Heating-medium heating unit and vehicle air conditioner using the same

A heating-medium heating unit, comprising:

• a flat PTC heater;
• a first heating-medium circulation box having at least a first box component and a second box component;
• and
• a second heating-medium circulation box having at least a third box component and a fourth box component are stacked on one another;
• a plurality of first heating-medium circulation passages formed in an interior of the first heating-medium circulation box;
• and
• a plurality of second heating-medium circulation passages formed in an interior of the second heating-medium circulation box,
• wherein the first heating-medium circulation box is in contact with a first surface of the flat PTC heater,
• wherein the second heating-medium circulation box is in contact with a second surface of the flat PTC heater,
• wherein the first heating-medium circulation box is stacked on the second heating-medium circulation box,
• wherein a heating medium that circulates through the plurality of first heating-medium circulation passages and the plurality of second heating-medium circulation passages in the first heating-medium circulation box and the second heating-medium circulation box is heated by heat from the PTC heater,
• the heating-medium heating unit further comprising a liquid gasket for sealing at least one of a stacked portion of the first box component and the second box component, a stacked portion of the third box component and the fourth box component, and a stacked portion of the first heating-medium circulation box and the second heating-medium circulation box,
• wherein at least one of the plurality first heating-medium circulation passages or at least one of the plurality second heating-medium circulation passages is for cooling the at least one of the stacked portions,
• wherein the flat PTC heater and the first heating-medium circulation box and second heating-medium circulation box are formed in a rectangular shape,
• wherein, in a plan view of the first box component of the first heating-medium circulation box, at least one of the stacked portion of the first box component and the second box component and the stacked portion of the third box component and the fourth box component has a first part consisting of a pair of sides opposing to each other in parallel to a direction perpendicular to a longitudinal direction of the first heating-medium circulation box at the stacked portion and a second part consisting of a pair of sides opposing to each other in parallel to a longitudinal direction of the first heating-medium circulation box at the stacked portion, the second part crossing the sides of the first part on a same surface as the stacked portion provided with the first part,
• wherein, in a plan view of the first box component of the first heating-medium circulation box, one end in the longitudinal direction of the first part is provided with a hole having a substantially rectangular shape through which a harness passes for connecting a board for controlling the PTC heater, and a distance between the plurality of first heating-medium circulation passages and a side of the hole, the side being nearest to the plurality of first heating-medium circulation passages, is larger than the width of the second part,
• wherein the second part seals a space between the plurality of first heating-medium circulation passages and the outside.