The winners of the Japan Powder Metallurgy Association’s (JPMA) 2014 Powder Metallurgy Awards reflect an industry continuing to develop and expand the range of applications suited to PM technology. The awards recognise innovations in new materials, manufacturing processes and component design. Evident again in this year’s awards are the increasing number of applications for PM in hybrid and electric vehicles, as well as opportunities for replacing traditional production routes with more environmentally friendly PM options.
Development prize: New design
Synchroniser hub for a Dual Clutch Transmission
Sumitomo Electric Industries Ltd received an award for a low speed synchroniser hub used in a seven speed Dual Clutch Transmission (DCT) for a hybrid electric vehicle. DCTs offer a number of features including computer controlled automatic shifting and efficiency as high as that of manual transmissions, due to the absence of a torque converter helping to reduce fuel consumption.
However, weight and cost reduction are also required for DCTs because of their complex design and large number of components. To address this a high strength synchroniser hub with a helical gear form and thin wall was developed (Fig. 1). The compaction punches were divided in order to adjust the density balance of the ridges on the flange section and to rotate the punch used to form the helical gear section. Material and surface condition of the compaction tooling were optimised to prevent sticking between the bottom of the punch and the die. An exacting 19 μm tolerance of the inner diameter was achieved by using a special machining chuck to reduce deformation.
Air compressor component with thin-walled part for electric vehicle
Diamet Corporation received an award for the development of the oldham ring of a scroll compressor used in the air conditioner of an electric vehicle.
In order to extend the mileage range of electric vehicles there is a high demand for smaller, lighter components. A 50% reduction in weight and flange thickness was required in comparison with a conventionally produced oldham ring. In addition, cost reduction was also requested by the customer.
The oldham ring was developed to be produced without machining in order to reduce cost. To achieve better flatness of the thin flange, filling conditions, sintering jigs and sizing conditions were optimised. To avoid cracks and deformation of the green compact with a thin flange during transfer, magnetic handling was utilised.
As a result, the mass production of the oldham ring was achieved and both the weight and flange thickness were successfully reduced by a half.
Sprocket with crank sensor for a diesel engine
Diamet Corporation also received an award for the development of a sprocket with crank sensor for use in a diesel engine. The assembly of a sintered sprocket and a sensor made from sheet metal was replaced with the new product for the purposes of cost reduction and downsizing. Because of the integration of the components the margin for assembly was eliminated.
The geometry of the crack sensor was modified to reduce size by utilising the near net shape method of sintering. In order to avoid breakage of the small teeth during compaction, both a lubricant addition and a tooling coating were used. The high precision of the inner diameter was achieved without grinding by optimising the powder filling and sizing process steps.
As a result, the mass production of the sprocket with crank sensor for diesel engines was achieved, with the forged crank sensor being successfully replaced.