Please select the most similar patent number from A, B, C and D. Which number is?
Provided are an embedded outer rotor electric motor direct-drive lawnmower drive wheel (9) and a lawnmower; the drive wheel (9) comprises a wheel side cover I (11), a wheel side cover II (12), and a drive wheel body assembled from a wheel body (2) and sandwiched between the wheel side cover I (11) and the wheel side cover II (12); the wheel side cover I (1), wheel side cover II (12), and wheel body (2) define a cavity (3); an outer rotor motor (4) is mounted within the cavity (3); the outer rotor part of said outer rotor motor (4) is fixedly arranged opposite the drive wheel body; the inner stator part of said outer rotor motor (4) has a fixed shaft (41) extending out of the wheel side cover I (11) to outside the drive wheel body; the wheel side cover I (11) is provided with a shaft bore I (111) used for causing the fixed shaft (41) to protrude outward. The drive wheel (9) has the outer rotor motor (4) mounted inside the drive wheel (9), and the outer rotor motor (4) directly drives the drive wheel (9) of the lawnmower, thus transmission is accurate and reliable, and the space inside the lawnmower is more reasonable.
A: Disclosed is a lawn mowing machine, comprising a machine body (10) and a lawn mowing mechanism (20), wherein the machine body (10) comprises two driving wheels (131), two driven wheels (132), a power mechanism (12), and a machine frame (11); the power mechanism (12) comprises a power supply device (121) and two electric motors (122) connected to the power supply device (121); the power supply device (121) is arranged on the machine frame (11) and extends in the direction from a rear end part (112) to a front end part (111) of the machine frame (11); the electric motors (122) are symmetrically arranged on two sides of the rear end part (112) of the machine frame (11); each of the driving wheels (131) is correspondingly arranged on each of the electric motors (122) in a drivable manner; the driven wheels (132) are symmetrically arranged on two sides of the front end part (111) of the machine frame (11) correspondingly, thus allowing the driving wheels (131) and the driven wheels (132) to match each other and so support the machine frame (11) to a preset height; and the lawn mowing mechanism (20) is arranged on the machine frame (11) and is kept in a lower space of the machine frame (11). By means of the arrangement, it can be guaranteed that the center of gravity of the lawn mowing machine is located in the middle of the lawn mowing machine by adjusting the balance weight of the lawn mowing machine, and the cruising ability of the lawn mowing machine is improved.
B: A drive wheel set, comprising a common shaft (10) and at least two external rotor motors (20) installed on the common shaft. External rotors (22) of the external rotor motors form drive wheels of the drive wheel set. Also disclosed are a vertical-type wire storage frame, a swing-type wire storage frame, a guide wheel frame, a traction mechanism and a multi-path conveying mechanism using the present drive wheel set. The present drive wheel set is small in size, occupies less space, and is suitable for a situation wherein a plurality of motors need to be driven but sufficient space is lacking.
C: A volute centrifugal fan provided with a permanent magnet brushless motor system, said fan comprising a volute (1), an outer rotor motor (2) mounted within the volute (1) via a support, and an impeller (3) externally sleeved on the outside of the outer rotor motor (2). The impeller (3) is located within the volute (1), the impeller (3) is connected to the outer rotor motor (2), the volute (1) consists of a spiral plate (4) and side plates (5) located on two sides of the spiral plate (4), air inlets (6) are arranged on the side plates (5) on the two sides, one side of the volute (1) is provided with an air outlet (7), a central position of the air outlet (7) is a horizontal plane (8), an opening (9) is arranged on a portion of the spiral plate (4) located above the horizontal plane (8), a bridge arch-type heat sink (10) matched with the opening (9) is mounted at the position thereof, heat dissipation ribs (15) of the bridge arch-type heat sink (10) are sunk via the opening (9) into air passages (16) formed between the volute (1) and the impeller (3), and the bridge arch-type heat sink (10) is closely fitted with a surface of the spiral plate (4). The volute centrifugal fan provided with the permanent magnet brushless motor system changes a heat dissipation effect of a driver in step with changes to a centrifugal fan load, the bigger the load, the better the heat dissipation effect of the driver, thereby ensuring that the driver is in a low temperature operating state, increasing the operational efficiency of the driver, and extending the service life of the driver.
D: Disclosed is a fan, comprising a volute (1), a wind wheel (2), an external rotor motor (3), and a mounting support (4), wherein the centre of the volute (1) is provided with a cavity (10), the two sides of the volute (1) are respectively provided with an air inlet (11), moreover, the volute is provided with an air outlet (12), both the air inlets (11) and the air outlet (12) are in communication with the cavity (10); the wind wheel (2) is located inside the cavity (10); the external rotor motor (3) is mounted outside the volute (1) and at the air inlets (11) of the cavity (10) via the mounting support (4), a shaft extension end (30) of the external rotor motor (3) extends into the cavity (10) to connect to the wind wheel (2), and the external rotor motor (3) and the wind wheel (2) are respectively located on both sides of the mounting support (4). The fan is simple in structure and has good stability.
Answer: A