Throttle device with cover for internal elements

A throttle device includes a throttle body (1) and a cover (18) adapted to be mounted to the throttle body. A coupling device (13, 15; 51, 53) includes a first engaging portion (15; 51) disposed on one of the throttle body and the cover and a second engaging portion (13; 53) disposed on the other of the throttle body and the cover. The first and second engaging portions are engageable with each other when the throttle body and the cover is moved toward each other in a first direction, so that the throttle body and the cover are prevented from moving away from each other in a second direction opposite to the first direction. Means (1d; 1e: 53b) is provided for preventing accidental or unauthorized intentional access to the first or second engaging portions in order to disengage the first and second engaging portions.