Valve seat machining device, and valve seat machining method using said valve seat machining device

A valve seat processing machine configured to process a valve seat in a valve device including a valve body portion which defines a flow passage of fluid and a valve drive portion which is detachably positioned on the valve body portion and which is configured to open and close the flow passage by driving a valve element capable of engaging with the valve seat in the valve body portion, the valve seat processing machine comprising:

• a base portion configured to be attached to the valve body portion;
• a main body portion on the base portion, the main body portion being movable relative to the base portion in two different axial directions;
• a support portion on the main body portion, the support portion being movable relative to the main body portion in a drive direction of the valve element;
• a main spindle on the support portion, the main spindle being rotatable relative to the support portion about an axis parallel to the drive direction of the valve element;
• a tool holding device on the main spindle, the tool holding device being configured to hold a cutting tool for processing the valve seat, and being movable relative to the main spindle in a direction intersecting the drive direction of the valve element;
• a controller configured to perform control of moving the support portion or the main spindle in the drive direction of the valve element and to perform control of moving the tool holding device relative to the main spindle in the direction intersecting the drive direction of the valve element;
• and
• a ring member rotatably attached to an outer periphery of the main spindle and fixable to the valve body portion,
• wherein the main body portion includes a pressing device for pressing the base portion to form a gap between the main body portion and the base portion from a state in which the main body portion and the base portion are in contact with each other.