Power tool

Abstract

The power tool comprises a longitudinally extending housing and a fan, a motor and a circuit board accommodated in the housing, the housing is provided with an air outlet, a first air inlet and a second air inlet, the first air inlet is adjacent to the motor, the second air inlet is adjacent to the circuit board, the first air inlet is located between the air outlet and the second air inlet, and the power tool comprises a first heat dissipation air path through the motor and a second heat dissipation air path through the circuit board formed by rotation of the fan. The power tool of the present application cools the motor and the circuit board respectively, improves the cooling efficiency, reduces the interference of temperature rise with each other, the first air inlet adjacent to the motor is located between the second air inlet adjacent to the circuit board and the air outlet discharging air to the outside, the circuit board is prevented from being affected by the temperature rise of the air flowing through the motor, the circuit board is further protected, and the path of the first heat dissipation air path is shorter, so as to strengthen the heat dissipation effect of the motor.

Description

[TECHNICAL FIELD]

[0001] The present application relates to the field of electric power tools, in particular to an electric power tool with improved heat dissipation effect. [BACKGROUND]

[0002] The existing electric power tools, especially the lithium battery powered electric power tools, need to strictly deal with the problem of battery fire or reduced life caused by overcharging and overdischarging of lithium battery, so a circuit board is designed to detect and protect the battery pack state. The circuit board will generate heat due to high load during use, and when the heat is too large, it is easy to cause its failure, thereby affecting the monitoring of the battery, causing abnormal conditions such as overdischarge of the battery, and ultimately leading to reduced life of the battery pack or damage to the motor.

[0003] Some existing solutions use a fan installed inside the electric power tool to move air flow to cool the circuit board, and the air flow first passes through the circuit board and then flows through the motor to complete heat dissipation for both. However, the air flow of this solution passes through multiple heat generating components in sequence, and the cooling efficiency is low and the heat dissipation effect is poor; and the motor and the circuit board share a cooling air duct, and the temperature rise of any one component will directly affect the other component, thereby worsening the temperature rise condition of the required heat dissipation components.

[0004] In view of this, it is necessary to provide an improved electric power tool to overcome the defects of the prior art. [SUMMARY]

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide an electric power tool with improved heat dissipation effect.

[0006] The technical solution adopted by the present application to solve the problems of the prior art is:

[0007] An electric power tool, comprising a housing extending in a longitudinal direction and a fan, a motor and a circuit board accommodated in the housing, the housing is provided with an air outlet, a first air inlet and a second air inlet, the first air inlet is adjacent to the motor, the second air inlet is adjacent to the circuit board, the first air inlet is located between the air outlet and the second air inlet, the electric power tool comprises a first heat dissipation air path through the motor and a second heat dissipation air path through the circuit board formed by rotation of the fan.

[0008] Further improved solution: the motor comprises an output shaft extending in the longitudinal direction, the output shaft is connected and drives the fan to rotate, the air outlet, the fan, the first air inlet and the second air inlet are arranged in sequence along the output shaft axis direction.

[0009] Further improved solution: the electric power tool has a lateral direction perpendicular to the output shaft axis direction, and the first air inlet is arranged in the lateral direction of the motor.

[0010] A further improvement is as follows: the first heat dissipation air path passes sequentially through the first air inlet and the motor to the air outlet, and the second heat dissipation air path passes sequentially through the second air inlet and the circuit board to the air outlet. The first heat dissipation air path and the second heat dissipation air path are independent of each other.

[0011] A further improvement includes a partition disposed within the housing, the partition separating the first and second heat dissipation air passages, and at least a portion of the partition surrounding the motor.

[0012] A further improvement is as follows: the partition is located between the motor and the housing, the first heat dissipation air passage is formed between the partition and the motor, and the second heat dissipation air passage is formed between the partition and the housing.

[0013] A further improvement is that the partition plate is provided with through holes for wires to pass through, and the through holes are provided with elastic elements or felt.

[0014] A further improvement is as follows: the partition and the outer shell together form a cooling cavity, the motor is located in the cooling cavity, one side of the motor in the cooling cavity is set as an opening facing the fan, and the other side is set as the first air inlet communicating with the cooling cavity.

[0015] A further improvement includes a guide plate located at one end of the open side of the cooling chamber. The open side is located in the middle of the guide plate, and several ventilation openings are provided around the open side on the guide plate. The second heat dissipation air path passes sequentially through the second air inlet, the circuit board, and the ventilation openings to the air outlet.

[0016] A further improvement is as follows: the outer casing has a main body portion for accommodating the motor, a grip portion extending longitudinally rearward from the main body portion, and a foot plate portion located at the longitudinal rear end of the grip portion. The circuit board is housed in the foot plate portion, and the second air inlet is disposed on the foot plate portion and corresponds to the circuit board.

[0017] Compared with the prior art, the present invention has the following beneficial effects: the first air inlet of the power tool is adjacent to the motor, and the second air inlet is adjacent to the circuit board. The first air inlet is located between the air outlet and the second air inlet. The power tool includes a first cooling air path formed by the rotation of the fan, passing through the motor and a second cooling air path, passing through the circuit board. The multiple cooling air paths formed by the rotating fan within the housing flow through the motor and the circuit board respectively, cooling the motor and the circuit board adjacent to the air inlets, improving cooling efficiency and reducing mutual interference of temperature rise. The first air inlet adjacent to the motor is located between the second air inlet adjacent to the circuit board and the air outlet that discharges air to the outside, avoiding the circuit board being affected by the temperature rise of the airflow flowing through the motor, further protecting the circuit board. Moreover, the path of the first cooling air path is shorter, thereby enhancing the heat dissipation effect on the motor. [Image Description]

[0018] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0019] Figure 1 This is an internal view of the power tool in an embodiment of the present invention;

[0020] Figure 2 This is a cross-sectional view of the power tool in an embodiment of the present invention;

[0021] Figure 3 This is a cross-sectional view of a power tool according to another embodiment of the present invention.

[0022] Meaning of the reference numerals in the diagram:

[0023] 1. Drive assembly 2. Transmission assembly 3. Operating assembly 4. Control assembly

[0024] 10. Outer casing; 11. Air outlet; 12. First air inlet; 13. Second air inlet; 20. Fan; 30. Motor; 40. Circuit board; 50. First heat dissipation air passage; 60. Second heat dissipation air passage; 70. Partition plate; 71. Through hole; 80. Cooling cavity; 81. Opening; 90. Guide plate; 91. Ventilation opening. [Detailed Implementation]

[0025] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," and "rear" that indicate orientation or positional relationship are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0026] Please see Figure 1 , Figure 2As shown, a preferred embodiment of the present invention relates to a power tool for performing grinding, drilling, cutting, and other operations on a workpiece or working surface under electric drive. It includes a housing 10, a fan 20, a motor 30, and a circuit board 40. The housing 10 extends longitudinally, and the circuit board 40, fan 20, and motor 30 are disposed inside the housing 10. The housing 10 is provided with an air outlet 11, a first air inlet 12, and a second air inlet 13. The circuit board 40 is used to control the operation of functional components, including the motor 30. The fan 20 is used to generate airflow inside the housing 10 for heat exchange, thereby reducing the temperature of the structures through which the airflow passes, particularly keeping the temperatures of the motor 30 and circuit board 40 below their tolerable temperatures.

[0027] In this embodiment, the air outlet 11 is used to discharge airflow from inside the housing 10 to the outside. The first air inlet 12 and the second air inlet 13 draw airflow from the outside into the housing 10. The first air inlet 12 and the second air inlet 13 are respectively adjacent to the motor 30 and the circuit board 40, so that the drawn-in airflow directly blows on the motor 30 and the circuit board 40, improving cooling efficiency. In addition, the first air inlet 12 is located between the air outlet 11 and the second air inlet 13. The airflow discharged from the housing 10 by the air outlet 11 enters through the first air inlet 12 and the second air inlet 13. Moreover, the airflow entering through the first air inlet 12 undergoes heat exchange with the motor 30 and then exits the housing 10 through the air outlet 11 without passing through the circuit board 40, thus avoiding the circuit board 40 from being affected by the temperature rise of the motor 30 and strengthening the protection of the circuit board 40. In one embodiment, the housing 10 has a main body portion that accommodates the motor 30, a grip portion that extends longitudinally rearward from the main body portion, and a foot plate portion located at the longitudinal rear end of the grip portion. The circuit board 40 is housed in the foot plate portion, and a second air inlet 13 is disposed on the foot plate portion and corresponds to the circuit board 40.

[0028] To reduce the interference between the temperature rise of the circuit board 40 and the motor 30, the power tool includes a first cooling air path 50 formed by the rotation of the fan 20, which flows through the motor 30 and the circuit board 40, and a second cooling air path 60 that flows through the circuit board 40. The second cooling air path 60 does not flow through the motor 30, and the first cooling air path 50 does not flow through the circuit board 40. Because the first air inlet 12 is closer to the air outlet 11 than the second air inlet 13, the path of the first cooling air path 50 is shorter. Under the vacuum effect of the same fan 20, the airflow of the first cooling path is greater, resulting in a stronger cooling effect for the motor 30, which has a larger heat dissipation capacity, thus optimizing the overall heat dissipation efficiency of the machine.

[0029] The aforementioned power tool includes a working component 3 and a transmission component 2. The working component 3 is used to directly perform grinding, drilling, cutting, and other operations on the workpiece or working surface. The transmission component 2 is used to transmit the kinetic energy output by the motor 30 to the working component 3. The motor 30 includes a longitudinally extending output shaft, which is connected to the transmission component 2 and drives the working component 3 through the transmission component 2. A fan 20 is connected to the output shaft and rotates with the output shaft. The air outlet 11, fan 20, first air inlet 12, and second air inlet 13 are arranged sequentially along the axis of the output shaft; in this embodiment, they are also arranged sequentially back and forth along the axial direction of the power tool. The airflow flows in a generally straight direction within the housing 10 to reduce airflow resistance and noise. The first cooling air passage 50 and the second cooling air passage 60 have, or may have, local bending angles not exceeding 45°, keeping the airflow deflection angle within a small range.

[0030] The power tool has a lateral direction perpendicular to the output shaft axis. In one embodiment, the outer casing 10 corresponding to the outer side of the motor 30 is located in this lateral direction, and the aforementioned first air inlet 12 is provided on the casing 10 of the motor 30 in this lateral direction. The fan 20 is located on the output shaft side of the motor 30, i.e., the front side, and generates airflow as a vacuum source. The air outlet 11 is located on the same side, while the first air inlet 12 is correspondingly located on the other side of the motor 30, i.e., the rear side, so that the airflow entering through the first air inlet 12 passes through the main body of the motor 30, especially between the stator and the rotor, to enhance the cooling effect. Specifically, the first air inlet 12 faces the rear area of ​​the motor 30 or the rear structure of the motor 30, such as the rear bearing of the motor 30, so that the first air inlet 12 is adjacent to the motor 30. In this embodiment, in order to facilitate the conversion of the lateral airflow into axial flow, the first air inlet 12 may be provided with several fins (not shown in the figure), which are bent towards the motor 30.

[0031] The heat dissipation air passage, as a gas flow path, is formed by the air duct structure enclosed by the power tool housing 10 and internal structural components. The air duct includes, but is not limited to, components that do not completely block the gas flow, such as wires and switching components.

[0032] The power tool includes at least two independent air ducts, which are used to pass through a first cooling air passage 50 and a second cooling air passage 60, respectively, so that the first cooling air passage 50 and the second cooling air passage 60 are set up independently. Different airflows of different temperatures can flow between the independently set cooling air passages, reducing and eliminating heat exchange between the airflows. The first cooling air passage 50 passes through a first air inlet 12 and a motor 30 to an air outlet 11, and the second cooling air passage 60 passes through a second air inlet 13 and a circuit board 40 to an air outlet 11.

[0033] The power tool also includes a partition 70 separating the first cooling air passage 50 and the second cooling air passage 60. The partition 70 is located within the housing 10, with at least a portion of the partition 70 surrounding the motor 30. By separating the first cooling air passage 50 and the second cooling air passage 60 with the partition 70, the cooling air passages are independently configured to protect the motor 30 and the circuit board 40 under different conditions, including: the motor 30 is not affected by the heat generated by the circuit board 40, especially since the partition 70 may be made of heat-insulating material; the circuit board 40 is not affected by the heat generated by the motor 30, especially since the partition 70 may be made of heat-insulating material; the heated airflow after cooling the circuit board 40 will not pass through the motor 30, thus reducing the cooling efficiency of the motor 30; the heated airflow after cooling the motor 30 will not pass through the circuit board 40, thus reducing the cooling efficiency of the circuit board 40; and when the heat resistance of the circuit board 40 is not as good as that of the motor 30, the circuit board 40 will not fail due to the continuous operation of the motor 30.

[0034] In different embodiments, the partition 70, as an internal structural component of the power tool, can be configured in various shapes, including flat and curved sections. Different parts of the partition 70 can be curved or straight. Preferably, at least a portion of the partition 70 is correspondingly arranged according to the shape of the housing 10, forming a regularly connected airflow channel between the housing 10 and the portion of the partition 70. When the partition 70 is located between the motor 30 and the housing 10, a first cooling air passage 50 is formed between the partition 70 and the motor 30, and the airflow of the first cooling air passage 50 cools the motor 30; a second cooling air passage 60 is formed between the partition 70 and the housing 10, and the airflow of the second cooling air passage 60 passes through without heat exchange.

[0035] The partition 70 may be further provided with a through hole 71 for the wire to pass through. In order not to reduce the ability of the partition 70 to separate the air passage, an elastic element or felt is provided in the through hole 71. The elastic element is preferably a rubber sheet. After the wire passes through the through hole 71, the elastic element rebounds or the felt blocks the remaining space of the through hole 71, so that the airflow does not pass through or passes through the through hole 71 in a small amount.

[0036] The partition 70 and the outer shell 10 together form a cooling chamber 80, which has a relatively enclosed internal space to reduce heat exchange with the outside of the chamber. The motor 30 is located inside the cooling chamber 80. One side of the motor 30 in the cooling chamber 80 is set as an opening 81 facing the fan 20, and the other side of the motor 30 is set as a first air inlet 12 connected to the cooling chamber 80. The airflow enters the cooling chamber 80 through the first air inlet 12 and flows towards the opening 81, cooling the motor 30 as it flows through it.

[0037] The cooling chamber 80 surrounds the motor 30 and isolates other components of the power tool, preventing the motor 30, the main heat source, from affecting other components such as the circuit board 40, switching components, sensors, and screen interfaces. The opening 81 facing the fan 20 keeps the temperature inside the cooling chamber 80 low when the fan 20 is operating normally. Even if the fan 20 malfunctions and the temperature inside the cooling chamber 80 rises to a high level, the chamber's sealing ensures that other components are not damaged by abnormal temperature increases. Please refer to [reference needed]. Figure 3 In another embodiment, the partition 70 is arranged less around the motor 30, and the external switch interface and screen interface on the top of the housing 10 are located inside the cooling cavity 80.

[0038] A guide plate 90 is provided at the opening 81 end of the cooling chamber 80, and the opening 81 is opened in the middle of the guide plate 90. Several vents 91 are also provided around the opening 81 on the guide plate 90. The vents 91 are not connected to the opening 81, but are connected to the second heat dissipation air passage 60. That is, the first heat dissipation air passage 50 passes through the first air inlet 12, the motor 30 and the opening 81 in sequence to the air outlet 11, and the second heat dissipation air passage 60 passes through the second air inlet 13, the circuit board 40 and the vents 91 in sequence to the air outlet 11.

[0039] In one embodiment, the power tool is an angle grinder. The angle grinder includes a housing 10, a drive assembly 1, a transmission assembly 2, a working assembly 3, and a control assembly 4. The drive assembly 1 includes a motor 30 and an output shaft, which is connected to the transmission assembly 2. The working assembly 3, including a grinding wheel, wire wheel, etc., is connected to the other side of the transmission assembly 2 opposite to the output shaft. The motor 30 drives the working assembly 3 through the transmission assembly 2 to act on the surface to be worked or the workpiece to be processed, thereby realizing the operation of the power tool. The control assembly 4 includes a circuit board 40 and controls the operation of the drive assembly 1. The drive assembly 1, transmission assembly 2, and control assembly 4 are disposed within the housing 10 of the power tool and are constrained and protected by the housing 10. A handle and an external switch may be provided on the outside of the housing 10, and a battery pack may be connected thereto.

[0040] As a preferred option, the power tool is a straight angle grinder.

[0041] This invention is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many alternative power tools can be developed without departing from the principles and scope of this invention. The scope of protection of this invention is defined by the claims.

Claims

1. A power tool comprising a housing extending in a longitudinal direction and a fan, a motor and a circuit board accommodated in the housing, the housing being provided with an air outlet, a first air inlet and a second air inlet, the motor comprising an output shaft extending in the longitudinal direction, the output shaft being connected to and driving the fan to rotate, characterized in that: The air outlet, the fan, the first air inlet and the second air inlet are arranged along the output shaft axis direction in sequence, and the airflow flows in a straight direction in the shell, the first air inlet is adjacent to the motor, the second air inlet is adjacent to the circuit board, the first air inlet is located between the air outlet and the second air inlet, the electric tool comprises a first heat dissipation air path formed by rotation of the fan and passing through the motor and not passing through the circuit board and a second heat dissipation air path passing through the circuit board and not passing through the motor, and the path of the first heat dissipation air path is shorter than that of the second heat dissipation air path.

2. The power tool of claim 1, wherein, The electric tool has a lateral direction perpendicular to the output shaft axis direction, and the first air inlet is arranged in the lateral direction of the motor.

3. The power tool of claim 1, wherein, The first heat dissipation air path sequentially passes through the first air inlet, the motor and the air outlet, and the second heat dissipation air path sequentially passes through the second air inlet, the circuit board and the air outlet, and the first heat dissipation air path and the second heat dissipation air path are independent of each other.

4. The power tool of claim 3, wherein, Further comprising a partition plate arranged in the shell, the partition plate separates the first heat dissipation air path and the second heat dissipation air path, and at least part of the partition plate is arranged around the motor.

5. The power tool of claim 4, wherein, The partition plate is located between the motor and the shell, the first heat dissipation air path is formed between the partition plate and the motor, and the second heat dissipation air path is formed between the partition plate and the shell.

6. The power tool of claim 4, wherein, The partition plate is provided with a through hole for the lead wire to pass through, and the through hole is provided with an elastic member or a felt.

7. The power tool of claim 4, wherein, The partition plate and the shell jointly form a cooling cavity, the motor is located in the cooling cavity, one side of the motor in the cooling cavity is arranged as an open end facing the fan, and the other side is arranged as the first air inlet communicating with the cooling cavity.

8. The power tool of claim 7, wherein, Further comprising a guide plate arranged at the open end of the cooling cavity, the open end is arranged in the middle of the guide plate, a plurality of air vents are arranged around the open end on the guide plate, and the second heat dissipation air path sequentially passes through the second air inlet, the circuit board and the air vent and reaches the air outlet.

9. The power tool of claim 1, wherein, The shell is provided with a main body portion accommodating the motor, a grip portion extending longitudinally rearward from the main body portion, and a foot plate portion located at the longitudinal rear end of the grip portion, the circuit board is accommodated in the foot plate portion, and the second air inlet is arranged on the foot plate portion and corresponds to the circuit board.

Images