Handheld power tool rear bearing dust protection device

Abstract

The invention discloses a handheld electric tool rear bearing dustproof device, including a housing, an intermediate cover, a stator, a rotor, and a permanent magnet. The housing rear end cover is provided with a second air inlet, the stator rear cover that is sealed with the housing rear end cover is fixed on the rear plate of the stator, a small fan blade corresponding to the stator rear cover is fixed on the motor shaft, the housing rear end cover, the stator rear cover and the stator form a closed cover for the rear bearing, the small fan blade and the rotor, the stator rear cover is provided with a third air inlet, the third air inlet is inlaid with a dustproof mesh, a rear bearing labyrinth dustproof structure is provided between the small fan blade and the stator rear cover, the third air inlet and the stator-rotor air gap constitute a motor cooling channel, and the rotor rotates to drive the small fan blade to work and can blow off the dust and iron filings adsorbed on the dustproof mesh. After adopting the above structure, it has the advantages of simple structure, convenient assembly, no clogging of the filter mesh, good dust filtering and ventilation cooling effect, and long service life.

Description

Technical Field

[0001] The invention relates to the technical field of electric tools, in particular to a handheld electric tool rear bearing dust prevention device used for electric tools such as angle grinders, polishers, cutters, slotters, etc. Background Art

[0002] Power tools such as angle grinders, polishers, cutters, slotters, impact drills and electric hammers are widely used handheld power tools with different purposes. According to different work requirements, different handheld power tools can be selected for grinding, polishing, cutting, slotting, drilling and other work. In order to ensure reliable heat dissipation of the motor, all power tool housings are provided with air inlets and outlets for reducing the temperature of the motor, and a labyrinth dustproof structure is provided on the front bearing. In order to achieve energy saving and increase motor power, the series-excited motors of the above-mentioned power tools are gradually replaced by permanent magnet brushless motors. Due to the relatively harsh working environment of the above-mentioned power tools, a large amount of dust and iron filings will be generated during work. At present, most power tools only have a straight-through filter mesh on the air inlet. Dust and iron filings directly enter the motor from the air inlet and the front bearing. The dust and iron filings will be adsorbed on the permanent magnets of the rotor, causing damage to key components such as bearings and stators and rotors, greatly reducing the service life of the product. In order to solve the above problems, the main measures currently taken are: First, the cooling air duct remains unchanged, the rotor does not have a dust-proof structure, but the power tool is regularly maintained and dust and iron filings are cleaned, which brings a lot of trouble to users. Second, the cooling air duct is cancelled and the entire rotor is sealed. The motor has poor heat dissipation effect and can only work for a short time. It can only be used as a household and maintenance tool, not as a professional tool for long-term work. The motor works at high temperature for a long time, which will cause the permanent magnet to demagnetize and reduce power, directly affecting the efficiency of the motor.

[0003] In order to solve the above problems, Chinese patent authorization announcement number CN205310191U discloses a multi-layer dustproof mechanism for the air inlet of an electric tool. The structure is provided with multiple dustproof structures on the air inlet, which better solves the problem of dust and iron filings entering the stator and rotor of the motor. The structure has the characteristics of simple and reasonable structure, convenient disassembly, cleaning and replacement, good filtering effect, and high purity of cooling air. However, the following problems still exist during use: First, due to untimely cleaning, the filter mesh is often blocked, resulting in poor ventilation and affecting the heat dissipation effect of the motor; second, in order to achieve better heat dissipation effect, a filter mesh with good ventilation will be selected. During operation, a small amount of dust and iron filings will enter the stator and rotor. After working for a certain period of time, key components such as the front bearing and the stator and rotor will be damaged, and the product life will be short. For this reason, many manufacturers and knowledgeable people have carried out development and research, but no ideal product has been launched so far. Summary of the invention

[0004] In order to overcome the above-mentioned defects of the prior art, the purpose of the present invention is to provide a handheld power tool rear bearing dustproof device with simple structure, easy assembly, no filter mesh clogging, good dust filtering and ventilation cooling effect, and long service life.

[0005] The present invention creates a technical solution adopted to solve the above-mentioned technical problems. It includes a casing, an intermediate cover, and a permanent magnet brushless motor. The permanent magnet brushless motor includes a stator installed on the casing and a rotor that can rotate relative to the stator. The rotor is equipped with a permanent magnet. The motor shaft of the rotor is correspondingly installed on the rear end cover and the intermediate cover of the casing through a rear bearing and a front bearing. The rear end cover of the casing is provided with a second air inlet. A stator rear cover that is sealed with the rear end cover of the casing is fixed on the rear end plate of the stator. A small fan blade corresponding to the stator rear cover is fixed on the motor shaft. The rear end cover of the casing, the stator rear cover and the stator form a closed cover for the rear bearing, the small fan blade and the rotor. A third air inlet is provided on the stator rear cover. A dustproof mesh is inlaid on the third air inlet. The third air inlet and the stator-rotor air gap constitute a motor cooling channel. A rear bearing labyrinth dustproof structure is provided between the small fan blade and the stator rear cover. When the rotor rotates to drive the small fan blade to work, dust and iron filings adsorbed on the dustproof mesh can be blown off.

[0006] According to a further solution of the present invention, the rear bearing labyrinth dustproof structure comprises a labyrinth groove arranged on the stator rear cover and a labyrinth convex ring arranged on the small wind blade and cooperating with the labyrinth groove.

[0007] According to a further solution created by the present invention, the second air inlet is horizontally arranged, the third air inlet is longitudinally arranged, and a 90-degree turn is arranged between the second air inlet and the third air inlet.

[0008] According to a further solution created by the present invention, a process hole is provided on the rear end cover of the housing, a rear bearing dust cover is buckled on the process hole, and the motor shaft is fixedly connected to the rear bearing rotating ring by screws and gaskets.

[0009] According to a further solution created by the present invention, the rear end of the casing is provided with left and right covers, the left and right covers are correspondingly provided with a first air inlet, the first air inlet is installed with detachable left and right dust covers, and a 90-degree turn is provided between the first air inlet and the second air inlet.

[0010] According to a further solution created by the present invention, a controller for controlling the operation of the permanent magnet brushless motor is installed in the left and right covers.

[0011] After adopting the above structure, compared with the prior art, it has the following advantages: First, due to the adoption of the two-way dustproof structure and the secondary 90-degree turning sedimentation structure, the larger dust and iron filings pass through the first dustproof structure and settle on the left and right covers, and the smaller dust and iron filings pass through the secondary turning sedimentation structure and settle on the casing. Second, due to the dustproof mesh inlaid on the third air inlet, the motor shaft is fixed with a small fan blade corresponding to the third air inlet of the stator rear cover, and the fine dust and iron filings are filtered by the dustproof mesh. The rotor rotates to drive the small fan blade to work and blow off the dust adsorbed on the dustproof mesh, which can prevent the fine dust and iron filings from clogging the dustproof mesh, which can not only effectively prevent the dust and iron filings from entering the motor cooling channel, but also ensure the smooth cooling airflow, thereby achieving a better dustproof and heat dissipation effect. Third, due to the labyrinth groove on the stator rear cover and the labyrinth convex ring on the small fan blade forming a rear bearing labyrinth dustproof structure, dust and iron filings can be prevented from entering the rear bearing, thereby ensuring the lubrication effect and service life of the rear bearing. Fourth, because the rear bearing and the rear bearing stop of the rear end cover of the casing are loosely matched during assembly, the motor shaft is fixedly connected to the rotating circle of the rear bearing by screws and gaskets, the processing accuracy requirements are low, the production and assembly are simple and convenient, and the product consistency is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the matching structure created by the present invention.

[0013] Figure 2 Created for this invention Figure 1 Schematic diagram of the local enlarged structure.

[0014] Figure 3 The present invention provides a three-dimensional structural schematic diagram of the stator rear cover.

[0015] Figure 4 Schematic diagram of the decomposition structure created by the present invention.

[0016] Among them, 1 is the left and right covers, 2 is the left and right dust covers, 3 is the controller, 4 is the first air inlet, 5 is the dust cover of the rear bearing, 6 is the rear end cover of the casing, 7 is the rear bearing, 8 is the second air inlet, 9 is the small fan blade, 10 is the stator rear cover, 11 is the dustproof mesh, 12 is the casing, 13 is the stator, 14 is the rotor, 15 is the permanent magnet, 16 is the motor shaft, 17 is the fan, 18 is the middle cover, 19 is the transmission box, 20 is the rear end plate, 21 is the labyrinth convex ring, 22 is the labyrinth groove, 23 is the stator and rotor air gap, and 24 is the third air inlet. DETAILED DESCRIPTION

[0017] Figures 1 to 4As shown, the present invention creates a specific implementation scheme of a rear bearing dustproof device for a handheld electric tool, which includes a housing 12, an intermediate cover 18, a permanent magnet brushless motor, and a transmission box 19 fixed to the intermediate cover 18. The permanent magnet brushless motor includes a stator 13 mounted on the housing 12, a rotor 14 that can rotate relative to the stator 13, a permanent magnet 15 mounted on the rotor 14, a fan 17 is fixed on the motor shaft 16 of the rotor 14 and is correspondingly mounted on the rear end cover 6 of the housing and the intermediate cover 18 through the rear bearing 7 and the front bearing, the rear bearing 7 is loosely matched with the rear bearing stop of the rear end cover 6 of the housing, the motor shaft 16 outputs power through the transmission box 19, the rear end cover 6 of the housing is provided with a second air inlet 8, and the rear end plate 20 of the stator 13 is fixed with a stator rear end that is sealed with the rear end cover 6 of the housing. The cover 10, a small fan blade 9 corresponding to the stator rear cover 10 is fixed on the motor shaft 16, the rear end cover 6 of the casing, the stator rear cover 10 and the stator 13 form a closed cover for the rear bearing 7, the small fan blade 9 and the rotor 14, the stator rear cover 10 is provided with a third air inlet 24, the third air inlet 24 is inlaid with a dustproof mesh 11, the third air inlet 24 and the stator-rotor air gap 23 constitute a motor cooling channel, the dustproof mesh 11 can prevent dust and iron filings from entering the motor cooling channel, a rear bearing labyrinth dustproof structure is provided between the small fan blade 9 and the stator rear cover 10, the rear bearing labyrinth dustproof structure can prevent dust and iron filings from entering the rear bearing 7, the rotor 14 rotates to drive the small fan blade 9 to work, and the dust and iron filings adsorbed on the dustproof mesh 11 can be blown off, thereby ensuring smooth ventilation of the dustproof mesh 11.

[0018] In order to achieve a better dustproof effect, the rear bearing labyrinth dustproof structure includes a labyrinth groove 22 arranged on the stator rear cover 10 and a labyrinth convex ring 21 arranged on the small wind blade 9 and cooperating with the labyrinth groove 22 .

[0019] In order to prevent dust and iron filings from entering the stator and rotor cooling channels, the second air inlet 8 is arranged horizontally, the third air inlet 24 is arranged longitudinally, and a 90-degree turn is provided between the second air inlet 8 and the third air inlet 24. When the cooling air flow passes through this channel, the flow direction is forced to turn, and the relatively small dust and iron filings mixed in the air flow will settle in the casing 12 of the turning channel due to centrifugal action, thereby preventing dust and iron filings from entering the stator and rotor cooling channels.

[0020] In order to reduce the assembly accuracy, a process hole is provided on the rear end cover 6 of the housing, and a rear bearing dust cover 5 is buckled on the process hole. The motor shaft 16 is fixedly connected to the rotating circle of the rear bearing 7 by screws and gaskets.

[0021] In order to further improve the dust-proof effect, the rear end of the casing 12 is provided with left and right covers 1, and the left and right covers 1 are correspondingly provided with a first air inlet 4, and the first air inlet 4 is installed with detachable left and right dust covers 2. A 90-degree turn is provided between the first air inlet 4 and the second air inlet 8. When the cooling airflow passes through this channel, the flow direction is forced to turn, and the relatively large dust and iron filings mixed in the airflow will settle in the left and right covers 1 of the turning channel due to centrifugal action. The left and right covers 1 can also be operating handles.

[0022] For the convenience of installation, a controller 3 for controlling the operation of the permanent magnet brushless motor is installed in the left and right covers 1 .

[0023] The above is only a specific embodiment of the present invention and does not limit the present invention in any form. Simple modifications, equivalent changes or modifications made without departing from the technical solution of the present invention are all within the protection scope of the present invention.

Claims

1. A handheld electric tool rear bearing dust prevention device, comprising a housing (12), an intermediate cover (18), and a permanent magnet brushless motor, wherein the permanent magnet brushless motor comprises a stator (13) mounted on the housing (12), a rotor (14) rotatable relative to the stator (13), a permanent magnet (15) mounted on the rotor (14), a motor shaft (16) of the rotor (14) being mounted on the housing rear end cover (6) and the intermediate cover (18) via a rear bearing (7) and a front bearing, and a second air inlet (8) being provided on the housing rear end cover (6), wherein the second air inlet (8) is provided on the housing rear end cover (6), wherein the second air inlet (8) is provided on the housing rear end cover (6), and the second air inlet (8) is provided on the housing rear end cover (6), wherein the second air inlet (8) is provided on the housing rear end cover (6), and the second air inlet (8) is provided on the housing rear end cover (6), and the second air inlet (8) is provided on the housing rear end cover (6), and the second air inlet (8) is provided on the housing rear end cover (6), and the second air inlet (8) is provided on the housing rear end cover (6), and the second air inlet (8) is provided on the housing rear end cover (6), and the second air inlet (8) is provided on the housing rear end cover (12 ... A stator rear cover (10) which is sealed with a housing rear cover (6) is fixed on the rear plate (20) of the stator (13); a small fan blade (9) corresponding to the stator rear cover (10) is fixed on the motor shaft (16); the housing rear cover (6), the stator rear cover (10) and the stator (13) form a closed cover for a rear bearing (7), the small fan blade (9) and a rotor (14); a third air inlet (24) is provided on the stator rear cover (10); a dustproof mesh (11) is inlaid on the third air inlet (24); the third air inlet (24) and the stator-rotor air gap (23) form a motor cooling channel; a rear bearing labyrinth dustproof structure is provided between the small fan blade (9) and the stator rear cover (10); when the rotor (14) rotates and drives the small fan blade (9) to work, dust and iron filings adsorbed on the dustproof mesh (11) can be blown off.

2. The dust prevention device for rear bearing of handheld electric tool according to claim 1, characterized in that: The rear bearing labyrinth dustproof structure comprises a labyrinth groove (22) arranged on the stator rear cover (10) and a labyrinth convex ring (21) arranged on the small fan blade (9) and cooperating with the labyrinth groove (22).

3. The dust prevention device for rear bearing of handheld electric tool according to claim 1 or 2, characterized in that: The second air inlet (8) is arranged horizontally, the third air inlet (24) is arranged longitudinally, and a 90-degree turn is arranged between the second air inlet (8) and the third air inlet (24).

4. The dust prevention device for rear bearing of handheld electric tool according to claim 3, characterized in that: The rear end cover (6) of the housing is provided with a process hole, a rear bearing dust cover (5) is buckled on the process hole, and the motor shaft (16) is fixedly connected to the rotating circle of the rear bearing (7) through screws and gaskets.

5. The dust prevention device for rear bearing of handheld electric tool according to claim 4, characterized in that: The rear end of the housing (12) is provided with left and right covers (1), and the left and right covers (1) are correspondingly provided with first air inlets (4). The first air inlet (4) is provided with detachable left and right dust covers (2), and a 90-degree turn is provided between the first air inlet (4) and the second air inlet (8).

6. The dust prevention device for rear bearing of handheld electric tool according to claim 5, characterized in that: A controller (3) for controlling the operation of the permanent magnet brushless motor is installed in the left and right covers (1).

Images