Damper Overfill Chamber to Increase Functional Robustness Regarding Variance in Parts and Processes

A drug delivery device comprising:

• a housing having a proximal end, a distal end, and a longitudinal axis extending between the proximal end and the distal end thereof;
• a needle assembly at least partially disposed within the housing at the proximal end thereof, the needle assembly comprising a syringe barrel containing a medicament and a needle or a cannula;
• a drive assembly at least partially disposed within the housing and operably coupled to the needle assembly to urge the medicament through the needle or cannula;
• and
• a damper mechanism at least partially disposed within the housing adjacent to the distal end thereof, the damper mechanism being operably coupled to the drive assembly and the housing, wherein upon activating the drive assembly, the damper mechanism dampens an effect thereof, the damper mechanism comprising:
• a frame member;
• a damper member operably coupled to the drive assembly;
• a damper fluid chamber formed between at least a portion of the frame member and the damper member;
• and
• a damper fluid disposed within the damper fluid chamber, wherein upon activating the drive assembly of the drug delivery device, the frame member and the damper member rotate relative to each other and the damper fluid exerts an opposing force on at least one of the frame member and the damper member, and
• wherein the damper fluid chamber includes a main section and an overfill section, the overfill section being configured to receive excess damper fluid from the main section to reduce an effect a variation in fill level in the damper fluid chamber has on the opposing force exerted on at least one of the frame member and the damper member, the main section having a first thickness defined between an inner surface of the frame member and an outer surface of the damper member, and the overfill section having a second thickness defined between the inner surface of the frame member and the outer surface of the damper member that is greater than the first thickness of the main section.