Wheel device, sole, and wheel extending and retracting operation method

A wheel device, comprising:

• a wheel seat, wherein the wheel seat is provided with an accommodation cavity that has an opening in a bottom and a mounting cavity that has an opening in a rear, the mounting cavity is arranged in a front-back extending manner and is in communication with the accommodation cavity, and a mounting recess and a limit member that detachably fits in the mounting recess are arranged at a rear side of the wheel seat and above the opening in the rear of the mounting cavity;
• an opening and closing assembly, wherein the opening and closing assembly comprises an opening and closing board that has an opening and closing hole and a return member configured to return the opening and closing board, the opening and closing board slidably fits in the mounting cavity, a rear end of the opening and closing board extends out of the mounting cavity, and the rear end of the opening and closing board has a retaining portion that upwards protrudes and movably abuts against the limit member;
• and
• a wheel assembly, wherein the wheel assembly comprises a central shaft, a control block and two wheels that are arranged at two ends of the central shaft in an axially fixed and circumferentially rotatable manner respectively;
• the control block sleeves the central shaft between the two wheels, the wheels protrude downwards relative to a bottom end of the control block, the wheel assembly vertically-liftably fits in the accommodation cavity, and an ejection member is mounted between a top wall of the accommodation cavity and the control block;
• and a first necking portion located at an upper portion of the control block and a second necking portion located at a lower portion of the control block are arranged at an interval on a peripheral surface of the control block, and the control block is further provided with an upper stopping portion above the first necking portion and a lower stopping portion below the second necking portion;
• wherein
• the opening and closing board has a locking work position where the rear end of the opening and closing board is far away from the limit member, an extending and retracting work position where the rear end of the opening and closing board abuts against the limit member, and a dismounting and mounting work position where the opening and closing board slides forwards to a frontmost end after the limit member is dismounted;
• under the condition that the opening and closing board is at the dismounting and mounting work position, the control block integrally enters and exits the opening and closing hole to dismount and mount the wheel assembly;
• under the condition that the opening and closing board is at the locking work position, the opening and closing board is snapped by the first necking portion to cause the wheel assembly to protrude from the wheel seat or is snapped by the second necking portion to cause the wheel assembly to retract into the wheel seat;
• and under the condition that the opening and closing board is at the extending and retracting work position, a portion, between the first necking portion and the second necking portion, of the control block lifts vertically in the opening and closing hole, and the opening and closing board blocks the upper stopping portion and the lower stopping portion.