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Hydraulic control apparatus and an automatic transmission control system

Imported: 24 Feb '17 | Published: 09 Sep '03

Suguru Futamura

USPTO - Utility Patents

Abstract

A hydraulic control apparatus includes a linear solenoid valve for outputting modulated pressure in response to electric current applied to the linear solenoid valve, a plurality of control valves outputting control pressure in response to the modulated pressure introduced from the linear solenoid valve, a shift valve for switching between the control valves to which is to be introduced the modulated pressure in response to hydraulic pressure supplied to the shift valve, and an ON-OFF solenoid valve for switching the supply of the hydraulic pressure to the shift valve in response to electric current applied to the ON-OFF solenoid valve.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The foregoing and additional features and characteristics of the present invention will become more apparent from the following detailed description considered with reference to the accompanying drawing figures in which like reference numerals designate like elements.

FIG. 1 is a block diagram schematically illustrating the overall control system for an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a schematic illustration of the automatic transmission in which the hydraulic control apparatus is used.

FIG. 3 is a table showing the engagement and release conditions of each of the friction engagement elements for producing various shift stages.

FIG. 4 is a schematic illustration of the hydraulic circuit of the hydraulic control unit of the automatic transmission during a lower speed operating condition.

FIG. 5 is a schematic illustration of the hydraulic circuit of the hydraulic control unit of the automatic transmission during a higher speed operating condition.

FIG. 6 is a table showing the relationships between the driving range and shift pattern set in response to controlling conditions of the hydraulic control unit under each driving range.

FIG. 7 is a schematic illustration of the hydraulic circuit of the hydraulic control unit of the automatic transmission according to a modified arrangement.

FIG. 8 is a schematic illustration of the hydraulic circuit of the hydraulic control unit of the automatic transmission according to a modified arrangement.

FIG. 9 is a schematic illustration of a known hydraulic control unit.

Claims

1. A hydraulic control apparatus comprising:

2. The hydraulic control apparatus according to claim 1, wherein the linear solenoid valve is arranged at a downstream side of the shift valve.

3. An automatic transmission control system comprising:

4. The automatic transmission control system according to claim 3, wherein the plural control valves includes a pair of control valves outputting the control pressure to each friction engaging element associated with any one of the shift stages at a higher speed and to each friction engaging elements associated with any one of the shift stages at a lower speed, and the shift valve which switches the friction engaging elements to which is supplied the control pressure being switched over upon shifting of the shift stage between the higher speed stage and the lower speed stage.

5. The automatic transmission control system according to claim 4, further comprising:

6. An automatic transmission control system comprising:

7. The automatic transmission control system according to claim 6, wherein the linear solenoid valve is arranged at a downstream side of the shift valve.

8. The automatic transmission control system according to claim 6, further comprising:

9. The automatic transmission control system according to claim 8, wherein the control unit controls the electric current applied to the ON-OFF solenoid valve to switch the friction engaging elements to which is to be introduced the control pressure via the shift valve.