CN103745647B - The teaching aid of non-circular gear drive ratio can be reflected - Google Patents

Abstract

<b>The present invention relates to a teaching aid that can reflect the transmission ratio of a non-circular gear. The teaching aid includes a box or a bracket, and a drive shaft with a driving non-circular gear driven by a motor is respectively installed on the box or bracket. and a driven shaft with a driven non-circular gear meshed with the driving non-circular gear; the teaching aid also includes a dotting timer and a round wheel installed at the end of the driven shaft, and the round wheel is provided with a dotting timer on the paper tape attached to the rope. The driven non-circular gear in the teaching aid drives the driven shaft to rotate at variable speed while rotating at variable speed, so that the paper tape passing through the dotting timer can be marked with interval points with different intervals according to the variable speed rotation law of the driven shaft, which can be responded The transmission ratio of the non-circular gear. </b>

Description

A teaching tool that reflects the transmission ratio of non-circular gears

technical field

The invention relates to a teaching aid capable of reflecting the transmission ratio of non-circular gears.

Background technique

The transmission ratio is the ratio of the angular velocity of the two rotating components in the mechanism. To understand the law of the transmission ratio, in the field of teaching, if the two rotating components use two circular gears that mesh with each other, because the angles of the circular gears are the same, the other The method of calculating the ratio is relatively simple; if two non-circular gears such as elliptical gears or oval gears are used, the method of calculating the ratio is relatively complicated, and non-circular gears are part of the gear transmission chapter of the course "Mechanical Principles". knowledge points in . Because the pitch curve of non-circular gears (equivalent to the indexing circle of circular gears) is non-circular, it is difficult for students to understand, master and skillfully use the normal meshing transmission and transmission ratio changes of non-circular gears when learning non-circular gears , and how the transmission ratio changes, etc. Therefore, it is not easy for students to learn solidly and thoroughly in the process of learning non-circular gear transmission ratio.

Chinese Patent No. 102705448A discloses a technical solution for calculating the motion of non-circular gears with variable transmission ratio, which is titled "Non-Circular Gear Pair with Fourier Function Pitch Curve". The non-circular gear pair uses the active non-circular gear and the driven non-circular gear to mesh to form a first-order or high-order non-circular gear pair, so that the pitch curves of the active non-circular gear and the driven non-circular gear are Fourier The function pitch curve, and two formulas are used to calculate the Fourier function pitch curve of the active non-circular gear and the driven non-circular gear. Although the transmission ratio can be calculated by referring to this kind of non-circular gear pair, it is difficult for students who are new to non-circular gear transmission ratio to understand, master, and skillfully use the normal meshing transmission of non-circular gears and the change of transmission ratio. Therefore, It is not easy for students to learn solidly and thoroughly by referring to this kind of non-circular gear pair.

Although the teaching aids can enhance the intuition of teaching and increase the density of knowledge, it can break through the difficulties and improve the interest in learning, but since the non-circular gears are in the process of rotation, it is not clear from the appearance how the transmission ratio of the non-circular gears is calculated Therefore, it is generally believed that the transmission ratio of non-circular gears can only be taught through language, and if teaching aids are used, it will cause a waste of educational resources.

Contents of the invention

The object of the present invention is to provide a teaching aid that can reflect the transmission ratio of non-circular gears to solve the problem of learning difficulties by displaying the rotation rules of non-circular gears.

The teaching aid that can reflect the transmission ratio of the non-circular gear proposed by the present invention includes a box body or a bracket, and a driving shaft with a driving non-circular gear driven by a motor and a drive shaft with a driving non-circular gear driven by a motor are respectively installed on the box body or a bracket. The driven shaft of the driven non-circular gear meshed with the circular gear; the teaching aid also includes a dotting timer and a round wheel installed at the end of the driven shaft, and the round wheel is provided with a paper tape connected to the dotting timer the rope. Both the driving non-circular gear and the driven non-circular gear are composed of oval gears or oval gears.

The dotting timer is printed with linear interval points on the paper tape, and the rotation speed change curve of the driven non-circular gear is drawn on the exhibition board by using the interval of the interval points.

The teaching aids proposed by the present invention that can reflect the transmission ratio of non-circular gears are mainly composed of non-circular gears, motors, and dotting timers. Therefore, this kind of teaching aids has a simple structure and low manufacturing cost; The meshing transmission makes the driven non-circular gear drive the driven shaft to rotate at a variable speed while the driven non-circular gear rotates at a variable speed, so that the paper tape passing through the dotting timer can be punched with different interval points according to the variable speed rotation of the driven shaft. Therefore, By plotting the distance values of each point in the Cartesian coordinate system of the display board, we can know the rule of the interval point changing with time, so as to reflect the transmission ratio of the non-circular gear.

Description of drawings:

Accompanying drawing 1 is the appearance structural representation of an embodiment of the teaching aid that can reflect non-circular gear transmission ratio that the present invention proposes;

Accompanying drawing 2 Fig. 1 is hit the schematic diagram of the first embodiment of interval point on the dotting timer paper tape;

Accompanying drawing 3 is the dot-pitch change diagram drawn on the display board with the interval points on the paper tape in Fig. 2;

Accompanying drawing 4 Fig. 1 is hit the schematic diagram of the second embodiment of interval point on the dotting timer paper tape;

Accompanying drawing 5 is the dot-pitch change diagram drawn on the display board with the punched out interval points on the paper tape in Fig. 4 .

detailed description:

Referring to FIG. 1 , this figure shows a schematic diagram of the appearance structure of an embodiment of the teaching aid proposed by the present invention that can reflect the transmission ratio of non-circular gears. The teaching aid includes a box body 1, a driving shaft 2 and a driven shaft 3 are installed on the upper part of the box body 1, a driving non-circular gear 4 is installed on the driving shaft 2, and a driven non-circular gear is installed on the driven shaft 3 5, and the driving non-circular gear 4 and the driven non-circular gear 5 are meshed. One end of the driving shaft 2 is connected with the output shaft of the motor 6, and when the motor 6 rotates, the driving shaft 2 can be driven to rotate. This teaching aid also comprises dotting timer 7, and dotting timer 7 can be placed on the casing 1, also can be placed on another position, provides dotting timer 7 and is placed on leaving casing 1 position in the present embodiment. The end of driven shaft 3 is equipped with circular wheel 8, and this circular wheel 8 is provided with rope 9, and the other end of rope 9 is connected with the paper tape 10 end of striking timer 7. When the driving shaft 2 rotates, the driving non-circular gear 4 drives the driven non-circular gear 5 to rotate, and the rotation of the driven non-circular gear 5 can drive the circular wheel 8 to rotate. Although the driving shaft 2 is driven by the motor 6 to rotate at a constant speed, the driven non-circular gear 5 rotates at a variable speed, so that the circular wheel 8 does not rotate at a constant speed, and the dotting timer 7 makes dots on the paper tape 10 according to the prescribed uniform time. Therefore, the interval points on the paper tape 10 can be determined according to the rotational speed of the round wheel 8 . The above-mentioned driving non-circular gear 4 and driven non-circular gear 5 can be oval gears or oval gears.

Referring to Fig. 2 and Fig. 3, Fig. 2 among them provides the schematic diagram of the first embodiment of the dot timer 7 (see Fig. 1) being punched out on the paper tape 10 at intervals, and Fig. The data of the interval points are plotted on the point distance change graph on the display board. The interval points on the paper tape 10 given in this embodiment are drawn out by using oval gears, and the parameters of the oval gears used are shown in Table 1.

Table 1

Modulus m Number of teeth z Eccentricity e semi-major axis a semi-minor axis b focal length c 2.5 27 0.3728 35 32.4769 13.0480

Referring to Fig. 4 and Fig. 5, Fig. 4 among them provides the schematic diagram of the second embodiment of the dot timer 7 (see Fig. 1) being punched out on the paper tape 10 at intervals, and Fig. 5 uses The data of the interval points are plotted on the point distance change graph on the display board. The interval points on the paper tape 10 given in this embodiment are drawn out by using an oval gear, and the parameters of the oval gear used are shown in Table 2.

Table 2

Modulus m Number of teeth z Eccentricity e semi-major axis a semi-minor axis b focal length c 2.4 30 0.2442 35 33.9404 8.547

Claims (2)

1. The teaching aid that can reflect the non-circular gear transmission ratio is characterized in that: the teaching aid includes a box or a bracket, and a driving shaft with an active non-circular gear driven by a motor and a belt drive are respectively installed on the box or bracket. There is a driven shaft with a driven non-circular gear meshed with the driving non-circular gear; the teaching aid also includes a dotting timer and a round wheel installed at the end of the driven shaft. The rope connected by the paper tape, the driving non-circular gear and the driven non-circular gear are both composed of oval gears or oval gears. 2. The teaching aid according to claim 1, characterized in that: the dotting timer is marked with linear interval points on the paper tape, and the speed change curve of the driven non-circular gear is drawn on the display board using the interval of the interval points .