Enclosed brushless motor structure and electric tool using same

Abstract

The utility model provides a closed brushless motor structure and an electric tool applying the motor structure, the motor structure comprises a casing, a rotor core shaft, an insulation shaft and a rotor iron core, two ends of the rotor iron core are sleeved with a first stator end plate and a second stator end plate, the first stator end plate and the second stator end plate are sleeved with a stator iron core, and the first stator end plate and the second stator end plate are sleeved with a rotor core. The rotor core is filled with magnetic steel, a first balance block and a second balance block are symmetrically sleeved outside the rotor core, the two balance blocks are respectively located at two ends of the rotor core, a heat dissipation block is sleeved outside the rotor core, one end of the heat dissipation block is sleeved with wool felt, and the other end of the heat dissipation block is sleeved with wool wool. The outer ring of the wool felt is in interference fit with an inner hole of the first stator end plate, the wool felt and the end of the heat dissipation block are tightly assembled with the first balance block, the second stator end plate is in sealed connection with the machine shell, and the rotor mandrel is further sleeved with fan blades. A closed motor structure is formed, and particulate matters such as metal dust are prevented from entering the motor rotor from the air inlet and being adsorbed on the surface of the iron core.

Description

Technical Field

[0001] This utility model relates to the field of brushless motors, specifically to a closed brushless motor structure and an electric tool using the motor structure. Background Technology

[0002] Current brushless motors consist of a stator made of slotted iron core wound with enameled wire, and a rotor embedded with permanent magnets. Because the stator core has many slots, it's difficult to structurally seal the gap between the stator and rotor. This allows external metal dust to easily enter and adhere to the rotor core surface, causing motor malfunction. Traditional enclosed solutions involve encasing the stator in a fully sealed aluminum shell. This method is structurally complex, increases size and cost, and cannot be placed inside small tool housings, or requires increasing the housing size. However, this increased size affects the machine's grip (e.g., angle grinders). Utility Model Content

[0003] The purpose of this utility model is to provide a closed brushless motor structure and an electric tool using the motor structure, which overcomes the problem that when various tools powered by brushless motors enter, metal dust will be attracted to the surface of the iron core of the embedded permanent magnet, causing the machine to fail to start or causing functional impact and making it unusable.

[0004] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0005] A closed brushless motor structure includes a housing and a rotor spindle. Both ends of the rotor spindle are connected to the housing via bearings. An insulating shaft and a rotor core are sequentially fitted around the rotor spindle. A first stator end plate and a second stator end plate are fitted around both ends of the rotor core. A stator core is fitted around the first and second stator end plates. The rotor core is filled with magnets. A first balance block and a second balance block are symmetrically fitted around the rotor spindle, located at opposite ends of the rotor core. A heat sink is also fitted around the rotor spindle. One end of the heat sink is fitted with felt, and the outer ring of the felt is interference-fitted with the inner hole of the first stator end plate. The ends of the felt and the heat sink are tightly fitted with the first balance block. The second stator end plate is sealed to the housing. A fan blade is also fitted onto the rotor spindle.

[0006] Preferably, one end of the heat sink is formed with a mounting platform, the wool felt is fitted on the mounting platform, and the outer end of the wool felt is flush with the outer end of the mounting platform, both being tightly fitted to the first balance block.

[0007] Preferably, the first stator end plate and the second stator end plate have the same structure. The stator end plate includes an annular body with an inner hole. The annular body has winding slots and slot openings spaced apart on its outer side. The stator end plate is connected to the stator core through the slot openings. The winding slots are filled with insulating materials, and enameled wire is wound from the slot openings into the winding slots.

[0008] An electric tool includes an electric tool body, on which a closed brushless motor structure is provided, and on which a controller for controlling the brushless motor structure is also provided.

[0009] This utility model has the following beneficial effects:

[0010] (1) The motor structure of this utility model achieves the sealing of the front end of the motor through the assembly of the first stator end plate, the first balance block and the wool felt, and achieves the sealing of the rear end of the motor through the sealed gapless connection between the second stator end plate and the housing, thus forming a closed motor structure, preventing metal dust and other particles from entering the motor rotor through the air inlet and adsorbing onto the iron core surface. Moreover, this closed motor solution abandons the traditional motor heat dissipation through the aluminum shell sleeved outside the motor, simplifies the structure and saves costs.

[0011] (2) The use of wool felt allows the internal gas to be discharged through the pores of the wool felt at high temperatures, reducing the increase in pressure caused by the rise in temperature of the gas inside the rotor core, and also further reducing the internal temperature of the rotor core, thus providing better heat dissipation. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model installed on a power tool;

[0013] Figure 2 This is a schematic diagram of the heat sink structure in this utility model;

[0014] Figure 3 This is a schematic diagram of the stator end plate in this utility model.

[0015] In the diagram: 1-Housing; 2-Rotor spindle; 3-Insulating shaft; 4-Rotor core; 5-First stator end plate; 6-Second stator end plate; 7-Stator core; 8-Magnet; 9-First balance block; 10-Second balance block; 11-Heat sink; 12-Wool felt; 13-Fan blade; 14-Mounting platform; 15-Annular body; 16-Inner hole; 17-Winding slot; 18-Slot opening; 19-Power tool body; 20-Controller; 21-Bearing. Detailed Implementation

[0016] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding of this utility model, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0017] like Figure 1-3 As shown, a closed brushless motor structure includes a housing 1 and a rotor spindle 2. The two ends of the rotor spindle 2 are connected to the housing 1 by bearings 21. An insulating shaft 3 and a rotor core 4 are sequentially fitted on the outside of the rotor spindle 2. A first stator end plate 5 and a second stator end plate 6 are fitted on the two ends of the rotor core 4. A stator core 7 is fitted on the outside of the first stator end plate 5 and the second stator end plate 6. The inside of the rotor core 4 is filled with magnets 8. A first balance block 9 and a second balance block 10 are symmetrically fitted on the outside of the rotor spindle 4, and the two balance blocks are located at the two ends of the rotor core 4 respectively. A heat sink 11 is also fitted on the outside of the rotor spindle 2. A wool felt 12 is fitted on one end of the heat sink 11, and the outer ring of the wool felt 12 is interference-fitted with the inner hole 16 of the first stator end plate 5. The ends of the wool felt 12 and the heat sink 11 are tightly fitted with the first balance block 9. The second stator end plate 6 is sealed to the housing 1. A fan blade 13 is also fitted on the rotor spindle 2.

[0018] The motor structure of this utility model achieves sealing at the front end of the motor through the assembly of the first stator end plate 5, the first balance block 9, and the felt 12. The sealing of the electronic rear end is achieved through the seamless, sealed connection between the second stator end plate 6 and the housing 1, thus forming a closed motor structure. This prevents metal dust and other particles from entering the motor rotor through the air inlet and adsorbing onto the iron core surface. Furthermore, this closed motor design eliminates the need for a traditional aluminum shell for heat dissipation, simplifying the structure and saving costs. The use of felt 12 allows internal gases to escape through its pores at high temperatures, reducing the pressure increase caused by temperature rise inside the rotor iron core and further lowering the internal temperature of the rotor iron core, resulting in better heat dissipation.

[0019] Specifically, the balance blocks at both ends of the rotor core 4 are made of copper to help dissipate heat. The first balance block 9 and the heat sink 11 are tightly fitted together, and thermal silicone can be applied during this process to improve heat dissipation. The heat sink 11 is made of aluminum alloy and is fitted with wool felt 12 and tightly fitted with the copper balance block. Here, the outer circle of the wool felt 12 and the inner hole of the first stator end plate 5 form a certain interference fit to prevent metal dust from adsorbing onto the surface of the rotor core 4 when the machine is in use or placed in a dusty space, which would eventually cause the machine to malfunction.

[0020] Furthermore, a mounting platform 14 is formed at one end of the heat sink 11. The wool felt 12 is fitted onto the mounting platform 14, and the outer end of the wool felt 12 is flush with the outer end of the mounting platform 14, both being tightly fitted to the first balance block 9. This design, specifically the mounting platform 14, forms a stepped cylinder at the rear end of the heat sink 11, facilitating the assembly of the wool felt 12, improving the seal between it and the first stator end plate 5, and enhancing dustproof performance.

[0021] Furthermore, the first stator end plate 5 and the second stator end plate 6 have the same structure. The stator end plate includes an annular body 15 with an inner hole 16. The annular body 15 has winding slots 17 and slot openings 18 spaced apart on its outer surface. The stator end plate is connected to the stator core 7 through the slot openings 18. The winding slots 17 are filled with insulating materials, and enameled wire is wound from the slot openings 18 into the winding slots 17. This design facilitates the interchange of the stator end plates and improves the sealing of the connection between the stator end plates and the stator core 7, thereby enhancing the tightness and dustproofness of the entire motor structure.

[0022] An electric tool includes an electric tool body 19, on which a closed brushless motor structure is disposed, and a controller 20 for controlling the brushless motor structure is also disposed on the electric tool body 19. The above design, especially for small electric tool angle grinders, solves the problems of metal dust inhalation during high-intensity metal grinding and cutting operations and metal powder adsorption when placed in a dusty environment. Simultaneously, the heat sink 11 effectively dissipates heat from the rotor core 4.

[0023] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A closed brushless motor structure, characterized by: The application relates to a closed brushless motor structure, which comprises a casing and a rotor shaft, the two ends of the rotor shaft are connected to the casing through bearings respectively, the outside of the rotor shaft is sequentially sleeved with an insulating shaft and a rotor core, the two ends of the rotor core are sleeved with a first stator end plate and a second stator end plate, the outside of the first stator end plate and the second stator end plate is sleeved with a stator core, the inside of the rotor core is filled with magnetic steel, the outside of the rotor shaft is symmetrically sleeved with a first balancing block and a second balancing block, the two balancing blocks are respectively located at the two ends of the rotor core, the outside of the rotor shaft is further sleeved with a heat dissipation block, one end of the heat dissipation block is sleeved with wool felt, the outer ring of the wool felt is assembled in the inner hole of the first stator end plate in an interference mode, the end of the wool felt and the heat dissipation block is assembled in close contact with the first balancing block, the second stator end plate is sealingly connected to the casing, and a fan blade is further sleeved on the rotor shaft.

2. A closed brushless motor structure according to claim 1, characterized in that: One end of the heat dissipation block is formed with a mounting table, the wool felt is sleeved on the mounting table, the outer end of the wool felt is flush with the outer end of the mounting table, and the wool felt and the heat dissipation block are assembled in close contact with the first balancing block.

3. A closed brushless motor structure according to claim 1, characterized in that: The first stator end plate and the second stator end plate are of the same structure, the stator end plate comprises a ring-shaped body, the ring-shaped body is provided with an inner hole, the outside of the ring-shaped body is provided with winding grooves and notches at intervals, the stator end plate is connected to the stator core through the notches, the winding grooves are filled with insulating pieces, and enameled wires are wound into the winding grooves from the notches.

4. A power tool comprising a power tool body, characterized by: The electric tool body is provided with the closed brushless motor structure as claimed in any one of claims 1-3, and the electric tool body is further provided with a controller for controlling the brushless motor structure.

Images