Hydraulic control device for automatic transmission and method for manufacturing the same

A hydraulic control device for an automatic transmission, the hydraulic control device comprising:

• a first layer having a first parting surface and a plurality of first grooves formed in the first parting surface;
• and
• a second layer that has a second parting surface and a plurality of second grooves formed in the second parting surface and facing the plurality of first grooves, and that is stacked on the first layer in a stacking direction with the second parting surface facing the first parting surface of the first layer, so that the plurality of first grooves and the plurality of second grooves form a plurality of first oil passages, wherein
• a first protrusion is formed either between adjacent grooves of the plurality of first grooves on the first parting surface of the first layer so as to protrude toward the second layer or between adjacent grooves of the plurality of second grooves on the second parting surface of the second layer so as to protrude toward the first layer,
• a first recess in which the first protrusion is fitted is either formed in the second parting surface of the second layer if the first protrusion is formed between the adjacent grooves of the plurality of first grooves, or formed in the first parting surface of the first layer if the first protrusion is formed between the adjacent grooves of the plurality of second grooves, and
• the first layer and the second layer are stacked such that the first protrusion is fitted in the first recess between adjacent ones of the first oil passages, and are joined via the first protrusion and the first recess.