Handheld power tools

Abstract

A handheld power tool comprises a housing, a motor arranged inside the housing, a gear box driven by the motor, and a fan blade; the gear box comprises a housing, a transmission gear set arranged inside the housing, a gear box cover arranged at the rear of the housing, and a gasket arranged between the gear box cover and the transmission gear set to prevent grease from overflowing; the transmission gear set comprises planetary gears driven by the motor and an inner ring gear meshing with the planetary gears; a ventilation opening is provided on the housing on the side of the inner ring gear corresponding to the transmission gear set, a notch corresponding to the ventilation opening is provided on the gear box cover, and an air inlet connected to the ventilation opening is provided on the housing; a protrusion is provided on the inner side of the gear box cover to push the gasket, so that the ventilation opening and the notch form an air duct. While performing air cooling, the handheld power tool reduces the possibility of dust entering the gear box and lubricating grease overflowing from the outside of the gear box.

Description

Technical field

[0001] The present invention relates to the technical field of electric tools, and in particular to a handheld electric tool. [Background Technology]

[0002] Existing handheld power tools are usually equipped with a cooling structure for cooling the motor. However, the primary transmission gear in the gearbox directly meshes with the output shaft of the motor, resulting in a very high rotation speed and extremely high heat generation. The high-speed operation causes heat and wear of the transmission gear, thereby affecting the normal service life of the gearbox. At the same time, the overall temperature increase of the gearbox will also cause the grease used for gear lubrication inside the gearbox to vaporize or carbonize prematurely, resulting in dry grinding of the gears. If the heat in the gearbox is not dissipated in time, the overall life of the gearbox will be greatly affected.

[0003] In view of this, it is indeed necessary to provide an improved handheld power tool to overcome the defects of the prior art. [Summary of the invention]

[0004] In view of the deficiencies of the prior art, an object of the present invention is to provide a handheld power tool which, while being air-cooled, reduces the possibility of dust entering the interior of the gear box and lubricating grease overflowing the exterior of the gear box.

[0005] The technical solution adopted by the present invention to solve the existing technical problems is: a handheld power tool, including a shell, a motor arranged inside the shell, a gear box driven by the motor and a fan blade driven by the motor; the gear box includes a box body, a transmission gear set arranged inside the box body, a gear box cover arranged at the rear of the box body and a gasket arranged between the gear box cover and the transmission gear set to prevent grease from overflowing; the transmission gear set has planetary gears driven by the motor and an inner gear ring meshing with the planetary gears; a vent is provided on the box body on the side of the inner gear ring of the transmission gear set corresponding to the vent, a notch is provided on the gear box cover corresponding to the vent for cooling air to pass through, and an air inlet connected to the vent is provided on the shell; a convex portion is provided on the inner side of the gear box cover to push the gasket, pressing the inner gear ring against the box body, and forming an air duct with the above-mentioned vent and the notch.

[0006] Preferably, the fan blade is a centrifugal fan blade, which is arranged behind the motor and rotates coaxially with the motor shaft of the motor to generate the cooling airflow. The cooling airflow passes through the inner gear ring and the outer surface of the gasket, and passes through the air duct to flow through the interior of the motor; an air outlet is provided on the outer casing corresponding to the outer periphery of the fan blade.

[0007] Preferably, a forward-protruding latching arm is provided at the edge of the gear box cover, and the latching arm protrudes into the above-mentioned vent to limit the relative displacement between the gear box cover and the box body.

[0008] Preferably, the transmission gear set includes a multi-stage transmission gear set, and the planetary gears and the inner ring gear constitute a first-stage transmission gear set.

[0009] Preferably, the housing includes a front housing and a rear housing that are connected to each other, and the first-stage transmission gear set is disposed in the rear housing.

[0010] Preferably, the transmission gear set further includes a second-stage transmission gear set meshing with the first-stage transmission gear set, and a third-stage transmission gear set meshing with the second-stage transmission gear set, and the output end of the third-stage transmission gear set is connected to the working shaft of the handheld power tool.

[0011] Preferably, there are more than two notches, and they are evenly distributed on the gear box cover in a circumferential direction with the axis of the gear box cover as the center.

[0012] Preferably, there are more than two protrusions, one end of the protrusion is fixedly connected to the notch, and the other end is a free end that presses against the surface of the gasket and provides axial support force for the gasket.

[0013] Preferably, the motor is configured as a brushless motor, comprising a rotor and a stator assembly surrounding an outer ring of the rotor, with a ventilation gap formed between the stator assembly and the rotor.

[0014] Preferably, the housing comprises a left half shell and a right half shell that are symmetrical and assembled with each other, and the left half shell and the right half shell respectively extend downward to form a gripping portion.

[0015] Compared with the prior art, the present invention has the following beneficial effects: a vent is provided on the gearbox body of the handheld power tool on the side of the inner gear ring corresponding to the transmission gear set, and a notch corresponding to the vent is provided on the gearbox cover for cooling air to pass through. The cooling air can directly flow through the outer surface of the inner gear ring and the gasket to take away the heat generated by the transmission gear set and flow out of the gearbox from the notch. The cooling air only flows through the outer surface of the inner gear ring and the gasket and will not bring dust into the interior of the transmission gear set. At the same time, the convex portion provided on the gearbox cover presses the gasket against the side surface of the inner gear ring, pressing the inner gear ring into the case body, and the lubricating grease in the gearbox is relatively sealed inside the gearbox to prevent it from overflowing.

Brief Description of the Drawings

[0016] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings:

[0017] Figure 1is a perspective schematic diagram of a handheld power tool according to an embodiment of the present invention;

[0018] Figure 2 yes Figure 1 Schematic diagram of the direction of cooling airflow of a handheld power tool shown;

[0019] Figure 3 yes Figure 1 A schematic diagram of the air duct of the handheld power tool shown;

[0020] Figure 4 yes Figure 1 A schematic cross-sectional view of an air duct of a handheld power tool is shown;

[0021] Figure 5 yes Figure 1 A partial cutaway view of the handheld power tool shown;

[0022] Figure 6 yes Figure 1 An exploded schematic diagram of a gearbox of a handheld power tool is shown;

[0023] Figure 7 It is a structural diagram of the gasket.

[0024] The meaning of the reference numerals in the figures:

[0025] 100, handheld electric drill 10, housing 101, left half housing 102, right half housing 103, grip 11, air inlet 12, air outlet 20, front housing 21, rear housing 211, vent 212, slot 213, step 22, gear box cover 221, notch 222, protrusion 223, holding arm 23, first-stage transmission gear set 231, inner ring gear 232, planetary gear 233, sun gear 24, second-stage transmission gear set 25, third-stage transmission gear set 3, working shaft 4, motor 41, stator assembly 42, rotor 43, gap 44, motor shaft 45, motor gear 5, fan blade 51, cooling airflow 52, ​​air duct 6, gasket 7, torque sleeve 8, drill chuck 200, battery pack [Specific implementation method]

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] like Figures 1 to 7FIG2 shows an embodiment of a handheld power tool of the present invention. The present invention is specifically described using a handheld electric drill 100 as an example. The handheld electric drill 100 includes a housing 10, a motor 4 disposed inside the housing 10, a gear box connected to a motor shaft 44 of the motor 4, and a fan 5 driven by the motor 4. In this embodiment, the housing 10 includes a left half shell 101 and a right half shell 102 that are symmetrical and assembled with each other. The left half shell 101 and the right half shell 102 respectively extend downward to form a grip portion 103. The lower end of the grip portion 103 is connected to a battery pack 200 that provides power to the handheld electric drill 100. The motor 4 is configured as a brushless motor, including a rotor 42 and a stator assembly 41 surrounding the outer ring of the rotor 42. A ventilation gap 43 is formed between the stator assembly 41 and the rotor 42. The motor shaft 44 is driven to rotate by the rotor 42. The fan 5 is a centrifugal fan blade, which is disposed behind the motor 4 and rotates coaxially with the motor shaft 44 to generate a cooling airflow 51.

[0028] Please refer to Figure 5 、 Figure 6 The gear box includes a box body, a transmission gear set arranged inside the box body for reducing the output speed of the motor 4, and a gear box cover 22 arranged at the rear of the box body to close the gear box. The box body includes a front box body 20 and a rear box body 21 connected to each other. The material of the box body can be set to a relatively low-priced plastic material or a more durable aluminum alloy material; the transmission gear set includes three-stage transmission gears, namely a first-stage transmission gear set 23, a second-stage transmission gear engaged with the first-stage transmission gear set 23, and a second-stage transmission gear set 24. The wheel set 24, and the third-stage transmission gear set 25 meshing with the second-stage transmission gear set 24, the transmission ratio between the three-stage transmission gears decreases successively, the first-stage transmission gear set 23 is arranged inside the rear box body 21, and a circular hole for the motor shaft 44 to extend into the center of the gear box cover 22 is provided, and a forward-protruding holding arm 223 is provided at the edge of the gear box cover 22. The holding arm 223 cooperates with the card slot 212 provided on the rear box body 21 to limit the relative displacement of the gear box cover 22 and the rear box body 21.

[0029] The motor shaft 44 is in transmission connection with the first-stage transmission gear set 23 of the transmission gear set. The first-stage transmission gear set 23 includes an inner ring gear 231, planetary gears 232 meshing with the inner ring gear 231, and a sun gear 233 meshing with the output end of the planetary gear 232. The front part of the motor shaft 44 is connected to a motor gear 45, and the motor gear 45 is arranged inside the gear box and meshes with the input end of the planetary gear 232. The output end of the transmission gear set, that is, the output end of the third-stage transmission gear set 25, is connected to the working shaft 3 driven by the motor 4.

[0030] A gasket 6 is provided between the first-stage transmission gear set 23 and the gear box cover 22 to prevent grease from overflowing from the box. In this embodiment, the gasket 6 is made of a metal material with better thermal conductivity. The gasket 6 is an annular metal gasket sleeved on the outer periphery of the motor shaft 44. The annular metal gasket covers the side surface of the inner gear ring 231 to prevent the grease used for lubrication inside the gear box from leaking out of the gear box.

[0031] Please refer to Figure 2 The housing is provided with a vent 211 on the side corresponding to the inner gear ring 231 of the transmission gear set. The vent 211 is provided on the rear housing 21 and is located above the inner gear ring 231. The gear housing cover 22 is provided with a notch 221 corresponding to the vent 211 for the cooling airflow 51 to pass through. The vent 211 is provided near the notch 221. Please refer to Figure 3 、 Figure 4 The vent 211 and the notch 221 form an air duct 52 for the cooling air flow to pass through. In this embodiment, the vent 211 and the slot 212 are integrally arranged, and the housing 10 is provided with an air inlet 11 corresponding to the vent 211. The air inlet 11 is located near the vent 211. An air outlet 12 is provided on the housing 10 corresponding to the outer periphery of the fan blade 5. After the cooling air flow 51 enters the handheld electric drill 100 through the air inlet 11, it passes through the vent 211 provided on the rear box body 21 and blows on the outer surface of the inner gear ring 231 and the gasket 6, passes through the notch 221, flows through the interior of the motor 4, and then passes through the gap 43. It is discharged from the air outlet 12, taking away a large amount of heat. At the same time, since the cooling air flow 51 only blows on the outer surface of the inner ring gear 231 and the gasket 6, dust will not be brought into the interior of the transmission gear set, while taking into account the needs of heat dissipation and dust prevention; it is further provided that the number of the notches 221 is more than two, and they are evenly distributed on the gear box cover 22 in the circumferential direction with the axis of the gear box cover 22 as the center. In this embodiment, there are two notches 221, and the corresponding ventilation holes 211 are also provided with two, and the air inlet 11 is provided with four, which are respectively provided on the left half shell 101 and the right half shell 102, and are symmetrical with respect to the connection between the left half shell 101 and the right half shell 102.

[0032] Please refer to Figure 7The inner side of the gear case cover 22 is provided with a convex portion 222 for pushing the gasket 6. The convex portion 222 presses the gasket 6 against the side surface of the inner gear ring 231, pressing the inner gear ring 231 against the case body. The convex portions 222 are provided with more than two corresponding to the notches 221. Similarly, in this embodiment, two convex portions 222 are provided. One end of the convex portion 222 is fixedly connected to the notch 221, and the other end is a free end pressing against the surface of the gasket 6. The convex portion 222 is deformed by the squeeze of the gasket 6, providing axial support force for the gasket 6, pressing the gasket 6 against the side surface of the inner gear ring 231. An annular step 213 is formed circumferentially inside the rear case body 21, and the other side surface of the inner gear ring 231 presses against the step 213. The gasket 6 seals the lubricating grease in the gear case relatively inside the gear case to prevent it from overflowing.

[0033] The front end of the front box body 20 is also provided with a torque sleeve 7 for adjusting the output torque of the handheld electric drill 100. The front end of the torque sleeve 7 is also provided with a drill chuck 8. The drill chuck 8 is transmission-connected to the front end of the working shaft 3 and is used to clamp tool accessories.

[0034] The present invention is not limited to the above-described specific embodiments. Those skilled in the art will readily appreciate that many alternatives to the handheld power tool of the present invention exist without departing from the principles and scope of the present invention. The scope of protection of the present invention shall be determined by the claims.

Claims

1. A handheld power tool comprising a housing, a motor disposed within the housing, a gearbox driven by the motor, and a fan blade driven by the motor; the gearbox comprising a housing, a transmission gear set disposed within the housing, a gearbox cover disposed at the rear of the housing, and a gasket disposed between the gearbox cover and the transmission gear set to prevent grease from leaking; the transmission gear set comprising planetary gears driven by the motor and an internal gear ring meshing with the planetary gears; and characterized in that: A vent is provided on the housing on the side corresponding to the inner gear ring of the transmission gear set, a notch is provided on the gear case cover corresponding to the vent for cooling air to pass through, an air inlet is provided on the outer shell connected to the vent, and the air inlet is arranged adjacent to the vent; a convex portion for pushing the gasket is provided on the inner side of the gear case cover, one end of the convex portion is fixedly connected to the notch, and the other end presses against the surface of the gasket, the convex portion presses the gasket against the side surface of the inner gear ring to press the inner gear ring into the housing, so that the vent and the notch form an air duct, which cools the outer peripheral surface of the inner gear ring, the outer peripheral surface of the gasket and the interior of the motor in turn.

2. The handheld power tool according to claim 1, wherein: The fan blade is a centrifugal fan blade, which is arranged behind the motor and rotates coaxially with the motor shaft of the motor to generate the cooling airflow. The cooling airflow passes through the inner gear ring and the outer surface of the gasket, and passes through the air duct to flow into the interior of the motor; an air outlet is provided on the outer shell corresponding to the outer periphery of the fan blade.

3. The handheld power tool according to claim 1, wherein: A forward-projecting latching arm is provided at the edge of the gear box cover, and the latching arm projects into the vent to limit relative displacement between the gear box cover and the box body.

4. The handheld power tool according to claim 1, wherein: The transmission gear set includes a multi-stage transmission gear set, and the planetary gears and the inner ring gear constitute a first-stage transmission gear set.

5. The handheld power tool according to claim 4, wherein: The housing comprises a front housing and a rear housing that are connected to each other, and the first-stage transmission gear set is arranged in the rear housing.

6. The handheld power tool according to claim 4, wherein: The transmission gear set also includes a second-stage transmission gear set meshing with the first-stage transmission gear set, and a third-stage transmission gear set meshing with the second-stage transmission gear set. The output end of the third-stage transmission gear set is connected to the working shaft of the handheld power tool.

7. The handheld power tool according to claim 1, wherein: There are more than two notches, and they are evenly distributed on the gear box cover in a circumferential direction with the axis of the gear box cover as the center.

8. The handheld power tool according to claim 7, wherein: There are more than two protrusions, one end of the protrusion is fixedly connected to the notch, and the other end is a free end that presses against the surface of the gasket and provides axial support force for the gasket.

9. The handheld power tool according to any one of claims 1 to 8, characterized in that: The motor is configured as a brushless motor, comprising a rotor and a stator assembly surrounding an outer ring of the rotor, with a ventilation gap formed between the stator assembly and the rotor.

10. The handheld power tool according to any one of claims 1 to 8, characterized in that: The housing comprises a left half shell and a right half shell which are symmetrical and assembled with each other, and the left half shell and the right half shell respectively extend downward to form a gripping portion.

Images