Hitachi Industrial Products Co., Ltd. (hereinafter referred to as Hitachi Industrial Products) has commercialized the copper die-cast*1 rotor, for use in main electric machines for railway vehicles for the first time in the world, achieving lightweighting. By combining its high-efficiency technology with lightweighting technology, Hitachi Industrial Products will contribute to further power saving and reducing environmental impact of future railway vehicles.

This time, Hitachi Industrial Products has developed a copper die-cast rotor for main electric machines for railway vehicles to further lightweight the rotor, a component of the main electric machine. The copper die-cast rotor is manufactured by casting copper which is a conductor, reducing the mass by approximately 15kg compared to the rotor joined by soldering the conventional copper bar and end ring*4 (hereinafter referred to as the copper bar type). It will be applied to targeted railway vehicle projects in the future.

*1Die-casting: A casting method that melts metal and pours it into a mold for pressurized shaping. *2Rotor: The rotating component that makes up the main electric machine. Here, it refers to the cage rotor. *3Our investigation (using a copper die-cast rotor for main electric machines for railway vehicles). *4End ring: A ring material that electrically connects and short circuits both ends of the rotor conductor, copper and brass are used.

Background and Challenges of the Development

Hitachi Industrial Products has two types of rotor lineup for main electric machines: the copper bar type, which consists of inserting rod-shaped copper bars into slots in the core, and the aluminum die-cast type, which manufactures aluminum conductors through die-casting.
In order to contribute to the realization of a carbon-neutral society, we are promoting the high efficiency of the main electric motor, and we have adopted a copper bar type that uses copper material with lower loss than aluminum as the conductor of the rotor for high efficiency products.
In considering the balance between efficiency and weight reduction, we have explored the application of copper die casting. By maintaining the efficiency through the use of copper material and simplifying the structure, it is possible to reduce the number of components. However, there was a challenge due to the fact that the melting point of copper (approximately 1086°C) is higher than that of aluminum (approximately 660°C), resulting in a high temperature for the molten copper used as the material and making it extremely difficult to achieve a good quality casting. Additionally, because it is for main electric motors for railway vehicles, there was a need for die casting of large rotors.
Hitachi Industrial Products applies the technology cultivated in aluminum die casting to copper, and by repeatedly prototyping and verifying the copper die-cast rotor for several years, we have established the optimal design and verification method for main electric motors for railway vehicles, and we are developing and commercializing high-quality copper die-cast rotors.

Introduction at the "InnoTrans 2024 International Railway Technology Exhibition"

The copper die-cast rotor will be exhibited at the "InnoTrans 2024 International Railway Technology Exhibition", which will be held in Berlin, Germany from September 24th (Tuesday) to 27th (Friday), 2024.

About Hitachi Industrial Products

Hitachi Industrial Products, as part of the "Connective Industries" that digitally connects products in a wide range of fields such as industry and distribution, water infrastructure, healthcare, home appliances and air conditioning systems, measurement and analysis systems, and building systems, contributes to the improvement of customers' environmental value through its product business.

Contact

Hitachi Industrial Products Co., Ltd.
Sales and Administration Headquarters, Electrical Systems Technology Department, Built-in Drive Group [Contact: Nakagomi, Kobayashi]
Sumitomo Real Estate Akihabara First Building, 1-5-1 Sotokanda, Chiyoda-ku, Tokyo 101-0021
Telephone: 03-6271-7068 (Direct)