Torsion balance type friction testing machine

Abstract

A torsion balance type friction testing machine relates to the technical field of friction testing machines and comprises a fixing mechanism, a torsion screw, a cross beam, a leveling weight, a loading weight, a force sensor, a friction pair, a driving mechanism and a control mechanism, the bottom end of the fixing mechanism is longitudinally connected with the torsion screw, and the bottom end of the torsion screw is hinged to the middle of the top end of the cross beam through a hinge seat. The cross beam swings along the longitudinal direction around a fixed shaft in the hinge seat, a leveling weight is sleeved on the cross beam on one side of the hinge seat in a sliding manner, the friction pair comprises an upper friction body and a lower friction body, one end of the cross beam far away from the leveling weight is used for installing the upper friction body and a loading weight, and the other end of the cross beam far away from the leveling weight is used for installing the loading weight. The sensing end of the force sensor is matched with the upper friction body, the lower friction body is driven by the driving mechanism, and the control mechanism is electrically connected with the force sensor, the driving mechanism and the power module through wires. The friction force testing device can effectively improve the friction force testing precision and reduce errors.

Description

Technical Field

[0001] This invention relates to the field of friction testing machine technology, specifically to a torsion balance friction testing machine. Background Technology

[0002] Friction and wear testing is an important analytical technique in engineering, enabling the study of the tribological properties of various materials under dry friction or liquid lubrication, and obtaining data such as friction force and coefficient of friction. Currently, there are many types of commonly used friction testing machines, among which ball-disc contact tribological testing instruments are widely used. In tribological research, testing ultra-low coefficients of friction, especially near-zero friction such as super-lubrication (broadly defined as a coefficient of friction below 0.01), requires high testing accuracy. However, achieving even higher testing accuracy remains a significant challenge.

[0003] The existing friction testing machine's testing principle is basically to directly convert friction force into strain or displacement change signals through a rigid structure. For example, Anton Paar's ball-and-disc friction and wear testing machine and Rtec's friction and wear testing machine are based on the conversion of friction force into rigid strain. During the strain generation process, the friction force is affected by the friction machine structure. The accuracy is poor in low friction force tests, and the test results are prone to errors. Utility Model Content

[0004] This invention discloses a torsion balance-type friction testing machine, aiming to overcome the shortcomings of existing friction force testing technologies. Based on the "torsion balance" testing structure, it enables the measurement of minute friction forces. Its basic principle is that, because the torsion suspension wire can provide a small torque, even very small friction forces during friction are far greater than the torsion of the torsion suspension wire. Therefore, the measured friction force has high accuracy, is unaffected by other structures, and can achieve near-zero friction force testing. The friction force testing accuracy using this friction testing machine is better than 0.01N.

[0005] To achieve the above objectives, the technical solution of this invention is as follows:

[0006] A torsion balance friction testing machine includes a fixing mechanism, a torsion wire, a crossbeam, a leveling weight, a loading weight, a force sensor, a friction pair, a drive mechanism, and a control mechanism. The fixing mechanism has a torsion wire connected longitudinally at its bottom end. The bottom end of the torsion wire is hinged to the middle of the top of the crossbeam via a hinge seat. The crossbeam swings longitudinally around a fixed axis in the hinge seat. A leveling weight is slidably mounted on the crossbeam on one side of the hinge seat. The friction pair includes an upper friction body and a lower friction body. The end of the crossbeam away from the leveling weight is used to mount the upper friction body and the loading weight. The sensing end of the force sensor cooperates with the upper friction body. The lower friction body is driven by the drive mechanism. The control mechanism is electrically connected to the force sensor, the drive mechanism, and the power module via wires.

[0007] Preferably, the leveling weight is a ring structure, with the inner wall of the leveling weight slidingly engaged with the outer wall of the crossbeam. The ring structure is provided with bolt holes penetrating the inner hole and the outer surface, and the bolt holes are equipped with first positioning bolts. The leveling weight is fixed relative to the crossbeam by the first positioning bolts.

[0008] Preferably, the end of the crossbeam away from the leveling weight has a through hole along the longitudinal direction, a fixing rod passes through the through hole, and a threaded hole is opened horizontally on the side wall of the through hole. The threaded hole is equipped with a second positioning bolt. The crossbeam is fixedly connected to the fixing rod by the second positioning bolt. The part of the fixing rod above the crossbeam is used to fit the loading weight. The bottom end of the fixing rod is provided with a fixing seat, and the upper part of the upper friction body is fixedly connected to the fixing seat.

[0009] Preferably, it also includes a workbench, the cross-section of the beam is rectangular, the force sensor is fixedly connected to the top of the workbench through a first bracket, and the sensing end of the force sensor is in contact with the outer surface of the beam at the location of the fixed rod.

[0010] Preferably, the driving mechanism includes a servo motor, an electric cylinder, and a pneumatic cylinder. The output shaft of the servo motor extends longitudinally upward and is fixedly connected to the center of the bottom of the lower friction body. The bottom end of the servo motor is fixedly connected to the piston rod end of the electric cylinder. A movable seat is fixedly connected to the bottom end of the electric cylinder. Slider structures are respectively provided on both sides of the bottom end of the movable seat. Linear slide rails are respectively provided on the upper surface of the worktable opposite to the slider structures. The cylinder barrel is fixedly connected to the upper surface of the worktable. The piston rod end of the pneumatic cylinder is fixedly connected to the reaction block on the lower surface of the movable seat. Driven by the pneumatic cylinder, the lower friction body reciprocates in the direction of the force sensor.

[0011] Preferably, the control mechanism is also electrically connected to a display screen via wires.

[0012] Preferably, the fixing mechanism is fixedly connected to the top of the workbench via a second bracket.

[0013] The beneficial effects of this novel torsion balance friction testing machine are as follows:

[0014] Because the torsion wire can provide a small torque, even a very small frictional force is much greater than the torsion of the torsion wire during the friction process. Therefore, the frictional force obtained by the test is highly accurate, unaffected by other structures, and can achieve near-zero frictional force testing. The frictional force test accuracy using this friction testing machine is better than 0.01N. Attached Figure Description

[0015] To more clearly illustrate the technical solution of this invention, the accompanying drawings used in the embodiments are briefly described below, which constitute a part of the specification and are used together with the embodiments of this invention to explain this invention, but do not constitute a limitation on this invention.

[0016] Figure 1 A schematic diagram of the overall structure of this novel invention;

[0017] Figure 2 A partial top view of the structure of this novel invention;

[0018] Figure 3 Partial top view of this new type of workbench.

[0019] 1. Fixing mechanism; 2. Torsion screw; 3. Hinge seat; 31. Fixing shaft; 4. Crossbeam; 5. Leveling weight; 51. First positioning bolt; 6. Loading weight; 7. Fixing rod; 8. Upper friction body; 9. Lower friction body; 10. Force sensor; 101. First bracket; 11. Drive mechanism; 111. Servo motor; 112. Electric cylinder; 113. Moving seat; 114. Slider structure; 115. Reaction block; 12. Linear slide rail; 13. Worktable; 14. Second bracket; 15. Cylinder. Detailed Implementation

[0020] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] The following embodiments can be understood as explaining a partial structure of the present invention individually, or as explaining a larger structure of the present invention through a combination of multiple embodiments.

[0022] Example 1

[0023] A torsion balance friction testing machine, such as Figure 1-3As shown, the device includes a fixing mechanism 1, a torsion wire 2, a crossbeam 4, a leveling weight 5, a loading weight 6, a force sensor 10, a friction pair, a drive mechanism 11, and a control mechanism. The bottom end of the fixing mechanism 1 is longitudinally connected to the torsion wire 2. The bottom end of the torsion wire 2 is hinged to the middle of the top of the crossbeam 4 through a hinge seat 3. The crossbeam 4 swings longitudinally around a fixed axis 31 in the hinge seat 3. The leveling weight 5 is slidably sleeved on the crossbeam 4 on one side of the hinge seat 3. The friction pair includes an upper friction body 8 and a lower friction body 9. The end of the crossbeam 4 away from the leveling weight 5 is used to install the upper friction body 8 and the loading weight 6. The sensing end of the force sensor 10 cooperates with the upper friction body 8. The lower friction body 9 is driven by the drive mechanism. The control mechanism is electrically connected to the force sensor, the drive mechanism, and the power module through wires.

[0024] In this embodiment, detecting friction requires eliminating interference from the testing machine itself. Existing equipment's friction mechanism applies a certain force to the friction pair, leading to inaccurate measurements due to resistance, especially for minute friction forces. To address this issue, this invention introduces a torsion wire 2. The structure of the torsion wire 2 should satisfy the following requirements: it should be able to support the weight of the load-bearing beam and its mounting components while possessing a small torque, thus minimizing interference with friction detection. The torsion wire can be made of metal, organic, or inorganic materials. The force sensor can be a resistive or capacitive sensor.

[0025] Example 2

[0026] like Figure 1 As shown, the leveling weight 5 has a ring-shaped structure. The inner wall of the leveling weight 5 slides against the outer wall of the crossbeam 4. The ring-shaped structure has bolt holes (a common configuration, not shown in the figure) that penetrate the inner hole and the outer surface. First positioning bolts 51 are installed in these bolt holes. The leveling weight 5 is fixed to the crossbeam 4 by the first positioning bolts 51. After the crossbeam is leveled, the leveling weight can be fixed in its current position, and then the friction test can begin. The leveling weight functions similarly to a counterweight.

[0027] Example 3

[0028] like Figure 1 , 2As shown, the end of the crossbeam 4 away from the leveling weight 5 has a through hole along the longitudinal direction. A fixing rod 7 passes through the through hole. A threaded hole is opened horizontally on the side wall of the through hole. A second positioning bolt (not marked in the figure) is configured in the threaded hole. The crossbeam 4 is fixedly connected to the fixing rod 7 by the second positioning bolt. The part of the fixing rod 7 located above the crossbeam is used to fit the loading weight 6. A fixing seat (not marked in the figure) is provided at the bottom end of the fixing rod 7. The upper part of the upper friction body 8 is fixedly connected to the fixing seat.

[0029] In this embodiment, the upper friction body can be a ball with a diameter of 0.1mm-20mm or other commonly used pins, needles, or other structures. The loading weight 6 is used to apply a certain degree of load to the upper friction body. After the load is applied, the leveling weight is adjusted to level the crossbeam.

[0030] Example 4

[0031] like Figure 1 As shown, it also includes a workbench 13, the cross-section of the beam 4 is rectangular, the force sensor 10 is fixedly connected to the top of the workbench 13 through the first bracket 101, and the sensing end of the force sensor 10 is in contact with the outer surface of the beam 4 at the location of the fixed rod 7.

[0032] In this embodiment, when the friction pairs begin to rub against each other in a linear manner, the upper friction pair will cause the crossbeam to rotate due to the frictional force. This will cause the force sensor to detect the corresponding force, and the control mechanism will determine the magnitude of the frictional force based on the data detected by the force sensor. The lower friction pair can move in a reciprocating linear motion or a rotation, such as... Figure 2 As shown, when the lower friction body rotates, it applies a force to the upper friction body along the tangent of its rotation trajectory. At this time, the force sensor is located on the opposite side of the direction of the force, thus achieving accurate detection of the friction force.

[0033] Example 5

[0034] like Figure 1 , 2As shown in Figure 3, the drive mechanism 11 includes a servo motor 111, an electric cylinder 112, and a pneumatic cylinder 15. The output shaft of the servo motor 111 extends longitudinally upward and is fixedly connected to the center of the bottom of the lower friction body 9. The bottom end of the servo motor 111 is fixedly connected to the piston rod end of the electric cylinder 112. A movable seat 113 is fixedly connected to the bottom end of the electric cylinder 112. Slider structures 114 are respectively provided on both sides of the bottom end of the movable seat 113. The upper surface of the worktable 13 opposite to the slider structure 114 is respectively provided with straight... The linear guide rail 12 is used. The cylinder barrel of the cylinder 15 is fixedly connected to the upper surface of the worktable 13, and the piston rod end of the cylinder 15 is fixedly connected to the reaction block 115 on the lower surface of the moving seat 113. Driven by the cylinder 15, the lower friction body 9 reciprocates in the direction of the force sensor 10, that is, the relative friction of reciprocating linear motion is achieved by the cylinder. After the cylinder fixes the moving seat in the set position, the electric cylinder extends to adjust the height of the lower friction body, and the servo motor starts to drive the lower friction body to rotate, realizing the rotational friction between the upper and lower friction bodies. The lower friction body can be made into the required shape as needed, and its material can be metal, polymer or inorganic non-metal. The movement mode of the lower friction body includes reciprocating sliding mode and rotational sliding mode.

[0035] Example 6

[0036] like Figure 1 As shown, the control mechanism is also electrically connected to a display screen via wires to display real-time friction data.

[0037] like Figure 1 As shown, the fixing mechanism 1 is fixedly connected to the top of the workbench 13 via the second bracket 14.

[0038] Working principle of the invention:

[0039] Because the torsion wire can provide a small torque, even a very small frictional force is much greater than the torsion of the torsion wire during the friction process. Therefore, the influence of this torque on the frictional force can be ignored when testing the frictional force, resulting in high accuracy of the obtained frictional force. It can achieve near-zero frictional force testing. The frictional force testing accuracy using this friction testing machine is better than 0.01N.

Claims

1. A torsion balance friction testing machine characterized by: The fixed mechanism is connected with the torsion spiral at the bottom end in the longitudinal direction, the bottom end of the torsion spiral is hinged with the middle part of the top end of the crossbeam through the hinge seat, the crossbeam swings along the longitudinal direction around the fixed shaft in the hinge seat, the leveling weight is sleeved on the crossbeam on the side of the hinge seat in sliding mode, the friction pair comprises an upper friction body and a lower friction body, the end of the crossbeam away from the leveling weight is used for mounting the upper friction body and the loading weight, the sensing end of the force sensor is matched with the upper friction body, the lower friction body is driven through the driving mechanism, and the control mechanism is electrically connected with the force sensor, the driving mechanism and the power module through wires.

2. A torsion pendulum friction tester as claimed in claim 1, characterized in that: The leveling weight is in the form of a ring structure, the inner hole wall of the leveling weight is in sliding fit with the outer wall of the crossbeam, the ring structure is provided with a bolt hole penetrating through the inner hole and the outer surface, the bolt hole is provided with a first positioning bolt, and the leveling weight is fixed relative to the crossbeam through the first positioning bolt.

3. A torsion pendulum friction tester as claimed in claim 2, characterized in that: The end of the crossbeam away from the leveling weight is provided with a through hole in the longitudinal direction, a fixed rod penetrates through the through hole, a threaded hole is horizontally formed in the side wall of the through hole, the threaded hole is provided with a second positioning bolt, the crossbeam is fixedly connected with the fixed rod through the second positioning bolt, the part of the fixed rod above the crossbeam is used for sleeving the loading weight, the bottom end of the fixed rod is provided with a fixing seat, and the upper part of the upper friction body is fixedly connected with the fixing seat.

4. A torsion pendulum friction tester as claimed in claim 3, characterized in that: The crossbeam is in the form of a rectangle, the force sensor is fixedly connected with the top end of the workbench through a first support, and the sensing end of the force sensor is in contact with the outer surface of the crossbeam at the position of the fixed rod.

5. A torsion pendulum friction tester as claimed in claim 4, characterized in that: The driving mechanism comprises a servo motor, an electric cylinder and a pneumatic cylinder, the output shaft of the servo motor extends upward in the longitudinal direction and is fixedly connected with the bottom center position of the lower friction body, the bottom end of the servo motor is fixedly connected with the end of the piston rod of the electric cylinder, the bottom end of the electric cylinder is fixedly connected with a moving seat, the two sides of the bottom end of the moving seat are respectively provided with sliding block structures, the upper surfaces of the workbench opposite to the sliding block structures are respectively provided with linear sliding rails, the cylinder barrel of the pneumatic cylinder is fixedly connected with the upper surface of the workbench, and the end of the piston rod of the pneumatic cylinder is fixedly connected with the reaction block on the lower surface of the moving seat.

6. A torsion pendulum friction tester as claimed in claim 5, characterized in that: The control mechanism is also electrically connected with a display screen through wires.

7. A torsion pendulum friction tester as claimed in claim 6, characterized in that: The fixed mechanism is fixedly connected with the top end of the workbench through a second support.

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