Lightweight digital speed-regulating brushless electric polishing tool

Abstract

This invention relates to the field of polishing tool technology, specifically a lightweight, digitally adjustable brushless electric polishing tool. It includes a motor body, which consists of a main body and a top-mounted conversion housing, integrating a power supply module, a control module, and a drive module. The drive module includes a brushless motor fixedly mounted on the top of the main body. This invention utilizes a swashplate mounted at an angle α to the output shaft. When the brushless motor drives the swashplate to rotate, each fan blade rotates around its own axis, drawing air from the bottom of the main body and simultaneously expelling it towards the rear and front vents. This forms a directional, forced cooling airflow covering multiple circumferential areas inside the motor body, solving the problem of existing technologies that rely solely on a rotor shaft fan along the motor axis to create a single cooling path, failing to provide differentiated cooling for the temperature distribution in different circumferential areas of the motor. This effectively avoids the accumulation of localized hot spots and improves the overall heat dissipation uniformity and thermal management capabilities.

Description

Technical Field

[0001] This invention relates to the field of polishing tool technology, specifically to a lightweight, digitally adjustable, brushless electric polishing tool. Background Technology

[0002] Electric grinding tools are handheld or portable mechanized grinding tools that use an electric motor as a power source and drive the working attachments through a transmission mechanism to perform cutting, grinding, polishing and other operations. Common rotary electric grinding tools include angle grinders, polishers, and straight grinders.

[0003] With the development of lithium battery and motor technologies, electric polishing tools are rapidly evolving from traditional brushed motor drives to brushless motor drives, and from AC power supplies to DC lithium battery platforms. Among them, brushless electric polishing tools refer to electric polishing tools that use brushless DC motors as the drive source and replace traditional carbon brush mechanical commutation with electronic commutation. They have the advantages of high efficiency, low noise, long life, and maintenance-free operation.

[0004] Digital speed control refers to a technical means of adjusting the motor speed and output torque in real time using microcontrollers and power electronic drive circuits through closed-loop control algorithms, which is different from traditional analog speed control or simple gear speed control.

[0005] Lightweighting refers to reducing the overall weight of the device by means of material selection, wall thickness optimization, and structural integration, while ensuring structural strength and functional reliability, in order to improve the comfort and operability of handheld operation.

[0006] The integrated application of the above three technologies has become an important development direction for high-end handheld electric grinding tools.

[0007] In the prior art, a typical brushless electric grinding tool head structure usually consists of a brushless motor, a gearbox, and an output shaft assembly. Such a structure satisfies the basic functions of power transmission and load support, but in actual use, it has revealed the following shortcomings.

[0008] A single heat dissipation channel and additional heat dissipation mechanisms result in a bulky internal structure. In terms of heat dissipation design, existing handheld electric grinders generally suffer from a single heat dissipation channel. Most grinders rely solely on a fan at the rotor shaft end to create a single-path cooling airflow along the motor axis. The airflow enters from the rear, passes straight through the gap between the stator and rotor, and exits near the gearbox. This single axial channel cannot provide differentiated cooling for the temperature distribution in different areas around the motor, easily leading to the accumulation of local hot spots.

[0009] To address insufficient heat dissipation, some technical solutions involve installing a separate air duct housing or heat dissipation mechanism outside the motor housing. While these additional mechanisms improve heat dissipation efficiency to some extent, they require additional radial or axial space as independent components, resulting in a bulky internal structure for the motor and conflicting with the design requirements of miniaturization and compactness for handheld grinding tools. Furthermore, the separately installed air duct housing not only increases the number of parts and assembly steps, but the assembly gap between it and the motor housing can easily generate noise under the vibration conditions of the grinding tool.

[0010] Furthermore, existing heat dissipation solutions have a single heat dissipation angle, and the cooling airflow is usually only introduced axially from the tail of the motor, lacking a directional cooling path for areas with concentrated heat, such as the front bearing housing and gearbox housing of the motor.

[0011] Therefore, a lightweight, digitally adjustable speed brushless electric polishing tool is proposed to solve the aforementioned technical problems. Summary of the Invention

[0012] The purpose of this invention is to provide a lightweight, digitally adjustable, brushless electric grinding tool to solve the problems mentioned in the background art.

[0013] To achieve the above objectives, the present invention provides the following technical solution: a lightweight digital speed-regulating brushless electric grinding tool, comprising a motor body, which consists of a main body and a top-mounted conversion housing, integrating a power supply module, a control module, and a drive module; the drive module includes a brushless motor fixedly mounted in the top area of ​​the main body, with a heat dissipation mechanism connected to the output shaft of the brushless motor; a rear vent and a front vent, respectively, are provided on both sides of the connection between the conversion housing and the main body for interaction with the outside environment. The heat dissipation mechanism includes a swashplate, with the output shaft passing through the central hole of the swashplate and being fastened to it. The mounting plane of the swashplate is set at an angle α with the axial direction of the output shaft, so that the swashplate as a whole is tilted and fixed relative to the end face of the output shaft. Several through ventilation holes are opened circumferentially at the bottom end of the swashplate, and several rotating holes are also opened circumferentially at the bottom end of the swashplate. A rotating rod is rotatably connected in each rotating hole. A fan blade is coaxially mounted on the top of the rotating rod, and a driven gear is coaxially fixedly connected to the lower part of the outer wall of the rotating rod. The upper part of the machine body is also equipped with a constraint mechanism, which is connected to a rotating inner ring. The rotating inner ring is coaxially connected to an annular groove opened in the inner wall of the swashplate. The bottom end of the rotating inner ring is coaxially connected to an internal gear ring, which meshes with the outer wall of multiple driven gears. When the brushless motor starts, the output shaft drives the swashplate to rotate. The constraint mechanism restricts the rotating inner ring from revolving with the swashplate as a whole, so that the driven gears and the internal gear ring mesh with each other, driving the fan blades to rotate, drawing in air and discharging it towards the rear and front vents. The included angle α is 5°±2°.

[0014] As a further improvement to the above solution, the constraint mechanism includes two side slide rails symmetrically installed on the upper part of the machine body. The two side slide rails are arranged parallel to the output shaft axis of the brushless motor. Each side slide rail has a slider vertically slidably connected inside. Both sliders have a rotating hole on the side facing the brushless motor. Each rotating hole has only one limiting rod rotatably connected inside. Each limiting rod has a rotating connector horizontally fixedly connected to the other side. The outer end of the rotating connector is hinged to a hinge plate. The other end of the hinge plate is hinged to the inner rotating ring through a protruding sleeve plate. The inner rotating ring is equipped with ball bearings at the connection with the annular groove and is coated with lubricating grease to keep the inner rotating ring relative to the swashplate when the swashplate is tilted and rotated. Each rotating rod is connected to the rotating hole via a bearing; each vent is located directly below the corresponding fan blade, used to draw air in when the fan blade rotates and guide it along the vent towards the rear and front vents.

[0015] As a further improvement to the above solution, the drive module also includes a gearbox assembly that is connected to the brushless motor drive. The gearbox housing of the gearbox assembly adopts a differential design with unequal wall thickness. The gearbox housing is divided into high stress zone, medium stress zone and low stress zone according to the stress level. The wall thickness of the high stress zone is greater than that of the low stress zone. The reinforcing ribs on the gearbox housing are arranged along the direction of the principal stress trace.

[0016] As a further improvement to the above solution, the front cover of the brushless motor and the input end of the gearbox housing are combined into a single die-cast part.

[0017] As a further improvement to the above solution, the control module is installed in the middle gripping area of ​​the motor body. It integrates a microcontroller, a motor drive circuit, and a speed detection module. The microcontroller receives the target speed command set by the user, obtains the actual speed signal of the brushless motor rotor in real time through the Hall sensor, compares the actual speed with the target speed to obtain the speed error, calculates the instantaneous current command based on the error and the built-in PID control algorithm, and controls the duty cycle of the PWM signal through the motor drive circuit to realize closed-loop speed regulation control of the brushless motor.

[0018] As a further improvement to the above solution, the motor body housing, the brushless motor mounting interface, the control module and its mounting structure are defined as a unified universal platform; the front end of the universal platform is equipped with standardized mechanical and electrical interfaces for installing different functional head components during the production assembly stage. The head components include angle grinder head components, polisher head components or straight grinder head components.

[0019] As a further improvement to the above solution, the front vent is located below the grinding disc, and the airflow discharged from the fan blades forms a positive pressure air curtain at the front vent to prevent external dust from entering the motor body.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses a swashplate installed at an angle α to the output shaft. When the brushless motor drives the swashplate to rotate, each fan blade rotates around its own axis under the drive of the swashplate. This draws air from the bottom of the motor body and discharges it towards the rear and front vents, forming a directional forced cooling airflow that covers multiple circumferential areas inside the motor body. This solves the problem in existing technologies that rely solely on the rotor shaft fan to form a single cooling path along the motor axis, which cannot provide differentiated cooling for the temperature distribution in different circumferential areas of the motor. This effectively avoids the accumulation of local hot spots and improves the overall heat dissipation uniformity and thermal management capabilities.

[0021] 2. This invention integrates the heat dissipation mechanism directly onto the output shaft of the brushless motor, eliminating the need for a separate air duct housing or heat dissipation mechanism outside the motor housing. It does not occupy additional radial or axial space, resulting in a compact structure that perfectly aligns with the miniaturization and compactness requirements of handheld grinding tools. Furthermore, the elimination of a separate air duct housing reduces the number of parts and assembly steps, fundamentally eliminating the noise problem caused by assembly gaps between the separate air duct housing and the motor housing under vibration conditions.

[0022] 3. This invention, through the inclined plate installation at an α angle and the layout of the front and rear bidirectional air vents, guides the airflow generated by the fan blade rotation at an α angle. The discharged airflow can form a positive pressure air curtain, which not only achieves directional heat dissipation but also provides dust protection by preventing external dust from entering the motor body.

[0023] 4. This invention employs a differential wall thickness design, based on the stress distribution cloud map obtained from finite element analysis. Wall thickness is increased in high-stress areas such as the bearing housing and flange root, while wall thickness is reduced or weight-reducing grooves are added in low-stress areas such as the housing. Reinforcing ribs are precisely arranged along the principal stress lines to achieve maximum structural rigidity with minimal material weight. Simultaneously, the brushless motor front cover and gearbox housing input end are integrated into a single die-cast part, eliminating connecting flanges and fasteners, shortening the axial length from the motor to the gearbox, and bringing the center of gravity of the machine head closer to the handle. This effectively reduces the cantilever bending moment when the user holds the grinder, significantly improving the comfort and stability of long-term grinding operations.

[0024] 5. This invention employs a dual closed-loop PID control strategy with both speed and current loops. By using a Hall sensor to detect rotor speed in real time, the PWM duty cycle can be instantly adjusted according to load changes for torque compensation, maintaining a constant speed and solving the problem of unstable speed in analog speed regulation under fluctuating loads. Simultaneously, the machine casing, motor mounting interface, control module, and its mounting structure form a unified and universal platform. Standardized mechanical and electrical interfaces are set at the front end, allowing for the configuration of different functional head components during the production and assembly stage to create various types of electric grinding tools. The high degree of commonality of core components reduces R&D and manufacturing costs at the system level. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 for Figure 1 A diagram from another perspective.

[0027] Figure 3 for Figure 2 Cross-sectional view.

[0028] Figure 4 This is an enlarged schematic diagram of the heat dissipation mechanism of the present invention.

[0029] Figure 5 This is a schematic diagram showing the installation status of the heat dissipation mechanism.

[0030] Figure 6 This is a schematic diagram of a brushless motor.

[0031] Figure 7 This is a schematic diagram of the constraint mechanism.

[0032] Figure 8 for Figure 7 Top view.

[0033] Figure 9 for Figure 8 Cross-sectional view along the AA direction.

[0034] Figure 10 for Figure 7 A three-dimensional cross-sectional schematic diagram.

[0035] In the diagram: 1. Motor body; 11. Power supply base; 12. Output spindle; 13. Rear vent; 14. Front vent; 2. Brushless motor; 21. Output shaft; 22. Swashplate; 23. Rotating rod; 24. Fan blade; 25. Driven gear; 26. Rotating inner ring; 27. Internal gear ring; 28. Protruding sleeve plate; 29. ​​Hinge plate; 210. Rotary connector; 211. Side slide rail; 212. Slider; 213. Vent hole. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] See Figures 1 to 10 This invention provides a lightweight, digitally adjustable, brushless electric grinding tool, including a motor body 1. The motor body 1 consists of a main body and a top-mounted conversion housing, which integrates a power supply module, a control module, and a drive module. Wherein: The power supply module is located at the bottom of the motor body 1 and includes a detachable battery pack. After the battery is connected, the power supply module provides stable DC power to the control module and drive module via the power socket 11. The battery pack is preferably a lithium-ion battery pack with a nominal voltage of 18V to 40V to meet the needs of grinding tools with different power levels.

[0038] The control module is installed in the central gripping area of ​​the motor body 1, connecting the power supply module and the drive module, and serving as the central hub for energy distribution and signal control. The control module includes a retractable drive button and an adjustment knob. The drive button controls the start / stop and speed adjustment of the brushless motor 2, while the adjustment knob adjusts the drive direction of the brushless motor 2, allowing for forward and reverse adjustments to meet the needs of different operating scenarios. The control module integrates a microcontroller (MCU), a motor drive circuit, and a speed detection module. The microcontroller receives the target speed command set by the user via the drive button, and simultaneously acquires the actual speed and position signals of the brushless motor 2 rotor in real time via a Hall sensor. The microcontroller compares the actual speed with the target speed to determine the speed error, calculates the required instantaneous current command based on the error and the built-in PID control algorithm, and then precisely controls the duty cycle of the PWM signal through the motor drive circuit to achieve closed-loop speed control of the brushless motor 2. When a sudden load change causes a speed drop, the control module can instantly increase the output current for torque compensation to maintain a constant speed.

[0039] The drive module is installed at the top of the motor body 1, i.e., the top area of ​​the machine body, and is used to install grinding discs and other working accessories at the conversion housing. A protective cover is required for protection. The drive module includes a brushless motor 2 fixedly installed here and a gearbox assembly connected to it for transmission. The gearbox assembly contains a bevel gear pair, which transmits the output power of the brushless motor 2 to the output spindle 12. The output spindle 12 drives the grinding disc to rotate for grinding, polishing, and other operations. A rear vent 13 and a front vent 14, respectively, are provided on both sides of the connection between the conversion housing and the machine body, allowing interaction with the outside environment. The front vent 14 is located below the grinding disc.

[0040] Specifically, the drive module is fixedly installed in the top area of ​​the machine body. Symmetrical protrusions, such as key structures or flat planes, are provided on the outer wall of the output shaft 21 of the brushless motor 2, and these protrusions connect to the heat dissipation mechanism. The brushless motor 2 is the core drive unit of the electric grinding tool described in this invention. It adopts a three-phase brushless DC motor (BLDC) and mainly includes a stator assembly, a rotor assembly, a Hall sensor, and a motor drive module. The stator assembly consists of a stator core made of stacked silicon steel sheets and three-phase windings wound on it. The rotor assembly includes a rotor shaft and multiple pairs of permanent magnets embedded in the rotor core. The Hall sensor is installed on the stator side to detect the position of the rotor permanent magnet poles, providing commutation signals to the motor drive circuit. Compared to brushed motors, the brushless motor 2 replaces mechanical carbon brushes and commutators with electronic commutation, fundamentally eliminating carbon brush wear, electrical sparks, and high noise problems, achieving higher energy conversion efficiency, lower operating heat generation, and a near-maintenance-free long service life.

[0041] The heat dissipation mechanism includes a swashplate 22. An output shaft 21 passes through the central hole of the swashplate 22, and the two are securely connected at the middle of the shaft. The mounting plane of the swashplate 22 forms an angle α with the axial direction of the shaft, causing the swashplate 22 to be fixed at an angle relative to the end face of the output shaft 21. Several through-hole ventilation channels 213 are circumferentially opened at the bottom end of the swashplate 22, and several rotating holes are also circumferentially opened at the bottom end of the swashplate 22, each rotating hole being located at the middle of two ventilation channels 213. A rotating rod 23 is rotatably connected to each rotating hole via a bearing. A fan blade 24 is coaxially mounted on the top of the rotating rod 23, and a driven gear 25 is coaxially fixedly connected to the lower part of the outer wall of the rotating rod 23.

[0042] It should be noted that the α angle is set at 5°±2°. This angle range is set based on the following engineering considerations: if the α angle is too large, the axial vibration component generated by the swashplate 22 will increase significantly, affecting the smooth operation of the brushless motor 2 and the bearing life; if the α angle is too small, the "8" shaped motion amplitude generated by the swashplate 22 driving the fan blades 24 will be insufficient, the air agitation ability will be weakened, and the heat dissipation efficiency will decrease. Experimental verification shows that an angle range of 5°±2° can achieve the best balance between heat dissipation efficiency and operational smoothness. When the heat dissipation mechanism is operating, this α angle tilt setting can guide the air at the bottom of the machine body to be discharged outwards through the rear vent 13 and the front vent 14. At the same time, the airflow barrier formed at the front vent 14 can effectively prevent dust generated during the grinding operation from entering the motor body 1.

[0043] Furthermore, each rotating rod 23 is connected to the rotating hole via a bearing to reduce rotational friction resistance and ensure the flexibility of the fan blade 24 rotation. Each vent 213 is located directly below the fan blade 24, used to draw air from bottom to top when the fan blade 24 rotates and guide it along the vent 213 toward the rear vent 13 or the front vent 14, forming a directional cooling airflow.

[0044] To achieve the driving of the driven gear 25 and the synchronous rotation of the fan blade 24, two side slide rails 211 parallel to the axis of the output shaft 21 of the brushless motor 2 are symmetrically installed on the upper part of the machine body. A slider 212 is vertically slidably connected within each side slide rail 211. Each slider 212 has a rotating hole facing the brushless motor 2, and a limiting rod is rotatably connected within each rotating hole. A rotating connector 210 is horizontally fixed to the other side of each limiting rod. A hinge plate 29 is hinged to the outer end of the rotating connector 210, and the other end of the hinge plate 29 is hinged to the rotating inner ring 26 via a protruding sleeve 28. The rotating inner ring 26 is coaxially rotatably connected to an annular groove opened in the inner wall of the swashplate 22. It should be added that the inner rotating ring 26 is equipped with ball bearings at the connection with the annular groove and is coated with an appropriate amount of lubricating grease to ensure that the inner rotating ring 26 can maintain a smooth and low-friction relative rotation with respect to the swashplate 22 when the swashplate 22 is tilted and rotated, i.e., in a figure-eight motion. The bottom end of the inner rotating ring 26 is coaxially connected to an internal gear ring 27 through several relatively vertical connecting posts. The internal gear ring 27 meshes with the outer walls of multiple driven gears 25.

[0045] The entire cooling mechanism operates as follows: When the brushless motor 2 starts, the output shaft 21 drives the swashplate 22 to rotate synchronously. Since the swashplate 22 is installed at an angle α, its rotational motion forms a figure-eight spatial oscillation trajectory. The swashplate 22 drives several rotating rods 23, fan blades 24, and driven gears 25 mounted on it to perform a figure-eight motion synchronously. Meanwhile, the rotating inner ring 26, through a constraint mechanism composed of a hinge plate 29, a rotating connector 210, a rotating hole, a limiting rod, and a slider 212, can adapt to the figure-eight movement trajectory of the swashplate 22. The slider 212 slides vertically along the side rail 211, the rotating connector 210 rotates within the rotating hole, and the hinge plate 29 and the raised sleeve 28 provide hinged degrees of freedom. This allows the entire constraint mechanism to restrict the rotating inner ring 26 from revolving around the swashplate 22 while simultaneously allowing it to adapt to the tilting and oscillation of the swashplate 22. This ensures that the rotating inner ring 26 remains macroscopically stable relative to the driven gear 25 on the swashplate 22 and does not undergo a following revolution. Thus, when the driven gear 25 moves in a figure-eight pattern with the swashplate 22, it will generate relative motion and mesh with the relatively stationary internal gear ring 27, thereby driving the driven gear 25 to rotate the rotating rod 23 and the fan blade 24 around its own axis. The rotation of fan blade 24 draws air from the bottom of the machine body and discharges it towards the rear vent 13 and front vent 14 at an angle of α, forming a directional forced cooling airflow covering multiple areas inside the motor body 1. Furthermore, since the front vent 14 is located below the grinding disc, the discharged airflow forms a positive pressure air curtain there, effectively preventing external grinding dust and other fumes from entering the motor body 1 through gaps, thus providing dust protection.

[0046] Regarding the lightweight gearbox head structure, this embodiment employs a differential design with unequal wall thicknesses for the gearbox housing. Specifically, based on the stress distribution cloud maps of the gearbox housing under various operating conditions obtained from finite element analysis, such as rated load, overload impact, and stall conditions, the housing area is divided into high-stress, medium-stress, and low-stress zones according to stress levels. In high-stress zones such as the bearing housing and flange root, which bear the radial and axial forces of the bevel gear meshing, the wall thickness is increased or local reinforcing bosses are provided, with the wall thickness increasing by 20% to 60% compared to the baseline value. In low-stress zones such as the housing, which is far from the load path and only serves a sealing and shape support function, the wall thickness is significantly reduced or weight-reducing grooves are provided, with the wall thickness decreasing by 30% to 50% compared to the baseline value.

[0047] Meanwhile, the reinforcing ribs are precisely arranged along the principal stress lines, starting from the front bearing housing of the motor and converging radially at the interface between the housing and the handle, achieving maximum structural rigidity with minimal material weight. Furthermore, the front cover of the brushless motor 2 and the input end of the gearbox housing are integrated into a single die-cast part, eliminating a pair of connecting flanges and multiple fasteners, shortening the axial length from the motor to the gearbox, and bringing the center of gravity of the motor head closer to the handle, thereby effectively reducing the cantilever bending moment when the user grips it.

[0048] Regarding the platform-based chassis structure, in this embodiment, the chassis housing of the motor body 1, the mounting interface of the brushless motor 2, the control module, and its mounting structure are defined as a unified universal platform. Standardized mechanical and electrical interfaces are designed at the front end of this universal platform. During the production and assembly stage, different functional head components can be installed using these interfaces. For example, an angle grinder head component can be installed to achieve right-angle output and a protective cover function; a polishing machine head component can be installed to achieve coaxial output and a polishing accessory interface; and a straight grinder head component can be installed to achieve a slender, high-speed output. This platform-based design allows different product types to share most of the core components, reducing the overall development and manufacturing costs of the product at the system level.

[0049] It should be noted that the lightweight head structure, digital speed control system, brushless motor drive system, and platform-based body structure in the above embodiments can be implemented individually or in any combination, and all fall within the protection scope of this invention. Furthermore, the accompanying drawings are merely illustrative and do not constitute a limitation on the scope of protection of this invention. For those skilled in the art, various improvements and modifications can be made without departing from the principles of this invention, and these improvements and modifications should also be considered within the protection scope of this invention.

Claims

1. A lightweight, digitally adjustable brushless electric grinding tool, comprising a motor body, the motor body consisting of a body and a top-mounted conversion housing, which integrates a power supply module, a control module, and a drive module; the drive module includes a brushless motor fixedly mounted on the top region of the body, with a heat dissipation mechanism connected to the output shaft of the brushless motor; a rear vent and a front vent, respectively, for interaction with the outside environment, are respectively provided on both sides of the connection between the conversion housing and the body, characterized in that: The heat dissipation mechanism includes a swashplate, with an output shaft passing through the central hole of the swashplate and being fastened to it. The mounting plane of the swashplate is set at an angle α with the axial direction of the output shaft, so that the swashplate is tilted and fixed relative to the end face of the output shaft. Several through ventilation holes are opened circumferentially at the bottom end of the swashplate, and several rotating holes are also opened circumferentially at the bottom end of the swashplate. A rotating rod is rotatably connected in each rotating hole. A fan blade is coaxially mounted on the top of the rotating rod, and a driven gear is coaxially fixedly connected to the lower part of the outer wall of the rotating rod. The upper part of the machine body is also equipped with a constraint mechanism, which is connected to a rotating inner ring. The rotating inner ring is coaxially rotatably connected to an annular groove opened in the inner wall of the swashplate. The bottom end of the rotating inner ring is coaxially connected to an internal gear ring, which meshes with the outer wall of multiple driven gears. When the brushless motor starts, the output shaft drives the swashplate to rotate. The constraint mechanism restricts the rotating inner ring from revolving with the swashplate as a whole, so that the driven gears and the internal gear ring mesh with each other, driving the fan blades to rotate, drawing in air and discharging it towards the rear and front vents.

2. The lightweight digital speed-adjustable brushless electric grinding tool according to claim 1, characterized in that: The included angle α is 5°±2°.

3. The lightweight digital speed-adjustable brushless electric grinding tool according to claim 1, characterized in that: The constraint mechanism includes two side slide rails symmetrically installed on the upper part of the machine body, and the two side slide rails are arranged parallel to the output shaft axis of the brushless motor; a slider is vertically slidably connected in each side slide rail, and a rotating circular hole is opened on the side of the two sliders facing the brushless motor. Only a limiting circular rod is rotatably connected in each rotating circular hole, and a rotating connector is horizontally fixedly connected to the other side of each limiting circular rod; a hinge plate is hinged to the outer end of the rotating connector, and the other end of the hinge plate is hinged to the rotating inner ring through a protruding sleeve plate.

4. A lightweight, digitally adjustable, brushless electric grinding tool according to claim 3, characterized in that: The inner rotating ring is equipped with ball bearings at the connection with the annular groove and is coated with lubricating grease to keep the inner rotating ring relative to the swashplate when the swashplate is tilted and rotated.

5. A lightweight, digitally adjustable, brushless electric grinding tool according to claim 1, characterized in that: Each of the rotating rods is connected to the rotating hole via a bearing; each vent is located directly below the corresponding fan blade, used to draw air in when the fan blade rotates and guide it along the vent towards the rear and front vents.

6. A lightweight, digitally adjustable, brushless electric grinding tool according to claim 1, characterized in that: The drive module also includes a gearbox assembly that is connected to the brushless motor. The gearbox housing of the gearbox assembly adopts a differential design with unequal wall thickness. The gearbox housing is divided into a high-stress zone, a medium-stress zone, and a low-stress zone according to the stress level. The wall thickness of the high-stress zone is greater than that of the low-stress zone. The reinforcing ribs on the gearbox housing are arranged along the direction of the principal stress line.

7. A lightweight, digitally adjustable brushless electric grinding tool according to claim 6, characterized in that: The front end cover of the brushless motor and the input end of the gearbox housing are combined into a single die-cast part.

8. A lightweight, digitally adjustable brushless electric grinding tool according to claim 7, characterized in that: The control module is installed in the middle gripping area of ​​the motor body and integrates a microcontroller, a motor drive circuit, and a speed detection module. The microcontroller receives the target speed command set by the user, acquires the actual speed signal of the brushless motor rotor in real time through the Hall sensor, compares the actual speed with the target speed to obtain the speed error, calculates the instantaneous current command based on the error and the built-in PID control algorithm, and controls the duty cycle of the PWM signal through the motor drive circuit to realize closed-loop speed regulation control of the brushless motor.

9. A lightweight, digitally adjustable brushless electric grinding tool according to claim 8, characterized in that: The motor body housing, the brushless motor mounting interface, the control module and its mounting structure are defined as a unified universal platform; the front end of the universal platform is provided with standardized mechanical and electrical interfaces for installing machine head components with different functions during the production assembly stage, the machine head components including angle grinder machine head components, polisher machine head components or straight grinder machine head components.

10. A lightweight, digitally adjustable, brushless electric grinding tool according to claim 6, characterized in that: The front vent is located below the grinding disc. The airflow discharged from the fan blades forms a positive pressure air curtain at the front vent to prevent external dust from entering the motor body.

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