Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
311 words
A hydraulic pressure control device for an automatic transmission for a vehicle, comprising: a manual shift valve (200) for selecting a forward range (D) in which at least one forward speed stage is enabled and a reverse range (R) in which a reverse stage is enabled; a first hydraulic pressure control valve (60) having a first and a second control signal port (66, 68) and controlling switching over of an operation of the automatic transmission according to conversion between supply and non supply of a first and a second signal hydraulic pressure (P L , P C4 ) to said first and said second control signal port, respectively, said second signal hydraulic pressure being available in a certain forward speed stage or stages but not available in the reverse stage, said first hydraulic pressure control valve being reactive to the conversion between supply and non supply of said first signal hydraulic pressure when and only when said second signal hydraulic pressure is supplied; a second hydraulic pressure control valve (100) having a third control signal port (108 or 104) and selectively interrupting transmission of a third signal hydraulic pressure (P L(R) ) according to conversion between supply and non supply of said first signal hydraulic pressure (P L ) to said third control signal port, said third signal hydraulic pressure being available when and only when the manual shift valve is set to the reverse range and serving to set up the reverse stage; and a third hydraulic pressure control valve (92) for controlling the conversion between supply and non supply of said first signal hydraulic pressure (P L ) so that in the forward speed stage at which said second signal hydraulic pressure is available said operation of the automatic transmission is selectively switched over and in the reverse range the setting up of the reverse stage is selectively interrupted.
Claim 2
Dependent Claim
311 words
A hydraulic pressure control device for an automatic transmission for a vehicle, comprising: a manual shift valve (200) for selecting a forward range (D) in which at least one forward speed stage is enabled and a reverse range (R) in which a reverse stage is enabled; a first hydraulic pressure control valve (60) having a first and a second control signal port (66, 68) and controlling switching over of an operation of the automatic transmission according to conversion between supply and non supply of a first and a second signal hydraulic pressure (P L , P C4 ) to said first and said second control signal port, respectively, said second signal hydraulic pressure being available in a certain forward speed stage or stages but not available in the reverse stage, said first hydraulic pressure control valve being reactive to the conversion between supply and non supply of said first signal hydraulic pressure when and only when said second signal hydraulic pressure is supplied; a second hydraulic pressure control valve (100) having a third control signal port (108 or 104) and selectively interrupting transmission of a third signal hydraulic pressure (P L(R) ) according to conversion between supply and non supply of said first signal hydraulic pressure (P L ) to said third control signal port, said third signal hydraulic pressure being available when and only when the manual shift valve is set to the reverse range and serving to set up the reverse stage; and a third hydraulic pressure control valve (92) for controlling the conversion between supply and non supply of said first signal hydraulic pressure (P L ) so that in the forward speed stage at which said second signal hydraulic pressure is available said operation of the automatic transmission is selectively switched over and in the reverse range the setting up of the reverse stage is selectively interrupted.
Claim 3
Dependent Claim
43 words
A hydraulic pressure control device according to claim 1, wherein said first hydraulic pressure control valve (60) is a lock-up clutch relay valve for controlling engagement and disengagement of a lock-up clutch (3) for a torque converter (1) incorporated in the automatic transmission.
Claim 4
Dependent Claim
73 words
A hydraulic pressure control device according to claim 1, wherein said third hydraulic pressure control valve (92) is a solenoid valve having a drain port (94) which is normally closed and selectively opened when energized to drain said first signal hydraulic pressure so as to effect the conversion from supply to non supply of said first signal hydraulic pressure (P L ) to said first and said third control signal port (66, 108).
Claim 5
Dependent Claim
89 words
A hydraulic pressure control device according to claim 1, wherein said third hydraulic pressure control valve (92) is a solenoid valve having a drain port (94) which is normally opened to drain said first signal hydraulic pressure so as not to supply said first signal hydraulic pressure to said first and said third control signal port (66, 104) and selectively closed when energized so as to effect the conversion from non supply to supply of said first signal hydraulic pressure to said first and said third control signal port.
Claim 6
Dependent Claim
60 words
A hydraulic pressure control device according to claim 3, further comprising a three-way check valve (120) which selectively conducts either said first signal hydraulic pressure (P L ) or said third signal hydraulic pressure (P L(R) ) delivered through said second hydraulic pressure control valve (100) to said third control signal port (108) of said second hydraulic pressure control valve.
Claim 7
Dependent Claim
97 words
A hydraulic pressure control device according to claim 4, wherein said second hydraulic pressure control valve (100) has a fourth control signal port (108) opposite to said third control signal port (104), and the hydraulic pressure control device further comprises a three-way check valve (120) which conducts either said third signal hydraulic pressure (P L(R) ) delivered through said second hydraulic pressure control valve (100) or a hydraulic pressure (P L(D, 2, L) ) available in said certain forward speed stage or stages to said fourth control signal port (108) of said second hydraulic pressure control valve.