Machine element or mechanism – Rotary member or shaft indexing – e.g. – tool or work turret – Preselected indexed position
Patent
1988-03-01
1990-02-27
Braun, Leslie A.
Machine element or mechanism
Rotary member or shaft indexing, e.g., tool or work turret
Preselected indexed position
74867, B60K 4106
Patent
active
049035509
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hydraulic control device particularly designed for an automatic transmission of an automobile having a multiple speed transmission such as a five speed automatic transmission, and in detail relates to a hydraulic control device for setting gear ratios which are different from those of a conventional automatic drive range during a "manual-shift-down" such as from Drive to 3rd, 2nd and 1st range by a shift lever.
2. Description of the Prior Art
An automatic transmission, in general, performs a shift down operation through an ordinary gear ratio as well as manual shift down performed by a shift lever to reduce the speed of a vehicle on a long down slope and when passing other cars.
An applicant of the present invention, as shown in the Japanese Pat. No. 57-37140, proposed an automatic transmission having a sub-transmission mechanism (two forward speeds) and a main-transmission mechanism (three forward speeds), with the transmission of both sub and main transmission mechanisms operated by respective shift valves, which makes possible an automatic transmission having six forward speeds. The thus proposed automatic transmission has six forward speeds in the Drive range from the combination of sub and main transmission mechanisms, while on the other hand, the automatic transmission has three forward speeds in the combined intermediate and low ranges when the submechanism is not used.
Accordingly, a conventional three or four forward speed automatic transmission only regulates shifting to a higher speed with an ordinary gear ratio and cannot select a suitable gear ratio for the running condition even though manual shift down is performed to obtain higher acceleration when passing other vehicles or applying the engine as a brake when a vehicle is running on a long down slope.
Furthermore, a multiple speed automatic transmission device having a main transmission mechanism and a sub transmission mechanism can have different shifting patterns in the Drive range and the intermediate and low ranges; however, in such an arrangement, three solenoid valves are required for first, second and third shift valves respectively. Incorporating expensive solenoid valves in the system causes the total cost of the automatic transmission to increase.
OBJECT AND BRIEF SUMMARY OF THE INVENTION
It is the object of the present invention to provide a hydraulic control device capable of providing shifting pattens different from ordinary shift patterns by manual shifting operations, but in which the number of solenoid valves is not increased beyond the number employed normally. To this end, there is provided a hydraulic control device which can be applied, for example, to a five speed automatic transmission with four selectable gear ranges D-3-2-1, and in which first and second solenoid valves are provided to constrain first, second and third shift valves and the down shift control valve in accordance with a certain range of movement of the manual valve. Because of the above arrangement, the structure of the hydraulic control device is kept simple and does not require adding expensive solenoid valves. Furthermore, a multiple speed transmission is provided which has different types of shift patterns having gear ratios different from an ordinary automatic transmission when manual shift down is performed. Because the hydraulic control device is simple and compact, in addition to having high fuel efficiency, suitable braking with the engine and suitable acceleration are obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic sectional view of a main portion of a hydraulic control device in accordance with the present invention;
FIG. 2 is a schematic view of an automatic transmission mechanism to which the control device of the present invention is applicable;
FIG. 3 is a diagrammatic view of a hydraulic control device applied to a transmission; and
FIG. 4 is an operation table showing the operation of the device of FIG. 3.
DESCRIPTION OF
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Kuwayama Yoshinari
Miura Masakatsu
Yokoyama Fumitomo
Aisin-Warner Kabushiki Kaisha
Braun Leslie A.
Campbell Christopher
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