Mechanical Component Description

Mechanical Component Description

General Description

The MVB automatic transaxle is used with the 1.8L engine models. This automatic transaxle is a compact and high-capacity 4-speed Electronic Controlled Transaxle. A low-viscosity type transmission fluid is used. For further details, refer to the owners manual.





Component Identification









Torque Converter

The torque converter has optimally designed fluid passages and impeller configuration, resulting in substantially enhanced transmission efficiency to ensure good starting, acceleration and fuel economy. Furthermore, a hydraulically operated lock-up mechanism which cuts power transmission losses due to slippage at medium and high speeds is used.









Fluid Pump





The fluid pump is combined with the torque converter, lubricates the planetary gear units and supplies operating pressure to the hydraulic control.





Valve Unit Body

The valve body consists of the upper and lower valve bodies and 5 solenoid valves. Apply orifice control, which controls the flow volume to the B3 brake, is used.

Solenoids









Upper Valve Body - MVB





Lower Valve Body - MVB





Centrifugal Fluid Pressure Cancelling Mechanism

There are two reasons for improving the conventional clutch mechanism:

* To prevent the generation of pressure by the centrifugal force that is applied to the fluid in piston fluid pressure chamber (hereafter referred to as "chamber A") when the clutch is released, a check ball is provided to discharge the fluid. Therefore, before the clutch can be subsequently applied, it takes time for the fluid to fill the chamber A.
* During shifting, in addition to the original clutch pressure that is controlled by the valve body, the pressure that acts on the fluid in the chamber A also exerts influence, which is dependent upon revolution fluctuations.





To address these two needs for improvement, a canceling fluid pressure chamber (hereafter referred to as "chamber B") has been provided opposite chamber A.





By utilizing the lubrication fluid such as that of the shaft, the same amount of centrifugal force is applied, thus canceling the centrifugal force that is applied to the piston itself. Accordingly, it is not necessary to discharge the fluid through the use of a check ball, and a highly responsive and smooth shifting characteristic has been achieved.

Planetary Gear Unit

A CR-CR type planetary gear is used in the planetary gear unit which is located on the input shaft. In this planetary gear unit, the front planetary carrier is joined to the rear ring gear, and the rear planetary carrier is joined to the front ring gear. As a result, the unit has been made significantly simple and compact.

Component ID and Function