Patent ID: 7273136

Claim:
A hydraulic parking brake device of a vehicle, wherein the device is selectively switched between a braking state and a non-braking state, the device comprising: a braking portion, which generates a braking force, the braking portion having a control oil chamber into which hydraulic oil flows, the braking force decreasing as the pressure in the control oil chamber increases and increasing as the pressure in the control oil chamber decreases; an oil tank; a hydraulic pump; a supply passage, which connects the hydraulic pump to the control oil chamber in the non-braking state; a discharge passage, which connects the control oil chamber to the oil tank in the braking state; a discharged oil restrictor located in the discharge passage; an accumulator connected to the control oil chamber, the accumulator being capable of releasing hydraulic oil to the control oil chamber when the braking force is greater than that at the time when the parking brake device is switched from the non-braking state to the braking state and the braking force can further be increased during the braking state of the parking brake device; an accumulator passage, which connects the accumulator to the control oil chamber; an oil accumulation restrictor located in the accumulator passage; an oil releasing bypass passage, which connects the accumulator to the control oil chamber bypassing the oil accumulation restrictor; and an oil releasing check valve located in the oil releasing bypass passage, wherein the oil releasing check valve permits flow of hydraulic oil from the accumulator to the control oil chamber.