Abnormality detection for hydraulic circuit and abnormality detection method for hydraulic circuit

An abnormality detection device for a hydraulic circuit comprising an oil pump capable of increasing a pressure of oil sucked through a suction port and discharging the oil through discharge ports, a switching unit that switches between a fully discharged state where oil is discharged to an oil passage through all the discharge ports and a partially discharged state where oil is discharged to the oil passage through part of the discharge ports, a pressure regulator that regulates a pressure of oil discharged in the oil passage in either one of the discharge states switched by the switching unit, a pressure regulation controller that controls the pressure regulation of the pressure regulator and a hydraulic detector that detects a hydraulic pressure regulated by the pressure regulator, the device comprising:

• a storage that stores a maximum discharge pressure of oil that is allowed to the discharged in the partially discharged state;
• a switching controller that performs switching control to switch to the fully discharged state by the switching unit;
• and
• a determination unit that determines that the switching unit has a fixation abnormality of the partially discharged state when a hydraulic pressure detected by the hydraulic detector approximately corresponds to the stored maximum discharge pressure in the partially discharged state in a state where, in conjunction with the switching control performed by the switching control unit directed towards switching to the fully discharged state, the pressure regulation controller sets a target hydraulic pressure to a hydraulic pressure higher than the maximum discharge pressure in the partially discharged state stored in the storage, and performs pressure regulation control on the pressure regulator in an effort to achieve the target hydraulic pressure.