Surface finishing method for tooth flank of heat-treated surface-hardened small gears using a gear-shaped tool composed of alumina-fiber-reinforced plastic

Abstract

a b s t r a c tHigh-accuracy gears are necessary to ensure the strength and silence of compact geared motors. Heattreated surface-hardened small gears are employed in the reducer of a compact geared motor. The heat treatment causes distortion, which deteriorates the gear accuracy. To remove this distortion, surfacehardened small gears are rehobbed with a carbide hob. The rehobbing makes a tool mark on the gear tooth surface. This tool mark leads not only to strength deterioration of the tooth surface, but also vibration and noise. Therefore, a surface finishing method that eliminates the tool mark is required. However, it is difficult to finish surface-hardened small gears. This study proposes a tooth surface finishing method for a surface-hardened small gear. The method employs a gear-shaped tool composed of alumina-fiberreinforced plastic (ALFRP) and a surface finishing device with an oscillation/traverse system. The proposed method was used in an experiment to remove the tool mark on the gear tooth flank of a surface-hardened small gear rehobbed by the carbide hob. The effectiveness of this method was verified. In addition, the processing mechanism of the ALFRP gearshaped tool was analyzed by observing the tool and the chips.

Theory study of a novel planar enveloping internal-meshing worm drive

“…The meshing theory [7][8][9][10][11][12][13][14][15][16] identifies a condition for the correct meshing of two teeth. The normal vector of the meshing point should be perpendicular to the vector of relative velocity at the point of contact between the surfaces of two teeth.…”

“…The contact curve describes the theoretical meshing of the instantaneous contact between a certain worm wheel tooth and the worm tooth profile of the planar enveloping internal-meshing worm. According to gear meshing theory [7][8][9][10][11][12][13][14][15][16], the equation for the contact curve of the planar worm wheel meshing in the envelope process for the planar worm wheel moveable coordinate frame S 2 0 can be obtained as…”

“…On the basis of meshing theory [7][8][9][10][11][12][13][14][15][16], a large number of such contact curves on this frame generate the planar enveloping internal-meshing worm tooth profile, which can be demonstrated in the following equation by integrating Eqs. (5), (15), and (18).…”

“…When the LA asymptotically approaches 90°, the two conjugate tooth surfaces can easily form a dynamic pressure oil film. In the planar meshing process, the LA can be calculated by the following formula [7][8][9][10][11][12][13][14][15][16]:…”

Dynamic Modelling and Analysis of the Microsegment Gear

“…From then on, gear transmission has entered the new era. Its theory systems on design [1,2], manufacture [3,4], measurement [5,6], standard [7], lubrication [8][9][10][11], and dynamics [12][13][14][15][16][17] of involute gear have been established gradually. As such, involute gear driving has developed to the most important transmission model.…”