Electric toothbrush device with built-in shrapnel assembly

An electric toothbrush device with a built-in shrapnel assembly, comprising:

• a toothbrush head, a brush assembly and an electric motor;
• wherein a bottom of the toothbrush head defines an installation hole, the toothbrush head defines a cavity therein, the cavity extends along a direction from the installation hole to the brush assembly, the electric motor comprises a drive shaft, and the drive shaft is configured to pass through the installation hole and is disposed in the cavity;
• wherein the built-in shrapnel assembly is disposed in the cavity, and the built-in shrapnel assembly is disposed to abut against the drive shaft;
• wherein the cavity defines a first segment of an installation position of the built-in shrapnel assembly, and the first segment of the installation position has a flat shaped bottom being fit to the built-in shrapnel assembly;
• wherein the built-in shrapnel assembly comprises an arch-shaped protrusion arched towards the drive shaft, a limiting groove portion, and a guide groove portion;
• the limiting groove portion comprises a left limiting wall and a right limiting wall protruding towards the drive shaft, the arch-shaped protrusion is disposed between the left limiting wall and the right limiting wall to prevent the drive shaft from shifting relative to the arch-shaped protrusion, a top of the guide groove portion is connected to the limiting groove portion, and a bottom of the guide groove portion extends towards the installation hole;
• the guide groove portion comprises a left guide wall, a right guide wall, and a first surface;
• the left guide wall and the right guide wall both protrude towards the drive shaft, and the first surface is disposed between the left guide wall and the right guide wall;
• the left limiting wall and the right limiting wall are respectively connected with the left guide wall and the right guide wall, thereby the left limiting wall and the right limiting wall are in combination with the left guide wall and the right guide wall respectively to extend across an entire length of the built-in shrapnel assembly;
• and
• wherein a side of the drive shaft facing towards the built-in shrapnel assembly defines a tooth groove matching the arch-shaped protrusion, and the drive shaft is disposed to press against the arch-shaped protrusion to cause the arch-shaped protrusion to undergo an elastic deformation, to thereby securely fix the drive shaft in the cavity.