Design and Simulation Analysis of the Transmission Scheme for the Mine Double Speed Winch

Mine winches are widely used in coal mine production, but the traditional operation mode still exists and the transmission efficiency is low. In order to improve the transmission efficiency of mine winches, this paper designs a transmission scheme for the mine double speed winch. Briefly, the transmission scheme is introduced and the degree of freedom of the winch mechanism is discussed to guarantee the rationality of the movement. The kinematics mathematical model of the winch is established. Theoretical derivation and simulation analysis show that the winch mechanism has superior performance at a high or low speed. The combination of fast speed and slow speed can effectively improve the transmission efficiency of the mine winch, which provide a design thought.


Introduction
As a commonly used auxiliary transportation equipment, winches are widely used in the mine, ocean, architecture and other engineering fields [1][2][3][4][5]. China is one of the largest coal producers in the world and coal plays an important role in the energy structure of China [6]. In the field of coal, mine auxiliary transportation, the winch is responsible for important tasks such as the material transportation, personnel dispatching, equipment traction, etc. Mine winches have become an indispensable transportation equipment in the coal mine production [7]. Therefore, how to design an efficient winch transmission scheme and improve the transportation efficiency has become a hot topic.
Although the winch has been widely used in the coal mine production, the traditional operation mode still exists. Figure 1(a) shows the JYB type mine winch. To make the winch operation and stop, the operator handles the operation handle to control the brake and the clutch. This kind of operation is timeconsuming and laborious, and there is a big personal safety hazard [8]. It is the JSDB type double speed winch in Figure 1(b). It realizes the meshing of different gears by shifting the sliding gear to receive the fast speed and slow speed of the winch. However, this type of transmission scheme has a risk of being out of gear, and the gear meshing accuracy is precise [9]. With the development of technology, the winch technology is also continuously improved. As shown in Figure 1(c) and Figure 1(d), Rv type hydraulic winch and SQ type variable speed winch are used in the engineering field, which has improved the winch transmission efficiency. However, their price limits the application [10]. Throughout the 2 development process of the winch, the winch is developing towards the miniaturization, standardization and intelligence [11][12][13][14].
In order to improve the transmission efficiency of the winch considering the economics, this paper designs a transmission scheme for the mine double speed winch. By analyzing the degree of freedom of the mechanism, it is proved that the transmission scheme has a clear movement. In addition, kinematics mathematical model of the winch is established, and the theoretical parameters of the roller speed are derived during the fast running and slow running of the winch. Theoretical and simulation analysis shows that the transmission scheme is reasonable in design and superior in performance.  Figure 2. The transmission principle is as follows. When the speed regulating brake A opens and the speed regulating B closes, the motor drives the-first stage sun gear. Because the second-stage planet carrier is fixed, the winch runs fast through two stages planetary gear transmission. In addition, the speed regulating brake A closes and the speed regulating brake B opens, and then the motor drives the first-stage sun gear. The third-stage ring gear is fixed to the rack so the winch runs slowly through three stages planetary gear transmission. The transmission scheme has disadvantages. Two stages planetary gear trains are placed in the roller and the winch has a small volume, which can effectively utilize the space. In order to ensure the rationality of the design, it is necessary to analyze the degree of freedom of the winch mechanism. Figure 3(a) is the schematic diagram of the winch mechanism at a high speed and Figure 3(b) is the schematic diagram of the winch mechanism at a low speed.
The formula for calculating the degree of the freedom of the winch mechanism is as follows: Where n is the number of active components, L P is the number of low pairs, L P is the number of high pairs. The winch is at a high speed as shown in figure 3(a). The winch has six components. Among them, there are five active components with five low pairs and six high pairs. According to the formula 1, the degree of freedom of the winch mechanism is one.
The winch is at a low speed as shown in figure 3(b). The winch has eight components. Among them, there are seven active components with seven low pairs and four high pairs. According to the formula 1, the degree of freedom of the winch mechanism is one.
By analyzing the degree of freedom of the winch mechanism at a high or low speed, the degree of freedom of the mechanism is equal to the number of its original parts and it is equal to 1, which proves that the winch mechanism has certain motion conditions. Therefore, the designed winch transmission scheme is reasonable. Table 1 shows the main parameters of gears. The following is the derivation of the kinematics mathematical model of winch.

Establishment of the kinematics mathematical model of the winch
Where 6 n is the rational speed of the second-stage ring gear.
Combined the formula 3, the formula 4 can be written as

Rotational speed of the roller at a low speed
When the speed regulating brake A closes and the speed regulating brake B opens, the winch operates through three stages planetary transmission. Thus, the winch works at a low speed.
The transmission ration of the first-stage planetary gear train can be obtained by  n is the rational speed of the second-stage planet carrier, 7 n is the rational speed of the third-stage sun gear, 8 n is the rational speed of the third-stage planet carrier.
For the third-stage planetary gear train, the transmission ratio is obtained by  Fig. 4 The three-dimensional model of the double speed winch. 1-the first-stage sun gear; 2-the firststage planetary gear; 3-the first-stage planet carrier; 4-the second-stage sun gear; 5-the second-stage planetary gear; 6-the second-stage planet carrier; 7-the third-stage sun gear; 8-the third-stage planetary gear; 9-the third-stage ring gear; 10-the third-stage planet carrier; 11-the winch roller; 12-the secondstage ring gear; 13-the first-stage ring gear.
From Figure 5, the angular velocity of the roller at a high speed is about -179.65 degrees/sec so the simulated rational speed of the winch roller is -29.94 r/min. Compared with the theoretical value, the error is within 0.03%. The simulation analysis verifies that the winch transmission scheme is feasible at a high speed. The winch is simulated at a low speed. The third-stage ring gear is fixed to the ground and the firststage sun gear is applied with a rational speed of 740 r/min. The simulation time is set to 5 seconds. As a result, the angular velocity of the roller at a low speed is obtained in Figure 7. and a partial enlarged view of the angular velocity of the roller is shown in Figure 8.
As can be seen in the figure 7, the angular velocity of the roller at a low speed is about 44.12 degrees/sec. Thus, the simulated rational speed of the winch roller is 7.3533 r/min. The maximum error is less than 0.005% in comparison with the theoretical value of the roller. Therefore, the winch transmission scheme is feasible at a high speed. Comparing Fig. 6 with Fig. 8, it is found that the fluctuation of the slow angular velocity is relatively small and the fluctuation at a high speed is relatively large. This simulation result is also in line with the actual operating work conditions of the winch.

Summary
A transmission scheme for mine double speed winch is designed in the paper, which combines the fast speed and slow speed to improve the transmission efficiency. The kinematics mathematical model of the winch is established to derive that the rational speed of the winch roller is -29.95 r/min at a high speed and it is 7.3592 r/min at a low speed. The rational speed of the winch roller at a high speed is -29.94 r/min simulated by the ADAMS software and its simulation rational speed at a low speed is 7.3533 r/min. The error is minimal comparing the simulated values with the theoretical values. Theoretical derivation and simulation analysis show that this transmission scheme is reasonable in design. The transmission scheme is efficient.