- 上一篇：绿化设计对城市房地产市场的影响英文文献和中文翻译
- 下一篇：石灰石夹层顺层滑坡分析英文文献和中文翻译
Consequently,a method specific for small gears is needed.This report proposesa novel removal method of the burrs and pits of small gearsusing a gear-shaped tool composed of glass-fiber-reinforced plas-tic (GFRP). This method can remove the minute burrs and pits ofsmall gears that are generated during the manufacturing process.In addition, this method uses simple, low-cost processing equip-ment. In the present study, a GFRP gear-shaped tool is proposedand manufactured, and experiments to remove burrs and pits areperformed on steel gears to verify the effectiveness of the proposedmethod. The stability and durability of the GFRP gear-shaped toolare also investigated. In this research, the target gears are smallgears with a module below 1 and an outer diameter less than40mm.2. Removal method of burrs and pits using GFRPgear-shaped tool and the tool manufacturingIn this chapter, the fundamentals of the proposed removalmethod are described and the manufacturing method of the toolis proposed.2.1. Fundamentals of proposed removal method of burrs and pitsFor normal-sized automotive gears, gear honing is used inthe finishing process and, in this process, burrs and pits canbe removed simultaneously. Thus, a deburring method suchas honing, which is based on the meshing between a gear-shaped tool and the work gear, is considered to be a promisingmethod for removing burrs and pits for not only normal-sizedgears but also small gears. In this method, a gear-shaped toolis necessary. Gear honing uses a gear-shaped grinding wheelcomposed of abrasive grains and a bonding agent (e. g., vit-rified bond or resin bond). However, the tip of the tooth ona gear-shaped grinding wheel for small gears is very sharpand the tooth is thin. Consequently, chipping of the tip of thegear-shaped grinding wheel is a problem for processing smallgears.To solve this problem, this research proposes a new GFRP gear-shaped tool. This tool has the possibility to prevent chipping of thetip of the tool. Deburring is realized by rotating the GFRP gear-shaped tool while meshing with the work gear. The materials andmanufacturing method of the tool are described in the followingsubsections.2.2. Material of the GFRP gear-shaped toolGlass fiber has very high tensile strength, equal to that of steel. Ithas a lowthermal expansion coefficient, high dimensional stability, high heat resistance and high chemical resistance. It is incom-bustible and does not absorb water. GFRP hardened by epoxy resinhas a tensile strength of 300MPa and a Rockwell hardness R of 120(Asahi Fiber Glass Company Ltd., 2007).2.3. Manufacturing method of the GFRP gear-shaped toolTo manufacture the GFRP gear-shaped tool, first a thick GFRPplate is made. A glass fiber thread 0.5mm diameter is made bytwisting a 10 m diameter glass fiber. This thread is weaved, piledand then laminated. The piled pattern of glass fibers that makeup the thick GFRP plate is shown in Fig. 3. This thick GFRP plateis processed into a disk-like gear blank having an outer diameterof 40mm, inner diameter of 10mm, and thickness of 7mm. Thedisk blank is cut into the gear-shaped tool using a carbide hob. TheGFRP gear-shaped tool is shown in Fig. 4(a) and enlargements of atooth are shown in Fig. 4(b) and (c). The left column in Table 1 liststhe tool dimensions. The glass fiber layer is parallel with the toothprofile, which looks similar to the cutting edge of a gear shavingcutter. As shown in Fig. 4(c), the glass fiber orientation varies fromtooth-to-tooth. Chipping of the tooth tips was not observed in themanufactured GFRP gear-shaped tools. 3.1. Experimental equipmentThe small, multipurpose lathe used in the experiment is shownin Fig. 5. As shown in this figure, a supporting jig for the GFRPgear-shaped tool with a shaft is installed on the tool post ofthe lathe. The work gear is supported in the center of the lathe,and the GFRP gear-shaped tool and the work gear are meshed.The work gear is driven by the rotation of the main spindle ofthe lathe and the GFRP gear-shaped tool is rotated by meshingwith the work gear. The applied load, which is determined bythe approach distance of the tool to the work gear, is adjustedby moving the tool post. The relationship between the appliedload and the deflection of the work gear shaft is evaluated priorto conducting the experiment. This allows the applied load to bedetermined by measuring the shaft deflection at a specific posi- tion. The equipment for this process is simple and does not costmuch.3.2. Removal experiment of secondary burr3.2.1. Experimental conditionsThe right column of Table 1 gives the dimensions of the workgear. Photographs showing the condition of the tooth side edge ofthe work gear prior to the experiment are shown in Fig. 6(a). Thework gear used in this experiment has a secondary burr (Fig. 1(b))that protrudes toward the tooth groove. The experimental condi-tions are listed in Table 2. A low-viscosity lubricating oil containinga rust-prevention agent is used as the processing fluid; it is sprayedonto the work gear for several seconds prior to conducting theexperiment.3.2.2. Experimental results and discussionThe tooth side edge of the work gear after the experiment isshown in Fig. 6(b). The burrs were removed in the experiment. Themeasurement results of the tooth profile formand lead formof the work gear by the gearmeasuringmachine Type P 26 (KlingelnbergGmbH) are shown in Fig. 7(a) and (b). The tooth profile and toothlead were each measured at three different locations. In the toothlead before the experiment, a 30 m protrusion is observed nearthe side edge of the tooth (left side of Fig. 7(b)), which correspondsto secondary burrs. However, the secondary burrs were removedafter using the