72 is fixedly connected to the fixed base 71, and the support frame 72 is fixedly connected to the stator 32 of the conductive slip ring 3, so that the stator 32 of the conductive slip ring 3 can maintain a stable state. Specifically, the support frame 72 includes a support leg 721 and a fixed ring 722, and the support leg 721 is fixedly connected to the fixed base 71, such as by welding or bolting. The fixing ring 722 is sleeved on the stator 32 of the conductive slip ring 3, and the fixing ring 722 is fixedly connected to the outer wall of the stator 32 of the conductive slip ring 3; specifically, a stopper 33 is fixed to the outer wall of the stator 32 of the conductive slip ring 3, and a stopper pin 723 is arranged on the inner side of the fixing ring 722, and the stator 32 of the conductive slip ring 3 is fixed by the fixing ring 722 through the plug-in fit or threaded connection between the stopper pin 723 and the stopper 33, so as to prevent the stator 32 of the conductive slip ring 3 from rotating; this fixing method effectively ensures the stability of the stator 32 of the conductive slip ring 3, and ensures the accuracy and reliability during the experiment. The length of the stopper pin 723 can be adjusted by adjusting the bolt.

[0058] Further, referring to FIG. 2 and FIG. 3 , at least two support legs 721 are provided, and each support leg 721 is fixedly connected to a fixing ring 722. Each support leg 721 is evenly arranged along the circumference of the stator 32 of the conductive slip ring 3, so that the stator 32 of the conductive slip ring 3 can obtain a more stable support and fixing effect. Among them, the fixing ring 722 can be a rectangular ring structure or a circular ring structure, which is not specifically limited in the embodiment of the present application. It should be noted that in order to further enhance the supporting effect of the stator 32 of the conductive slip ring 3, the setting height of the fixing ring 722 does not exceed the top of the stator 32 of the conductive slip ring 3, that is, the setting height of the fixing ring 722 is not higher than the end of the conductive slip ring 3 away from the fixed base 71.

[0059] Further, referring to Figure 4, the liquid pool 4 is a hollow cavity with an open upper end, and the cross-section of the liquid pool 4 can be rectangular or circular. The outer side of the closed end of the liquid pool 4 is coaxially fixed to the end of the transmission shaft 2 away from the rotating part 1, so that the liquid pool 4 can maintain concentric stability when rotating with the transmission shaft 2 and will not be subjected to uneven centrifugal force. At the same time, the fixed seat 41 is fixed in the hollow cavity of the liquid pool 4, and the fixed seat 41 is fixedly connected to the inner side of the closed end of the liquid pool 4, that is, the fixed seat 41 is fixedly connected to the bottom end surface of the liquid pool 4 in the hollow cavity of the liquid pool 4. Among them, the fixed seat 41 can be an annular clamp, and the fixed seat 41 is fixed to the bottom end of the liquid pool 4 by bolts.

[0060] Specifically, referring to Figure 4, the connecting end of the annular clamp is connected by bolts, that is, the tightness of the clamp can be adjusted by adjusting the degree of screwing in and out of the bolts. In the embodiment of the present application, the test piece 5 for the rotational friction electrification is a metal test piece 5, and the test piece 5 is built in the middle of the fixing seat 41 in the liquid pool 4. By adjusting the bolts of the annular clamp, the annular clamp clamps the test piece 5, thereby stably fixing the test piece 5 on the fixing seat 41.

[0061] In one of the embodiments, referring to FIG. 4 , a groove for fixing a reference electrode 8C may be provided on the inner wall of the hollow cavity of the liquid pool 4, and the reference electrode 8C may be snapped into the groove for fixation; the reference electrode 8C is electrically connected to an output end of the rotor 31 of the conductive slip ring 3 through a wire, and the wire connecting the reference electrode 8C may be fixed accordingly along a path extending to the rotor 31 of the conductive slip ring 3, such as by bonding or bundling, which is not specifically limited in the embodiments of the present application; as long as the wire can maintain a stable state relative to the transmission shaft 2 when the transmission shaft 2 drives the rotor 31 of the conductive slip ring 3 and the liquid pool 4 to rotate.

[0062] Further, the working electrode 8B can be fixed to the fixing seat 41, such as by bundling or welding; the working electrode 8B can also be fixed between the specimen 5 and the fixing seat 41, that is, the specimen 5 and the working electrode 8B are clamped by the fixing seat 41, so that the specimen 5 and the working electrode 8B are fixed on the fixing seat 41. The working electrode 8B is electrically connected to an output end of the rotor 31 of the conductive slip ring 3 through a wire, and the wire connecting the working electrode 8B can be fixed accordingly along the path extending to the rotor 31 of the conductive slip ring 3, such as by bonding or bundling, which is not specifically limited in the embodiment of the present application; as long as the transmission shaft 2 drives the rotor 31 of the conductive slip ring 3 and the liquid pool 4 to rotate, the wire can remain stable relative to the transmission shaft 2.

[0063] Furthermore, the liquid pool 4 may contain an electrolyte, which can be used as a lubricant during friction. On the other hand, the presence of the electrolyte can form a hydrated adsorption layer on the surface of the test piece 5, thereby reducing the electrostatic interaction between the friction surfaces of the test piece 5. The effect of the electrolyte will be described in more detail below, and will not be described in detail here. The electrolyte can be a mixture of one or more of a water-based electrolyte, an oil-based electrolyte, and a grease.

[0064] Furthermore, the support portion 7 also includes a support rod; the support rod is used to fix the friction portion 6; when the transmission shaft 2 drives the fixed seat 41 of the fixed specimen 5 to rotate, thereby realizing the rotational friction between the specimen 5 and the friction portion 6, the support rod can support the friction portion 6, so that the friction portion 6 can maintain a relatively stable position.

[0065] In a possible implementation, the support rod can be an independent support member, one end of the support rod is bent and fixedly connected to the fixed base 71, so that the bent end of the support rod and the fixed base 71 can be placed on the same horizontal plane; the other end of the support rod is arranged parallel to the transmission shaft 2, that is, the vertical part of the support rod and the transmission shaft 2 are both arranged perpendicular to the horizontal plane where the fixed base 71 is located.

[0066] In another possible implementation, the support rod may also be a cantilever of the friction and wear testing machine, and the friction portion 6 is connected to the cantilever of the support rod, thereby fixing the friction portion 6.

[0067] It should be noted that the joint 63 is connected to the support rod, and the displacement assembly can drive the joint to approach or move away from the fixing seat 41 in the vertical direction, so that the friction part 6 can adjust its position on the support rod along the direction of approaching or moving away from the fixing seat 41.

[0068] In one embodiment, referring to Figure 5, the friction part 6 includes a friction ball 62, a ball holder 61, and a joint 63; wherein the joint 63 is fixed to the support part 7, and the joint 63 is fixedly connected to the ball holder 61, for forming a stable support for the ball holder 61; the ball holder 61 is used to fix the friction ball 62, so that the friction ball 62 can be aligned with the test piece 5 fixed on the fixing seat 41, thereby realizing the rotational friction between the friction ball 62 and the test piece 5.

[0069] Specifically, referring to FIG. 5 , the ball holder 61 includes a base 611 and a ball holder cage 612, wherein the mating ball 62 is fixed to the base 611, the ball holder cage 612 is covered on the outside of the mating ball 62, the end of the ball holder cage 612 away from the base 611 is open, and the mating ball 62 protrudes from the open end of the ball holder cage 612. The ball holder cage 612 is detachably connected to the base 611; the specific connection method is that the ball holder cage 612 is a cage with a circular cross section, and the outer wall of the end of the ball holder cage 612 close to the base 611 is provided with an external thread, the base 611 is provided with a hole for installing the ball holder cage 612, and the hole is provided with an internal thread, the external thread of the ball holder 61 matches the internal thread of the hole of the base 611, and the ball holder cage 612 is connected to the base 611 by screwing, and the detachable effect can be achieved.

[0070] Furthermore, when the support rod is an independent support member, the joint 63 is fixedly connected to the support rod; and the joint 63 can bear the vertical load force provided by the outside; that is, the joint 63 can bear the pressure in the direction of the vertical fixing seat 41 and transmit it to the friction ball 62. The end of the joint 63 away from the base 611 is connected to the force sensor, and the magnitude of the vertical load force applied to the joint 63 can be measured by the sensor, so as to facilitate better monitoring of the magnitude of the load force applied to the joint 63.

[0071] Specifically, referring to FIG. 5 , a positioning hole 613 is provided on the base 611, and the reference electrode 8C is fixed in the positioning hole 613, so that the reference electrode 8C obtains better stability. Furthermore, the reference electrode 8C can be one of a graphite electrode, an Ag / AgCl electrode or a calomel electrode, and the specific type of the reference electrode 8C is not specifically limited in the embodiment of the present application. Among them, the axis distance of the positioning hole 613 and the closest distance to the Mo ball 62 can be in the range of [0.5mm-2mm]. Among them, in an achievable manner, the axis distance of the positioning hole 613 and the closest distance to the Mo ball 62 can be any one of 0.5mm, 1mm and 2mm; among them, the preferred scheme is 1mm, so that the reference electrode 8C can provide a constant and accurate reference potential for the Mo ball 62. The reference electrode 8C is not only used to accurately control the potential of the specimen 5 (i.e., the working electrode 8B), but also protects the specimen 5 from damage caused by excessive oxidation or reduction by avoiding the application of an excessively high potential, thereby ensuring the accuracy of the electrochemical measurement and the repeatability of the experiment.

[0072] The above content explains a friction charging device provided in an embodiment of the present application from the perspective of structure; the following content further explains the effect of the friction charging device provided in an embodiment of the present application from the perspective of the method of use and the principle of friction charging of the test piece 5. In addition, in the following content, the concepts of super-lubricity and liquid super-lubricity involved are first explained here. Super-lubricity: refers to the sliding friction state in which the sliding friction coefficient between relatively moving surfaces is 0.01 or less. The friction coefficient of ordinary oil lubrication is around 0.05-0.10. Liquid super-lubricity: refers to the super-lubricity state achieved by liquid lubricants.

[0073] Preliminary preparations are performed: a specimen 5 made of metal or semiconductor material is fixed in the liquid pool 4. Since the specimen 5 is connected to the working electrode 8B, the specimen 5 itself can be used as the working electrode 8B; the specimen 5 is installed and fixed through the fixing seat 41. For the friction part 6, an auxiliary electrode 8A is fixed on a base 611 made of metal or other conductive materials, and the friction ball 62 can be made of a polymer material. Therefore, the base 611 and the friction ball 62 made of conductive material are equivalent to the auxiliary electrode 8A. The reference electrode 8C is directly fixed in the liquid pool 4, and an electrolyte is added to the liquid pool 4 so that the reference electrode 8C is partially or completely immersed in the electrolyte; and the specimen 5, the base 611 and the friction ball 62 are completely immersed in the electrolyte. Among them, the distance between the reference electrode 8C and the specimen 5 is less than or equal to 1.5 mm, and preferably can be 1 mm.

[0074] When installing the test piece 5 on the fixing seat 41, firstly, the connecting bolts of the fixing seat 41 are rotated forward to loosen the fixing seat 41, and then the test piece 5 is placed in the fixing seat 41, or the test piece 5 and the working electrode 8B are placed in the fixing seat 41 together, wherein the test piece 5 is placed between the fixing seat 41 and the test piece 5; then, the connecting bolts of the fixing seat 41 are reversed, so that the fixing seat 41 clamps the test piece 5, or the fixing seat 41 clamps the test piece 5 and the working electrode 8B, so as to ensure that the test piece 5 is fixed in the liquid pool 4. This fixing method ensures the stability and safety of the test piece 5 during the experiment.

[0075] After the test piece 5 is fixed, the height of the friction part 6 is adjusted so that the friction ball 62 is located above the test piece 5 and just contacts the surface of the test piece 5; the rotational friction movement between the friction ball 62 and the test piece 5 is realized by the friction and wear testing machine, that is, the rotating part 1 drives the rotor 31 of the conductive slip ring 3 and the liquid pool 4 to rotate through the transmission shaft 2; the test piece 5 fixed by the fixing seat 41 in the liquid pool 4 rotates synchronously; that is, the test piece 5 rotates while the friction ball 62 remains fixed, thereby realizing the rotational friction between the two.

[0076] Furthermore, the friction charging device in the embodiment of the present application allows the load applied to the joint 63 to be controlled, the rotation speed of the rotating part 1 to be adjusted, and the rotation radius of the specimen 5 relative to the friction ball 62 (the horizontal distance between the axis of the specimen 5 and the axis of the friction ball 62) to be adjusted. A liquid lubricant is added to the liquid pool 4, and the electrochemical workstation 9 is started, and the input voltage is set to generate a voltage between the working electrode 8B and the auxiliary electrode 8A, thereby generating a voltage between the specimen 5 and the friction ball 62. At the same time, the reference electrode 8C maintains a constant potential of the electrolyte for controlling the electrode potential.

[0077] The experimental process of rotary friction electrification is as follows: start the electrochemical workstation 913, apply a negative voltage of -2V, and operate the friction and wear tester to apply a load at the joint 63 of the friction part 6; set the rotation speed and rotation radius of the rotating part 1. After setting the rotation speed of the rotating platform of the tester, the transmission shaft 2 will drive the rotor 31 of the conductive slip ring 3, the liquid pool 4, and the test piece 5 fixed in the liquid pool 4 to perform uniform rotation. This allows the friction ball 62 and the test piece 5 to perform a rotational friction motion under the set voltage. During this process, the sensor collects the signal of the rotational motion in real time, the electronic equipment of the friction and wear tester begins to record the friction force and / or friction coefficient in the rotational friction motion, and the electrochemical workstation 9 records the current in the friction motion in real time until it is observed that the friction coefficient gradually decreases to the super-slip state and remains stable.

[0078] In the related art, the layout of three ceramic balls and a circular ring disk is adopted, which makes the alignment of the three-ball center of gravity and the circular ring center extremely high in the related art, so the alignment effect cannot be guaranteed; if the three ceramic balls and the circular ring center cannot be accurately aligned, eccentricity will cause multiple wear marks on the surface of the circular ring disk, which is not conducive to the surface analysis of the sample after the friction test. In the device of the present application, there is only one rubbing ball 62, and the difficulty of aligning one rubbing ball 62 with the test piece 5 is significantly reduced, so that it is easier to achieve the alignment effect, so that the results of the rotational friction test conducted by the device of the present application can be more accurate.

[0079] Furthermore, in the related art, the structure is set so that the brush is exposed, and dust, moisture, etc. in the air will affect the resistivity between the brush and the motor shaft. Whether powered by a DC power supply or an electrochemical workstation, the applied voltage will be unstable, resulting in poor repeatability of the experimental results. In the device of the present application, the stator 32 of the conductive slip ring 3 can also be used as a protective device to reduce dust and moisture in the air from entering the brush between the rotor 31 and the stator 32 of the conductive slip ring 3, thereby making the voltage applied to the working electrode 8B and the reference electrode 8C more stable, thereby making the reproducibility of the experimental results better.

[0080] Furthermore, in the related art, the structure is set such that the graphite electrode (reference electrode 8C) is placed directly above the workpiece (working electrode 8B), so that the graphite chips after the graphite electrode is oxidized and peeled off / peeled off directly remain on the surface of the workpiece, seriously contaminating the ball-disk contact area and interfering with the friction test results. In the device of the present application, the working electrode 8B and the reference electrode 8C are effectively connected to the rotating specimen 5 and the auxiliary position near it (the inner wall of the liquid pool 4), that is, in the device of the present application, the reference electrode 8C will not cause any interference to the surface of the specimen 5 (working electrode 8B), so that more accurate experimental results can be obtained.

[0081] Referring to FIG6 , during the test, the sudden decrease in the friction coefficient and the stabilization after the gradual decrease reflect two main processes: first, after the negative voltage is applied to the specimen 5, the surface is negatively charged, and the positive charge of strong hydration is adsorbed to form a hydrated adsorption layer on the surface of the specimen 5, and the friction is reduced by the hydration effect, so the friction coefficient shows a sudden downward trend; second, the triboelectrochemical reaction causes the ball holder 61 to slowly anodic oxidation and the electrolyte solution to slowly cathode precipitate, and these reactions generate a triboelectrochemical reaction film on the surface of the specimen 5, so the friction coefficient gradually decreases and then tends to stabilize. The synergistic coupling of the two realizes the super-slip state or ultra-low friction state between the specimen 5 and the friction ball 62.

[0082] In the electrochemical system, after applying a voltage to charge the surface of the specimen 5 (positive or negative), water molecules are attracted to the charged surface due to their polar properties (oxygen atoms are negatively charged and hydrogen atoms are positively charged). These water molecules are arranged in an orderly manner to form a structure called a "hydration layer". This layer is mainly composed of water molecules, which are connected to each other through hydrogen bonds and form hydrogen bonds with charged groups or atoms on the surface. The ordered structure of the hydration layer significantly reduces the direct contact between the two friction surfaces, thereby reducing friction and wear. This hydration layer acts as a "lubricating pad" that allows the surfaces to slide against each other with less resistance. In addition, the hydration layer forms a "buffer layer" between the two surfaces, effectively reducing the adhesion phenomenon caused by chemical bonds and physical adsorption. The formation of the hydrated adsorption layer is accompanied by the attraction and accumulation of positive and negative charges, which further reduce the electrostatic interaction between the friction surfaces (the contact surface of the specimen 5 and the friction ball 62) through shielding.

[0083] At the same time, the hydration layer provides load-bearing capacity through its thickness and density. Between the two interacting surfaces (the contact surface of the specimen 5 and the friction ball 62), this layer of hydrated water molecules can bear the load orthogonal to the surface, reducing the direct contact of the surface and the corresponding mechanical wear. The load-bearing capacity of the hydration layer depends on its integrity and stability, which is usually determined by the applied electric field strength and the thickness of the hydration layer.

[0084] During the experiment, the shear force mainly acts in the horizontal direction of the hydration layer, as shown in Figure 6. When one surface moves relative to another, the hydration layer needs to adjust its structure to accommodate the movement, reducing the direct friction between the surfaces through internal sliding. The ordered structure of the hydration layer makes shear between the surfaces easier than direct metal-to-metal contact, because the interaction between water molecules in the hydration layer is much weaker than the interaction between metal atoms.

[0085] During the experiment, the shear force mainly acts in the horizontal direction of the hydration layer. When one surface moves relative to another, the hydration layer needs to adjust its structure to accommodate the movement, reducing the direct friction between the surfaces through internal sliding. The ordered structure of the hydration layer makes shear between the surfaces easier than direct metal-to-metal contact, because the interaction between water molecules in the hydration layer is much weaker than the interaction between metal atoms.

[0086] Further, the triboelectrochemical reaction is explained as follows:

[0087] Triboelectrochemical reactions are complex phenomena involving electrochemical and mechanical interactions at tribointerfaces, which are enhanced by friction and relative motion. In tribopairs involving metal surfaces, applying voltage can promote or change the electrochemical properties of the materials, thereby affecting friction and wear behavior.

[0088] Referring to Figure 7, in an electrochemical tribosystem, an oxidation reaction occurs on the surface of the anode connected to the positive electrode of a power source. This oxidation reaction involves the loss of electrons from the surface metal atoms, which are converted into metal ions. These metal ions may dissolve in the surrounding electrolyte or react with oxygen in the environment to form metal oxides. This process forms an oxide film or thin layer on the metal surface that may provide lubrication or prevent further chemical reactions from occurring.

[0089] In the system, the surface that serves as the cathode undergoes a reduction reaction, and the metal ions in the electrolyte may be reduced on the surface and deposited as metal elements, forming a protective layer or lubricating layer. In some cases, water electrolysis may occur at the cathode to produce hydrogen ( ), this hydrogen generation may affect the lubrication effect.

[0090] The friction shear-induced effect is a phenomenon in which the electrochemical reaction is affected by shear stress generated by the relative motion of the friction contact. Shear force can first change the microstructure of the surface, making certain areas more susceptible to oxidation or reduction. In some cases, shear may cause the protective film to break, exposing new material surfaces and restarting the electrochemical reaction process. In addition, shear force can promote the transfer of substances between surfaces, increase local temperature and energy, and accelerate the kinetics of electrochemical reactions. Wear particles generated during the friction process may participate in the electrochemical reaction as a bridge, promote electron transfer or change the surface chemical composition.

[0091] Therefore, as the electrochemical reaction proceeds, the metal atoms on the surface of the ball holder, which acts as the anode, will lose electrons and oxidize when receiving a positive voltage, thereby forming a metal oxide layer. In tribology, these oxide layers are generally considered to have lubricating properties because they have a relatively low hardness and can act as solid lubricants. At the same time, the electrolyte solution undergoes a reduction reaction on the surface of the workpiece, which acts as the cathode, resulting in the formation of a mixed triboelectrochemical reaction film on the contact interface. This film can significantly reduce the friction coefficient due to its unique chemical and structural properties. Certain oxides can act as a sliding layer during the friction process, while the reduction deposition of metals may improve the surface micromorphology and reduce the surface roughness. As this reaction film is formed and stabilized, the friction coefficient will gradually decrease and tend to stabilize. This stability is mainly because the reaction film stabilizes the state of the contact interface at the mechanical and chemical levels, providing a more uniform and predictable friction behavior.

[0092] The thickness of the triboelectrochemical reaction film generated in situ in this experiment is about 100-200 nm, and it is amorphous as a whole, with an elastic modulus of about 50 GPa and a hardness of about 1 GPa.

[0093] The rotary friction charging device provided in the embodiment of the present application realizes the effective transmission of current and voltage from the fixed position of the electrochemical workstation to the reference electrode 8C and the specimen 5 (working electrode 8B) rotating in the liquid pool 4, and the device effectively avoids the problem of winding and twisting of the wires connecting the electrochemical workstation and each electrode during the rotation process. In the device of the embodiment of the present application, the auxiliary electrode 8A is connected to the base 611, ensuring that a uniform and stable voltage is generated between the ball holder 61 and the specimen 5, allowing it to be used as the voltage between the friction ball 62 and the specimen 5, thereby ensuring the accuracy and rationality of the applied electric field and the charging position.

[0094] The rotary friction charging device provided in the embodiment of the present application can effectively control the voltage intensity of the rotary friction interface between the friction ball 62 and the specimen 5 through an external electric field. By applying positive or negative voltages of different sizes, the scheme of the present application explores its influence on the friction performance, aiming to achieve ultra-low friction and liquid super-slip effect on the surface of non-insulators. In order to solve the technical difficulties caused by electrification during rotational motion, the present application adopts the ingenious structural design of the friction part 6 and the application of the conductive slip ring 3, effectively connecting the working electrode 8B and the reference electrode 8C to the rotating specimen 5 and its auxiliary position near the inner wall of the liquid pool 4 respectively. The scheme of the present application successfully achieves ultra-low friction in electrolyte solution on the surface of metal (friction coefficient as low as 0.02), and achieves super-slip in electrolyte solution on the surface of semiconductor materials (friction coefficient as low as 0.01 or less). The friction charging device provided by the present application overcomes the ultra-low friction phenomenon that previous technologies cannot achieve on a macroscopic scale, and expands the application scope of electric control friction research, providing a new solution for friction control of industrial materials.

[0095] The mechanism of the super-slip state achieved by the present invention is mainly attributed to the synergistic coupling of strong hydration and triboelectrochemical reaction film; this system can achieve ultra-low friction state in the boundary lubrication, mixed lubrication and fluid dynamic lubrication stages, significantly reducing the friction coefficient and wear rate by more than one order of magnitude. This super-slip state is not only stable and reliable, but also the triboelectrochemical reaction film formed in situ has moderate mechanical strength; thus, the rotating friction charging device provided by the embodiment of the present application or the test piece 5 / component constructed by the rotating friction device of the present application can be applied in the environment of high-end equipment manufacturing, deep-sea components, ship systems and other fields.

[0096] It should be emphasized that the present application not only covers a three-electrode point contact rotary friction electric control system composed of a test piece 5 made of metal / alloy / semiconductor and other materials, a metal or alloy base 611, a friction ball 62 made of a polymer material, and a liquid lubricant such as an electrolyte solution, but also protects a similar two-electrode rotary friction electric control system; that is, in the rotary friction charging device provided in the embodiment of the present application, the above-mentioned rotary friction test process can be achieved without a reference electrode 8C. In addition, the present invention also includes corresponding test pieces 5, ball holders 61, friction balls 62 and lubricants made of other materials, as well as applications covering various friction interface forms such as point contact, line contact, and surface contact.

[0097] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A rotary friction charging device, characterized in that: The device comprises a rotating part (1), a transmission shaft (2), a conductive slip ring (3), a liquid pool (4), a friction part (6) and a supporting part (7), wherein: One end of the transmission shaft (2) is fixed to the rotating part (1), and the other end of the transmission shaft (2) is fixed to the liquid pool (4); The inner cavity of the liquid pool (4) is provided with a fixing seat (41) for fixing the test piece (5); The rotor (31) of the conductive slip ring (3) is sleeved on the transmission shaft (2) and fixed, and the stator (32) of the conductive slip ring (3) is fixed by the support part (7); The friction part (6) is fixedly connected to the support part (7), and the friction part (6) is placed above the fixed seat (41); The friction part (6) is fixed with an auxiliary electrode (8A), the inner cavity of the liquid pool (4) is fixed with a reference electrode (8C), and the fixing seat (41) is connected with a working electrode (8B); the auxiliary electrode (8A) is electrically connected to an electrochemical workstation, the reference electrode (8C) and the working electrode (8B) are both electrically connected to the rotor (31) of the conductive slip ring (3), and the stator (32) of the conductive slip ring (3) is electrically connected to the electrochemical workstation (9).

2. The device according to claim 1, characterized in that The fixing seat (41) is coaxially fixed to the liquid pool (4) on the bottom surface of the inner cavity of the liquid pool (4), and the outer bottom end of the liquid pool (4) is coaxially fixed to the transmission shaft (2).

3. The device according to claim 1, characterized in that The friction part (6) comprises a friction ball (62), a ball holder (61) and a joint (63), wherein: The joint (63) is fixed to the ball holder (61), the ball holder (61) is fixed to the support portion (7), and the rubbing ball (62) is fixed to the ball holder (61).

4. The device according to claim 3, characterized in that The ball holder (61) comprises a base (611) and a ball holder cage (612), wherein: The matching ball (62) is fixed to the base (611), the ball support cage (612) is arranged outside the matching ball (62), and the ball support cage (612) is detachably connected to the base (611); The ball cage (612) is open at one end away from the base (611), and the rubbing ball (62) protrudes from the open end of the ball cage (612).

5. The device according to claim 4, characterized in that One end of the joint (63) away from the base (611) is connected to a force sensor, and the joint (63) is capable of bearing a vertical load force provided externally.

6. The device according to claim 4 or 5, characterized in that The support part (7) comprises a fixed base (71) and a support rod, wherein: The support rod is fixed to the fixed base (71), the support rod is vertically arranged and is higher than the top of the liquid pool (4); The joint (63) is connected to the support rod via a displacement assembly, and the displacement assembly can drive the joint (63) to move closer to or farther from the fixing seat (41) in a vertical direction.

7. The device according to claim 6, characterized in that The support portion (7) further comprises a support frame (72), wherein: The support frame (72) is fixedly connected to the fixed base (71); The support frame (72) is fixedly connected to the stator (32) of the conductive slip ring (3).

8. The device according to claim 7, characterized in that The support frame (72) comprises a support leg (721) and a fixing ring (722), wherein: The supporting leg (721) is fixed to the fixing seat (41), and at least two supporting legs (721) are provided; The fixing ring (722) is sleeved on the outside of the conductive slip ring (3), and the fixing ring (722) is fixedly connected to each of the supporting legs (721); The support frame (72) is not higher than the stator (32) of the conductive slip ring (3).

9. The device according to any one of claims 1 or 2, characterized in that: The fixing seat (41) is an annular clamp, and the connecting ends of the annular clamp are connected by bolts.

10. The device according to claim 1 or 2, characterized in that: The liquid pool (4) can contain electrolyte.

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