Spur Gears Transmission Analysis on Countinous Passive Motion Machine Design for Shoulder Joint

An analysis of gear transmission on a continuous passive machine (CPM) from the 3-dimensional design has been carried out using SolidWorks software. Analysis of the strength of the gear structure is affected by the weight of the patient's arm. Analysis of gear transmission that is affected by the load of the passive arm uses static simulation, by entering the patient's arm load. The facilities used are static simulation with the condition of fixed geometry in the parts related of the shaft, the effect of gravity of 10 m/s, making mesh, and running simulation. The maximum stress that occurs in gear3 z = 100 is 4.5524e + 006 N/m, the maximum stress on gear2 z = 80 is 4.81729e + 006 N/m, the maximum stress on gear100 z = 20 is 9.08982e + 006 N/m.


Introduction
Continuous passive machine (cpm) is a therapeutic tool used to train patients in joint movements after joint surgery [1].The CPM machine is designed to move flexion and horizontal adduction using spur gear transmission.The gears are used to reduce the speed from the actuator and increase torque, so that it can passively move the patient's shoulder to do therapy.With the development of computer aided design (CAD) technology is very helpful in designing a product or machine.The process of designing in manufacturing industries used a lot of time.An engineer who has experience in using CAD can use various tools/facilities in CAD software in various applications in mechanical engineering, so that the time spent designing can be done shorter, productivity and quality can be produced better.One CAD software for design and analyzing a 3-dimensional design is Solidworks.
The purpose of this study was to analyze the strength of material from the gear transmission to the patient's arm load.The strength of material of the gears are analyzed by the stress and strain on the gears.All analyzes of this study use SolidWorks software.

Research Methodology
To complete the analysis in this study, the steps taken before doing the simulation are as follows.

Research methods
The research methods is done by designing 3 Dimensional CPM machine, from the results of the design will be analyzed the transmission of straight gears.By using software, the stress and strain experienced by each gear that is exposed to the specified load will be carried out.The research method is carried out by the following steps: a. Collect the geometry of the CPM machine that will be designed.d.Analyzing the strength of material of the spur gear of the CPM machine using Solidworks software.

Design Methods of 3-Dimensional CPM Machine
In the CPM machine that will be designed there are 2 gearboxes that are used to reduce speed and increase the torque of a DC motor actuator.Two gearboxes are used for flexion movement and horizontal adduction has the same transmission pair.The method for carrying out the analysis of CPM gears transmission using the SolidWorks software is as follows:

Results and Discussions
In this section will explain the results and discussion of the simulation of the spur gears that used in CPM machine.The analysis that will be carried out in this study includes: 1. Analysis of spur gear 1 ( = 20)

Results
From he design of CPM machine is shown as show in the figure 2.    In Table 1.It shows the results of the analysis of the structure due to the patient's arm load on the gear1  = 20, the displacement/deflection on gear1 is 0.000249418 .
And the strain that happened on gear1 is 3.18916 − 005.The gear1 is still relatively safe because the maximum Yield Strength is 9.08982 + 006 / 2 , and far below the allowable Yield Strength which is equal to 5.800 + 008 / 2 .

Simulation analysis of load on gear2 𝒛 = 𝟖𝟎
In the analysis of the results of the design of gear2 with  = 80 are shown in Figure 6, Figure 7, and Figure 8.

Simulation analysis of load on gear3 𝒛 = 𝟏𝟎𝟎
In the analysis of the results of the design of gear3 with  = 100 are shown in Figure 9,

Discussions
Analysis of the strength of spur gear material due to patient's arm load, to analyze the gearbox transmission of the affected part of the transmission gear to transmit torque to the spur gear of each gears.This can be simulated because when the rotating gears of each gear will experience the same load and direction .
From the design and simulation the maximum stress on the gear1  = 20 is 9.08982 + 006 / 2 .On gear2  = 80 the maximum stress that occurs is equal to

Conclusion
For designing and simulating three dimensions, it is very helpful in evaluating the design of a device.Loading on the simetris section can be assumed on one part that is exposed to the load of the tool.The analysis in this study was carried out with static loading.The possibility of analysis through simulation can still be done using the dynamic loading method

b. Design 3
Dimensional CPM machine with spur gear transmission using Solidworks software.International Journal of Applied Sciences and Smart TechnologiesVolume 1, Issue 1, pages 11-22 ISSN 2655-8564 13 c.Analyzing the strength of material of the spur gear transmission of the CPM machine designed with the influence of the load determined using Solidworks software.

a. Design spur gear 1 .
Determine the patient's arm load 2. Determine the torque that is required for the movement of the CPM machine 3. Determine the gear ratio used in design of the CPM machine 4. Determine the level of spur gear transmission that used at CPM machine 5. Determine dimensions, modules, number of teeth of spur gears based on the ratio of each gear transmission level 6.Determine the material of spur gear in the design of CPM machine b.Design of spur gear transmission.It is assumed that the patient's arm weight is 5  and the patient's arm is 80  long, so that the torque produced by the arm is 20 .Shown in the equation below. = ½  ℎ   ℎ    = 40   5   10 /2  = 20  The Dc motor actuator used has a torque characteristic of 1.5  and a rotational speed of 70 , so the gear transmission ratio is obtained by the equation From the results of the calculation the ratio is obtained at 17.75.The ratio value is increased for the safety factor to 20.The total ratio can be divided into 2 levels of gear transmission which are equal to 4 and 5.The gears are directly connected to the actuator gear1, then transmitted to gear2.Gear2 and gear3 are on the same axis.Next gear3 is transmitted to gear4.All gears are determined using the same module, which is equal to 1mm.Gear1 is determined to have 20 teeth.So that in the first transmission the number of teeth obtained in gear2 is equal to: From these calculations of the level of the spur gears transmissions ore obtained as shown in figure 1.

Figure 1 .
Figure 1.Spur gears transmission in CPM machine

Figure 3 .
Figure 3. Stress on gear1  = 20 due to the patient's arm load

Figure 9 .
Figure 9. Stress on gear3  = 100 due to the patients arm load safe because the maximum Yield Strength is 9.08982 + 006 / 2 , and far below the allowable Yield Strength which is equal to 5.800 + 008 / 2 .

Table 1 .
Table of results of analysis due to of patient arm load on spur gear1  = 20

Table 2 .
3Table of results of analysis due to of patient arm load on spur gear 2  = 80

Table 2
shows the results of the analysis of the structure due to the patient's arm load on gear2  = 80, the displacement/deflection on gear2 is 0.000274988  and the strain that happened on gear2 is 1. 77017 − 005.The gear2 is still relatively safe because the

International Journal of Applied Sciences and Smart Technologies
is 4.81729 + 006 / 2 and far below the allowable Yield Strength which is equal to 5.800 + 008 / 2 .

Journal of Applied Sciences and Smart Technologies
4.81729 + 006 /2.The maximum stress that occurs in gear3  = 100 is equal to 9.08982 + 006 / 2 .The value of maximum stress indicates that teeth of the spur gear is affected by load of patients arm.The results of the simulations show that material 1.0503 (45) still safe.This is indicated by the maximum stress occurs in each gear is still far below Yield Strength. Mterial yield strength is 1.0503 (45) which is equal to 5.8 + 008 / 2 .