Fuel injection device

A fuel injection device for injecting fuel through an injection hole, comprising:

• a control chamber that fuel flows out from or flows into;
• an injection hole valve element configured to open or close the injection hole due to a change of fuel pressure in the control chamber made by the fuel flowing out from or flowing into the control chamber;
• a valve chest connected to the control chamber through a control chamber channel;
• an exhaust channel connected to the valve chest and through which to discharge fuel from the valve chest, an exhaust throttle part of the exhaust channel throttling the exhaust channel to limit a flow rate of fuel flowing through the exhaust channel;
• a control valve displaced in the valve chest to open or close the exhaust channel;
• a pressing part extending in a displacement direction in which the control valve is displaced and configured to move in the displacement direction to press the control valve;
• and
• a pressing passage connecting together the valve chest and the exhaust channel and through which the pressing part is inserted,
• wherein:
• an exhaust port, forming an upstream end portion of the exhaust channel, is provided on an inner peripheral surface of the pressing passage;
• the pressing part includes:
• an abutment part capable of being in contact with the inner peripheral surface of the pressing passage;
• a depressed opposite part opposing the exhaust port at a position away from the exhaust port in a perpendicular direction perpendicular to the displacement direction due to an outer peripheral surface of the pressing part recessed from the abutment part even when the abutment part is in contact with the inner peripheral surface of the pressing passage;
• and
• a pin stepped-surface arranged between the abutment part and the depressed opposite part;
• when the abutment part is in contact with the inner peripheral surface of the pressing passage, a depression dimension of the depressed opposite part relative to the abutment part is set, such that an amount of fuel discharged from the valve chest is defined by the exhaust throttle part instead of a gap between the depressed opposite part and the inner peripheral surface of the pressing passage, and
• the pressing passage includes:
• a first passage part through which the abutment part is inserted;
• a second passage part provided on the valve chest side of the first passage part and expands the pressing passage more than the first passage pan expands the pressing passage;
• and
• a stepped passage part having a passage stepped-surface connecting the first and second passage parts;
• the exhaust port provided on an inner peripheral surface of the second passage part;
• a length dimension of the depressed opposite part is larger than an outer diameter of the depressed opposite part;
• a step dimension as a width dimension of the passage stepped-surface is larger than a depression dimension of the pin stepped-surface in the radial direction of the pressing passage;
• and
• the depression dimension of the pin stepped-surface is set to a value such that an outer circumferential area of an extension region is larger than a channel area of the exhaust throttle part, when the outer circumferential area of the extension region corresponds to the sum of an outer circumferential area of the inside region and the outer circumferential area of the outside region.