As the advancement of technology, most people nowadays increasingly depend on various electronic devices; however, the electronic elements in the electronic devices, such as Personal Computers, Laptops, generate higher and higher heat during operation thereof to cause a greatly raised temperature inside the electronic devices. Yet the high temperature environment adversely affects the performance of the electronic elements and can even cause damage to the electronic elements. In order to keep the electronic device work normally, it is necessary to use a fan to maintain the electronic device at an optimal working temperature.
Please refer to FIG. 1, which is a perspective exploded view of a conventional series fan 1. The series fan 1 includes a fan frame 10, fan impeller 11, a fastening element 12, and a motor (not shown). As shown, all the fan frames 10 of the series fan 1 have the same size. The fan frame 10 is assembled with the fan impeller 11, the motor to combine into the fan. The fan tends to produce vibration during the operation thereof due to motor torque; in particular the series fan 1 is composed of two fans which are serially connected to each other. Conventionally, two fans are serially connected to each other with the fastening element 12, such as a clamping or a screwing structure.
Since the fans are axially connected to each other, and therefore, the vibration cannot be redacted. The vibration also brings noise and reduces the system stability. Moreover, two fan frames 10 generate a great amount of noise and resonance when the fan impellers 11 of the two fan frames 11 operate at the same time. In addition, the air is blown in one fan of the series fan 1 cannot be flow out of the other fan of the series fan 1 since they are serially connected when operation, so as to have low air volume.
According to the above, the conventional series fan has the following shortcomings: (1). the vibration absorption effect is poor; (2). more noise is made due to poor vibration effect; and (3). incapable of providing higher air volume.
It is therefore tried by the inventor to develop an improved series fan structure to overcome the drawbacks and problems in the conventional series fan structure.