Kazumasa Kawasaki

Analytical and Experimental Tooth Contact Pattern of Large-Sized Spiral Bevel Gears in Cyclo-palloid System

Demand for large-sized spiral bevel gears has increased in recent years and a trend expected to continue. The large-sized spiral bevel gears with equi-depth teeth are usually manufactured based on Klingelnberg cyclo-palloid system. In this paper, the tooth contact pattern of large-sized spiral bevel gears in this system are investigated analytically and experimentally. First, the tooth contact pattern and transmission errors of such gears are analyzed. The analysis method is based on simultaneous generations of tooth surface and simulations of meshing and contact. Next, the large-sized spiral bevel gears are manufactured and the tooth contact pattern of these gears is investigated experimentally. Moreover, the real tooth surfaces are measured using a coordinate measuring machine and the tooth flank form errors are detected using the measured coordinates. It is possible to analyze the tooth contact pattern of the spiral bevel gears with consideration of the tooth flank form errors expressing the errors as polynomial equations. Finally, the influence of alignment errors due to assembly on the tooth contact pattern is also investigated analytically and experimentally. These analyzed results were compared with experimental ones. As a result, the two results showed a good agreement.

Accuracy Measurement and Evaluation of Straight Bevel Gear Manufactured by End Mill Using CNC Milling Machine

Straight bevel gears are usually manufactured with various machines and systems, and the tooth profiles are produced by grinding or machining by means of a tool with many cutting edges. In recent years, the straight bevel gear has been manufactured by an end mill using a computer numerical control (CNC) milling machine because the use of the auxiliary apparatus, special cutters, and special machine tools is not needed. Using this method, the gear manufacturing with high accuracy is an important problem. In this paper, the coordinate measurement of the straight bevel gear manufactured in this method is performed and the gear accuracy is evaluated. The tooth profiles of the straight bevel gear generated by a quasi-complementary crown gear instead of a conventional complementary crown gear are introduced. For this study, the tooth profiles of the straight bevel gear were modeled using a 3D computer-aided design system and the gear was manufactured by an end mill using a CNC milling machine based on a computer-aided manufacturing process. Afterward, the coordinates of many points on the gear tooth surfaces were measured at random using a coordinate measuring machine. This coordinate measurement provides the information about the factors related to the gear accuracy such as pressure angle, tooth angle error, workpiece setting angle, apex to back, and so on. Therefore, the values of the above factors were estimated and were compared with the theoretical ones, respectively.

DESIGN AND MANUFACTURE OF STRAIGHT BEVEL GEAR FOR PRECISION FORGING DIE BY DIRECT MILLING

In the manufacture of straight bevel gears, a precision forging method has been mainly used in recent years and the precision forging die has been usually manufactured using electric discharge machining. However, it is difficult to content the high productivity and low manufacturing cost using electric discharge machining because the gears are produced through a process of several steps. In this article, a design and manufacture of a straight bevel gear for a precision forging die by direct milling is developed in order to improve the productivity and manufacturing cost for the gear production. The tooth profile of a straight bevel gear generated by a quasi-complementary crown gear instead of a usual complementary crown gear is introduced. For this study, first the numerical coordinates on the tooth surface of the straight bevel gear were calculated and the tooth profiles were modeled using a 3D-CAD system. Afterward, the direct milling of the precision forging die of the straight bevel gear in the hardened state was carried out using a CNC milling machine based on a CAM process through the calculated numerical coordinates.

Manufacturing method of double-helical gears using CNC machining center

Double-helical gears are usually manufactured using special type of machine tools, such as gear hobbing and shaping machines. In this paper, a manufacturing method of double-helical gears using a CNC machining center instead of the special type of machine tools is proposed. This manufacturing method has the following advantages: (i) the tooth surfaces can be modified arbitrarily, (ii) all we have to do in gear machining is only one machine setting, (iii) the hole and blank diameter and so on except the tooth surface can be also machined, and (iv) the auxiliary apparatus, special type of tools, and special type of machine tools are not needed. For this study, first the tooth profiles of the double-helical gear were modelled using a 3D computer-aided design system and the gear was machined using a CNC machining center based on a computer-aided manufacturing system. Next, the profile deviations, helix deviations, pitch deviations, and surface roughnesses of the manufactured double-helical gears were measured. Afterwards, the relationship between the tool wear and life time of the end mill were made clear. Finally, this manufacturing method was applied to the gears for a double-helical gear pump. As a result, the validity and effectiveness of the manufacturing method of double-helical gears using a CNC machining center were confirmed.

Machining and Running Test of High-Performance Face Gear Set

The purpose of this research is to develop a high-performance face gear set for aircraft. The geometrical design method of the face gear has already been proposed, and how to decide an effective engagement area under the design parameter has been clarified. A numerical example is presented based on the proposed method. Before machining test, the modified-tooth was decided by the developed Tooth Contact Analysis (TCA) program in order to control the tooth contact pattern. The influence of alignment error of each axis of gear was investigated using TCA. The designed modified-tooth was processed by the Multi-Tasking machine. Finally, running test was performed at a pinion rotating speed of 970 rpm. The face gear set can be operated continuously at an maximum load torque 1390 N · m, without any trouble. The transmission efficiency reached 98.9% under maximum load torque. This cutting method of the face gear introduces a new degree of freedom for defining optional shapes of tooth modification.© 2011 ASME

Accuracy of Straight Bevel Gear by End Mill Using CNC Milling Machine

Straight bevel gears are usually manufactured with various machines and systems, and the tooth profiles are produced by grinding or machining by means of a tool with many cutting edges. In recent years, the straight bevel gear has been manufactured by an end mill using a CNC milling machine because the use of the auxiliary apparatus, special cutters, and special machine tools are not needed. Using this method, the gear manufacturing with high accuracy is important problem. In this paper, the coordinate measurement of the straight bevel gear manufactured in this method is performed and the gear accuracy is evaluated. The tooth profiles of a straight bevel gear generated by a quasicomplementary crown gear instead of a conventional complementary crown gear is introduced. For this study, first the tooth profiles of the straight bevel gear were modeled using a 3D-CAD system and the gear was manufactured by an end mill using a CNC milling machine based on a CAM process. Afterward, the coordinates of many points on the gear tooth surfaces were measured at random using a coordinate measuring machine. This coordinate measurement provides the information about the factors relation to the gear accuracy such as pressure angle, tooth angle error, root cone angle, and apex to back and so on. Therefore, the values of the above factors were estimated and were compared with the theoretical ones, respectively.Copyright

Effect of Cutting Edge Profile on Meshing and Contact of Spiral Bevel Gears in Cyclo-Palloid System #

Abstract The effect of cutting edge profile on meshing and contact of spiral bevel gears in the Klingelnberg cyclo-palloid system is investigated analytically. The analysis method is based on simultaneous generations of tooth surfaces and simulations of meshing and contact. In this paper, both straight lined and circular arc cutting edges are considered. Using straight lined cutting edges, the functions of transmission errors are discontinuous linear ones and the level of transmission errors become large by alignment errors. The use of circular arc cutting edges enables the absorption of the alignment errors. This means that noise and vibration are reduced substantially. A numerical example was presented based on the analysis method above.

PRECISION CUTTING OF MOLDING DIE USING SQUARE END MILL

The precision cutting of a molding die is realized using a square end mill on a 5-axis control machine. In this study, first the tool setting errors are analyzed and the compensation method of the errors is proposed. The effectiveness of compensation in precision cutting is confirmed. Next, the form accuracy of the spiral tool pass is compared with contour one in precision cutting of a spherical surface. Finally, the molding die with spherical surface is manufactured using a square end mill made out of single-crystal diamond based on the results of the compensation of the errors and the comparison of the two tool passes, and the form accuracy and surface roughness of the molding die are measured.

Tooth Contact Analysis and Manufacture on Multi-Tasking Machine of Large-Sized Straight Bevel Gears

Straight bevel gears are widely used in the plant of large-sized power generation when the gears have large size. The purpose of this study is to manufacture the large-sized straight bevel gears with equi-depth on multi-tasking machine. The manufacturing method has the advantages of arbitrary modification of the tooth surface and machining of the part without the tooth surface. For this study, first the mathematical model of straight bevel gears by complementary crown gears considering manufacture on multi-tasking machine is proposed, and the tooth contact pattern and transmission errors of these straight bevel gears with modified tooth surfaces are analyzed in order to clarify the meshing and contact of these gears. Next, the numerical coordinates on the tooth surfaces of the bevel gears are calculated and the tooth profiles are modeled using a 3D-CAD system. 5-axis control machines were utilized. The gear-work was machining by a swarf cutting using a coated carbide end mill. After rough cutting, the gear-work was heat-treated, and it was finished based on a CAM process through the calculated numerical coordinates. The pinion was also machined similarly. The real tooth surfaces were measured using a coordinate measuring machine and the tooth flank form errors were detected using the measured coordinates. As a result, the obtained tooth flank form errors were small. In addition, the tooth contact pattern of the manufactured large-sized straight bevel gears was compared with those of tooth contact analysis. As a result, there was good agreement.Copyright

Analytical and Experimental Tooth Contact Pattern of Large-Sized Spiral Bevel Gears in Cyclo-Palloid System

The demand of large-sized spiral bevel gears has increased in recent years and hereafter the demand may increase more and more. The large-sized spiral bevel gears with equi-depth teeth are usually manufactured based on Klingelnberg cyclo-palloid system. In this paper, the tooth contact pattern of large-sized spiral bevel gears in this system are investigated analytically and experimentally. First, the tooth contact pattern and transmission errors of such gears are analyzed. The analysis method is based on simultaneous generations of tooth surface and simulations of meshing and contact. Next, the large-sized spiral bevel gears are manufactured and the tooth contact pattern of these gears is investigated experimentally. Moreover, the real tooth surfaces are measured using a coordinate measuring machine and the tooth flank form errors are detected using the measured coordinates. It is possible to analyze the tooth contact patterns of the spiral bevel gears with consideration of the tooth flank form errors expressing the errors as polynomial equations. Finally, the influence of alignment errors due to assembly on the tooth contact pattern is also investigated analytically and experimentally. These analyzed results were compared with experimental ones. As a result, two results showed a good agreement.Copyright