Vibration Characteristics and Surface Durability of Non-Involute Helical Gear

Two non-involute helical gears that have an involute-cycloid composite tooth profile and a modified cycloid tooth profile were designed and made to obtain high performance. Using these non-involute helical gears, the circumferential vibration acceleration of the helical gears, the tooth root stress, and the transmission error were measured on running tests. The experimental results showed that the vibration characteristics of the non-involute helical gears do not differ from those of the involute helical gear. Furthermore, we proved from pitting test results that the surface durability of the non-involute helical gears is superior to that of the involute helical gear

POWER LOSS OF SPUR GEAR DRIVE LUBRICATED WITH TRACTION OIL

ABSTRACT This paper describes the effect of traction oil on the power loss of spur gear drive. In this study, we measured the power loss of super gear drive using several traction oils. We separated the power loss into gear friction loss and oil churning loss. Furthermore, we measured the surface temperature on the gear tooth by the dynamic thermocouple method, and observed the lubrication condition between meshing teeth by the electrical resistance method. Then, we investigated the relationships between the power loss of the gear drive lubricated with the traction oil, the surface temperature on the gear tooth, and the lubrication condition. INTRODUCTION Traction drive is a mechanism which transmits a power by a shear force of an EHL film between two rolling elements. A lubricating oil used in the traction drive is required to have a high traction coefficient. Therefore, the exclusive lubricating oil, called traction oil, was developed for the traction drive. The traction drive is used as a continuously variable transmission (CVT) combining with a gear drive. In the CVT with traction drive and gear drive, the gear drive is lubricated with the traction oil. Since the traction oil has a high traction coefficient, the power loss of gear drive lubricated with traction oil may be larger than that with the ordinary gear oil. In this study, we measured the power loss of spur gear drive using four traction oils and a turbine oil by the method, which is based on the oil temperature rise due to the power loss in the gear drive. We separated the power loss into the gear friction loss and the oil churning loss. Furthermore, we measured the surface temperature on the gear tooth by the dynamic thermocouple method, and observed the lubrication condition between meshing teeth by the electrical resistance method. Then, we investigated the relationships between the power loss of the gear drive lubricated with the traction oil, the surface temperature on the gear tooth, and the lubrication condition

Optimum Design of the Involute-Cycloid Composite Tooth Profile Helical Gear

The tooth bending and tooth contact strengths of the involute-cycloid composite tooth profile helical gear, which was developed as a non-involute tooth profile gear based on cycloid tooth profile, are directly affected by its tooth profile. The involute-cycloid composite tooth profile curve changes with some design parameters such as pressure angle and radius of rolling circle. In this study, we developed a method to calculate the tooth root stress and the tooth contact stress of the involute-cycloid composite tooth profile helical gear. Then we compared the tooth root and tooth contact stresses calculated by this method with the experimentally measured data, and the validity of the present calculation method was certified by the good agreement of the calculated values with the measured data. Furthermore, we discussed the effects of the design parameters on the tooth bending and tooth contact strengths of the involute-cycloid composite tooth profile helical gear considering the results of the tooth root and the tooth contact stresses calculated in the case of various values of the design parameters

DRIVING PERFORMANCE AND STRENGTH OF PIN-RACK GEAR MECHANISM USING A TROCHOID TOOTH PROFILE

ABSTRACT A pin-rack gear mechanism, which consists of a rack bar and a sprocket pinion, transforms a rotation motion into a liner one. The rack-bar has a series of pin train, and meshes with the sprocket pinion. In the previous study, we clarified the problem caused by using the sprocket pinion with an involute tooth profile. In this study, we adopted a trochoid tooth profile to the sprocket pinion of the pin-rack gear mechanism to obtain the higher strength. We measured the tooth root stress of the sprocket pinion with a trochoid tooth profile, the driving torque, and the horizontal force of the rack bar using a pin-rack gear mechanism testing machine. Additionally, we calculated the tooth root stress of sprocket pinion, the contact stress on the tooth surface, the flash temperature and the power loss. We considered on the driving performance and the strength of the pin-rack gear mechanism using a trochoid tooth profile by comparing the measured data with the calculated results