Handheld polishing machine convenient to dissipate heat

Abstract

The utility model discloses a handheld polisher convenient for heat dissipation, which comprises a shell, a driving motor, a circuit board assembly and a polishing disk, the shell comprises a grip, a front shell fixed at the front end of the grip and a rear shell fixed at the rear end of the grip, the driving motor is arranged in the front shell, the polishing disk is connected with the driving motor, and the circuit board assembly is arranged in the rear shell. The circuit board assembly is installed in the rear shell, the interior of the grip is hollow, the two ends of the grip are communicated with the rear shell and the front shell respectively, a motor shaft extending out of the front end of the driving motor is connected with a first cooling fan, a motor shaft extending out of the rear end of the driving motor is connected with a second cooling fan, and an air inlet is formed in the rear shell. An air outlet is formed in the front shell, when the driving motor drives the first cooling fan and the second cooling fan to rotate, air enters the rear shell from the air inlet, sequentially passes through the circuit board assembly and the driving motor and then is exhausted from the air outlet, and therefore the good cooling effect on the circuit board assembly and the driving motor is achieved.

Description

Technical Field

[0001] This utility model relates to a polishing machine, and more particularly to a handheld polishing machine that facilitates heat dissipation. Background Technology

[0002] Handheld polishers, also known as grinding machines, are electric tools that use a motor-driven transmission mechanism to drive a polishing work unit connected to the output shaft to perform processing operations. They remove surface contamination, oxide layers, shallow scratches, and other defects by rubbing the high-speed rotating polishing disc against the surface to be polished, thereby obtaining a bright and smooth surface.

[0003] Existing handheld polishing machines generally include a housing, a motor, and a polishing disc. The housing includes a handle and a motor housing fixed to the front end of the handle. The motor is installed inside the motor housing as a power source. The polishing disc is connected to the motor. An air inlet is provided between the motor housing or the handle. A centrifugal cooling fan is connected to the motor shaft extending from the front end of the motor. The rotation of the cooling fan causes air to enter the motor housing from the air inlet, pass through the motor, and then be discharged. In order to balance the weight of the polishing machine from front to back, a controller mounting section is provided at the rear of the handle, and the control circuit board assembly is installed in the controller mounting section.

[0004] The control board assembly located at the rear of the polishing machine also generates heat during machine operation. Excessive heat can affect the stability of the control board assembly and even damage it. However, existing polishing machines only dissipate heat from the motor through a cooling fan connected to the motor shaft extending from the front of the motor, leaving the control board assembly at the rear of the machine poorly cooled. Utility Model Content

[0005] Based on the fact that the control board assembly located at the rear of the polishing machine also generates heat during machine operation, and that excessive heat can affect the stability of the control board assembly and even damage it, the existing polishing machines can only dissipate heat from the motor by means of a cooling fan connected to the motor shaft extending from the front of the motor. The control board assembly located at the rear of the machine cannot be well cooled. Therefore, this utility model provides a handheld polishing machine that facilitates heat dissipation.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a handheld polishing machine with convenient heat dissipation, including a housing, a drive motor, a circuit board assembly, and a polishing disc. The housing includes a handle, a front housing fixed to the front end of the handle, and a rear housing fixed to the rear end of the handle. The drive motor is located in the front housing, and the polishing disc is connected to the drive motor. The circuit board assembly is installed in the rear housing. The handle is hollow inside and its two ends are respectively connected to the rear housing and the front housing. Both ends of the drive motor are provided with protruding motor shafts. A first cooling fan is connected to the motor shaft protruding from the front end of the drive motor, and a second cooling fan is connected to the motor shaft protruding from the rear end of the drive motor. An air inlet is provided on the rear housing, and an air outlet is provided on the front housing. When the drive motor drives the first cooling fan and the second cooling fan to rotate, the gas enters the rear housing from the air inlet, passes through the circuit board assembly and the drive motor in sequence, and is discharged from the air outlet.

[0007] A further preferred embodiment of this utility model is that air inlets are provided on the front and rear parts of both the left and right sides of the rear housing.

[0008] A further preferred embodiment of this utility model is that a filter screen is provided at the air inlet.

[0009] A further preferred embodiment of this utility model is as follows: the front housing includes a housing fixedly connected to the front end of the handle, a head shell fixed to the front side of the housing, and a bottom cover fixed to the bottom of the head shell. The head shell is provided with a flange, which is fixedly connected to the front side of the housing by screws. The drive motor is installed inside the housing. An output shaft that drives the motor shaft in a different direction is installed inside the head shell. One end of the output shaft extends out from the bottom cover. A polishing disc is connected to the end of the output shaft that extends out from the bottom cover. The air outlet includes a first air outlet provided on the side wall of the housing and a second air outlet provided on the flange. The first air outlet is opposite to the side of the first cooling fan, and the second air outlet is opposite to the front side of the first cooling fan. The first cooling fan is a centrifugal fan, and the second cooling fan is an axial fan.

[0010] A further preferred technical solution of this utility model is as follows: the upper and lower parts of the flange are provided with second air outlets, the head shell and the flange are covered with air guide shells, the second air outlets located at the upper part are connected to the inside of the air guide shell and the inside of the machine housing, and there is a gap between the air guide shell and the head shell for air flow. After the air enters the air guide shell, it is discharged from the opening at the bottom of the air guide shell.

[0011] A further preferred embodiment of this utility model is as follows: the polishing disc is threadedly connected to the output shaft, and a locking assembly for locking the output shaft rotation is provided between the bottom cover and the output shaft. The locking assembly includes a locking sleeve and a movable locking member disposed on the bottom cover. The locking sleeve is fitted onto the output shaft and restricts relative rotation with respect to the output shaft. At least one locking groove is provided on the side wall of the locking sleeve. The movable locking member can move radially relative to the bottom cover along the output shaft. The movable locking member can be moved into the locking groove to lock the relative rotation of the output shaft and the bottom cover. An elastic member is provided on the bottom cover to provide a restoring force for the movable locking member.

[0012] A further preferred technical solution of this utility model is as follows: the bottom of the bottom cover is provided with a downward-opening receiving groove, the locking sleeve is received in the receiving groove, the side wall of the bottom cover is provided with a guide channel communicating with the receiving groove, the guide channel is opposite to the locking sleeve, the movable locking member is movably inserted in the guide channel, the movable locking member is provided with a long groove, and a limit bolt is threadedly connected to the bottom of the bottom cover, the limit bolt is inserted into the long groove to limit the range of motion of the movable locking member.

[0013] A further preferred technical solution of this utility model is as follows: a button located on one side of the bottom cover is connected to the movable locking component; a positioning groove opposite to the button is provided on the side wall of the bottom cover; a positioning post opposite to the positioning groove is provided on the button; the elastic component is a return spring; one end of the return spring is inserted into the positioning groove; and the other end of the return spring is sleeved on the positioning post.

[0014] A further preferred embodiment of this utility model is as follows: the guide channel is disposed on the side wall of the front side of the bottom cover, the button is disposed on the front side of the bottom cover, the bottom cover is at least partially covered by the air guide shell, the bottom of the air guide shell is provided with an avoidance notch, and the button is exposed to the outside through the avoidance notch for pressing.

[0015] A further preferred technical solution of this utility model is as follows: the lock sleeve is annular, and a two-stage channel is opened at the center of the lock sleeve along its axial direction. A first step is provided between the upper first-stage channel and the lower second-stage channel. The output shaft passes through the channel, and an integral annular protrusion is fixed on the output shaft. The first step abuts against the upper surface of the annular protrusion, and the second-stage channel is sleeved outside the annular protrusion. The upper bottom of the receiving groove is limited at the upper part of the lock sleeve, and there is a gap between the two. A scissor is provided at a symmetrical position on both sides of the annular protrusion. The inner walls of the second-stage channel are provided with snap-fit ​​surfaces that respectively engage with the two snap-fit ​​surfaces. When the lock sleeve moves up and down along the output shaft, the snap-fit ​​surfaces are always engaged with the snap-fit ​​surfaces.

[0016] Compared with the prior art, the advantages of this utility model are that a first cooling fan is installed on the motor shaft extending from the front end of the drive motor, and a second cooling fan is installed on the motor shaft extending from the rear end of the drive motor. An air inlet is provided on the rear housing where the circuit board assembly is installed, and an air outlet is provided on the front housing where the drive motor is installed. The handle connects the front housing and the rear housing. When the drive motor drives the first and second cooling fans to rotate, air can enter the rear housing from the air inlet, pass through the circuit board assembly and the drive motor in sequence, and then be discharged from the air outlet. This allows the circuit board assembly and the drive motor to achieve a cooling effect, thereby improving their service life. By adding a second cooling fan at the rear of the drive motor, the second cooling fan can better introduce air from the rear housing into the front housing, forming a flowing airflow. Furthermore, the cooperation of the two cooling fans can create a greater air pressure inside the housing, thereby increasing the air volume and improving the cooling effect. Attached Figure Description

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the present invention. Furthermore, unless specifically indicated, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated depictions, and the drawings are not necessarily drawn to scale.

[0018] Figure 1 This is a structural schematic diagram of the present invention from the left side view;

[0019] Figure 2 This is a structural schematic diagram of the present invention from the right side view;

[0020] Figure 3 This is a cross-sectional view of the polishing machine;

[0021] Figure 4 for Figure 3 A magnified view of part A;

[0022] Figure 5 for Figure 3 A magnified view of section B;

[0023] Figure 6 for Figure 3 A magnified view of a portion at point C;

[0024] Figure 7 A cross-sectional view of the polishing machine when the output shaft is locked;

[0025] Figure 8 for Figure 7 A magnified view of a portion at point D;

[0026] Figure 9 This is a split view of the air guide shell and the outer shell;

[0027] Figure 10 This is a schematic diagram of the air guide shell structure;

[0028] Figure 11 A schematic diagram of the structure of a polishing machine after removing the air guide shell;

[0029] Figure 12 This is a breakdown diagram of the filter and polishing machine.

[0030] Figure 13 Schematic diagram of the lock sleeve structure Figure 1 ;

[0031] Figure 14 Schematic diagram of the lock sleeve structure Figure 2 ;

[0032] Figure 15 This is a schematic diagram of the output shaft.

[0033] In the diagram: 1. Housing; 2. Rear housing; 3. Filter screen; 4. Handle; 5. Front housing; 6. Air guide shell; 7. Polishing disc; 8. Housing; 9. First air outlet; 10. Side opening; 11. Circuit board assembly; 12. Second cooling fan; 13. Drive motor; 14. First cooling fan; 15. Head shell; 16. Output shaft; 17. Middle cover; 18. Vent; 19. Flange; 20. Second air outlet; 21. Bottom cover; 22. Locking sleeve; 23. Receiving groove; 24. 25. Stepped channel; 26. Positioning groove; 27. Return spring; 28. Positioning post; 29. ​​Button; 30. Movable locking element; 31. Annular protrusion; 32. Second-stage channel; 33. Motor shaft; 34. First bevel gear; 35. Second bevel gear; 36. Second through hole; 37. First through hole; 38. Bearing groove; 39. Locking groove; 40. Limiting bolt; 41. Long groove; 42. Guide channel; 43. Clearance notch; 44. Air inlet; 45. First step; 46. Snap-fit ​​surface; 47. Cut surface. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate that these descriptions are merely descriptive and exemplary and should not be construed as limiting the scope of protection of the present invention.

[0035] It should be noted that similar labels in the following figures indicate similar items; therefore, once an item is defined in one figure, it may not be further defined and explained in subsequent figures.

[0036] Figures 1-15As shown, a handheld polisher with good heat dissipation includes a housing 1, a drive motor 13, a circuit board assembly 11, and a polishing disc 7. The housing 1 includes a handle 4, a front housing 5 fixed to the front end of the handle 4, and a rear housing 2 fixed to the rear end of the handle 4. The drive motor 13 is located in the front housing 5, and the polishing disc 7 is connected to the drive motor 13. The circuit board assembly 11 is installed in the rear housing 2 and can control the operating status of the drive motor 13. When the drive motor 13 is working, the polishing disc 7 rotates to polish the object to be polished.

[0037] Figure 3 As shown, the grip 4 is hollow inside and its two ends are connected to the interior of the rear housing 2 and the front housing 5 respectively. Both ends of the drive motor 13 are provided with protruding motor shafts 32. The motor shaft 32 protruding from the front end of the drive motor 13 is connected to a first cooling fan 14, and the motor shaft 32 protruding from the rear end of the drive motor 13 is connected to a second cooling fan 12. The rear housing 2 is provided with an air inlet 43, and the front housing 5 is provided with an air outlet. When the drive motor 13 drives the first cooling fan 14 and the second cooling fan 12 to rotate, the gas enters the rear housing 2 from the air inlet 43, passes through the circuit board assembly 11 and the drive motor 13 in sequence, and is discharged from the air outlet.

[0038] This patent provides an air inlet 43 on the rear housing 2 containing the circuit board assembly 11 and an air outlet on the front housing 5 containing the drive motor 13. A first cooling fan 14 is connected to the front of the drive motor 13, and a second cooling fan 12 is connected to the rear of the drive motor 13. When the drive motor 13 starts, a cooling airflow is formed that enters the rear housing 2 from the air inlet 43, flows through the handle 4 into the front housing 5, and finally exits from the air outlet. This cooling airflow passes through the circuit board assembly 11 and the drive motor 13, cooling them and improving their service life. By adding a second cooling fan 12 to the rear of the drive motor 13, the second cooling fan 12 can better introduce air from the rear housing 2 into the front housing 5, forming a flowing airflow. Furthermore, the cooperation of the two cooling fans can create greater air pressure inside the housing 1, thereby increasing the air volume and improving the cooling effect.

[0039] Figure 1 , Figure 2 As shown, preferably, air inlets 43 are provided on the front and rear positions of both sides of the rear housing 2, so that air can enter from all sides of the rear housing 2 at the same time, and the circuit board assembly 11 inside the rear housing 2 can be cooled by airflow. In addition, the arrangement of this structure can also increase the air intake area.

[0040] Figure 12As shown, preferably, a filter 3 is provided at the air inlet 43 to separate dust particles and prevent external dust particles from entering the housing 1 and affecting the use of the drive motor 13 or electronic components. Specifically, the filter 3 is surrounded by a rigid frame, which is fastened to the air inlet 43 by a snap-fit ​​mechanism.

[0041] Figure 3 , Figure 4 , Figure 5 , Figure 11 As shown, the front housing 5 includes a housing 8 fixedly connected to the front end of the handle 4, a head shell 15 fixed to the front side of the housing 8, and a bottom cover 21 fixed to the bottom of the head shell 15. A flange 19 is provided on the head shell 15, and the flange 19 is fixedly connected to the front side of the housing 8 by screws, thus fixing the head shell 15 to the front side of the housing 8. The aforementioned drive motor 13 is installed inside the housing 8. An output shaft 16 that drives the motor shaft 32 in a different direction is installed inside the head shell 15. One end of the output shaft 16 extends out from the bottom cover 21. A polishing disc 7 is connected to the end of the output shaft 16 that extends out of the bottom cover 21. The air outlet includes a first air outlet 9 provided on the side wall of the housing 8 and a second air outlet 20 provided on the flange 19. The first air outlet 9 is opposite to the side of the first cooling fan 14, and the second air outlet 20 is opposite to the front side of the first cooling fan 14. The first cooling fan 14 is a centrifugal fan, and the second cooling fan 12 is an axial fan.

[0042] When the drive motor 13 drives the first cooling fan 14 and the second cooling fan 12 to rotate, external air is drawn into the rear housing 2 through the air inlet 43, enters the front housing 5 along the handle 4, and the second cooling fan 12 at the rear blows the air forward along the axis of the drive motor 13. The air blown forward passes through the first cooling fan 14, and the first cooling fan 14 at the front blows air radially out, exhausting the air from the first air outlet 9. The air blown forward passes through the gap between the first cooling fan 14 and the inner wall of the housing 8, and finally exits from the second air outlet 20.

[0043] Figure 3 , Figure 4 , Figure 9 , Figure 10 , Figure 11As shown, the upper and lower parts of the flange 19 are provided with second air outlets 20. The head shell 15 and the flange 19 are covered by a guide shell 6. The upper second air outlet 20 connects the inside of the guide shell 6 and the inside of the housing 8. There is a gap between the guide shell 6 and the head shell 15 for airflow. The air discharged from the upper second air outlet 20 enters the guide shell 6 and is discharged from the opening at the bottom of the guide shell 6. The air passes between the guide shell 6 and the head shell 15, which can carry away some of the heat on the head shell 15, thus playing a role in heat dissipation of the head shell 15. The head shell 15 is an aluminum shell with good thermal conductivity. The guide shell 6 can be a plastic shell with openings on the side and bottom. The guide shell 6 is fixedly installed on the outside of the head shell 15 by screws.

[0044] The rear housing 2 is integrally connected to the rear of the grip 4. The housing 8 is fixedly connected to the front of the grip 4 by screws. The bottom cover 21 is fixedly connected to the bottom of the head housing 15 by screws. The rear housing 2 and the grip 4 are divided into a left half-shell and a right half-shell. After the left half-shell and the right half-shell are joined together, they are clamped at the tail of the rear side of the housing 8 and fixed to the housing 8 by screws.

[0045] An intermediate cover 17 is provided between the flange 19 and the housing 8. The intermediate cover 17 is fixed between the flange 19 and the housing 8 and covers the opening at the front of the housing 8. The intermediate cover 17 has a first through hole 36 through which the motor shaft 32 passes. The head shell 15 has a second through hole 35 through which the motor shaft 32 passes. The motor shaft 32 passes through the first through hole 36 and the second through hole 35 and extends into the head shell 15 to drive the output shaft 16 in a different direction. A first bevel gear 33 is fixed to the end of the motor shaft 32. A second bevel gear 34 that meshes with the first bevel gear 33 is fixed to the output shaft 16. When the motor shaft 32 rotates, it drives the second bevel gear 34 to rotate through the first bevel gear 33, thereby causing the output shaft 16 to drive the polishing disc 7 to rotate. The side of the intermediate cover 17 facing the head shell 15 has a bearing groove 37. The bearing groove 37 is located in front of the first through hole 36 and the two are connected. A bearing is installed in the bearing groove 37, and the motor shaft 32 passes through the inner ring of the bearing.

[0046] The intermediate cover 17 is provided with a vent 18 opposite to the second air outlet 20 at the top and bottom of the flange 19. After passing through the vent 18, the air is discharged from the second air outlet 20. The intermediate cover 17 is also provided with a side opening 10 opposite to the side of the first cooling fan 14 to increase the radial air volume of the first cooling fan 14.

[0047] Figures 6-8As shown, the polishing disc 7 is threaded onto the output shaft 16. A locking assembly is provided between the bottom cover 21 and the output shaft 16 to prevent the output shaft 16 from rotating. The locking assembly includes a locking sleeve 22 and a movable locking member 29 disposed on the bottom cover 21. The locking sleeve 22 is fitted onto the output shaft 16 and restricts its rotation relative to the output shaft 16. At least one locking groove 38 is provided on the side wall of the locking sleeve 22. The movable locking member 29 can move radially relative to the bottom cover 21 along the output shaft 16. The movable locking member 29 can be moved into the locking groove 38 to lock the relative movement of the output shaft 16 and the bottom cover 21. An elastic member is provided on the bottom cover 21 to provide a restoring force for the movable locking member 29.

[0048] When the movable locking piece 29 moves and engages in the locking groove 38 on the side wall of the locking sleeve 22 to lock the output shaft 16 relative to the bottom cover 21, the user can unscrew the polishing disc 7 from the output shaft 16 by hand, making the removal of the polishing disc 7 without the need for a wrench, which is convenient and quick. Furthermore, the locking groove 38 is set on the locking sleeve 22, so there is no need to machine the locking groove 38 on the output shaft 16, thus ensuring the overall strength of the output shaft 16.

[0049] Figure 14 As shown, preferably, the lock sleeve 22 has four lock grooves 38 on its side wall, and the four lock grooves 38 are evenly arranged on the circumferential outer wall of the lock sleeve 22.

[0050] The bottom of the bottom cover 21 is provided with a downward-facing receiving groove 23, in which the locking sleeve 22 is received. The side wall of the bottom cover 21 is provided with a guide channel 41 that connects to the receiving groove 23. The guide channel 41 is opposite to the locking groove 38. The movable locking member 29 is movably inserted into the guide channel 41 and guided by the guide channel 41. The movable locking member 29 is provided with a long groove 40. The bottom of the bottom cover 21 is threaded with a limiting bolt 39. The limiting bolt 39 is inserted into the long groove 40 to limit the range of motion of the movable locking member 29. The limiting bolt 39 prevents the movable locking member 29 from detaching from the guide channel 41.

[0051] A button 28 is connected to the movable locking member 29 on one side of the bottom cover 21. The side wall of the bottom cover 21 is provided with a positioning groove 25 opposite to the button 28. The button 28 is provided with a positioning post 27 opposite to the positioning groove 25. The elastic element is a return spring 26. One end of the return spring 26 is inserted into the positioning groove 25, and the other end of the return spring 26 is sleeved on the positioning post 27. The return spring 26 acts on the button 28 and exerts an outward pushing force on the button 28. When the button 28 is pressed, the movable locking member 29 moves into the receiving groove 23 and is locked into the locking groove 38 on the locking sleeve 22, locking the rotation of the output shaft 16. When the button 28 loses force, the return spring 26 pushes the button 28 outward, causing the button 28 to drive the movable locking member 29 to move outward and reset. The movable locking member 29 disengages from the locking groove 38, and the output shaft 16 can rotate relative to the bottom cover 21.

[0052] The guide channel 41 is located on the side wall of the front side of the bottom cover 21, and the button 28 is located on the front side of the bottom cover 21. The bottom cover 21 is at least partially covered by the air guide shell 6. The bottom of the air guide shell 6 is provided with an avoidance notch 42. The button 28 is exposed to the outside through the avoidance notch 42 for pressing. The button 28 is located at the front to facilitate the user to apply force to press it.

[0053] Figures 13-15 As shown, the locking sleeve 22 is annular. A two-stage channel is formed along its axial direction at the center of the locking sleeve 22. A first step 44 is provided between the upper first-stage channel 24 and the lower second-stage channel 31. The output shaft 16 passes through the channel, and an integral annular protrusion 30 is fixed on the output shaft 16. The first step 44 abuts against the upper surface of the annular protrusion 30, and the second-stage channel 31 is fitted around the outside of the annular protrusion 30. The upper bottom of the receiving groove 23 is limited at the upper part of the locking sleeve 22. There is a gap between the two. The annular protrusion 30 has symmetrical cut surfaces 46 on both sides. The inner wall of the second-order channel 31 has two locking surfaces 45 that respectively engage with the two cut surfaces 46. The annular protrusion 30 and the upper bottom of the receiving groove 23 limit the upward and downward movement of the locking sleeve 22. When the locking sleeve 22 moves up and down along the output shaft 16, the locking surface 45 is always engaged with the cut surface 46, so that the locking sleeve 22 and the output shaft 16 will never rotate relative to each other.

[0054] The locking sleeve 22 is limited in the upper and lower positions by the annular protrusion 30 and the upper bottom of the receiving groove 23. The structure is simple, and there is a gap between the locking sleeve 22 and the upper bottom of the receiving groove 23, so that the locking sleeve 22 will not make hard contact with the upper bottom of the receiving groove 23 when the output shaft 16 drives the polishing disc 7 to rotate and polish, thus avoiding hard contact friction that increases the resistance to the rotation of the output shaft 16.

[0055] The above describes the handheld polishing machine with convenient heat dissipation provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand this utility model and its core ideas. It should be noted that those skilled in the art can make several improvements and modifications to this utility model without departing from its principle, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A handheld polisher with easy heat dissipation, comprising a housing, a drive motor, a circuit board assembly, and a polishing disc, wherein the housing includes a handle, a front housing fixed to the front end of the handle, and a rear housing fixed to the rear end of the handle; the drive motor is disposed within the front housing; the polishing disc is connected to the drive motor; and the circuit board assembly is housed within the rear housing, characterized in that... The handle is hollow inside and communicates with the rear shell and the front shell at two ends respectively, both ends of the driving motor are provided with an extended motor shaft, the first heat dissipation fan is connected to the motor shaft extended at the front end of the driving motor, the second heat dissipation fan is connected to the motor shaft extended at the rear end of the driving motor, the rear shell is provided with an air inlet, the front shell is provided with an air outlet, when the driving motor drives the first heat dissipation fan and the second heat dissipation fan to rotate, the gas enters the rear shell from the air inlet, sequentially passes through the circuit board assembly and the driving motor and is discharged from the air outlet.

2. The hand-held polisher with facilitated heat dissipation according to claim 1, characterized in that, The front and rear parts of the left and right sides of the rear shell are provided with air inlets.

3. The hand-held polisher with facilitated heat dissipation according to claim 1 or 2, characterized in that, The air inlet is provided with a filter screen.

4. The hand-held polisher with facilitated heat dissipation of claim 1, wherein, The front shell comprises a casing fixedly connected to the front end of the handle, a head shell fixedly connected to the front side of the casing and a bottom cover fixedly connected to the bottom of the head shell, the head shell is provided with a flange plate, the flange plate is fixedly connected to the front side of the casing through screws, the driving motor is installed in the casing, an output shaft is installed in the head shell and is reversely driven by the motor shaft, one end of the output shaft extends out of the bottom cover, the polishing disc is connected to the end of the output shaft extending out of the bottom cover, the air outlet comprises a first air outlet arranged on the side wall of the casing and a second air outlet arranged on the flange plate, the first air outlet is opposite to the side of the first heat dissipation fan, the second air outlet is oppositely arranged on the front side of the first heat dissipation fan, the first heat dissipation fan is a centrifugal fan and the second heat dissipation fan is an axial flow fan.

5. The hand-held polisher with facilitated heat dissipation according to claim 4, characterized in that, The upper part and the lower part of the flange plate are both provided with the second air outlet, the head shell and the outside of the flange plate are covered with a wind guide shell, the second air outlet located at the upper part communicates the inside of the wind guide shell and the inside of the casing, a gap for air flow is arranged between the wind guide shell and the head shell, the air enters the wind guide shell and is discharged from the opening at the bottom of the wind guide shell.

6. The hand-held polisher with facilitated heat dissipation of claim 4, wherein, The polishing disc is threadedly connected to the output shaft, a locking assembly for locking the rotation of the output shaft is arranged between the bottom cover and the output shaft, the locking assembly comprises a locking sleeve and a movable locking piece arranged on the bottom cover, the locking sleeve is sleeved on the output shaft and is rotationally limited relative to the output shaft, at least one locking groove is arranged on the side wall of the locking sleeve, the movable locking piece is movable relative to the bottom cover along the radial direction of the output shaft, the movable locking piece can be movably clamped into the locking groove to lock the relative rotation of the output shaft and the bottom cover, an elastic member is arranged on the bottom cover to provide the movable locking piece with an elastic force for resetting.

7. The hand-held polisher with facilitated heat dissipation according to claim 6, characterized in that, The bottom of the bottom cover is provided with a receiving groove opening downward, the locking sleeve is received in the receiving groove, a guide channel communicating with the receiving groove is arranged on the side wall of the bottom cover and opposite to the locking sleeve, the movable locking piece is movably arranged in the guide channel, a long groove is arranged on the movable locking piece, a limiting bolt is threadedly connected to the bottom of the bottom cover and inserted into the long groove to limit the movement range of the movable locking piece.

8. The hand-held polisher with facilitated heat dissipation according to claim 7, characterized in that, A button located at one side of the bottom cover is connected to the movable locking piece, a positioning groove opposite to the button is arranged on the side wall of the bottom cover, a positioning column opposite to the positioning groove is arranged on the button, the elastic member is a reset spring, one end of the reset spring is inserted into the positioning groove and the other end of the reset spring is sleeved on the positioning column.

9. The hand-held polisher with facilitated heat dissipation according to claim 8, characterized in that, The guide channel is arranged on the sidewall of the front side of the bottom cover, the button is arranged on the front side of the bottom cover, the head shell and the outer cover of the flange are covered by the air guide shell, the bottom cover is at least partially covered in the air guide shell, the bottom of the air guide shell is provided with an avoiding gap, and the button is exposed outside through the avoiding gap and used for pressing.

10. The hand-held polisher with facilitated heat dissipation according to claim 7, characterized in that, The lock sleeve is annular, two-stage hole channels are formed in the center of the lock sleeve along the axial direction, a first step is arranged between the upper one-stage hole channel and the lower two-stage hole channel, the output shaft passes through the hole channels, an integral annular convex edge is fixed on the output shaft, the first step abuts against the upper surface of the annular convex edge, and the two-stage hole channel is sleeved outside the annular convex edge, the upper bottom of the accommodating groove is limited on the upper part of the lock sleeve and has a spacing therebetween, the symmetrical positions on both sides of the annular convex edge are provided with cut surfaces, the inner walls of the two-stage hole channels are provided with clamping surfaces which are respectively clamped with the two cut surfaces, and the clamping surfaces are always in the clamped state with the cut surfaces when the lock sleeve moves up and down along the output shaft.

Images