Academic Journal of Science and Technology 
ISSN: 2771-3032 | Vol. 10, No. 2, 2024 

 

125 

Structural Analysis of High-power Cycloidal Pinwheel 
Drive for Drilling Rig Winch 
Tengteng Wei 

College of Mechanical Engineering, Xi’an Shiyou University, Xi’an, Shanxi 710065, China 

 
Abstract: Because the maximum power that can be transmitted by the ordinary cycloidal pinwheel reducer cannot meet the 
transmission applied to the drilling rig winch, the transmission part is improved, and the high-power cycloidal pinwheel 
transmission mechanism is designed. The three-dimensional model of the cycloidal pinwheel transmission mechanism was drawn 
by SOLIDWORKS software, the design of the two-piece cycloidal wheel in the ordinary cycloidal pinwheel reducer was changed 
to four cycloidal wheels, the needle tooth shell was partially reinforced, and finally the strength finite element analysis of the 
needle tooth shell and cycloidal wheel structure of the cycloidal pinwheel transmission mechanism was carried out by 
ANSYSWorkbench finite element software. Through the improvement, compared with the ordinary double-piece cycloidal 
pinwheel structure, the stress and deformation are reduced by 68.7% and 57%, and this new structure is more suitable for high-
power cycloidal transmission. 

Keywords: Drilling rig winch; High-power cycloidal transmission; four cycloidal wheels; Finite element analysis. 
 

1. Design Background 
In order to meet the needs of the on-board drilling winch of 

shallow wells, medium and shallow wells and small boreholes, 
it is necessary to reduce the weight and volume of the drilling 
rig winch as much as possible under the premise of 
maintaining the original normal function of the drilling rig 
winch. 

Consult the relevant information and find that the cycloidal 
pinwheel transmission mechanism as a kind of transmission 
machinery that adopts the KHV less tooth difference 
transmission principle and cycloidal needle tooth meshing, 
due to its many advantages such as large number of 
simultaneous meshing teeth, compact structure and small size, 
high transmission efficiency, etc., has been widely valued at 
home and abroad, and is widely used in the driving and 
deceleration transmission mechanism in the fields of textile 
printing and dyeing, light industry and food, metallurgy and 
mining, petrochemical industry, lifting and transportation and 
construction machinery. 

At present, the transmission power of the domestic cycloid 
pinwheel planetary drive is less than 132kW, and the 
transmission power of the ordinary horizontal direct-
connected one-stage cycloidal pinwheel planetary reducer is 
lower, which is completely less than the output power 
required for the transmission of the drilling rig winch. 

2. Transmission Scheme Design and 3D 
Modeling  

According to the oil drilling rig winch standard SY/T5609-
1999, it can be known that the maximum fast rope tension of 
the 10-level drilling rig winch needs to be 115000N, and the 
diameter of the drum is set to 0.4m, therefore, the torque of 
the output shaft of the drilling rig winch drum needs to be at 
least T(N•m)=23000, and the transmission ratio of the high-
power cycloidal pin wheel reducer for the drilling rig winch 
is designed and calculated. According to the formula of 
formula 2-1 for calculating the output torque of the general 
reducer, the data T=23000N•m, P=120kw, n_H=1480r/min, 

η=0.9, and i =33 are obtained 
 

          (2-1) 

 
Referring to the introduction of the structure of the 

planetary transmission of large cycloidal pinwheels in the 
new edition of the mechanical design manual by Academician 
Wen Bangchun, an academician of the Chinese Academy of 
Sciences, it is proposed that under the same radial size, as long 
as the axial size is slightly greater than the width of the two 
rotor bearings, the transmitted power and torque can be 
doubled. In this paper, the structure is changed on the basis of 
the ordinary two-piece cycloidal pinwheel transmission, and 
the high-power cycloidal pinwheel transmission mechanism 
of the four-piece cycloidal wheel is designed, the input power 
is P=120kw, the input speed is n_H=1480r/min, and the 
transmission ratio is i =33, and its motion diagram is shown 
in Figure 1, the basic parameters are shown in Table 1, and 
the three-dimensional model is shown in Figure 4.5.6.

 

 
1. an input shaft; 2 needle tooth shells; 3. Cycloidal wheel 

No. 1; 4. Cycloidal wheel No. 2; 5. cycloidal wheel No. 3; 6. 
Cycloidal wheel No. 4; 7 pin pins; 8 output shafts 

Figure 1. Schematic diagram of the movement of 
cycloidal transmission 

 



 

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Table 1. Basic parameters of cycloidal needle tooth 
transmission 

Parameter 
Name 

Parameter 
Value 

Parameter 
Name 

Parameter 
value 

 
The number 
of cycloidal 

teeth 
33 the number of 

pins 34 

The number 
of pinwheel 

teeth 
34 the cycloidal 

tooth width 60 

The 
diameter of 
the center 

circle of the 
pinwheel 

640 
the diameter of 
the cycloidal 

pin hole 
100

Eccentricity 7 
short 

amplitude 
factor 

0.74 

 

 
Figure 2. Geometric Model of Needle Gear Shell 

 

 
Figure 3. Geometric model of cycloidal wheel 

 

 
Figure 4. Cycloidal Pinwheel Transmission Model 

 

3. Finite Element Analysis of Key 
Components  

Based on the finite element analysis method, the contact 
state of the cycloidal wheel and the needle wheel under the 
loading condition is studied, and the analysis can quickly find 
the critical point of the structure, that is, the position where 
the maximum stress and deformation occur, and determine the 
possibility of failure, so as to facilitate better improvement of 
the structural design. 

3.1. Model import and simplification 
The simplification of these models is often crucial, and if 

they are not simplified, they may not pass the software check, 
and if the inspection needs to be very small, and the smaller 
the element, the longer the computer will take to solve, which 
will not work. Therefore, the model is simplified as follows: 

1. The needle tooth and the needle tooth shell are made into 
an integrated design, eliminating the need to add bearings at 
both ends of the needle tooth in order to reduce friction; 

2. The input shaft and the bearing, and the bearing and the 
cycloidal wheel are regarded as one. 

In the SOLIDWORKS software environment, save the 
built 3D model in .x_t format, and it can only be named in 
English and cannot contain Chinese name, otherwise it is 
difficult for the system to recognize, and then import it into 
ANSYSWorkbench software, select the entity format for 
display. 

3.2. Meshing and Material Attribute Settings 
Due to the large size of the cycloidal wheel and the tooth, 

in order to facilitate convergence, the mixed division method 
of tetrahexahedral is selected, the 5mm mesh is selected for 
the tooth part, the 10mm mesh is selected for the contact 
surface of the cycloidal wheel, and the automatic default mesh 
is selected for the surface of the remaining parts. 

Because the needle teeth and cycloidal wheels are wear-
resistant parts, relying on friction between each other to 
transmit power and speed, so the choice of GCr15 steel, that 
is, the representative steel grade of high carbon chromium 
bearing steel, its quenching and tempering hardness is high 
and uniform, with high wear resistance, high elastic limit and 
high contact fatigue strength, the basic parameters of CGr15 
material are shown in Table 2. 

 
Table 2. Basic data of GCr15 material of high-carbon 

chromium steel bearing steel 

Material Name 
High Carbon Chrome Steel 

Bearing Steel (GCr15) 
 

Density 7850kg/m3 
Hardness HRC58~62 

Young's modulus 2.19e+11 
Poisson's ratio 0.3 

Allowable safety stress
 1000~1200MPa

3.3. Boundary conditions and load application 
Before applying the load, the two end face support of the 

needle tooth shell are selected according to the general 
working state. Because it is a static analysis, and in order to 
ensure the safety and reliability of the structure, the huge 
torque transmitted by the input shaft is directly applied to the 
cycloidal wheel, so as to completely reflect the force 



 

127 

deformation of each part of the structure when the cycloidal 
wheel transmits torque. 

Each cycloidal wheel in the ordinary double-piece 
cycloidal wheel will bear 0.55 torque (is the total torque 
transmitted), which is approximately equal to 12929, and each 
cycloidal wheel in the improved four-piece cycloidal wheel 
will bear 0.3 torque, which is approximately equal to 7053. 

 

 
Figure 5. (only two swing wheels) deformation cloud 

map of total load bearing 
 

 
Figure 6. (Cloud diagram of load deformation borne by 

four swing wheels) 
 

From the cycloidal pinwheel deformation cloud diagram of 
Fig. 7 and 8, it can be seen that the maximum deformation of 
the ordinary double cycloidal wheel is 0.007mm, and the 
maximum deformation of the four-cycloidal pinwheel is 
0.003mm, which is reduced by 57% compared with the 
ordinary double-cycloidal wheel transmission mechanism. It 
can be seen from the two deformation contours that relative 
to the whole structure, in the process of transmitting torque, 
the largest deformation is the cycloidal wheel, not the needle 
teeth, so although the needle teeth are stressed more, the 
structure is stable, and under the same interaction force, in the 
high-power cycloidal pinwheel transmission design, the 
torque transmitted along with the cycloidal wheel is greater, 
and the structure of the cycloidal wheel should need to be 
strengthened. 

 

 
Figure 7. (stress cloud map of the total load borne by only 

two swing wheels) 
 

 
Figure 8. (Cloud Chart of Load Stress on Four Cycloidal 

Gears) 
 

It can be seen from the stress contour diagram of the 
cycloidal pinwheel in Fig. 9 and 10 that the maximum stress 
of the ordinary double cycloidal wheel is 11.095MPa, and the 
maximum stress of the four-cycloidal pinwheel is 3.466MPa, 
which is 68.7% less than that of the ordinary double-cycloidal 
pinwheel transmission mechanism. In summary, it can be seen 
that when transmitting the same torque, the four-cycloid 
wheel has significant structural advantages, with smaller 
structural deformation and less stress. 

4. Conclusion 
(1) When designing the needle tooth shell structure of high-

power cycloidal reducer, compared with the traditional two 
beams, it can be considered to add a circle of beams in the 
middle position, and the design width of the beam is kept as 
much as possible with the thickness of the front and rear 
beams of the needle tooth shell, and the advantages of this 
design will be more significant in the process of high-power 
and high-torque transmission. 

(2) Because the four-cycloid structure bears less stress, the 
contact surface between the cycloid wheel and the needle 
teeth will produce a small deformation, thereby indirectly 
improving the meshing rate of the cycloidal needle wheel 
transmission, which also improves the transmission 
efficiency and reduces the mechanical energy loss. 



 

128 

(3) Whether it is an ordinary double cycloid structure or a 
quadrichoidal structure, the maximum stress occurs at the 
needle tooth part, so it is necessary to pay attention to the 
structural strength of the needle tooth part, and different 
materials can be used for the shell and the needle tooth part 

(4) Under the condition of satisfying the volume limit, from 
the economic consideration, the four-cycloid pinwheel bears 
less stress, so it is not necessary to consider the expensive and 
wear-resistant bearing steel material. 

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