Interrelated power delivery controls – including engine control – Transmission control – Transmission controlled by engine
Patent
1996-07-08
1999-07-13
Ta, Khoi Q.
Interrelated power delivery controls, including engine control
Transmission control
Transmission controlled by engine
477143, 477158, F16H 6126
Patent
active
059218886
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an automatic transmission system for automotive vehicle and, more particularly, to an automatic transmission system wherein four solenoid valves are adopted to control shift valves such that a construction of the system can be simplified and shift feeling can be improved.
2. Description of the Conventional Art
A conventional automatic transmission for an automotive vehicle has a torque converter and a multiple stage transmission gear mechanism connected to the torque converter. The torque converter includes hydraulically activated friction elements for selecting one of the gear stages of a transmission gear mechanism according to the vehicles operating condition.
A hydraulic control system pressurized by a hydraulic pump provides the hydraulic pressure required to operate the friction elements and control valves.
A commonly used automatic transmission of a vehicle has a hydraulic torque converter which generally includes a pump impeller connected with an engine output shaft to be driven thereby, a turbine runner with an output shaft member, and a stator disposed between the pump impeller and the turbine runner, so that the fluid is circulated by the engine driven pump impeller through the turbine runner with the aid of the stator which functions to deflect the fluid from the turbine runner to a direction where the fluid flow does not disturb the rotation of the pump impeller when the fluid flows into the pump impeller.
Automatic shifting is performed by operating the friction elements such as clutches or a kick-down brake at each shifting stage.
Also, a manual valve (where ports are converted by selecting a position of the selector lever), is supplied with fluid from the hydraulic pump and supplies the fluid to a shift control valve.
U.S. Pat. No. 3,754,482 discloses one of the automatic transmissions described above having first and second shifting devices, wherein two friction elements among four friction elements are activated, selectively, to perform several speed stages.
Because known automatic transmission systems of the kind explained above can perform four forward speed stages and one reverse speed stage only, it is difficult to improve power transmission efficiency; and, because the systems cannot perform skip shifting, they exhibit slow responsiveness.
These conventional automatic transmission systems have a complicated valve body construction. Thus, the valve body is expensive and difficult to manufacture because there are many valves in the systems. Also, shift feeling is not good when shifting a speed stage.
SUMMARY OF THE INVENTION
An object of the invention is to solve the above-mentioned problems of the conventional system. Provided for this purpose is an automatic transmission system which can perform five forward speeds and one reverse speed and can perform skip shifting such that shifting responsiveness can be improved.
Another object of the invention is to provide an automatic transmission system wherein four solenoid valves are adopted to control shift valves and control is performed sequentially. By doing so the construction of the system can be simplified and shift feeling can be improved.
In order to accomplish these and other objectives, the invention provides an automatic transmission for an automotive vehicle comprising a hydraulic pump driven by an engine for pressurizing fluid; a pressure regulating valve for varying hydraulic pressure supplied from the hydraulic pump when driving the vehicle forward or rearward; a torque converter for transmitting power from the engine to an input shaft of the transmission; a converter clutch regulator valve for activating a damper clutch to improve a transmission efficiency of the torque converter; a solenoid supply valve for receiving line pressure from the pressure regulating valve and supplying reduced pressure to the first, second, third, fourth, fifth, sixth and seventh solenoid valves; a first friction element commonly activated at each speed stage; a se
REFERENCES:
patent: 3754482 (1973-08-01), Sanders et al.
patent: 4776240 (1988-10-01), Miki
patent: 5582559 (1996-12-01), Jang et al.
patent: 5637056 (1997-06-01), Park
Form PCT/ISA/210 for PCT/KR95/00049.
Hyundai Motor Company
Ta Khoi Q.
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