Machine element or mechanism – Rotary member or shaft indexing – e.g. – tool or work turret – Preselected indexed position
Patent
1984-02-29
1985-07-30
Krizmanich, George H.
Machine element or mechanism
Rotary member or shaft indexing, e.g., tool or work turret
Preselected indexed position
192 331, 192 358, 74752A, 74866, B60K 4116, B60K 4118
Patent
active
045314330
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an automatic transmission which is capable of effecting an automatic speed change in accordance with a predetermined shift pattern by actuating shift valves by means of hydraulic pressure representing the vehicle speed and of hydraulic pressure representing the engine load.
BACKGROUND ART
Vehicle having automatic transmission may include auxiliary devices which should be controlled at the time of shifting or corresponding to shift positions, e.g. direct clutch lock-up device, ignition advance device, exhaust processing device and the like. In this case, the automatic transmission must include a shift position detector. Conventionally, such a shift position detector is known, which includes a hydraulic pressure switch operated by detecting working hydraulic pressure which is delivered to friction elements for selecting each shift position of the automatic transmission, e.g. rear clutch, front clutch, band brakes and the like, wherein shifting is detected by ON or OFF of the pressure switch. However, the working hydraulic pressure to actuate the friction elements is not applied at the same instant with the actuation of the shift valve, and is applied with some time lag from the actuation of the shift valve due to delayed response of hydraulic system. Thus, conventional shift detector can not detect the shifting at the actual instant thereof when the shift valve is actuated, and accompanies some actuation delay. Also such a shift detector requires a design modification to add a hydraulic circuit for operating the pressure switch to a hydraulic system of shift control apparatus of automatic transmission. Besides, the pressure switch itself is relatively expensive. Consequently, manufacturing cost of such a shift detector inevitably increases.
DISCLOSURE OF THE INVENTION
Accordingly, an object of the present invention is to provide an automatic transmission including an improved shift detecting apparatus which can detect shift positions without accompanying actuation delay, which does not require design modification the hydraulic control system of the shift controlling apparatus, and which is simple in construction and can be produced economically.
The automatic transmission according to the present invention includes at least one shift valve having a spool which is applied with the hydraulic pressure representing the vehicle speed and, in opposite relation thereto, with the hydraulic pressure representing the engine load, said shift valve being operated in accordance with a predetermined relation between the vehicle speed and the engine load to selectively supply hydraulic pressure to a plurality of friction elements to cause engagement and disengagement of said friction elements selectively, and is characterized by shift valve operation detecting switch means which is directly responsive to the displacement of said spool between one end position and the other end position of the spool to detect said displacement to thereby produce electric output signal representing the operation of the shift valve.
Thus, according to the present invention, shift signal can be detected simultaneously with the operation of the shift valve, i.e. before the actual operation of the friction element(s) so that the detected signal may be utilized to control a lock-up apparatus of a direct drive clutch. By this measure, it is possible to realize normal lock-up condition all through first to third speeds of a forward automatic shifting position (D range), and the lock-up is released only during the actual shifting operation. By this, acceleration and deceleration characteristics and fuel consumption can be substantially improved when compared with a conventional automatic transmission without the lock-up apparatus, or with an automatic transmission which performs the lock-up only at the third speed range.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic illustration showing the construction of a power transmission mechanism for an automatic transmission with a torque co
REFERENCES:
patent: 3002063 (1961-09-01), Giladett
patent: 3621167 (1971-11-01), Burke
patent: 3871250 (1975-03-01), Miyanchi et al.
patent: 3960124 (1976-06-01), Payne
patent: 4041809 (1977-08-01), Dick et al.
patent: 4086456 (1978-04-01), Boue
patent: 4213021 (1980-07-01), Alexander
patent: 4232699 (1980-11-01), Hsu
patent: 4243856 (1981-01-01), Gratzmuller
patent: 4274308 (1981-06-01), Iwanaga et al.
Krizmanich George H.
Nissan Motor Co,. Ltd.
Wright Dirk
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