Patent ID: 7648057

Claim:
An ultrasonic joining method comprising: arranging a first horn and a second horn of a horn unit in a circumferential direction of a flange portion of a first member on a first side of the flange portion, a second side of the flange portion, which is opposite to the first side, facing a portion of a second member, the first horn being connected to an oscillator; and joining the flange portion to the portion of the second member by applying vibration to the flange portion by the first horn and the second horn in a condition that the first horn and the second horn are pressurized to the flange portion so that the flange portion is vibrated while being pressurized to the portion of the second member, wherein in the arranging, the second horn is biased against the first horn such that the first horn and the second horn are in press-contact with each other at press-contact portions thereof, in the joining, the first horn is vibrated by the oscillator and the second horn is vibrated by receiving vibration of the first horn through the press-contact portions, and the arranging includes connecting the first horn and the second horn such that a tubular portion of the first member is located in an opening defined by the first horn and the second horn.