The 2nd EV & HEV Drive System Technology Expo (Report 1)

Motor Technologies



 The following is a report on the products and technologies related to drive systems, motors (parts, materials), motors (coil winding machines) and machining technologies exhibited by 27 manufacturers at the 2nd EV & HEV Drive System Technology Expo ("EV Japan") held in Tokyo Big Site on January 19-21, 2011.

 EV Japan this year saw a significant increase in the number of manufacturers from varying categories including motors, motor parts, materials and manufacturing equipment, and machining technologies. Among those that exhibited machining technologies, ten small- to medium-sized companies exhibited their original machining technologies in the booth of NC Network Co., Ltd., an engineering trading company that sells their products (only six in the previous EV Japan; four of them returned to the show this year).

 Exhibits of rechargeable batteries, next-generation batteries, chargers, and related parts and materials will be introduced in Report 2.

Category Manufacturer Product/Technology
Drive systems  YASKAWA Electric Corp.  EV motor drive systems
 PUES Corp.  Support in EV system development
 TGMY/Shigehara Mfg.  DC brushless motors, primary reduction gears
 WATEX Co., Ltd.  Electric compressor for air-conditioning systems on converted EVs
 Myway Plus Corp.  On-board motor rating system for EV/HEVs
(parts, materials)
 Toray Industries, Inc.  Motor insulation materials (PPS fiber, film)
 Tsuda Industries Co., Ltd.  Motor shafts for HEVs (cold-forging method)
 Shicoh Co., Ltd.  Coreless motors
 SHT Corp.  Choke coil
 Akiyama Mfg Co., Ltd.  Motor shafts (friction welding method)
 Ryoden Kasei Co., Ltd.  Bus bars
 NOA Co., Ltd.  Coil testers
 Toyodensan Co., Ltd.  On-board power generation system
(coil winders)
 Odawara Engineering Co., Ltd.  Winding machines
 Taga Mfg. Co., Ltd.  Winding machines
 Alphatec Co., Ltd.  Precision plaster casting process
 Ito Precision Co., Ltd.  Precision turnery technology
 Inatec Corp.  Thin-wall sand casting process
 LSI Cooler Co., Ltd.  Specialized in heat sink technology
 Climb Works, Inc.  Component weight saving technology
 Daishin Seiki Corp.  Simultaneous five-axis thin-wall machining technology
 Nisshin Seiko Inc.  Precision press working technology
 Miyaki Co., Ltd.  Alumite treatment processes
 Musashi Co., Ltd.  Simultaneous five-axis machining technology
 Yamagishi Seisakusho Co., Ltd.  Thin-wall turnery technology
 Namitei Co., Ltd.  Cold-forging methods
 Atect Corp.  Powder injection molding methods

(Note) Click the images below for enlarged views.

Drive systems

 YASKAWA Electric Corporation  (EV motor drive system)

 A newcomer in automotive markets, Yaskawa unveiled its HEV/EV motor drive system dubbed QMET Drive (Qualified Magneto-Electronic Transmission featuring electronic motor speed switching control) that the company announced last year, and YMEV (Yaskawa Motordrive for Electric Vehicle) which is a smaller version of QMET Drive and developed for commuter-class to minicar-class vehicles. YMEV is similar to QMET but is without the motor speed switching control and focuses on low speed ranges. An EV venture company called Zero Sports (located in Kakamigahara City, Gifu Pref.) is likely to place an order for YMEV for 1,000 vehicles and install them on a van EV that will be used by Japan Post companies (Press Release, in Japanese). Yaskawa also had a reference exhibit of SiC-QMET that uses SiC (silicon carbide) power semiconductor devices. SiC power devices are used in the main circuit of the motor drive inverter and the motor speed switching control to halve the volumetric capacity of the control. The SiC power devices are the trench type MOS FET and Schottky barrier diodes (SBD) supplied by Rohm.

Small YMEV for minicar EVs Sic-QMET using SiC power devices
Motor speed switching control using SiC power devices Inverter using SiC power devices
QMET DRIVE for small to standard sized vehicles  

 PUES Corporation  (Support in EV system development)

 PUES, reputed for EV development and prototyping service, exhibited DC brushless motors (same as IPM synchronous motors), inverters, battery packs, battery control units (BMS), etc. The company has delivery records of HEV drive motors (10kW-30kW rated output), drive motors for small EV (600W-5kW), etc. The compact 600W-class motor system (M600 Motor System) integrates the motor mechanism, inverter and controller into a single unit to reduce part count and total weight as well for use on electric motorcycles. Measures to prevent high-voltage current leaking to the body chassis are critical on HEV/EVs as they use such high-voltage current. PUES is proposing an insulation deterioration sensor addressing this specific problem. The sensor, called CEL4, constantly monitors the insulation resistance between high-voltage current up to 420V and the body chassis. When deterioration of insulation is detected, the sensor gives an alarm signal.

Outline of automotive DC brushless motor
development for a customer
Specifications of a power unit integrating a
600W-class motor, inverter and controller
12kW-class motor for hybrid vehicles CEL4 sensor for detecting deteriorated
insulation in high-voltage DC circuits


 TGMY Co. Ltd. (DC brushless motors, Motor ECU) / Shigehara Manufacturing Co., Ltd. (Primary reduction gears) (in Japanese) / (in Japanese)

 "Himiko" is an EV envisioned with a 550km range per charge and jointly developed by TGMY (importer of key components for EV conversion and provider of EV conversion service) and Shigehara Manufacturing (automotive prototype manufacturer). The reduction gear for EV (FR 2-speed transmission type) developed by Shigehara Manufacturing allows modification of an existing AT (automatic transmission) vehicle to an electric vehicle. The company has already developed upright and horizontal type two-speed reduction gears having high-speed or high-power gear ratio in addition to the fixed gear ratio of the primary reduction gears for FF, MR and RR, and also for FR.

(Note) Conversion to electric vehicles is currently limited to vehicles with the MT systems. Conversion of the AT vehicles is not available since the motor rpm does not match the engine rpm, making AT control difficult.

Examples of EV conversion by TGMY Specs of the converted EV "Himiko"
Converted EV "Himiko" on display
(motor and controls supplied by Azure)
Converted EV "Himiko" on display
FF 2-speed reduction gear for EV
by Shigehara Mfg on display (for Mira Van)

 WATEX Co., Ltd.  (Air-conditioning systems for converted EV [electric compressors for cooling])

 Developed to meet the growing need for converting existing vehicles into EV. The original A/C cannot be used on the vehicle after the engine and the compressor are removed and WATEX developed an electric compressor to fill the gap. The compressor is designed for cooling exclusively. All other A/C components are reused but the addition of extra batteries is required to run the A/C. The company is currently developing ceramic heaters for heating.

A/C system diagram for converted EVs Outline of A/C system for converted EVs

 Myway Plus Corporation  (On-board motor rating system for EV/HEV) (in Japanese)

 Myway Plus began manufacturing automotive parts that include PM synchronous motors and drivers for EVs, and Li-ion battery chargers. The company has 18 years of expertise in the development, manufacture and sales of R&D tools and testing equipment in the power electronics field. This year, the company exhibited MES-Complete, a rating system for motors that are the key component on EVs, with applicable motor capacities spanning 1kW-200kW. The rating system ensures higher efficiency with new functions that automatically measure the otherwise most time-consuming torque maps, inductances, N-T characteristics, etc. It may also be used for measuring copper loss and iron loss.

Outline of the testing equipment for electric vehicles  


Motors (parts, materials)

 Toray Industries, Inc.  (Motor insulation materials)

 PPS (polyphenylene sulfide) is a highly functional, crystalline thermoplastic engineering plastic and PPS fiber (product name: Torcon) is an insulation material used to make motor conductor bundling cords and the cord protectors. Toray also suggested using PPS film (product name: Torelina) and NSN film (product name: Namli) as insulation paper in motors.

PPS fiber insulator for motors Motor using PPS fibers on display
Two types of films used as insulator paper in motors

 Tsuda Industries Co., Ltd.  (Motor shafts for HEVs) (in Japanese)

 The HEV motor shaft (cold forged with deep holes) used in the Prius allows net shaping (in place of the conventional cutting and thread rolling process), while the deep holes and narrow holes are being formed by cold forging. This leads to a 15% reduction of manufacturing cost compared to the conventional method comprising hot forging, drilling and cutting. The new generator shafts are intended for single-piece flow style of production rather than the lot production style. This has led to 30% cost reduction.

(Note) Visit Tsuda Industries website for details of the cold forging method. (in Japanese)

Motor shafts for HEVs on display Generator shafts for HEVs on display
Cost reduction by cold forging method  

 Shicoh Co., Ltd. (Coreless motors) (in Japanese)

 Shicoh manufactures ultra-small coreless motors that use stators made of copper sheet rather than coil, and is a leading manufacturer of vibration motors used in cellphones. The company is also the world's leading manufacturer of cooling fan motors for car navigation, car audio and other automotive systems. It has leveraged on its original coreless motor technology to produce power generation systems for wind power plants on a commercial basis. Shicoh has now developed in-wheel motors (3kW, 5kW) for electric vehicles. The company envisions a total of four in-wheel motors in the four-wheel vehicle to produce enough power that is available from the existing gasoline-powered minicars.

 (Note) IR information about the development found below (in Japanese)

Outline of in-wheel coreless motors Newly-developed 5kW in-wheel motor on display
(Note) Disc brake may be stored in the hollow motor case.

 SHT Corporation Ltd.  (Choke coil)

 SHT Corporation is specialized in the development of product structures and processes such as the internationally patented side-gap structures and banked coil winding method. The company has expanded its product range from the electromagnetic steel sheet core that forms the core of the motor, to the side gap choke coils (inductors) having a side-back structure for inserting automatically wound coil through the gap, and electromagnetic steel sheet cut-core reactors for noise elimination.

Typical applications of reactor choke coil Characteristics of reactor choke coil

 Akiyama Manufacturing Co., Ltd.  (Motor shafts) (in Japanese)

 Akiyama Manufacturing, a specialized manufacturer of crankshafts and shafts, exhibited an ultra-lightweight motor shaft having a hollow structure formed by friction welding of a solid material and a hollow structure. This method achieves a 45% weight reduction (2.75kg⇒1.52kg).

 The manufacturing method is patentable but the company has not applied for patent protection. Instead, Akiyama has disclosed the method on its website to make it public knowledge and available to all.

Characteristics of an ultra-lightweight motor shaft (1) An ultra-lightweight motor shaft on display
Characteristics of an ultra-lightweight motor shaft (2)  

 Ryoden Kasei Co., Ltd.  (Bus bars) (in Japanese)

 Ryoden Kasei, jointly formed by Mitsubishi Electric and Mitsubishi Gas Chemical, exhibited laminated bus bars that are conductors for large currents. Bus bars are used between terminals of the DC high-voltage relays that connect the drive battery and the inverter on HEV/EV. They are formed by punching a flat conductive sheet made from copper, copper alloy and other ingredients. Ryoden Kasei's laminated bus bars effectively suppress switching surge voltages in the electronic circuit for power electronics.

Outline of laminated bus bars for HEV/EVs Outline of laminated bus bars for large-current circuits
Laminated bus bars on display  

 NOA Co., Ltd.  (Coil testers) (in Japanese)

 NOA, specialized in the development and manufacture of in-circuit testers and other testing equipment for electronic circuits, exhibited its coil tester designed to prove insulation performance of coils in HEV drive motors (results are rated by voltages up to 6kV). The tester features a unique impulse generating mechanism (patented) consisting of power MOS FET (semiconductors). It detects slight corona (initial arc phenomenon caused by poor insulation and that leads to short-circuit if left intact) and warns of a possible short-circuit between coil layers.

Characteristics of coil testers Outline of the unit for testing insulation
between motor coil layers

 Toyodensan Co., Ltd.  (On-board power generation system) (in Japanese)

 Toyodensan, specialized in aluminum casting for automotive industries, exhibited an on-board power generation system. The 1-shaft 2-line system is capable of generating 12VDC and 100VAC and is used in broadcast relay vehicles, emergency vehicles, maintenance vehicles, etc. The 15kVA-HMG NMG power generation system on reference display is characterized by a brushless construction and voltage control that does not require DC/DC converter.

Characteristics of 15kVA-class power generation system 15kVA-HMG NMG power generation system on display
(installed in the engine compartment)


Motors (coil winders)

 Odawara Engineering Co., Ltd.

 Odawara Engineering, specialized in coil winding machines for motors (winders, automatic winding line), has a long history of manufacturing automotive products that are used in Toyota, Nissan and other vehicles including Toyota's first Prius that was launched 13 years ago. The inserter type fully-automated stator coil winding line shown below (for a set price of 600 million yen) is currently used in Toyota vehicles among others. According to Odawara Engineering, customers are demanding PPM-class precision but it normally takes at least six months before the operator develops the necessary skill to run the manufacturing line at such a high precision.

Fully-automated stator coil winding line  

 Taga Manufacturing Co., Ltd.

 Taga Manufacturing, a company with a long history of making coil winding machines (founded in 1887), including Japan's first automated coil winder it developed in 1948, has supplied drive motors for Honda's Insight. Its drive motors have also been supplied to Nissan, Hyundai, etc. The company is promoting a complete manufacturing line incorporating a general-purpose machine (for a set price of 50 million yen). The company's competitors for its coil winding machine business are often its customers' fabrication departments engaged in in-house fabrication of coil winders and manufacturing lines.

Winding machine on display Part-wound coil in HEV motor on display


Processing technologies

Alphatec Co., Ltd. (Precision plaster casting process) (in Japanese)

Alphatec, a member company of NC Network and a manufacturer of automotive parts, introduced its precision plaster casting process. This process uses plaster rather than metallic molds and is said to be an ideal choice, in terms of cost, for small-lot production of prototypes ranging from 5 to 100 pieces in quantity. Compared to the popular sand casting, the plaster casting may be used for producing parts having more complex shapes. The company, having its head office and plant in Aichi Prefecture, also operates mass production plants in Shanghai, China, and Haryana, India.

Precision plaster cast parts on display Characteristics of precision plaster casting process (1)
Specs of precision plaster casting process Characteristics of precision plaster casting process (2)

Ito Precision Co., Ltd. (Precision turnery technology) (in Japanese)

Ito Precision, a member company of NC Network and a secondary manufacturer of automotive parts, has 130 machines including NC automatic lathes and is engaged in centralized production in its head office and plant located in Gifu Prefecture.

Examples of machined parts Samples of parts from combined
working on a precision lathe

Inatec Corporation (Thin-wall sand casting process) (in Japanese)

Inatec, a member company of NC Network and the main supplier of Aisin Group, introduced precision sand casting and five-axis NC machining technologies. Among the displays were samples of sand-cast housings for HEVs having a complex hollow structure designed for higher cooling performance. The company has plants in three locations in Aichi Prefecture.

Characteristics of thin-wall precision sand-casting process

LSI Cooler Co., Ltd. (Heat sink technology) (in Japanese)

LSI Cooler, a member company of NC Network and specialized in heat sink technologies, is making heat sinks in its Fukushima plant. Its Vietnamese company is also producing heat sinks, a device designed to suppress the heat generated by motors and batteries, to meet the rapidly growing global demand with the progress of HEV/EVs and other electrified vehicles. LSI Cooler's heat sink manufacturing process has achieved a significant cost reduction by cold welding in which fins are press-fit into the base (both made of aluminum) and jointed together ("comb-fit jointing principle": patent pending).

Outline of the principle of comb-fit jointing Heat sink samples on display

ClimbWorks, Inc. (Component weight saving technology) (in Japanese)

ClimbWorks, a member company of NC Network and founded in Ota Ward in Tokyo, is committed to providing its customers with "one-stop service" in support of the entire phase of their product development. Toward this goal, the company is proposing prototyping for development and mass production, and prototyping for modification to improve material or strength and correct defects. The company appealed "replacing metallic parts with plastics" at the EV Japan as a method of prototyping for modification using its three dimensional CAD/CAE/CAM technologies to achieve cost reduction.

Replacing metallic parts with plastics ClimbWorks' technologies

Daishin Seiki Corporation (Simultaneous five-axis thin-wall machining technology)

Daishin Seiki, a member company of NC Network and specialized in the development of prototyping, exhibited its advanced simultaneous five-axis machining technology. The helmet in the photo below (right) won OPEN MIND 2009 CAM AWARD (gold medal). Using "hypermill" CAM software, it was machined from a 120kg aluminum mass to only 3.6kg after 150 hours of meshing and thinning.

Ultra thin-wall machining technology (1) Ultra thin-wall machining technology (2)

Nisshin Seiko Inc. (Precision press working technology) (in Japanese)

Nisshin Seiko, a member company of NC Network, specializes in design and manufacture of press die and mold, and press working. The company appealed its precision press working technology that integrates two parts in a single shot without the conventional cutting, die-casting and welding (of bearings) processes. This technology has achieved 90% cost reduction.

Advantage of precision press working technology Application of precision press working technology
Samples of precision press worked parts

Miyaki Co., Ltd. (Alumite treatment processes) (in Japanese)

Miyaki, a member company of NC Network, introduced two types of alumite treatment processes. Kashima coating is an ultra-lubricant hard alumite treatment and WR coating is composite alumite treatment of high resistance against electric erosion and chemicals, both processes are used to make aluminum parts in four-wheeled and two-wheeled automobiles. WR coating is used to form an insulator for hydrogen fuel in FCV and Kashima coating is used in making rocker arms in an engine. In the latter case, the conventional steel-made part was replaced by Kashima coating-treated aluminum counterpart having self-lubricating properties. This leads to the elimination of bearings which, in turn, results in notable weight and cost reduction.

Samples of alumite treatment

Musashi Co., Ltd. (Simultaneous five-axis machining technology) (in Japanese)

Musashi, a member company of NC Network, is fully equipped with advanced machines that include simultaneous five-axis machining centers and vertical CNC lathes. The company has now developed a hale machining process with submicron-scale finished surface roughness that normally belongs to the art of highly skilled engineers. The machined surface after rotary cutting presents spiral cutter marks. The hardly visible marks nevertheless cause gas or fluid to leak and must be removed by a post-cutting polishing by a skilled technician. The hale machining process developed by Musashi gives surfaces free of cutter marks and thus eliminates the need for polishing by technicians.

Characteristics of simultaneous five-axis hale machining

Yamagishi Seisakusho Co., Ltd. (Thin-wall turnery technology) (in Japanese)

Yamagishi Seisakusho is a member company of NC Network. Its main customers are the NSK group companies. Specialized in thin-wall machining. The company had disclosed, during the last year's EV Japan, that its thin-wall precision machined parts were used in the drive motor case on an American automaker's PHEV (ordered through NC Network). This year, Yamagishi again exhibited its expertise in thin-wall turnery technology for manufacturing prototypes.

Characteristics of thin-wall turnery technology Samples of thin-wall machined parts
(motor parts) on display

Namitei Co., Ltd. (Cold-forging method: Irregular-shaped wire processing, terminals and other precision parts) (in Japanese)

Founded in Higashi Osaka City and engaged in cold forging. In 2007, Namitei developed original technology for precision cutting (shearing) of irregular-shaped wires. This won the company a gold prize for the art of manufacturing from the city and also a listing in the 300 small- to medium-sized manufacturers in 2007 by the Japanese Ministry of Economy, Trade and Industry.

Characteristics of cold-forging machining
of irregular-shaped wires
Samples of cold-forged irregular-shaped wires on display

Atect Corporation (Powder injection molding method: Aluminum nitride heat sinks, metallic separators for fuel cells)

Atect, founded in Higashi Osaka City, appealed its aluminum nitride heat sinks and metallic separators for fuel cells leveraging on its power injection moulding technology (PIM). The company is making special efforts to expand business to automotive parts industries and acquired Trial Corporation and Daipla Corporation as consolidated subsidiaries through M&A to gain material development technologies and mass production technologies needed for the PIM business.

Samples of aluminum nitride heat sinks
made by powder injection molding
Samples of metallic separators for fuel cells

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