RELATED APPLICATIONS

The present application claims the priority of Taiwan Application No. 108203792, filed Mar. 28, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure generally relates to a gearbox with motor fixing structure, and, more particularly, to a gearbox that uses a metal piece to connect the motor, and then uses a upper casing and a lower casing to engage and clamp the metal piece to fix the motor.

2. Description of the Related Art

Handheld machine tools, such as polishing machines or waxing machines, mainly include the internal components of a motor plus a gearbox according to the mechanism design. When designing the component configuration of the internal mechanism of the handheld machine tools, designers usually need to consider some issues, like temperature, stability, strength of the system and running noise. Since the motor shaft is connected to the gear set inside of the gearbox, the vibration produced by the motor during the operation itself will affect the structural stability inside the gearbox and the temperature will rise caused by the operation of the gear set.

Furthermore, some designers of handheld machine tools on the market replace the gear set materials from metal to plastic materials to reduce the noise and the heat during the operation. However, the structure containing both plastic components and metal components may result in poor structural strength when the plastic gear set and the metal motor are assembled.

Therefore, how to improve the internal structure of the current gearbox to overcome the poor structural strength of the motor gearbox configured with plastic gear set and metal motor is a problem still to be solved in the industry.

SUMMARY OF THE INVENTION

The present inventive concept provides a gearbox with motor fixing structure used to fix a motor on the gearbox. The motor has a body and a shaft protruding from the leading edge of the body. The gearbox with motor fixing structure comprises a box having a gear set configured inside, wherein an outer edge of a side wall of the box has a first hole; and a metal part configured inside the box, wherein the motor is embedded in the first hole, the leading edge of the body of the motor is locked on the metal part, and the shaft of the motor passes through the metal part into the box to connect with the gear set.

In an exemplary embodiment, the box comprises there inside a first space and a second space. The gear set comprises a worm and an epicyclic gear set engaged with the worm. The worm is disposed in the first space, and the epicyclic gear set is disposed in the second space.

In an exemplary embodiment, the box and the gear set are made of plastic material.

In an exemplary embodiment, the metal part is a U-shaped structure and disposed in the first space. The metal part has a first passing hole at one end and a second passing hole aligned with the first passing hole at the other end, and the shaft of the motor passes through the first passing hole and the second passing hole to connect with the worm.

In an exemplary embodiment, the metal part has an opening, and the shaft of the motor passes through the opening to connect with the worm.

In an exemplary embodiment, the gearbox further comprises a partition wall and the first space further comprising a first accommodating portion and a second accommodating portion, wherein the partition wall is disposed in the first space inside the box. The partition wall is used to separate the first space to form the first accommodating portion and the second accommodating portion, and the worm is disposed in the first accommodating portion and the second accommodating portion is used to accommodate the metal part.

In an exemplary embodiment, the second accommodating portion has a groove and the metal part further has a convex portion. The convex portion is inserted into the groove, so that the metal part is fixed to the second accommodating portion.

In an exemplary embodiment, the partition wall has a second hole, and the shaft of the motor passes through the metal part and the second hole to connect with the worm.

In an exemplary embodiment, the box comprises an upper casing and a lower casing. The upper casing and the lower casing can be joined together to form the box.

In an exemplary embodiment, the partition wall comprises an upper partition wall and a lower partition wall, which are respectively disposed on the upper casing and the lower casing. The upper partition wall and the lower partition wall are joined together to form the partition wall.

In an exemplary embodiment, the gearbox further comprises a second convex portion disposed on the upper casing. The second convex portion is configured along the edge of the upper casing and extending to the end surface of the upper partition wall.

In an exemplary embodiment, the lower casing is extending to a side wall of the first space, and the end surface of the lower partition wall is configured with a stepped structure corresponding to the shape of the second convex portion.

In an exemplary embodiment, the gearbox further comprises a plurality of screws. The metal part further has a plurality of through holes. The leading edge of the body of the motor has a plurality of threaded holes corresponding to the through holes, and the screws pass through the through holes and thread into the threaded holes, so that the motor is fixed to the metal part.

In summary, the gearbox with motor fixing structure according to the present inventive concept has the motor fixed on the metal part, and the metal part with the motor fixed thereon is further embedded in the gearbox to fasten the motor to the gearbox, thereby increasing the structural strength and reducing the temperature rise and noise caused by the gear set driven by the motor.

