Abstract: A heat exchanger includes a tank, multiple tubes, a tube support member that supports the multiple tubes, and a shell body joined to the tube support member. The tube support member is cylindrical and includes a first-end cylindrical portion, a second-end cylindrical portion, and an intermediate cylindrical portion having a diameter smaller than that of the first-end cylindrical portion and having a predetermined length in an axial direction between the first-end cylindrical portion and the second-end cylindrical portion. The tank and the first-end cylindrical portion are welded to each other. The shell body and the second-end cylindrical portion are brazed to each other. Outer peripheral portions of the tubes are in contact with and brazed to an inner surface of the intermediate cylindrical portion.

Abstract: A motor control device for controlling a brushless DC motor in a PWM control manner using an inverter circuit according to a position-sensorless method includes: a ripple current estimating device; and a control device. When the magnitude of the ripple current is less than or equal to a threshold value, the control device performs balanced-drive switching that a first output terminal of the inverter circuit is repeatedly and alternately connected to high and low voltage sides of a drive power supply, and the second output terminal of the inverter circuit is repeatedly and alternately connected to the low and high voltage sides. When the magnitude of the ripple current exceeds the threshold value, the control device performs unbalanced-drive switching that the first output terminal is repeatedly and alternately connected to the high and low voltage sides, and the second output terminal is connected only to the low voltage side.

Abstract: A motor control device for controlling a brushless DC motor in a PWM control manner using an inverter circuit according to a position-sensorless method includes: a ripple current estimating device; and a control device. When the magnitude of the ripple current is less than or equal to a threshold value, the control device performs balanced-drive switching that a first output terminal of the inverter circuit is repeatedly and alternately connected to high and low voltage sides of a drive power supply, and the second output terminal of the inverter circuit is repeatedly and alternately connected to the low and high voltage sides. When the magnitude of the ripple current exceeds the threshold value, the control device performs unbalanced-drive switching that the first output terminal is repeatedly and alternately connected to the high and low voltage sides, and the second output terminal is connected only to the low voltage side.