Ceiling fan having double-layer blades

1. A ceiling fan, comprising:

a motor unit, including a motor, the motor having a rotating component;

a blade frame unit, having a blade frame body, the blade frame body being arranged on an outer peripheral side of the motor, the blade frame body being fixedly connected to the rotating component of the motor, an upper end of the blade frame body having an upper mounting portion, a lower end of the blade frame body having a lower mounting portion;

a first blade unit, including a plurality of first blades, the first blades each having a first fixing portion, a first extension wall and a first blade portion, the first fixing portions of the first blades being fixed to the upper mounting portion, the first extension wall and the first blade portion of each first blade being connected to each other, the first extension walls of the first blades extending axially along the blade frame body, the first extension walls of the first blades surrounding an outside of the blade frame body to collectively form a first casing, the first casing having a first accommodating space therein; and

a second blade unit, including a plurality of second blades, the second blades each having a second fixing portion, a second extension wall and a second blade portion, the second fixing portions of the second blades being fixed to the lower mounting portion, the second extension wall and the second blade portion of each second blade being connected to each other, the second extension walls of the second blades extending axially along the blade frame body, the second extension walls of the second blades surrounding the outside of the blade frame body to collectively form a second casing, the second casing having a second accommodating space therein, the first accommodating space of the first casing and the second accommodating space of the second casing being configured to accommodate the blade frame body and the motor,

wherein the second extension walls of the second blades are adjacent to and beneath the first extension walls of the first blades;

one side of a top of the first extension wall of each first blade, adjacent to the first blade portion, and the first blade portion have a first inner arc portion extending toward an axis of the blade frame body, the first fixing portions of the first blades are disposed on the first inner arc portions respectively, another side of the top of the first extension wall of each first blade, opposite to the first blade portion, is formed with a first edge, the first edge of each first blade is lower than the first inner arc portion, each first edge corresponds to the first inner arc portion of a coupled one of the first blades for the first inner arc portion of the coupled first blade to pass therethough, one side of the first inner arc portion of each first blade, adjacent to the first edge, is provided with a first abutting surface to abut against the first inner arc portion of the coupled first blade; and

one side of a top of the second extension wall of each second blade, adjacent to the second blade portion, and the second blade portion have a second inner arc portion extending toward the axis of the blade frame body, the second fixing portions of the second blades are disposed on the second inner arc portions respectively, another side of the top of the second extension wall of each second blade, opposite to the second blade portion, is formed with a second edge, the second edge of each second blade is lower than the second inner arc portion, each second edge corresponds to the second inner arc portion of a coupled one of the second blades for the second inner arc portion of the coupled second blade to pass therethough, and one side of the second inner arc portion of each second blade, adjacent to the second edge, is provided with a second abutting surface to abut against the second inner arc portion of the coupled second blade.

2. The ceiling fan as claimed in claim 1 , wherein the blade frame body has an annular wall, a top end of the annular wall has an upper flange extending radially and outwardly, the upper mounting portion is disposed on the upper flange, the first inner arc portions are arranged on top of the upper flange so that the upper flange supports the first inner arc portions, a bottom end of the annular wall has a lower flange extending radially and outwardly, the lower mounting portion is disposed on the lower flange, the second inner arc portions are arranged on top of the lower flange so that the lower flange supports the second inner arc portions, a motor mounting portion extends from an inner side of the annular wall toward the axis, and the rotating component of the motor is connected to the motor mounting portion.

3. The ceiling fan as claimed in claim 2 , wherein an upper retaining portion is fixedly connected to a top of the motor, the upper retaining portion is fixedly connected to a down rod to be fixed to a ceiling, the ceiling fan further comprises an upper cover, the down rod is inserted through the upper cover, the upper cover is located between the first inner arc portions of the first blades, a lower retaining portion is fixedly connected to a bottom of the motor, the ceiling fan further comprises a lamp, the lamp has a lamp module and a lampshade, the lamp module is fixedly connected to the lower retaining portion, and the lampshade is fixed to an outside of the lamp module and located under the second extension walls of the second blades.

4. The ceiling fan as claimed in claim 3 , wherein the first blade portions of the first blades and the second blade portions of the second blades are arranged crosswise, the upper retaining portion is fixedly connected to the down rod through a connecting seat, the upper cover is disposed on an outside of the connecting seat, and the upper cover is located above the blade frame body.

5. The ceiling fan as claimed in claim 4 , wherein the upper mounting portion and the first fixing portions of the first blades are composed of screw holes and are locked with screws; the lower mounting portion and the second fixing portions of the second blades are composed of screw holes and are locked with screws.

6. The ceiling fan as claimed in claim 2 , wherein the first blade portions of the first blades and the second blade portions of the second blades are arranged crosswise.

7. The ceiling fan as claimed in claim 1 , wherein the first blade portions of the first blades and the second blade portions of the second blades are arranged crosswise.