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AISIN AW has developed a new FWD 6-speed automatic transmission “TF-80SC” for luxury cars with high torque engines. This newly developed automatic transmission (A/T) is based on the concept of the FWD 6-speed A/T “TF-60SN” that we have already introduced to the world market. The basic concept for the 6-speed A/T is to achieve weight saving and compact as well as better fuel efficiency and driving performance in comparison with conventional 5-speed A/Ts. Of course the shift feel must be the top level in the world, so we increased torque capacity of the TF-80SC to cover luxury cars with high torque engine. One of the outstanding features of the A/T is an advanced band brake that allows simultaneous pursuits of high capacity, weight saving, size reduction and high efficiency as well as high-quality shift feeling qualified for luxury cars. This paper describes the advantages and structure of the new A/T with a focus on our approach to new technology of the band brake system.

As requirements for protecting the global environment are being heightened on a worldwide scale in recent years, the development of low fuel consumption technologies in order to inhibit the discharge of CO2 is an important issue for the automotive industry. Recently, Toyota has developed a Super CVT for the 1.3-to 1.5-liter class vehicles to further improve their fuel economy. This CVT has been adopted on vehicles equipped with the ‘idling stop system’. The ‘idling stop system’ automatically stops the engine when the vehicle is stopped and the transmission shift lever is in the ‘D’ position (e.g. when the vehicle is at a stoplight). This improves the fuel economy of the vehicle by eliminating fuel consumption while the vehicle is stopped. The conventional CVT poses unique conditions such as startoff time lag or shock after the engine is restarted. These conditions occur because the CVT oil pump cannot generate hydraulic pressure while the engine is stopped.

This paper presents a study on a design methodology for lightweight automatic transmission parts for vehicles. To improve fuel economy of the vehicle, weight reduction is a primary issue when designing automobile parts. Topology optimization, a particularly flexible type of structural optimization method, is an effective tool for developing lightweight designs. However, topology optimization methods available in most commercial software often provide optimization results that include grayscale areas, which cause the designs to be impractical from an engineering and manufacturing standpoint. To overcome this difficulty, we apply a level set-based topology optimization method that yields clear optimal configurations and therefore facilitates further improvement of the product design by engineers. In addition, we consider the imposition of a uniform cross-section constraint to improve the manufacturability of the obtained optimization results.

Recently, 5-speed automatic transmissions have become mainstream through the world, and 6-speed automatic transmissions have also been introduced in the market. Consequently, the issue of shift control is gaining importance, and a trend toward increasing number of gears in automatic transmissions has become apparent. On the other hand, weight saving and downsizing of the transmission, including the hydraulic control unit, are strongly required in order to promote fuel efficiency. To meet these requirements, an electro-hydraulic control unit offering sophisticated functionality desired in order to provide excellent shift quality. As an answer to these requirements AISIN AW developed two types of new 6-speed automatic transmissions in 2002: “TR-60SN” for RWD vehicles and “TF-60SN” for FWD vehicles. Both TR-60SN and TF-60SN have the same structural characteristics.

Aisin AW (AW) and Toyota Motor Corporation (TMC) have developed a new rear wheel drive (RWD) 10-speed automatic transmission, AWR10L65 (TMC name: AGA0), suitable for RWD/AWD luxury passenger cars and sports cars. This 10-speed automatic transmission provides enhanced drivability leading to outstanding driver satisfaction. This has been accomplished using a close ratio gear train with optimized gear steps for rhythmic shift changes and quick acceleration. Low rpm lock-up and highly responsive shift changes result in a direct shift feel. This automatic transmission contributes to improved fuel economy by having higher efficiency and lower mass than current 8-speed RWD automatic transmissions.

AISIN AW has developed a new transmission control module (hereinafter referred to as “TCM”), which can be applied to the world wide FWD 6-speed automatic transmission (hereinafter referred to as “A/T”). This newly developed TCM can contribute to the whole vehicle system as it is integrated to mechanical A/T in the meaning of ‘hardware’, and completed and ensured the functions in the A/T system. This TCM allows us to greatly reduce the number of the wire harness and the connector, and the space for installing TCM, which are required for the conventional style: A/T and TCM are separately installed, so that it can contribute to fuel economy, weight saving, utilization of the space in the engine room and cost reduction. Our Integrated TCM on A/T integrates the functions with the conventional neutral safety switch (hereinafter referred to as “N.S.S/W”) for detecting shift position, so that it allows compact installation to the limited space on A/T.

Aisin AW (AW) and Toyota Motor Corporation (TMC) have developed a new RWD 6 speed automatic transmission, AWR6B45(AC60), suitable for SUV’s and LDT’s in the worldwide market, not only for North America but also for other countries including emerging nations. This 6 speed automatic transmission has achieved low cost, equivalent to AW and TMCs’ current 5 speed automatic transmission, while realizing improvement in both fuel economy and driving performance against current in-house 5-speed automatic transmissions, in addition to satisfying both toughness against various usage and light weight/compactness. They are accomplished by using a compact gear train structure, the latest efficiency improvement technologies, and a high-response, compact hydraulic control system. In addition, the compactness of this 6 speed automatic transmission enables it to replace current 4 speed and 5 speed automatic transmissions for various engine applications.

The new eight-speed automatic transmission direct shift-8AT (UA80) is the first automatic transmission to be developed based on the Toyota New Global Architecture (TNGA) design philosophy. Commonizing or optimizing the main components of the UA80 enables compatibility with a wide torque range, including both inline 4-cylinder and V6 engines, while shortening development terms and minimizing investment. Additionally, it has superior packaging performance by optimizing the transmission size and arrangement achieving a low gravity center. It contributes to Vehicle’s attractiveness by improving driving performance and NVH. At the same time, it drastically improves fuel economy and quietness.

Toyota Motor Corporation has developed a new five-speed automatic transmission (A750E/A750F) for longitudinal front engine rear wheel drive (RWD) vehicles. The development of this transmission has been aimed at improving fuel economy and power performance, achieving the world's top-level weight and compactness, while maintaining high torque capacity. In order to achieve this purpose, the gear train, torque converter, and other components are completely changed, and advanced technology has been applied. Moreover, this automatic transmission has achieved high-quality shift feel and quiet performance. This paper describes the major features and performance of this transmission in detail.

Toyota Motor Corporation has recently developed a new six-speed automatic transmission (A761E) for Front Engine Rear Wheel Drive (FR) vehicles. Following the general trend of increased shift stages and a wider range of gear ratios, this six-speed automatic transmission has been developed with attention paid to the gear steps and a wider range of gear ratios. By balanced selection of close-ratio gears in a wider range, the change greatly improves the power performance and fuel economy of the vehicle. To further improve fuel economy we have adopted new technologies such as low-viscosity ATF, neutral control, and deceleration control by extending the fuel cut range (reset speed). We have also adopted a flat-shaped torque converter, small solenoids, an aluminum oil pump cover, etc. to realize the lightest six-speed automatic transmission in the world.

Toyota Motor Corporation has developed a new six-speed automatic transmission AB60E for longitudinal front engine rear wheel drive (RWD) vehicles. This transmission development was aimed at an improvement of power performance and fuel economy, while achieving a lightweight, compact package and a high torque capacity. In order to achieve this target, a high-capacity ultra-flat torque converter, a highly-rigid transmission case, and an ATF warmer with a valve to switch ATF circuits to an air-cooled ATF cooler have been newly developed. Moreover, a new transmission mode control logic “TOW / HAUL” has been developed to improve power performance and driveability during trailer towing. This automatic transmission has adopted the same gear train and hydraulic control system as the conventional six-speed automatic transmission A760E. This paper describes the structure, major features and performance of the transmission in detail.

TOYOTA has developed the world's first eight-speed automatic transmission (AA80E) for front-engine, rear-drive passenger cars. The AA80E developed for high-torque engines raises the level of power performance and fuel efficiency. To meet the size requirements needed for mounting in a passenger car application, an 8-speed geartrain, torque converter, transmission case and hydraulic control device were all newly-developed. Furthermore, the AA80E has benefited from technical developments to achieve an extremely high level of quietness and shifting performance. In this paper, the details of the AA80E are introduced.