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Figure 4. (a) CAD CVT in Normal mode; (b) CAD CVT in reverse mode.

Figure 4 (a) CAD CVT in Normal mode; (b) CAD CVT in reverse mode.

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Figure 1. (a) CAD CVT with four CADs; (b) CAD CVT with two sides transparent for better viewing.
Figure 1. (a) CAD CVT with four CADs; (b) CAD CVT with two sides transparent for better viewing.
Table 1. Description of part numbers shown in Figures 2 and 3.
Table 1. Description of part numbers shown in Figures 2 and 3.
Figure 5. (a) Normal Mode. (b) Neutral Mode. (c) Reverse Mode.
Figure 5. (a) Normal Mode. (b) Neutral Mode. (c) Reverse Mode.
Figure 6. 2D side view of CAD CVT with four circumferentially arranged disks (CADs).
Figure 6. 2D side view of CAD CVT with four circumferentially arranged disks (CADs).
Now, from Figure 6, Rag can be positive, zero, or negative; therefore, for an accurate prediction of the transmission ratio, we should consider Rgo as a vector quantity. So, we can write Equation (13) as It is pertinent to mention that if the axes of rotation of CADs do not lie in the same plane, then each CAD will rotate at different speeds. In this situation, each CAD will try to rotate the output disk at different speeds. This will result in slippage at the traction points of CADs.
Now, from Figure 6, Rag can be positive, zero, or negative; therefore, for an accurate prediction of the transmission ratio, we should consider Rgo as a vector quantity. So, we can write Equation (13) as It is pertinent to mention that if the axes of rotation of CADs do not lie in the same plane, then each CAD will rotate at different speeds. In this situation, each CAD will try to rotate the output disk at different speeds. This will result in slippage at the traction points of CADs.
Figure 7. Graph showing transmission ratio vs. Rao.
Figure 7. Graph showing transmission ratio vs. Rao.
Figure 8. Two-dimensional side view of CAD CVT with four circumferentially arranged disks, depicting tractive forces between the circumferentially arranged disks and input disk and output disk. In order to calculate the maximum torque capacity of the new CVT, we consider Figure 8. For the sake of simplicity, we confine our scope to a case in which the Transmission Ratio TR = —1.
Figure 8. Two-dimensional side view of CAD CVT with four circumferentially arranged disks, depicting tractive forces between the circumferentially arranged disks and input disk and output disk. In order to calculate the maximum torque capacity of the new CVT, we consider Figure 8. For the sake of simplicity, we confine our scope to a case in which the Transmission Ratio TR = —1.
Figure 9. Torque capacity of CAD CVT for different numbers of CADs. Transmission Ratio, TR = —1. Ue = 0.35, Ro = 26 mm forn =4, Ro =2.5 x 26mm for n = 10, Ro =5 x 26 mm for n = 20. Figure 9. Torque capacity of CAD CVT for different numbers of CADs. Transmission Ratio, TR = —1
Figure 9. Torque capacity of CAD CVT for different numbers of CADs. Transmission Ratio, TR = —1. Ue = 0.35, Ro = 26 mm forn =4, Ro =2.5 x 26mm for n = 10, Ro =5 x 26 mm for n = 20. Figure 9. Torque capacity of CAD CVT for different numbers of CADs. Transmission Ratio, TR = —1
Figure 10. (a) CAD in frictional contact with output disk. (b) Spinning of different points of CAD, which are in frictional contact with output disk. To calculate spin losses, we consider Figure 10.
Figure 10. (a) CAD in frictional contact with output disk. (b) Spinning of different points of CAD, which are in frictional contact with output disk. To calculate spin losses, we consider Figure 10.
Let
Let
Figure 11. (a) CAD CVT with Transmission ratio, TR = —1 (b) —1< TR < 0. Equation (63) defines a condition in which the bearings of the CAD experience maxi- mum load and hence maximum bearing losses. We assume that the output shaft of the CVT is subjected to the maximum torque that it can support and TR = —1. In this condition, the free-body diagram of a single CAD is given in Figure 12.
Figure 11. (a) CAD CVT with Transmission ratio, TR = —1 (b) —1< TR < 0. Equation (63) defines a condition in which the bearings of the CAD experience maxi- mum load and hence maximum bearing losses. We assume that the output shaft of the CVT is subjected to the maximum torque that it can support and TR = —1. In this condition, the free-body diagram of a single CAD is given in Figure 12.
Figure 12. Free-body diagram of a CAD when TR = —1
Figure 12. Free-body diagram of a CAD when TR = —1
Figure 13. Power Loss due to friction of a CAD CVT with n = 4, a = 2.5 mm, and w = {50,100,150,200,250}.
Figure 13. Power Loss due to friction of a CAD CVT with n = 4, a = 2.5 mm, and w = {50,100,150,200,250}.
Figure 14. Power Loss due to friction of aCAD CVT with n = 4, a= 1mm, and w = {50,100,150,200,250}.
Figure 14. Power Loss due to friction of aCAD CVT with n = 4, a= 1mm, and w = {50,100,150,200,250}.
2.6. Contact Pressure It is important to calculate the maximum contact pressure at the traction points of CADs in order to ensure that the stress at the traction points does not exceed the limit of 2.5 GPa, which can be supported by commercially available steel grades.
2.6. Contact Pressure It is important to calculate the maximum contact pressure at the traction points of CADs in order to ensure that the stress at the traction points does not exceed the limit of 2.5 GPa, which can be supported by commercially available steel grades.
Figure 15. Power Loss due to friction of a CAD CVT with n = 4, a = 0.5 mm, and w = {50,100,150,200,250}. Table 2. Maximum efficiency at different contact lengths.
Figure 15. Power Loss due to friction of a CAD CVT with n = 4, a = 0.5 mm, and w = {50,100,150,200,250}. Table 2. Maximum efficiency at different contact lengths.
Figure 16. Pressure (Pascal) vs. Axial Force Fn (N) for CAD CVT with n = 4 and contact lengths of L=1mm (blue), L = 2 mm (red), and L = 5 mm (yellow).
Figure 16. Pressure (Pascal) vs. Axial Force Fn (N) for CAD CVT with n = 4 and contact lengths of L=1mm (blue), L = 2 mm (red), and L = 5 mm (yellow).
Figure 17. Pressure (Pascal) vs. Axial Force Fn (N) for CAD CVT with n = 10 and contact lengths of L=1mm (blue), L = 2 mm (red), and L = 5 mm (yellow).
Figure 17. Pressure (Pascal) vs. Axial Force Fn (N) for CAD CVT with n = 10 and contact lengths of L=1mm (blue), L = 2 mm (red), and L = 5 mm (yellow).
Figure 18. Pressure (Pascal) vs. Axial Force Fn (N) for CAD CVT with n = 20 and contact lengths of L=1 mm (blue), L = 2 mm (red), and L = 5 mm (yellow). 2.7. Experimental Validation/Proof of Concept In order to verify the proposed design, a Proof of Concept (PoC ) was manufactured. The PoC was manufactured as per the model given in Figures 1-3. The main purpose of the PoC was to verify the basic functionality of the CAD CVT, which is:
Figure 18. Pressure (Pascal) vs. Axial Force Fn (N) for CAD CVT with n = 20 and contact lengths of L=1 mm (blue), L = 2 mm (red), and L = 5 mm (yellow). 2.7. Experimental Validation/Proof of Concept In order to verify the proposed design, a Proof of Concept (PoC ) was manufactured. The PoC was manufactured as per the model given in Figures 1-3. The main purpose of the PoC was to verify the basic functionality of the CAD CVT, which is:
Figure 19. Transmission Ratio vs. Output Shaft Length of Proof of Concept. Ensuring the stability and alignment of the output disk is important because it rotates inside the circumferentially arranged disks (CADs). In order to maintain the stability of the output shaft and the output disk, especially during gear-changing operations, alignment shaft ‘15’ has been introduced. For reference, see Figure 3. For a better understanding, please see the two assemblies shown in Figure 21i,j.
Figure 19. Transmission Ratio vs. Output Shaft Length of Proof of Concept. Ensuring the stability and alignment of the output disk is important because it rotates inside the circumferentially arranged disks (CADs). In order to maintain the stability of the output shaft and the output disk, especially during gear-changing operations, alignment shaft ‘15’ has been introduced. For reference, see Figure 3. For a better understanding, please see the two assemblies shown in Figure 21i,j.
Figure 20. Transmission Ratio vs. Rdo of Proof of Concept (PoC).
Figure 20. Transmission Ratio vs. Rdo of Proof of Concept (PoC).
Table 3. Transmission ratios for different displacements of output shaft of CAD CVT Proof of Concept (PoC).
Table 3. Transmission ratios for different displacements of output shaft of CAD CVT Proof of Concept (PoC).
Figure 21. (a) Experimental setup; (b—-h) pictures of CAD CVT Proof of Concept (PoC) /prototype, representing different parts of the CVT for better understanding and visualization. (i,j) Assemblies representing design features incorporated into CAD CVT for improved stability and alignment of output disk and output shaft during normal operation and gear-changing operation. representing different parts of the CVT for better understanding and visualization. (i,j) Assemblies Pp gs Pp gs J
Figure 21. (a) Experimental setup; (b—-h) pictures of CAD CVT Proof of Concept (PoC) /prototype, representing different parts of the CVT for better understanding and visualization. (i,j) Assemblies representing design features incorporated into CAD CVT for improved stability and alignment of output disk and output shaft during normal operation and gear-changing operation. representing different parts of the CVT for better understanding and visualization. (i,j) Assemblies Pp gs Pp gs J
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