Hydraulic control device for automatic transmission

A hydraulic control device for an automatic transmission provided with a plurality of engagement elements including a first engagement element that is operated by hydraulic pressure and engaged at both a first shift speed and a second shift speed, a second engagement element that is operated by hydraulic pressure, engaged when establishing the first shift speed, and disengaged when establishing the second shift speed, and a third engagement element that is operated by hydraulic pressure, disengaged when establishing the first shift speed, and engaged when establishing the second shift speed, the hydraulic control device for the automatic transmission comprising:

• a solenoid valve capable of supplying an engagement pressure to the second engagement element;
• a pressure regulating valve capable of supplying a first signal pressure;
• a switching valve having
• a first input port to which a first source pressure is input,
• a second input port to which a second source pressure is input,
• an output port that is allocated between the first input port and the second input port,
• a valving element that is movably allocated between the first input port and the second input port, moves to an input port side of a source pressure with a lower pressure between the first source pressure and the second source pressure, blocks communication between the input port of the source pressure with the lower pressure and the output port, establishes communication between an input port of a source pressure with a higher pressure and the output port, and causes the source pressure with the higher pressure to be output from the output port,
• a moving member capable of switching between a locked state in which the valving element is pressed to the first input port side and locked at a blocking position at which the communication between the first input port and the output port is blocked and an unlocked state in which the valving element is movable, and
• an oil chamber that receives an input of the first signal pressure from the pressure regulating valve and causes the first signal pressure to operate to move the moving member to the blocking position, and
• capable of selectively supplying the first source pressure and the second source pressure to the solenoid valve;
• and
• a control unit that, when shifting from the first shift speed to the second shift speed, causes the first signal pressure to be input to the oil chamber of the switching valve with the pressure regulating valve at least until the third engagement element is brought into an engaged state from a disengaged state.