Cooking appliance

A cooking appliance comprising:

• a housing having a bottom part, two side parts, and a back part, and a cooking compartment formed therein, wherein the housing has an upper surface and a front surface which are open;
• a door for opening and closing the upper surface and the front surface of the housing, wherein the door is rotatable about a rotation axis parallel to an upper edge of the back part of the housing, and wherein the door includes a door upper surface part for covering the upper surface of the housing and a door front surface part extending from a front portion of the door upper surface part for covering the front surface of the housing;
• a tray disposed in the cooking compartment;
• and
• a hinge assembly including a hinge case disposed at a side part of the housing and accommodating a hinge part, a mounting protrusion, and a converting and outputting part therein, the hinge part for rotatably mounting the door to the housing, and the converting and outputting part includes a gear connected to the hinge part and rotatable with changes in a posture of the hinge part, and a rack gear movable by the gear for converting a force input by the changes in the posture of the hinge part to a linear force for moving the mounting protrusion with the movement of the rack gear linearly in the front-rear direction, wherein the rack gear moves forward with a rotation of the gear in response to a first change in the posture of the hinge part when the door is opened thereby moving the mounting protrusion forward and moves rearward with the rotation of the gear in response to a second change in the posture of the hinge part when the door is closed thereby moving the mounting protrusion rearward, wherein the mounting protrusion protrudes toward an inside of the cooking compartment for removably mounting the tray thereon, wherein an opening or closing motion of the door causes the mounting protrusion to move forward to withdraw the tray forward from the cooking compartment when the door is opened and to move rearward to insert the tray rearward into the cooking compartment when the door is closed.