CN206301514U - Table tennis rotating circulation demonstration instrument - Google Patents

Abstract

The utility model is related to the table tennis rotary circulation demonstrator used during a kind of a kind of sports apparatus, more particularly to table tennis technology theory teaching.The main frame of the demonstrator is made up of air flow pattern 1, spheroid 2, big garden seat 3, square base 4, direction board 5, column 6, oblique frame 7, axostylus axostyle 8, indicated angle 9, flow line 10, montant 11, small garden seat 12 and base plate 13；The spheroid of the demonstrator can be around axostylus axostyle according to clockwise or counterclockwise, can demonstrating the upper and lower rotary motion phenomenon of table tennis.Air flow pattern can demonstrate table tennis ambient gas circulation phenomenon, and flow line can demonstrate the phenomenon met obstructions in table tennis.Using the instrument aided education, student can be made intuitively to see the spheroid ambient gas situation of change of upper and lower rotation.So as to, deepen understanding of the student to table tennis rotary and the characteristics of motion, learning interest is improved, fast understanding and table tennis technology knowwhy can be grasped in a short time.

Description

Table tennis rotating circulation demonstration instrument

technical field

The utility model relates to a sports apparatus, in particular to a table tennis rotation and circulation demonstrator used in the teaching of table tennis technical theory.

Background technique

When the table tennis ball rotates in the air, it drives the air around the ball to rotate with the rotation of the ball. This is because the fluid has the property of viscosity. Due to the effect of viscosity, a regularly rotating airflow is formed around the sphere, which is called circulation. For example: when the rotation property of the ball is topspin, a circulation following its rotation is formed around the ball. The upper part of the sphere has a slow flow velocity, and the lower part of the sphere has a faster flow velocity. According to the Bernoulli equation in fluid mechanics, it can be known that the faster the flow rate, the lower the pressure; the slower the flow rate, the greater the pressure. Therefore, the upper part of the topspin ball has a strong pressure, while the lower part has a lower pressure, and there is a pressure difference between the upper part and the lower part, which makes the ball "submerge" in the trajectory of the arc. When the nature of the ball's rotation is downspin, its situation is just opposite to that of topspin; The law is usually explained through diagrams using the above-mentioned principles of fluid mechanics. However, in actual teaching, it is difficult for students to understand the changing law of the arc of the table tennis ball when it is flying in the air because there are no relevant and suitable teaching aids to cooperate with the demonstration explanation.

In order to solve the above problems, the utility model proposes a table tennis rotation and circulation demonstration instrument, which is specially used in the teaching of table tennis technology theory, and demonstrates the phenomenon of gas changes around the sphere when the table tennis ball rotates up and down.

The technical solution adopted by the utility model is: a table tennis rotating circulation demonstration instrument, the main frame of the demonstration instrument is composed of an airflow circle, a sphere, a large round seat, a square base, an indicator board, a column, an inclined frame, a shaft rod, and an indicating angle. , airflow line, vertical bar, small round seat and bottom plate; among them, the lower end of the small round seat is connected with the upper end of the bottom plate by screws, the upper end of the small round seat is fixedly connected with the lower end of the vertical bar, and the side parts of the vertical bar are respectively connected with one end of the four air flow lines. Fixed connection, the other ends of the four airflow lines are fixedly connected to one side of the airflow circle, the other side of the airflow circle is fixedly connected to the arrow of the sign, the lower end of the signboard is fixedly connected to the upper end of the square base, and the lower end of the square base is connected to the bottom plate The upper end is connected by screws; the lower end of the large round seat is connected with the upper end of the base plate by screws; The upper part of the shaft is fixedly connected; the outer surface of the shaft rod is connected with the sphere, and the upper end of the air flow ring is provided with a screw hole, and the screw hole is connected by a screw to indicate the angle.

The indicated angle consists of an upper angle and a lower angle.

The main structure of the sphere is composed of a bearing, a shaft sleeve, a nut and a ball sleeve.

The table tennis rotating circulation demonstration instrument has a simple structure and is easy to use. The sphere of the demonstrator can rotate clockwise or counterclockwise around the shaft, and can demonstrate the phenomenon of the up and down rotation of the table tennis ball. The airflow circle can demonstrate the phenomenon of air circulation around the table tennis ball, and the airflow line can demonstrate the phenomenon of air resistance encountered in the table tennis movement. Using the demonstrator to assist teaching can enable students to intuitively see the gas changes around the sphere rotating up and down. Thus, students can deepen their understanding of table tennis rotation and movement laws, and improve their interest in learning, so that they can quickly understand and master the theoretical knowledge of table tennis technology in a short period of time. The application of the demonstrator can make the teaching method more standardized and scientific, and has practical significance for improving the teaching effect of table tennis technical theory.

Description of drawings

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is described in further detail.

Fig. 1 is the three-dimensional sketch map of the utility model;

Fig. 2 is an A-A sectional view of the spherical part.

detailed description

The table tennis rotation and circulation demonstrator proposed by the utility model adopts the following structure, as shown in Figures 1 and 2, the lower end of the small round seat 12 of the demonstrator is connected with the upper end of the base plate 13 by screws, and the upper end of the small round seat is connected with the lower end of the vertical bar 11. Fixed connection, the side of the vertical bar is fixedly connected to one end of the four airflow lines 10, the other ends of the four airflow lines are respectively fixedly connected to one side of the airflow circle 1, and the other side of the airflow circle is connected to the arrow on the sign 5 Fixed connection, the lower end of the sign is fixedly connected with the upper end of the square base 4, the lower end of the square base is connected with the upper end of the base plate by screws; the lower end of the large round seat 3 is connected with the upper end of the base plate by screws, the upper end of the large round seat is fixedly connected with the lower end of the column 6, and the upper end of the column is connected with the shaft 8, one end is fixedly connected, the lower end of the shaft rod is fixedly connected with one end of the inclined frame 7, and the other end of the inclined frame 7 is fixedly connected with the side of the column; The angle 9 is indicated by the screw connection.

The above-mentioned indicating angle consists of an upper angle and a lower angle, which can be turned along the screw.

The main structure of the above-mentioned sphere consists of a rolling bearing 17 that can be sleeved on the outside of the shaft, and a corresponding axle sleeve 15 is arranged outside the bearing, a nut 14 fastens the inner ring end face of the bearing, and a ball sleeve 16 is arranged outside the axle sleeve.

When in use, put the demonstrator on a table tennis table or podium, use the airflow circle to demonstrate the circulation phenomenon, the indicator angle indicates the circulation direction, the airflow line demonstrates the air resistance, and the indicator board indicates the movement direction of the ball; when demonstrating the law of topspin ball movement , turn the indicating horn so that it points counterclockwise, and turn the ball so that it rotates counterclockwise along the shaft. Then, combined with the demonstration, the nature of the rotation of the sphere at this time is an upspin, and a circulation is formed around the sphere to follow its rotation. The upper part of the sphere forms convection current due to the air resistance direction and the circulation direction, so the flow velocity is slow, and the lower part of the sphere forms a downstream flow due to the air resistance direction and the circulation direction, so the flow velocity is fast. According to the Bernoulli equation in fluid mechanics, it can be known that the faster the flow rate, the lower the pressure; the slower the flow rate, the greater the pressure. Therefore, the upper part of the topspin ball has a strong pressure, while the lower part has a lower pressure, and there is a pressure difference between the upper part and the lower part, which makes the ball "submerge" in the trajectory of the arc.

When demonstrating the movement law of the backspin ball, turn the indicating angle to make it point clockwise, and turn the ball to make it rotate clockwise along the shaft. Then, combined with the demonstration, the nature of the rotation of the sphere at this time is downspin, forming a circulation around the sphere that follows its rotation. At this time, because the upper part of the sphere encounters the direction of air resistance and the direction of circulation forms a downstream flow, the flow velocity is fast, and the lower part of the sphere forms a convection current due to the direction of encountering air resistance and the direction of circulation, so the flow velocity is slow. According to the Bernoulli equation in fluid mechanics, it can be known that the faster the flow rate, the lower the pressure; the slower the flow rate, the greater the pressure. Therefore, the pressure on the upper part of the backspin ball is small, while the pressure on the lower part is strong, and there is a pressure difference between the upper and lower parts, so that the ball is in a "upward warped" state in the arc trajectory of the ball.

Claims (1)

1. A table tennis rotating circulation demonstration instrument is characterized in that: the main frame of this demonstration instrument consists of airflow circle (1), spheroid (2), large round seat (3), square base (4), indicator board (5) , column (6), inclined frame (7), shaft rod (8), indicating angle (9), airflow line (10), vertical rod (11), small round seat (12) and base plate (13); wherein , the lower end of the small round seat is connected with the upper end of the bottom plate by screws, the upper end of the small round seat is fixedly connected with the lower end of the vertical bar, the side parts of the vertical bar are respectively fixedly connected with one end of the four airflow lines, and the other ends of the four airflow lines are respectively connected with the airflow circle. One side is fixedly connected, the other side of the airflow circle is fixedly connected with the arrow of the sign, the lower end of the sign is fixedly connected with the upper end of the square base, the lower end of the square base is connected with the upper end of the base plate by screws; the lower end of the large round seat is connected with the upper end of the base plate by screws, The upper end of the large round seat is fixedly connected with the lower end of the column, the upper end of the column is fixedly connected with one end of the shaft, the lower end of the shaft is fixedly connected with one end of the inclined frame, and the other end of the inclined frame is fixedly connected with the side of the column; the outside of the shaft is connected with the sphere, and the The upper end of the airflow ring is provided with a screw hole, and the screw hole is connected with an indicating angle by a screw.