Static and dynamic friction force experiment device

Abstract

The invention discloses a static and dynamic friction force experiment device, and relates to the technical field of teaching aids, the static and dynamic friction force experiment device comprises an experiment table, the experiment table is provided with a friction assembly, the friction assembly comprises a friction plate, the friction plate is provided with a friction block, the friction block is movably provided with a metering block, the bottom of the metering block is fixedly provided with a sliding rod, and the outer side of the sliding rod is sleeved with a first spring; a fixed block is fixedly arranged at the top of the friction block close to one end, a graduated scale is fixedly arranged on the metering block in the moving direction, and a pointer matched with the graduated scale is fixedly arranged on the friction block. The pointer and the graduated scale are matched to display the moving distance of the metering block and the stiffness coefficient of the first spring, the static friction force between the friction block and the friction plate can be calculated, students can visually know the change of the static friction force through the movement of the metering block, and a teacher can conveniently carry out corresponding explanation.

Description

Technical Field

[0001] The invention relates to the technical field of teaching tools, in particular to a static and dynamic friction force experimental device. Background Art

[0002] Physics is a natural science based on experiments. Through experiments, students can understand how physical concepts and laws are established on the basis of experiments, thereby effectively helping students to form concepts, derive laws, master theories, and correctly and deeply understand physical knowledge. Static friction and dynamic friction are two different types of friction. Static and dynamic friction experiments are an important part of physics teaching courses. At present, the static and dynamic friction experimental devices used in physics classroom teaching have the defects of making it difficult for students to intuitively observe the changes in the magnitude of static and dynamic friction and inconvenient operation, which is not conducive to teaching use. Therefore, in view of the defects of the existing static and dynamic friction experimental devices that cannot intuitively observe the changes in the magnitude of static and dynamic friction and are inconvenient to operate, a solution for a static and dynamic friction experimental device is proposed. Summary of the invention

[0003] The purpose of the present invention is to provide a static and dynamic friction force experimental device in order to solve the above problems.

[0004] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0005] A static and dynamic friction force experimental device comprises an experimental platform, wherein a friction assembly is arranged on the experimental platform, wherein the friction assembly comprises a friction plate, a friction block is placed on the friction plate, a metering block is movably arranged on the friction block, a sliding rod is fixedly arranged at the bottom of the metering block, a first spring is sleeved on the outer side of the sliding rod, a fixed block is fixedly arranged at the top of the friction block near one end, the sliding rod crosses the fixed block and the two are slidably connected, a pull rope is fixedly arranged at one end of the metering block, a pulley is fixedly arranged at one end of the experimental platform, one end of the pull rope is fixedly connected to the metering block, the other end of the pull rope passes around the pulley and is fixedly arranged with a counterweight block, a scale is fixedly arranged on the metering block along the moving direction, and a pointer matching the scale is fixedly arranged on the friction block.

[0006] Preferably, the experimental bench is provided with a conversion mechanism, a through slot is provided on the top of the experimental bench along the length direction, and the conversion mechanism includes a first fixed frame, the through slot is fixedly installed with a first fixed frame near both ends, a round rod is rotatably arranged between the two first fixed frames, a first guide rod is fixedly arranged on the side of the round rod near both ends, the two first guide rods form a group, there are multiple groups of first guide rods and are distributed around the round rod, a second spring is sleeved on the outer side of the first guide rod, a base plate is slidably arranged on each group of the first guide rods, a friction plate is fixedly arranged on the base plate, the length and width of the friction plate are smaller than the length and width of the through slot, and the friction coefficients of the multiple friction plates are all different, brackets are fixedly installed near both ends of the through slot, guide wheels are rotatably installed on the two brackets, and rotating wheels corresponding to the guide wheels are rotatably installed at both ends of the base plate, and a driving element is fixedly arranged on the experimental bench at one end of the round rod, and the driving element can drive the round rod to rotate.

[0007] Preferably, the number of the friction plates is 3 to 6.

[0008] Preferably, the driving element is a stepping motor.

[0009] Preferably, a limit assembly is provided on the laboratory bench, and the limit assembly includes a seat plate. The laboratory bench is fixedly provided with seat plates at positions close to both sides of the through slot, and fixed plates are fixedly provided on both sides of the base plate. A limit rod is slidably provided on the seat plate, and a handle is fixedly provided on the top of the limit rod. A limit groove is provided at a position corresponding to the fixed plate and the limit rod, and the limit rod can be extended into the limit groove.

[0010] Preferably, a guide assembly is fixedly provided on the laboratory bench, a second fixed frame is fixedly provided near both ends of the top of the laboratory bench, a second guide rod is fixedly provided between the two second fixed frames, the second guide rod is distributed along the sliding direction of the friction block, a second guide groove is provided on the metering block, the second guide rod crosses the second guide groove and the two are slidably connected.

[0011] Preferably, the number of the second guide rods is one or two.

[0012] Preferably, a tilting assembly is provided at the bottom of the laboratory bench, and the tilting assembly includes a base, a support is fixedly provided at the top position of the base near one end of the pulley, the support is rotatably connected to the end of the bottom of the laboratory bench, a support block is fixedly provided at the top position of the base away from one end of the pulley, the bottom of the laboratory bench is located on the top of the support block, support rods are rotatably provided on both sides of the laboratory bench near the support blocks, and the laboratory bench can be inclined with respect to the horizontal plane by rotating the support rods to cooperate with the support blocks.

[0013] Preferably, the support block is approximately L-shaped.

[0014] The beneficial effects of the present invention are as follows: (1) the present invention can calculate the magnitude of the static friction between the friction block and the friction plate by displaying the moving distance of the metering block and the stiffness coefficient of the first spring through the cooperation of a pointer and a scale. Then, by replacing counterweight blocks of different weights, students can intuitively know the change in the magnitude of the static friction through the movement of the metering block, that is, students can intuitively judge the magnitude of the static friction by seeing the displacement of the metering block, which is convenient for teachers to give corresponding explanations and easy to operate; (2) since the friction coefficients of different materials will directly affect the magnitude of the friction, it is also necessary to demonstrate the friction between different materials for comparison during the teaching process. The traditional method of disassembling and replacing the friction plate is time-consuming and laborious, while the conversion mechanism can quickly and conveniently switch friction plates with different friction coefficients for experiments, which is convenient for teachers to use; (3) the second guide rod of the guide assembly allows the friction block to slide along a straight line, and the second fixed frame can limit the maximum moving distance of the friction block to prevent the friction block from falling off the experimental table. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a first stereoscopic diagram of the overall structure of the present invention;

[0016] Figure 2 It is a second stereoscopic diagram of the overall structure of the present invention;

[0017] Figure 3 It is a first stereoscopic view of the friction assembly of the present invention;

[0018] Figure 4 is a second stereoscopic view of the friction assembly of the present invention;

[0019] Figure 5 It is a first stereoscopic diagram of the conversion mechanism of the present invention;

[0020] Figure 6 is a second stereoscopic view of the conversion mechanism of the present invention;

[0021] Figure 7 It is a three-dimensional diagram of the limiting component of the present invention;

[0022] Figure 8 It is a first stereoscopic view of the guide assembly of the present invention;

[0023] Fig. 9 is a second stereoscopic view of the guide assembly of the present invention;

[0024] Fig.10 It is a three-dimensional diagram of the tilting component of the present invention.

[0025] Description of reference numerals:

[0026] 1. Experimental table; 11. Through slot;

[0027] 21. friction plate; 22. friction block; 221. fixed block; 23. metering block; 231. slide bar; 232. second guide groove; 24. pull rope; 25. counterweight; 26. pulley; 27. first spring; 28. scale; 29. ​​pointer;

[0028] 3. conversion mechanism; 31. first fixing frame; 32. round rod; 33. first guide rod; 34. base plate; 341. first guide groove; 35. second spring; 36. bracket; 37. guide wheel; 38. rotating wheel;

[0029] 4. Limiting assembly; 41. Seat plate; 42. Fixing plate; 43. Limiting rod; 44. Handle;

[0030] 5. guide assembly; 51. second fixing frame; 52. second guide rod;

[0031] 6. Tilt assembly; 61. Base; 62. Support; 63. Support block; 64. Support rod;

[0032] 7. Stepper motor; 71. Output shaft. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings:

[0034] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the present invention provides a static and dynamic friction force experimental device, including an experimental platform 1, on which a friction assembly is arranged. The friction assembly includes a friction plate 21, on which a friction block 22 is placed, and the friction block 22 can slide on the friction plate 21. A metering block 23 is movably arranged on the friction block 22, a sliding rod 231 is fixedly arranged at the bottom of the metering block 23, a fixed block 221 is fixedly arranged at the top of the friction block 22 near one end, and the sliding rod 231 crosses the fixed block 221 and the two are slidably connected. A first spring 27 is sleeved on the outer side of the sliding rod 231, one end of the first spring 27 is fixedly connected to the metering block 23, and the other end of the first spring 27 is fixedly connected to the fixed block 221. A pull rope 24 is fixedly arranged at one end of the metering block 23, a pulley 26 is fixedly arranged at one end of the experimental platform 1, one end of the pull rope 24 is fixedly connected to the metering block 23, and the other end of the pull rope 24 passes through the pulley 26 and is fixedly arranged with a counterweight 25. The pulley 26 is used to reduce the friction between the pull rope 24 and the test bench 1, and improve the accuracy of the static and dynamic friction force experiment. The metering block 23 is fixedly provided with a scale 28 along the moving direction, and the scale 28 can be glued and fixed on the metering block 23. The friction block 22 is fixedly provided with a pointer 29 that matches the scale 28, and the pointer 29 can be glued and fixed on the friction block 22.

[0035] like Figure 2 , Figure 5 and Figure 6 As shown, on the basis of the above embodiment, further, a conversion mechanism 3 is provided on the test bench 1, and a through slot 11 is provided on the top of the test bench 1 along the length direction. The conversion mechanism 3 includes a first fixed frame 31, and the through slot 11 is fixedly installed with the first fixed frame 31 near both ends. A round rod 32 is rotatably provided between the two first fixed frames 31, and a bearing is installed between the round rod 32 and the first fixed frame 31. A first guide rod 33 is fixedly installed near both ends of the side of the round rod 32 by welding. The two first guide rods 33 form a group, and there are multiple groups of first guide rods 33 and they are distributed around the round rod 32. A second spring 35 is sleeved on the outer side of the first guide rod 33, and a base plate 34 is slidably provided on each group of the first guide rods 33, and first guide grooves 341 are provided at both ends of the base plate 34, and the first guide rod 33 is slidably matched with the first guide groove 341, and one end of the second spring 35 is fixedly connected to the round rod 32, and the other end of the second spring 35 is fixedly connected to the base plate 34. A friction plate 21 is fixedly arranged on the base plate 34, and the friction plate 21 can be fixedly connected to the base plate 34 by screws. The length and width of the friction plate 21 are smaller than the length and width of the through slot 11. The friction coefficients of the multiple friction plates 21 are different. Brackets 36 are fixedly installed near both ends of the through slot 11, and guide wheels 37 are rotatably installed on the two brackets 36. Rotating wheels 38 corresponding to the guide wheels 37 are rotatably installed at both ends of the base plate 34. A driving element is fixedly arranged at one end of the round rod 32 on the experimental table 1, and the driving element can drive the round rod 32 to rotate. The driving element can be a stepper motor 7, such as the output shaft 71 of the stepper motor 7 is fixedly connected to the round rod 32 through a coupling, and then the round rod 32 is driven to rotate by the stepper motor 7. The number of friction plates 21 is 3 to 6, and the number of friction plates 21 can be determined according to specific teaching needs. For example, in this embodiment, the number of friction plates 21 is 4, and the 4 friction plates 21 are arranged at an angle of 90 degrees.

[0036] like Figure 1 , Figure 2 and Figure 7As shown, on the basis of the above embodiment, further, a limit assembly 4 is provided on the test bench 1, and the limit assembly 4 includes a seat plate 41. The seat plate 41 is fixedly installed at the positions of the test bench 1 near both sides of the through slot 11, and fixed plates 42 are fixedly provided on both sides of the base plate 34. A limit rod 43 is slidably provided on the seat plate 41, and a handle 44 is fixedly provided on the top of the limit rod 43. A limit groove is provided at the position corresponding to the fixed plate 42 and the limit rod 43, and the limit rod 43 can extend into the limit groove. The limit rod 43 cooperates with the limit groove to fix the friction plate 21 in the working state that extends through the through slot 11 to the upper part of the test bench 1, to prevent it from shaking left and right, affecting the static and dynamic friction force experiments, and improving the stability of the friction plate 21 in the working state. The seat plate 41 also has a shielding function to prevent debris from entering the interior of the test bench 1 from the through slot 11.

[0037] like Figure 2 , Figure 8 and Fig. 9 As shown, on the basis of the above embodiment, further, a guide assembly 5 is fixedly arranged on the test bench 1, and second fixing frames 51 are fixedly installed near both ends of the top of the test bench 1 by screws. A second guide rod 52 is fixedly arranged between the two second fixing frames 51, and the second guide rod 52 is distributed along the sliding direction of the friction block 22. A second guide groove 232 is arranged on the metering block 23, and the second guide rod 52 crosses the second guide groove 232 and the two are slidably connected. The number of the second guide rods 52 is one or two. For example, in this embodiment, the number of the second guide rods 52 is two.

[0038] like Figure 1 and Fig.10 As shown, on the basis of the above embodiment, further, a tilting assembly is provided at the bottom of the experimental table 1, and the tilting assembly includes a base 61, and a support 62 is fixedly provided at the top position of the base 61 near one end of the pulley 26. The support 62 is rotatably connected to the end of the bottom of the experimental table 1, and the support 62 and the experimental table 1 can be rotatably connected through a pin. A support block 63 is fixedly provided at the top position of the base 61 away from one end of the pulley 26, and the bottom of the experimental table 1 is located at the top of the support block 63. When the experimental table 1 is placed on the top of the support block 63, the working surface of the experimental table 1 is parallel to the horizontal plane. Support rods 64 are rotatably provided at both sides of the experimental table 1 near the support block 63. The rotation of the support rods 64 and the support blocks 63 can make the experimental table 1 tilted with the horizontal plane, that is, the working surface of the experimental table 1 has an angle with the horizontal plane. The support block 63 is approximately L-shaped, which is convenient for cooperation with the support rod 64. When students are watching and learning, the experimental table 1 only needs to be placed flat. When it is necessary to demonstrate to students, the experimental table 1 can be tilted at this time. When the experimental table 1 is tilted, the precise value of the friction force needs to take into account the influence of gravity on the tilt. If only the change in the magnitude of the friction force needs to be demonstrated, this does not need to be considered.

[0039] like Figures 1 to 10As shown, when working, (1) first, place the friction block 22 on the friction plate 21 located in the through slot 11 of the experimental table 1. Then, hang a counterweight block 25 of known weight at the end of the pull rope 24. At this time, the metering block 23 is subjected to tension. Due to the static friction, the friction block 22 will not move. The metering block 23 will move a certain distance on the friction block 22, so that the first spring 27 is compressed. The static friction between the friction block 22 and the friction plate 21 can be calculated according to the movement distance of the metering block 23 displayed by the pointer 29 and the scale 28 and the stiffness coefficient of the first spring 27. Then, repeat the above process by replacing the counterweight block 25 of different weights. Students can intuitively know the change in the magnitude of the static friction through the movement of the metering block 23. The dynamic friction force remains unchanged under theoretical conditions. When the weight of the counterweight block 25 can overcome the static friction force to move the friction block 22, the size of the dynamic friction force is determined by the gravity of the counterweight block 25 and the tension applied to the friction block 22 by the pull rope 24. At this time, the displacement of the metering block 23 can intuitively reflect the size of the dynamic friction force. A value close to the dynamic friction force can be obtained by replacing counterweight blocks 25 of different weights. (2) When it is necessary to replace the friction plate 21 with a different friction coefficient, the stepper motor 7 is controlled to work. The stepper motor 7 drives the round rod 32 to rotate a certain angle through the output shaft 71, and the round rod 32 drives the friction plate 21 to rotate. When the friction plate 21 rotates to a position corresponding to the through slot 11 of the experimental table 1, the guide wheel 37 on the bracket 36 contacts the rotating wheel 38 at the end of the base plate 34 and the guide wheel 37 moves upward against the rotating wheel 38. The upward movement of the rotating wheel 38 drives the friction plate 21 on the base plate 34 to move upward, and the second spring 35 is stretched, so that the friction plate 21 extends out of the through slot 11; then, the limit rod 43 is pressed downward by hand through the handle 44, so that the limit rod 43 extends into the limit slot of the fixing plate 42 on the base plate 34 to fix the friction plate 21; then, the friction block 22 is placed on the friction plate 21, and the static and dynamic friction force experiments can be carried out. (3) When it is necessary to continue to replace the friction plate 21 with a different friction coefficient, the stepper motor 7 drives the round rod 32 to rotate a certain angle, and the round rod 32 drives the friction plate 21 in the through groove 11 to rotate, so that the guide wheel 37 on the bracket 36 is separated from the rotating wheel 38 at the end of the base plate 34. At this time, the second spring 35 contracts and drives the friction plate 21 in the through groove 11 to move downward and out of the through groove 11. When the other friction plate 21 rotates to the position corresponding to the through groove 11 of the experimental table 1, the process in step (2) is repeated. In this way, the friction plates 21 with different friction coefficients can be quickly switched, which is convenient for teachers to teach.

[0040] The above are only preferred embodiments of the present invention, and the scope of the present invention is not limited thereby. It should be understood by those skilled in the art that various changes, modifications, substitutions and deformations may be made to these embodiments without departing from the principles and purposes of the present invention, and all of them should be included in the protection scope of the present invention. The protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. A static and dynamic friction force experimental device, comprising a test bench, characterized in that: The experimental bench is provided with a friction assembly, which includes a friction plate, a friction block is placed on the friction plate, a metering block is movably provided on the friction block, a sliding rod is fixedly provided at the bottom of the metering block, a first spring is sleeved on the outer side of the sliding rod, a fixed block is fixedly provided at the top of the friction block near one end, the sliding rod crosses the fixed block and the two are slidably connected, a pull rope is fixedly provided at one end of the metering block, a pulley is fixedly provided at one end of the experimental bench, one end of the pull rope is fixedly connected to the metering block, the other end of the pull rope passes around the pulley and is fixedly provided with a counterweight block, a scale is fixedly provided on the metering block along the moving direction, and a pointer matching the scale is fixedly provided on the friction block.

2. A static and dynamic friction force experimental device according to claim 1, characterized in that: The experimental bench is provided with a conversion mechanism, a through slot is provided on the top of the experimental bench along the length direction, and the conversion mechanism includes a first fixed frame, the through slot is fixedly installed with a first fixed frame near both ends, a round rod is rotatably arranged between the two first fixed frames, a first guide rod is fixedly arranged on the side of the round rod near both ends, the two first guide rods form a group, there are multiple groups of first guide rods and are distributed around the round rod, a second spring is sleeved on the outer side of the first guide rod, a base plate is slidably arranged on each group of the first guide rods, a friction plate is fixedly arranged on the base plate, the length and width of the friction plate are smaller than the length and width of the through slot, and the friction coefficients of the multiple friction plates are all different, brackets are fixedly installed near both ends of the through slot, guide wheels are rotatably installed on the two brackets, and rotating wheels corresponding to the guide wheels are rotatably installed at both ends of the base plate, and a driving element is fixedly arranged on the experimental bench at one end of the round rod, and the driving element can drive the round rod to rotate.

3. A static and dynamic friction force experimental device according to claim 2, characterized in that: The number of the friction plates is 3 to 6.

4. The static and dynamic friction force experimental device according to claim 2, characterized in that: The driving element is a stepping motor.

5. The static and dynamic friction force experimental device according to claim 2, characterized in that: A limit assembly is provided on the laboratory bench, and the limit assembly includes a seat plate. The laboratory bench is fixedly provided with seat plates at positions close to both sides of the through slot, and fixed plates are fixedly provided on both sides of the base plate. A limit rod is slidably provided on the seat plate, and a handle is fixedly provided on the top of the limit rod. A limit groove is provided at a position corresponding to the fixed plate and the limit rod, and the limit rod can be extended into the limit groove.

6. The static and dynamic friction force experimental device according to claim 1, characterized in that: A guide assembly is fixedly arranged on the laboratory bench, a second fixed frame is fixedly arranged near both ends of the top of the laboratory bench, a second guide rod is fixedly arranged between the two second fixed frames, the second guide rod is distributed along the sliding direction of the friction block, a second guide groove is arranged on the metering block, the second guide rod crosses the second guide groove and the two are slidably connected.

7. The static and dynamic friction force experimental device according to claim 6, characterized in that: The number of the second guide rods is one or two.

8. The static and dynamic friction force experimental device according to claim 1, characterized in that: A tilting assembly is provided at the bottom of the laboratory bench, and the tilting assembly includes a base, a support is fixedly provided at the top position of the base near one end of the pulley, the support is rotatably connected to the end of the bottom of the laboratory bench, a support block is fixedly provided at the top position of the base away from the pulley end, the bottom of the laboratory bench is located on the top of the support block, support rods are rotatably provided on both sides of the laboratory bench near the support blocks, and the laboratory bench can be inclined with respect to the horizontal plane by rotating the support rods to cooperate with the support blocks.

9. The static and dynamic friction force experimental device according to claim 8, characterized in that: The supporting block is approximately L-shaped.

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