Patent ID: 7073647

Claim:
A hydraulic pressure control apparatus for a vehicular hydraulic power transmission device with a lock-up clutch whose operating state is changed using a hydraulic pressure difference between an engagement side oil chamber and a disengagement side oil chamber, comprising: a first oil passage that communicates with the disengagement side oil chamber; a second oil passage that communicates with the engagement side oil chamber; a third oil passage that communicates with the engagement side oil chamber; a high pressure oil passage that hydraulic oil is introduced; a low pressure oil passage that hydraulic oil whose pressure is lower than that in the high pressure oil passage is introduced; and a switching control valve which selectively connects each of the second oil passage and the third oil passage to the high pressure oil passage or the low pressure oil passage, according to an operating state of the lock-up clutch, wherein the switching control valve allows one of the second oil passage and the third oil passage to be connected to the high pressure oil passage, and allows the other oil passage to be connected to the low pressure oil passage when the lock-up clutch is in a slip state, wherein the switching control valve allows the second oil passage and the third oil passage to be connected to the high pressure oil passage when the lock-up clutch is completely engaged.